微纳尺度螺旋纤维的制备及其生长机理研究
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摘要
螺旋结构赋予材料独特的物理和化学性能,如超弹性、高比强度、手征性和电磁交叉极化特性等。随着纳米科学技术的发展,多种尺度的螺旋结构被发现或人工合成出来,其中螺旋纤维是最早被发现并受到持续高度关注的一类新材料。尽管人们可以通过合理设计实验温度、催化剂成份和原料配比等工艺条件,获得不同尺度和多种形貌的螺旋纤维,但要实现其精确调控还需要进行更多深入系统的研究,特别是螺旋纤维的生长机理和多层次结构调控机制等基础性学术问题,亟待从理论基础和实验验证方面取得实质性突破。本论文针对这两方面的问题,以微纳尺度螺旋纤维为研究对象,通过理论上的模拟计算和实验方法上的系统研究,在纳米Cu和纳米Ni这两种有代表性的纳米催化剂晶体生长、可控制备、催化机理与活性调控等方面开展了系统研究,深入探究和分析了微纳尺度螺旋纤维的生长机理,为实现螺旋纤维的化学结构、微观形貌、尺度分布、理化性能等本征特性调控,以及螺旋结构的功能化设计和应用开发奠定学术基础。
(1)采用沉淀法制备了酒石酸铜纳米颗粒,通过热失重(TG)和示差扫描量热仪(DSC)表征了作为纳米铜催化剂前驱体的酒石酸铜,发现其分解历程包括脱结晶水阶段(Ⅰ)和酒石酸铜分解阶段(Ⅱ)。通过设置系列升温速度,研究了酒石酸铜的热分解动力学过程,采用Flynn-Wall-Ozawa法进行数据处理,得出上述两个阶段的热分解机理函数分别为过程(Ⅰ)：G(α)=1-(1-α)1/3和过程(Ⅱ)：G(α)=lnα2(α<0.5)；(1-α)-1(α>0.5),其热分解活化能分别为94.24和177.33kJ/mol。在此基础上,系统研究了反应条件对纳米铜催化剂的影响,发现调控升温速率小于5℃/min,分解温度在271℃时,在惰性气氛Ar或者N2中,酒石酸铜粉末分解得到的纳米铜相对较大,基本为椭球体形；而在H：气氛中制备的纳米铜存在大尺寸及小尺寸两种Cu颗粒。
(2)系统研究了酒石酸铜分解生成纳米铜及其催化乙炔原位生长制备纳米螺旋纤维的过程和条件,采用多种现代仪器分析技术研究了纳米铜催化剂在螺旋纤维生长前后的晶体结构和微观形貌演变规律及其催化制备的纳米纤维多层次结构。结果表明,在271℃、乙炔气氛条件下,酒石酸铜分解生成纳米铜催化乙炔可以得到形态和尺寸均匀的高纯度螺旋纤维,其化学结构类似聚乙炔,并含有少量CH3和C=O等基团。通过系统的实验研究和针对纳米铜催化剂的模拟计算,发现在乙炔气氛中,纳米铜催化剂颗粒从准球形被诱导转变为规则形貌的多面体晶体；提出了基于乙炔分子在纳米铜表面发生配位聚合,并通过纳米催化剂的晶面活性差异,发生不对称生长成纳米螺旋聚合物纤维的新机理。基于第一性原理开展模拟计算,采用Materials Studio软件中的DMol3模块,研究了Ar,N2,H2和C2H2四种气体分子在Cu8团簇和纳米Cu晶体不同晶面上的吸附行为,发现不同气体表现出不同的吸附行为,同一种气体的化学吸附也因吸附位和吸附结构的不同,而在纳米铜表面表现出差异性吸附；乙炔与Cu表面的相互作用最强,H2次之,Ar和N2最小；乙炔和H2均存在化学吸附,而Ar和N2仅存在物理吸附。基于实验研究和理论计算结果,提出通过气体诱导可控制备线形或螺旋形纳米纤维的新方法,并阐明了气体诱导效应与催化剂的纳米效应和热效应之间的竞争关系以及对纳米纤维形貌的影响规律,即：纳米效应有利于直线形纤维生长,气体诱导促进催化剂形成规则多面体而有利于螺旋结构生长,热效应则主导诱发“Y”形结构或微米螺旋纤维形成。
(3)通过水合肼还原硫酸镍制备了微观形貌为准球形颗粒状的纳米镍催化剂,发现当反应温度控制在660～750℃,纳米Ni的粒径可以通过气氛控制,调控在90～500nm之间。采用纳米Ni催化乙炔合成了多种形态的螺旋碳纤维,发现通过对反应气氛的调整和控制,可分别得到线形纳米碳纤维、单螺旋纳米碳纤维、单螺旋微米碳纤维、双螺旋微米碳纤维。系统的表征和分析认为,这是由于气氛条件影响了纳米镍晶体的形貌、尺寸和分散性,并由于不同晶面的催化活性差异导致了碳纤维各向异性生长。此外,我们还发现,传统的双螺旋微米碳纤维具有“孪生”螺旋结构,并认为其形成是由于规则形貌催化剂晶体的棱边和顶点等部位与表平面对乙炔气体的吸附活性、以及催化分解和碳原子沉积形成纤维结构的能力差异导致的。
(4)制备了以MgO和四针状氧化锌晶须(T-ZnO)为载体的负载型催化剂前驱体,并通过原位热分解得到负载型纳米催化剂催化乙炔发生配位聚合制备了纳米螺旋聚合物纤维。MgO载体使得纳米铜催化剂的粒径降低,当MgO/酒石酸铜质量比为3：1时,有利于制备高纯纳米螺旋纤维；偏离该配比时,所得纤维为线形和螺旋形混合纤维,或者不利于纳米聚合物纤维生长。在T-ZnO负载纳米Cu催化剂体系中,Cu与ZnO之间形成了有结合力的杂化结构；含铜原料的加入量对T-ZnO负载纳米Cu催化剂的粒径及均匀性有显著影响；原料配比中,Cu的含量低于0.4mo1%时,所得催化聚合产物的微观形貌呈颗粒状,粘附于T-ZnO表面；随着Cu加入量的增加,颗粒尺寸增大,当Cu加入量为0.6mo1%时,纳米铜尺寸和分布都比较均匀,有利于制备出高纯螺旋纤维围绕在T-ZnO表面；当Cu加入量大于0.8mo1%时,由于催化剂均匀性较差,得到线形和螺旋形混合纤维。高纯螺旋纤维/T-ZnO在Ar气氛中900℃下热处理,可得到四针状多孔螺旋碳纤维,该新型结构包含微米尺度的孔穴和纳米尺度的螺旋碳纤维。
(5)通过对纳米螺旋聚合物纤维、纳米螺旋碳纤维、四针状多孔螺旋碳纤维等新型结构进行电磁学性能研究,采用矢量网络分析系统,测试了同轴波导样品的复介电常数和复磁导率,并通过反射率模拟软件得到各样品的反射率曲线,对比分析了样品的电磁波损耗特性。发现在2-18GHz频段内,纳米螺旋聚合物纤维的介电损耗和磁损耗值均很小,对电磁波的衰减性能很差；纳米螺旋碳纤维具有一定的介电损耗,电磁波响应频带较宽,但反射率衰减值不高；四针状多孔螺旋碳纤维表现出优异的电磁波损耗性能,当涂层厚度为2mm时,在3.2～18GHz频率范围内,反射衰减值均优于-4dB,峰值达到-17.57dB。分析认为,四针状多孔螺旋碳纤维由于具有独特的微纳复合多级结构和多层次界面效应,有利于满足入射电磁波的阻抗匹配,并通过多层次介电极化、界面共振和涡流损耗等形式实现对电磁波能量的损耗。
Benefiting from their helical characteristics in morphology, helical materials display remarkable elasticity, mechanical strength, chirality and electro-magnetic properties. With the development of nanotechnology, materials with helical structure in molecular, nano-or macro-scale have been prepared in recent years. As to helical fibers, commonly, they are prepared and controlled by varying reaction temperature, catalyst type, gas composition and so on. The alteration of these variables will result in a significant change in helical structure and yield of the obtained helical fibers. To realize this control, a deeply understanding of the growth mechanism and the effects of the adjustable condition are essential. To date, precise control over the structure of helical fibers has been met with only limited success. In this thesis, by applying nano Cu and nano Ni catalysts to prepare helical fibers, we selectively obtained the helical fibers with desired morphology, and explored the underlying growth mechanism of corresponding helical materials. The main achievements and conclusions are summarized as follows.
(1) As a catalyst precursor, cupric (Ⅱ) tartrate was prepared by a precipitation method. From the results of dynamics analysis using characterization by TG and DSC, we found the decomposition of cupric (Ⅱ) tartrate existed two different stages:loss of its crystalline water (Ⅰ) and the main decomposition of Cu(C4H4O6). The kinetic model and the parameters of the decomposition processes were also determined using Flynn-Wall-Ozawa method. The apparent activation energy of the two decomposition stages (Ⅰ) and (Ⅱ) were94.24and177.33kJ/mol, respectively. The probable integral form of kinetic mechanism function were G(α)=1-(1-α)1/3at stage (Ⅰ) and G(α)=lna2(α<0.5),(1-α)-1(α>0.5) at stage (II). Meanwhile, influence factors on the growth of Cu nanocrystal were also systematically investigated. The nano Cu crystals obtained at271℃under Ar or N2at the heating rate of less than5℃/min, had relatively large size and spheroidal shape, while Cu nanocrystals prepared under H2had a wide size distribution.
(2) Helical nanofibers were synthesized using acetylene as the reactant and nanocopper crystals, produced by in situ decomposition of cupric (Ⅱ) tartrate, as the catalyst. Their chemical structures were confirmed to be organic compounds including the main polymer chain of-CH=CH-, with a few other groups such as CH3, C=O, etc. according to FT-IR,1H-NMR and elemental analyses. The morphologies of the catalyst before, during and after the fiber growth were observed by SEM and TEM, and the results revealed that the shape of the nanocopper particles changed from quasi-spherical to polyhedral during the adsorption of acetylene. Besides, density functional theory (DFT) calculations of adsorption behavior of four kinds of gases (Ar, N2, H2and C2H2) on Cug cluster and Cu facets were carried out to clarify the interaction between the catalyst and the absorbed gases. The four gases had different values of adsorption energy, so do different adsorbing sites on Cug and surfaces of nano Cu crystals, revealing that the adsorption is gas-and site-selective for Cu nanoparticles (NPs). The atmosphere of Ar and N2had very little effect on the Cu NPs growth, while H2was adsorbed dissociatively on the Cu surfaces and C2H2was either molecularly or dissociatively adsorbed. Based on the experimental and theoretical evidence, a growth mechanism of coordination polymerization and asymmetric growth on distinctive crystal planes was proposed to interpret the structural and morphological variations of the helical nanofibers. We also proposed for the first time a modified gas-induced technique to realize the in situ preparation of high-purity straight or helical carbon nanofibers (CNFs) on the formed nano Cu catalysts from the decomposition of cupric (II) tartrate. Interplay among gas-inducing, thermal and size effects on the formation of carbon fibers was also put forward. Thin and straight CNFs grow when "nano effect" was dominant, helical fiber grew under gas-inducing effect, some abnormal fiber with Y-shape and microscaled helix fromed by thermal effect.
(3) Straight CNFs and three types of carbon coils (single-helix carbon nanocoils, single-helix carbon microcoils and twinning double-helix carbon microcoils) were prepared at the reaction temperature of660-750℃, by using the Ni catalyst obtained by liquid phase reduction with hydrazine hydrate as catalyst. A simple approach of controlling the gas composition to control the growth of carbon fibers was developed based on the bottom-up regulation adjusting the particles size of Ni at the scale range of90-500nm. Twinning structure existed in each fiber of the double-helix carbon microcoils regardless of circular or flat shape, which might be separated by tips of a catalyst particle due to the different rates of carbon deposition on edge and vertex, respectively. A mechanism was proposed based on different adsorptive capacity, decomposition and growth rates of carbon nanoparticles on the facet, edge and vertex of catalyst grain.
(4) Two types of supported nanocopper catalysts for helical nanofibers have been prepared by decomposing cupric (Ⅱ) tartrate that grown on the carriers of MgO and T-ZnO respectively. In the case of MgO carried n-Cu, the helical CNFs could only be prepared at the MgO/cupric (Ⅱ) tartrate mass ratio of3:1; otherwise, straight CNFs co-existed in the helical fibers. By combining the co-deposition technology with gas-induced method, the cob-like tetrapod-ZnO, helical CNFs warpping T-ZnO and mixed fibers warpping T-ZnO were prepared at the molar ratio of less than0.4mol%,0.6mol%and more than0.8mol%, respectively. The formed "helical CNFs/T-ZnO" materials became "carbon coil with tetrapod-hollow" after heat treatment under Ar at900℃. This novel material, named "carbon coil with T-hollow", displays a lot of hollows with tetrapod-shape in micro-scale.
(5) Addtionally, comparative researches on electromagnetic properties were conducted for several kinds of helical materials:the as-prepared helical polymer fibers, carbon coils obtained from carbonization under Ar, and carbon coil with T-hollow. The relative permeability and permittivity values of the samples were determined with vector network analyzer by using coaxial line method, and reflection loss curves of the products were calculated by reflection loss simulation soft. In the frequency of2～18GHz, carbon coils had only dielectric loss and the reflection loss values were higher than-10dB, while the helical polymer fibers exhibited neither dielectric loss nor magnetic loss. Interestingly, carbon coil with T-hollow exhibited remarkably improvement in electromagnetic wave loss compared with the pure helical nanofibers. The enhanced loss ability might be arised from the efficient dielectric friction, eddy current impedance, interface resonate in the complex nanostructures and the micro-scaled tetrapod-hollow structure.
(1)采用沉淀法制备了酒石酸铜纳米颗粒,通过热失重(TG)和示差扫描量热仪(DSC)表征了作为纳米铜催化剂前驱体的酒石酸铜,发现其分解历程包括脱结晶水阶段(Ⅰ)和酒石酸铜分解阶段(Ⅱ)。通过设置系列升温速度,研究了酒石酸铜的热分解动力学过程,采用Flynn-Wall-Ozawa法进行数据处理,得出上述两个阶段的热分解机理函数分别为过程(Ⅰ)：G(α)=1-(1-α)1/3和过程(Ⅱ)：G(α)=lnα2(α<0.5)；(1-α)-1(α>0.5),其热分解活化能分别为94.24和177.33kJ/mol。在此基础上,系统研究了反应条件对纳米铜催化剂的影响,发现调控升温速率小于5℃/min,分解温度在271℃时,在惰性气氛Ar或者N2中,酒石酸铜粉末分解得到的纳米铜相对较大,基本为椭球体形；而在H：气氛中制备的纳米铜存在大尺寸及小尺寸两种Cu颗粒。
(2)系统研究了酒石酸铜分解生成纳米铜及其催化乙炔原位生长制备纳米螺旋纤维的过程和条件,采用多种现代仪器分析技术研究了纳米铜催化剂在螺旋纤维生长前后的晶体结构和微观形貌演变规律及其催化制备的纳米纤维多层次结构。结果表明,在271℃、乙炔气氛条件下,酒石酸铜分解生成纳米铜催化乙炔可以得到形态和尺寸均匀的高纯度螺旋纤维,其化学结构类似聚乙炔,并含有少量CH3和C=O等基团。通过系统的实验研究和针对纳米铜催化剂的模拟计算,发现在乙炔气氛中,纳米铜催化剂颗粒从准球形被诱导转变为规则形貌的多面体晶体；提出了基于乙炔分子在纳米铜表面发生配位聚合,并通过纳米催化剂的晶面活性差异,发生不对称生长成纳米螺旋聚合物纤维的新机理。基于第一性原理开展模拟计算,采用Materials Studio软件中的DMol3模块,研究了Ar,N2,H2和C2H2四种气体分子在Cu8团簇和纳米Cu晶体不同晶面上的吸附行为,发现不同气体表现出不同的吸附行为,同一种气体的化学吸附也因吸附位和吸附结构的不同,而在纳米铜表面表现出差异性吸附；乙炔与Cu表面的相互作用最强,H2次之,Ar和N2最小；乙炔和H2均存在化学吸附,而Ar和N2仅存在物理吸附。基于实验研究和理论计算结果,提出通过气体诱导可控制备线形或螺旋形纳米纤维的新方法,并阐明了气体诱导效应与催化剂的纳米效应和热效应之间的竞争关系以及对纳米纤维形貌的影响规律,即：纳米效应有利于直线形纤维生长,气体诱导促进催化剂形成规则多面体而有利于螺旋结构生长,热效应则主导诱发“Y”形结构或微米螺旋纤维形成。
(3)通过水合肼还原硫酸镍制备了微观形貌为准球形颗粒状的纳米镍催化剂,发现当反应温度控制在660～750℃,纳米Ni的粒径可以通过气氛控制,调控在90～500nm之间。采用纳米Ni催化乙炔合成了多种形态的螺旋碳纤维,发现通过对反应气氛的调整和控制,可分别得到线形纳米碳纤维、单螺旋纳米碳纤维、单螺旋微米碳纤维、双螺旋微米碳纤维。系统的表征和分析认为,这是由于气氛条件影响了纳米镍晶体的形貌、尺寸和分散性,并由于不同晶面的催化活性差异导致了碳纤维各向异性生长。此外,我们还发现,传统的双螺旋微米碳纤维具有“孪生”螺旋结构,并认为其形成是由于规则形貌催化剂晶体的棱边和顶点等部位与表平面对乙炔气体的吸附活性、以及催化分解和碳原子沉积形成纤维结构的能力差异导致的。
(4)制备了以MgO和四针状氧化锌晶须(T-ZnO)为载体的负载型催化剂前驱体,并通过原位热分解得到负载型纳米催化剂催化乙炔发生配位聚合制备了纳米螺旋聚合物纤维。MgO载体使得纳米铜催化剂的粒径降低,当MgO/酒石酸铜质量比为3：1时,有利于制备高纯纳米螺旋纤维；偏离该配比时,所得纤维为线形和螺旋形混合纤维,或者不利于纳米聚合物纤维生长。在T-ZnO负载纳米Cu催化剂体系中,Cu与ZnO之间形成了有结合力的杂化结构；含铜原料的加入量对T-ZnO负载纳米Cu催化剂的粒径及均匀性有显著影响；原料配比中,Cu的含量低于0.4mo1%时,所得催化聚合产物的微观形貌呈颗粒状,粘附于T-ZnO表面；随着Cu加入量的增加,颗粒尺寸增大,当Cu加入量为0.6mo1%时,纳米铜尺寸和分布都比较均匀,有利于制备出高纯螺旋纤维围绕在T-ZnO表面；当Cu加入量大于0.8mo1%时,由于催化剂均匀性较差,得到线形和螺旋形混合纤维。高纯螺旋纤维/T-ZnO在Ar气氛中900℃下热处理,可得到四针状多孔螺旋碳纤维,该新型结构包含微米尺度的孔穴和纳米尺度的螺旋碳纤维。
(5)通过对纳米螺旋聚合物纤维、纳米螺旋碳纤维、四针状多孔螺旋碳纤维等新型结构进行电磁学性能研究,采用矢量网络分析系统,测试了同轴波导样品的复介电常数和复磁导率,并通过反射率模拟软件得到各样品的反射率曲线,对比分析了样品的电磁波损耗特性。发现在2-18GHz频段内,纳米螺旋聚合物纤维的介电损耗和磁损耗值均很小,对电磁波的衰减性能很差；纳米螺旋碳纤维具有一定的介电损耗,电磁波响应频带较宽,但反射率衰减值不高；四针状多孔螺旋碳纤维表现出优异的电磁波损耗性能,当涂层厚度为2mm时,在3.2～18GHz频率范围内,反射衰减值均优于-4dB,峰值达到-17.57dB。分析认为,四针状多孔螺旋碳纤维由于具有独特的微纳复合多级结构和多层次界面效应,有利于满足入射电磁波的阻抗匹配,并通过多层次介电极化、界面共振和涡流损耗等形式实现对电磁波能量的损耗。
Benefiting from their helical characteristics in morphology, helical materials display remarkable elasticity, mechanical strength, chirality and electro-magnetic properties. With the development of nanotechnology, materials with helical structure in molecular, nano-or macro-scale have been prepared in recent years. As to helical fibers, commonly, they are prepared and controlled by varying reaction temperature, catalyst type, gas composition and so on. The alteration of these variables will result in a significant change in helical structure and yield of the obtained helical fibers. To realize this control, a deeply understanding of the growth mechanism and the effects of the adjustable condition are essential. To date, precise control over the structure of helical fibers has been met with only limited success. In this thesis, by applying nano Cu and nano Ni catalysts to prepare helical fibers, we selectively obtained the helical fibers with desired morphology, and explored the underlying growth mechanism of corresponding helical materials. The main achievements and conclusions are summarized as follows.
(1) As a catalyst precursor, cupric (Ⅱ) tartrate was prepared by a precipitation method. From the results of dynamics analysis using characterization by TG and DSC, we found the decomposition of cupric (Ⅱ) tartrate existed two different stages:loss of its crystalline water (Ⅰ) and the main decomposition of Cu(C4H4O6). The kinetic model and the parameters of the decomposition processes were also determined using Flynn-Wall-Ozawa method. The apparent activation energy of the two decomposition stages (Ⅰ) and (Ⅱ) were94.24and177.33kJ/mol, respectively. The probable integral form of kinetic mechanism function were G(α)=1-(1-α)1/3at stage (Ⅰ) and G(α)=lna2(α<0.5),(1-α)-1(α>0.5) at stage (II). Meanwhile, influence factors on the growth of Cu nanocrystal were also systematically investigated. The nano Cu crystals obtained at271℃under Ar or N2at the heating rate of less than5℃/min, had relatively large size and spheroidal shape, while Cu nanocrystals prepared under H2had a wide size distribution.
(2) Helical nanofibers were synthesized using acetylene as the reactant and nanocopper crystals, produced by in situ decomposition of cupric (Ⅱ) tartrate, as the catalyst. Their chemical structures were confirmed to be organic compounds including the main polymer chain of-CH=CH-, with a few other groups such as CH3, C=O, etc. according to FT-IR,1H-NMR and elemental analyses. The morphologies of the catalyst before, during and after the fiber growth were observed by SEM and TEM, and the results revealed that the shape of the nanocopper particles changed from quasi-spherical to polyhedral during the adsorption of acetylene. Besides, density functional theory (DFT) calculations of adsorption behavior of four kinds of gases (Ar, N2, H2and C2H2) on Cug cluster and Cu facets were carried out to clarify the interaction between the catalyst and the absorbed gases. The four gases had different values of adsorption energy, so do different adsorbing sites on Cug and surfaces of nano Cu crystals, revealing that the adsorption is gas-and site-selective for Cu nanoparticles (NPs). The atmosphere of Ar and N2had very little effect on the Cu NPs growth, while H2was adsorbed dissociatively on the Cu surfaces and C2H2was either molecularly or dissociatively adsorbed. Based on the experimental and theoretical evidence, a growth mechanism of coordination polymerization and asymmetric growth on distinctive crystal planes was proposed to interpret the structural and morphological variations of the helical nanofibers. We also proposed for the first time a modified gas-induced technique to realize the in situ preparation of high-purity straight or helical carbon nanofibers (CNFs) on the formed nano Cu catalysts from the decomposition of cupric (II) tartrate. Interplay among gas-inducing, thermal and size effects on the formation of carbon fibers was also put forward. Thin and straight CNFs grow when "nano effect" was dominant, helical fiber grew under gas-inducing effect, some abnormal fiber with Y-shape and microscaled helix fromed by thermal effect.
(3) Straight CNFs and three types of carbon coils (single-helix carbon nanocoils, single-helix carbon microcoils and twinning double-helix carbon microcoils) were prepared at the reaction temperature of660-750℃, by using the Ni catalyst obtained by liquid phase reduction with hydrazine hydrate as catalyst. A simple approach of controlling the gas composition to control the growth of carbon fibers was developed based on the bottom-up regulation adjusting the particles size of Ni at the scale range of90-500nm. Twinning structure existed in each fiber of the double-helix carbon microcoils regardless of circular or flat shape, which might be separated by tips of a catalyst particle due to the different rates of carbon deposition on edge and vertex, respectively. A mechanism was proposed based on different adsorptive capacity, decomposition and growth rates of carbon nanoparticles on the facet, edge and vertex of catalyst grain.
(4) Two types of supported nanocopper catalysts for helical nanofibers have been prepared by decomposing cupric (Ⅱ) tartrate that grown on the carriers of MgO and T-ZnO respectively. In the case of MgO carried n-Cu, the helical CNFs could only be prepared at the MgO/cupric (Ⅱ) tartrate mass ratio of3:1; otherwise, straight CNFs co-existed in the helical fibers. By combining the co-deposition technology with gas-induced method, the cob-like tetrapod-ZnO, helical CNFs warpping T-ZnO and mixed fibers warpping T-ZnO were prepared at the molar ratio of less than0.4mol%,0.6mol%and more than0.8mol%, respectively. The formed "helical CNFs/T-ZnO" materials became "carbon coil with tetrapod-hollow" after heat treatment under Ar at900℃. This novel material, named "carbon coil with T-hollow", displays a lot of hollows with tetrapod-shape in micro-scale.
(5) Addtionally, comparative researches on electromagnetic properties were conducted for several kinds of helical materials:the as-prepared helical polymer fibers, carbon coils obtained from carbonization under Ar, and carbon coil with T-hollow. The relative permeability and permittivity values of the samples were determined with vector network analyzer by using coaxial line method, and reflection loss curves of the products were calculated by reflection loss simulation soft. In the frequency of2～18GHz, carbon coils had only dielectric loss and the reflection loss values were higher than-10dB, while the helical polymer fibers exhibited neither dielectric loss nor magnetic loss. Interestingly, carbon coil with T-hollow exhibited remarkably improvement in electromagnetic wave loss compared with the pure helical nanofibers. The enhanced loss ability might be arised from the efficient dielectric friction, eddy current impedance, interface resonate in the complex nanostructures and the micro-scaled tetrapod-hollow structure.
引文
[1]Pokroy B, Kang SH, Mahadevan L, Aizenberg J. Self-organization of a mesoscale bristle into ordered, hierarchical helical assemblies. Science,2009; 323(5911): 237-240.
[2]Su DS. Inorganic materials with double-helix structures. Angew Chem Int Ed, 2011; 50(21):4747-4750.
[3]Hanes CS. The action of amylases in relation to the structure of starch and its metabolism in the plant. Parts Ⅳ-Ⅶ. New Phytol,1937; 36(3):189-239.
[4]Watson J, Crick F. Molecular structure of nucleic acids:a structure for deoxyribose nucleic acid. Nature,1953; 171:737-738.
[5]Natta G, Pino P, Corradini P, Danusso F, Mantica E, Mazzanti G, et al. Crystalline high polymers of a-olefins. J Am Chem Soc,1955; 77(6):1708-1710.
[6]Nakano T, Okamoto Y. Synthetic helical polymers:conformation and function. Chem Rev,2001; 101(12):4013-4038.
[7]Yashima E, Maeda K, Iida H, Furusho Y, Nagai K. Helical polymers:synthesis, structures, and functions. Chem Rev,2009; 109(11):6102-6211.
[8]Yashima E, Maeda K, Furusho Y. Single- and Double-stranded helical polymers: synthesis, structures, and functions. Accounts Chem Res,2008; 41(9):1166-1180.
[9]Shinohara K, Aoki T, Kaneko T. Helical chirality of π-conjugated main-chain induced by polymerization of phenylacetylene with chiral bulky pinanyl groups: Effects of the flexible spacer and polymerization catalyst. J Polym Sci Pol Chem, 2002; 40(11):1689-1697.
[10]Eckhardt CJ, Peachey NM, Swanson DR, Takacs JM, Khan MA, Gong X, et al. Separation of chiral phases in monolayer crystals of racemic amphiphiles. Nature, 1993; 362(6421):614-616.
[11]Yashima E, Maeda K, Nishimura T. Detection and amplification of chirality by helical polymers. Chem-Eur J,2004; 10(1):42-51.
[12]Guo J, Yu L, Liu F, Guo R, Ma G, Cao H, et al. Effect of specific rotation of chiral dopant and polymerization temperature on reflectance properties of polymer stabilized cholesteric liquid crystal cells. J Polym Sci Pol Phys,2008; 46(15): 1562-1570.
[13]Yashima E, Maeda K. Chirality-responsive helical polymers. Macromolecules, 2007; 41(1):3-12.
[14]Green MM, Peterson NC, Sato T, Teramoto A, Cook R, Lifson S. A helical polymer with a cooperative response to chiral information. Science,1995; 268(5219): 1860-1866.
[15]Maxein G, Keller H, Novak BM, Zentel R. Opalescent cholesteric networks from chiral polyisocyanates in polystyrene. Adv Mater,1998; 10(4):341-345.
[16]Kauranen MM, Verbiest T, Persoons A, Meijer EW, Teerenstra MN, Schouten AJ, et al. Chiral effects in the second-order optical nonlinearity of a poly(isocyanide) monolayer. Adv Mater,1995; 7(7):641-644.
[17]Koeckelberghs G, Sioncke S, Verbiest T, Persoons A, Samyn C. Synthesis and properties of chiral helical chromophore-functionalised polybinaphthalenes for second-order nonlinear optical applications. Polymer,2003; 44(14):3785-3794.
[18]Motojima S, Chen Q. Three-dimensional growth mechanism of cosmo-mimetic carbon microcoils obtained by chemical vapor deposition. J Appl Phys,1999; 85(7):3919-3921.
[19]Yang S, Chen X, Motojima S, Ichihara M. Morphology and microstructure of spring-like carbon micro-coils/nano-coils prepared by catalytic pyrolysis of acetylene using Fe-containing alloy catalysts. Carbon,2005; 43(4):827-834.
[20]Motojima S, Hasixgawa I, Kagiya S, Andoh K, Iwanaga H. Vapor phase preparation of micro-coiled carbon fibers by metal powder catalyzed pyrolysis of acetylene containing a small amount of phosphorus impurity. Carbon,1995; 33(8): 1167-1173.
[21]Tang N, Wen J, Zhang Y, Liu F, Lin K, Du Y. Helical carbon nanotubes:catalytic particle size-dependent growth and magnetic properties. ACS Nano,2010; 4(1): 241-250.
[22]Gao PX, Ding Y, Mai W, Hughes WL, Lao C, Wang ZL. Conversion of zinc oxide nanobelts into superlattice-structured nanohelices. Science,2005; 309(5741): 1700-1704.
[23]Morito H, Yamane H. Double-helical silicon microtubes. Angew Chem Int Ed, 2010; 49(21):3638-3641.
[24]Xu F, Lu W, Zhu Y. Controlled 3d buckling of silicon nanowires for stretchable electronics. ACS Nano,2010; 5(1):672-678.
[25]Lin G-L, Tsai Y, Lin H, Tang C, Lin C. Synthesis of mesoporous silica helical fibers using a catanionic-neutral ternary surfactant in a highly dilute silica solution: biomimetic silicification. Langmuir,2007; 23(8):4115-4119.
[26]Zhang H, Wang C-M, Buck E, Wang L-S. Synthesis, Characterization, and manipulation of helical SiO2 nanosprings. Nano Lett,2003; 3(5):577-580.
[27]Zhang H, Wang C, Wang L. Helical Crystalline SiC/SiO2 Core-Shell Nanowires. Nano Lett,2002; 2(9):941-944.
[28]Motojima S, Ueno S, Hattori T, Goto K. Growth of regularly coiled spring-like fibers of Si3N4 by iron impurity-activated chemical vapor deposition. Appl Phys Lett,1989; 54(11):1001-1003.
[29]Jung JH, Kobayashi H, van Bommel KJC, Shinkai S, Shimizu T. Creation of novel helical ribbon and double-layered nanotube TiO2 structures using an organogel template. Chem Mater,2002; 14(4):1445-1447.
[30]Motojima S, Suzuki T, Noda Y, Hiraga A, Yang S, Chen X, et al. Preparation of helical TiO2/CMC microtubes and pure helical TiO2 microtubes. J Mater Sci,2004; 39(8):2663-2674.
[31]Li G, Jiang L, Pang S, Peng H, Zhang Z. Molybdenum trioxide nanostructures:the evolution from helical nanosheets to crosslike nanoflowers to nanobelts. J Phys Chem B,2006; 110(48):24472-24475.
[32]Davis WR, Slawson RJ, Rigby GR. An unusual form of carbon. Nature,1953; 171(4356):756-756.
[33]Baker RTK, Rodriguez NM. Carbon fiber structures having improved interlaminar properties.:United States Patents 1992, p. US0051449584A.
[34]Kim M, Rodriguez N, Baker R. The role of interfacial phenomena in the structure of carbon deposits. J Catal,1992; 134(1):253-268.
[35]Baker RTK, Harris PS, Terry S. Unique form of filamentous carbon. Nature,1975; 253(5486):37-39.
[36]Motojima S, Kawaguchi M, Nozaki K, Iwanaga H. Growth of regularly coiled carbon filaments by ni catalyzed pyrolysis of acetylene, and their morphology and extension characteristics. Appl Phys Lett,1990; 56(4):321-323.
[37]Motojima S, Chen X, Yang S, Hasegawa M. Properties and potential applications of carbon microcoils/nanocoils. Diam Relat Mater,2004; 13(11-12):1989-1992.
[38]Liu Y, Shen Z. Preparation of carbon microcoils and nanocoils using activated carbon nanotubes as catalyst support. Carbon,2005; 43(7):1574-1577.
[39]杜金红,苏革,白朔,孙超,成会明.螺旋形炭纤维的固相催化生长机制.中国科学E辑：技术科学,2003；(07)：604-608.
[40]Cheng J, Du J, Shuo BAI. Growth mechanism of carbon microcoils with changing fiber cross-section shape. New Carbon Mater,2009; 24(4):354-358.
[41]Bi H, Kou K, Ostrikov K, Wang Z. High-yield atmospheric-pressure CVD of highly-uniform carbon nanocoils using Co-P catalyst nanoparticles prepared by electroless plating. J Alloy Compd,2009; 484(1-2):860-863.
[42]Bi H, Kou KC, Ostrikov K, Yan LK, Zhang JQ, Zheng Ji T, et al. Unconventional Ni-P alloy-catalyzed CVD of carbon coil-like micro-and nano-structures. Mater Chem Phys,2009; 116(2-3):442-448.
[43]Lau K, Lu M, Hui D. Coiled carbon nanotubes:Synthesis and their potential applications in advanced composite structures. Compos Part B-Eng,2006; 37(6): 437-448.
[44]Lau K-t, Lu M, Liao K. Improved mechanical properties of coiled carbon nanotubes reinforced epoxy nanocomposites. Compos Part A-Appl S,2006; 37(10): 1837-1840.
[45]Li X-F, Lau K-T, Yin Y-S. Mechanical properties of epoxy-based composites using coiled carbon nanotubes. Compos Sci Technol,2008; 68(14):2876-2881.
[46]Fejes D, Hernadi K. A review of the properties and cvd synthesis of coiled carbon nanotubes. Materials,2010; 3(4):2618-2642.
[47]Biro L, Ehlich R, Osvath Z, Koos A, Horvath Z, Gyulai J, et al. Room temperature growth of single-wall coiled carbon nanotubes and Y-branches. Mater Sci Eng, 2002; 19(1):3-7.
[48]Wang J, Kemper T, Liang T, Sinnott SB. Predicted mechanical properties of a coiled carbon nanotube. Carbon,2012; 50(3):968-976.
[49]Lu M, Lau K, Xu J, Li H. Coiled carbon nanotubes growth and DSC study in epoxy-based composites. Colloid Surface A,2005; 257-258(0):339-343.
[50]Volodin A, Buntinx D, Ahlskog M, Fonseca A, Nagy JB, Van Haesendonck C Coiled carbon nanotubes as self-sensing mechanical resonators. Nano Lett,2004; 4(9):1775-1779.
[51]Hernadi K, Thien-Nga L, Forro L. Growth and microstructure of catalytically produced coiled carbon nanotubes. J Phys Chem B,2001; 105(50):12464-12468.
[52]Hou H, Jun Z, Weller F, Greiner A. Large-scale synthesis and characterization of helically coiled carbon nanotubes by use of Fe (CO)5 as floating catalyst precursor. Chem Mater,2003; 15(16):3170-3175.
[53]Kawaguchi M, Nozaki K, Motojima S, Iwanaga H. A growth mechanism of regularly coiled carbon fibers through acetylene pyrolysis. J Cryst Growth,1992; 118(3-4):309-313.
[54]苏革,杜金红,范月英,沈祖洪,康宁,成会明.用不同催化剂制备纳米炭纤维的生长机理.材料研究学报,2001；15(06)：623-628.
[55]李文军,徐海涛,郭燕川,陈丽娟.碳微线圈的气-液-固-固生长机理.物理化学学报,2006；22(6)：768-770.
[56]Qin Y, Li H, Zhang Z, Cui Z. Symmetric and helical growth of polyacetylene fibers over a single copper crystal derived from cupric (Ⅱ) tartrate decomposition. Org Lett,2002; 4(18):3123-3125.
[57]Qin Y, Zhang Z, Cui Z. Helical carbon nanofibers prepared by pyrolysis of acetylene with a catalyst derived from the decomposition of cupric (Ⅱ) tartrate. Carbon,2003; 41(15):3072-3074.
[58]Qin Y, Jiang X, Cui Z. Low-temperature synthesis of amorphous carbon nanocoils via acetylene coupling on copper nanocrystal surfaces at 468 K:A reaction mechanism analysis. J Phys Chem B,2005; 109(46):21749-21754.
[59]Zhou X, Cui G, Zhi L, Zhang S. Large-area helical carbon microcoils with superhydropho-bicity over a wide range of pH values. New Carbon Mater,2007; 22(1):1-5.
[60]Hanus M, Harris A. Synthesis, characterisation and applications of coiled carbon nanotubes. J Nanosci Nanotechnol,2010; 10(4):2261-2283.
[61]Shaikjee A, Coville NJ. The synthesis, properties and uses of carbon materials with helical morphology. J Adv Res,2012; 3(3):195-223.
[62]孙军海,周祚万,简贤.螺旋炭纤维的制备及其吸波性能研究进展.材料导报,2008；(01)：49-52.
[63]孙军海.螺旋纤维的制备与表征.西南交通大学,硕士,2008.
[64]Lee CJ, Lee TJ, Park J. Carbon nanofibers grown on sodalime glass at 500℃ using thermal chemical vapor deposition. Chem Phys Lett,2001; 340(5-6):413-418.
[65]Pan L, Zhang M, Nakayama Y. Growth mechanism of carbon nanocoils. J Appl Phys,2002; 91(12):10058-10061.
[66]Yang S, Chen X, Kusunoki M, Yamamoto K, Iwanaga H, Motojima S. Microstructure and microscopic deposition mechanism of twist-shaped carbon nanocoils based on the observation of helical nanoparticles on the growth tips. Carbon,2005; 43(5):916-922.
[67]Carneiro OC, Rodriguez NM, Baker RTK. Growth of carbon nanofibers from the iron-copper catalyzed decomposition of CO/C2H4/H2 mixtures. Carbon,2005; 43(11):2389-2396.
[68]Nitze F, Abou-Hamad E, Wagberg T. Carbon nanotubes and helical carbon nanofibers grown by chemical vapour deposition on C60 fullerene supported Pd nanoparticles. Carbon,2011; 49(4):1101-1107.
[69]Dong L, Yu L, Cui Z, Dong H, Ercius P, Song C, et al. Direct imaging of copper catalyst migration inside helical carbon nanofibers. Nanotechnology,2012; 23(3): 035702/1-7.
[70]Li X, Xu Z. Controllable synthesis of helical, straight, hollow and nitrogen-doped carbon nanofibers and their magnetic properties. Mater Res Bull,2012; 47(12): 4383-4391.
[71]Kuzuya C, In-Hwang W, Hirako S, Hishikawa Y, Motojima S. Preparation, morphology, and growth mechanism of carbon nanocoils. Chem Vapor Depos, 2002; 8(2):57-62.
[72]Chen X, Yang S, Takeuchi K, Hashishin T, Iwanaga H, Motojiima S. Conformation and growth mechanism of the carbon nanocoils with twisting form in comparison with that of carbon microcoils. Diam Relat Mater,2003; 12(10):1836-1840.
[73]Chen X, Takeuchi K, Yang S, Motojima S. Morphology and growth mechanism of single-helix spring-like carbon nanocoils with laces prepared using Ni/molecular sieve (Fe) catalyst. J Mater Sci,2006; 41(8):2351-2357.
[74]Yang S, Chen X, Kikuchi N, Motojima S. Catalytic effects of various metal carbides and Ti compounds for the growth of carbon nanocoils (CNCs). Mater Lett, 2008; 62(10-11):1462-1465.
[75]Zhang Q, Yu L, Cui Z. Effects of the size of nano-copper catalysts and reaction temperature on the morphology of carbon fibers. Mater Res Bull,2008; 43(3): 735-742.
[76]Chen X, Motojima S, Iwanga H. Vapor phase preparation of super-elastic carbon micro-coils. J Cryst Growth,2002; 237-239(3):1931-1936.
[77]Tang N, Kuo W, Jeng C, Wang L, Lin K, Du Y. Coil-in-coil carbon nanocoils:11 gram-scale synthesis, single nanocoil electrical properties, and electrical contact improvement. ACS Nano,2010; 4(2):781-788.
[78]Shaikjee A, Coville NJ. The role of the hydrocarbon source on the growth of carbon materials. Carbon,2012; 50(10):3376-3398.
[79]Shaikjee A, Coville NJ. The effect of substituted alkynes on nickel catalyst morphology and carbon fiber growth. Carbon,2012; 50(3):1099-1108.
[80]Li D, Pan L, Wu Y, Peng W. The effect of changes in synthesis temperature and acetylene supply on the morphology of carbon nanocoils. Carbon,2012; 50(7): 2571-2580.
[81]Khosravi M, Amini MK. Flame synthesis of carbon nanofibers on carbon paper: Physicochemical characterization and application as catalyst support for methanol oxidation. Carbon,2010; 48(11):3131-3138.
[82]Pramanik S, Kar KK. Synthesis of carbon nanofibers on hydroxyapatite by flame deposition. Fuller Nanotub Carbon Nanostr,2011; 19(7):605-616.
[83]Wang L, Li C, Gu F, Zhang C. Facile flame synthesis and electrochemical properties of carbon nanocoils. J Alloy Compd,2009; 473(1):351-355.
[84]Height MJ, Howard JB, Tester JW, Vander Sande JB. Flame synthesis of single-walled carbon nanotubes. Carbon,2004; 42(11):2295-2307.
[85]Akagi K, Piao G, Kaneko S, Sakamaki K, Shirakawa H, Kyotani M. Helical polyacetylene synthesized with a chiral nematic reaction field. Science,1998; 282(5394):1683-1686.
[86]Kyotani M, Matsushita S, Nagai T, Matsui Y, Shimomura M, Kaito A, et al. Helical carbon and graphitic films prepared from iodine-doped helical polyacetylene film using morphology-retaining carbonization. J Am Chem Soc,2008; 130(33): 10880-10881.
[87]Matsushita S, Kyotani M, Akagi K. Preparation of helical carbon and graphite films using morphology-retaining carbonization. Synthetic Met,2009; 159(21-22): 2198-2201.
[88]Iijima S. Helical microtubules of graphitic carbon. Nature,1991; 354(6348): 56-58.
[89]Hata K, Futaba DN, Mizuno K, Namai T, Yumura M, Iijima S. Water-assisted highly efficient synthesis of impurity-free single-walled carbon nanotubes. Science, 2004; 306(5700):1362-1364.
[90]Qu L, Dai L, Stone M, Xia Z, Wang ZL. Carbon nanotube arrays with strong shear binding-on and easy normal lifting-off. Science,2008; 322(5899):238-242.
[91]Yu M, Funke HH, Falconer JL, Noble RD. High Density, Vertically-aligned carbon nanotube membranes. Nano Lett,2008; 9(1):225-229.
[92]Lima MD, Fang S, Lepro X, Lewis C, Ovalle-Robles R, Carretero-Gonzalez J, et al. Biscrolling nanotube sheets and functional guests into yarns. Science,2011; 331(6013):51-55.
[93]Jiang K, Li Q, Fan S. Nanotechnology:Spinning continuous carbon nanotube yarns. Nature,2002; 419(6909):801-801.
[94]Li QW, Zhang XF, DePaula RF, Zheng LX, Zhao YH, Stan L, et al. Sustained growth of ultralong carbon nanotube arrays for fiber spinning. Adv Mater,2006; 18(23):3160-3163.
[95]Shang Y, He X, Li Y, Zhang L, Li Z, Ji C, et al. Super-stretchable spring-like carbon nanotube ropes. Adv Mater,2012; 24(21):2896-2900.
[96]Motojima S, Asakura S, Kasemura T, Takeuchi S, Iwanaga H. Catalytic effects of metal carbides, oxides and Ni single crystal on the vapor growth of micro-coiled carbon fibers. Carbon,1996; 34(3):289-296.
[97]Chen X, Yang S, Motojima S. Morphology and growth models of circular and flat carbon coils obtained by the catalytic pyrolysis of acetylene. Mater Lett,2002; 57(1):48-54.
[98]Motojima S, Itoh Y, Asakura S, Iwanaga H. Preparation of micro-coiled carbon fibres by metal powder-activated pyrolysis of acetylene containing a small amount of sulphur compounds. J Mater Sci,1995; 30(20):5049-5055.
[99]Wen Y, Shen Z. Synthesis of regular coiled carbon nanotubes by Ni-catalyzed pyrolysis of acetylene and a growth mechanism analysis. Carbon,2001; 39(15): 2369-2374.
[100]Ma H, Pan L, Zhao Q, Zhao Z, Zhao J, Qiu J. Electrically driven light emission from a single suspended carbon nanocoil. Carbon,2012; 50(15):5537-5542.
[101]Wang G, Gao Z, Tang S, Chen C, Duan F, Zhao S, et al. Microwave absorption properties of carbon nanocoils coated with highly controlled magnetic materials by atomic layer deposition. ACS Nano,2012; 6(12):11009-11017.
[102]Kong XY, Ding Y, Yang R, Wang ZL. Single-crystal nanorings formed by epitaxial self-coiling of polar nanobelts. Science,2004; 303(5662):1348-1351.
[103]Snir Y, Kamien RD. Entropically driven helix formation. Science,2005; 307(5712): 1067-1067.
[104]Talapin DV, Lee J-S, Kovalenko MV, Shevchenko EV. Prospects of colloidal nanocrystals for electronic and optoelectronic applications. Chem Rev,2009; 110(1):389-458.
[105]Tao AR, Habas S, Yang P. Shape control of colloidal metal nanocrystals. Small, 2008; 4(3):310-325.
[106]Wang Y, Chen P, Liu M. Synthesis of well-defined copper nanocubes by a one-pot solution process. Nanotechnology,2006; 17(24):6000-6006.
[107]Kim MH, Lim B, Lee EP, Xia Y. Polyol synthesis of Cu2O nanoparticles:use of chloride to promote the formation of a cubic morphology. J Mater Chem,2008; 18(34):4069-4073.
[108]Xia Y, Xiong Y, Lim B, Skrabalak SE. Shape-controlled synthesis of metal nanocrystals:simple chemistry meets complex physics? Angew Chem Int Ed,2009; 48(1):60-103.
[109]Qin Y, Zhang Z, Cui Z. Helical carbon nanofibers with a symmetric growth mode. Carbon,2004; 42(10):1917-1922.
[110]Shi Y, Wang Y, Wang D, Liu B, Li Y, Wei L. Synthesis of Hexagonal Prism (La, Ce, Tb)PO4 Phosphors by Precipitation Method. Cryst Growth Des,2012; 12(4): 1785-1791.
[111]李晓辉,薛韩,张澜萃,朱再明.单核和双核酒石酸铜配合物的水热合成及晶体结构.化学试剂,2010；(06)：537-540.
[112]覃勇.螺旋碳纳米纤维的生长样式控制及其生长机理研究.中国海洋大学,博士,2005.
[113]Schmid RL, Felsche J. Thermal decomposition of Cu(Ⅱ)(C4H4O6)·3H2O and Co(Ⅱ)(C4H4O6)·2.5 H2O. Determination of mechanism by means of simultaneous thermal analysis and mass spectrometry. Thermochim Acta,1982; 59(1):105-114.
[114]Hansen PL. Atom-resolved imaging of dynamic shape changes in supported copper nanocrystals. Science,2002; 295(5562):2053-2055.
[115]Voorhees PW. The theory of ostwald ripening. J Stat Phys,1985; 38(1-2):231-252.
[116]Brailsford A, Wynblatt P. The dependence of Ostwald ripening kinetics on particle volume fraction. Acta Metallurgica,1979; 27(3):489-497.
[117]Ozawa T. Initial kinetic parameters from thermogravimetric rate and conversion data. Bull Chem Soc Jpn,1965; 38(11):1881-1886.
[118]Flynn JH, Wall LA. A quick, direct method for the determination of activation energy from thermogravimetric data. J Polym Sci Pol Lett,1966; 4(5):323-328.
[119]胡荣祖,高胜利,赵凤起,史启祯,张同来,张建军.热分析动力学.北京：科学出版社;2008.
[120]Malek J, Mitsuhashi T, Criado JM. Kinetic analysis of solid-state processes. J Mater Res,2001; 16(6):1862-1871.
[121]Kissinger HE. Reaction kinetics in differential thermal analysis. Anal Chem,1957; 29(11):1702-1706.
[122]Starink M. A new method for the derivation of activation energies from experiments performed at constant heating rate. Thermochim Acta,1996; 288(1): 97-104.
[123]Qi X, Deng Y, Zhong W, Yang Y, Qin C, Au C, et al. Controllable and large-scale synthesis of carbon nanofibers, bamboo-like nanotubes, and chains of nanospheres over Fe/SnO2 and their microwave-absorption properties. J Phys Chem C,2010; 114(2):808-814.
[124]Qi X, Ding Q, Zhong W, Au C-T, Du Y. Controllable synthesis and purification of carbon nanofibers and nanocoils over water-soluble NaNO3. Carbon,2013; 56(0): 383-385.
[125]Guo W, Liu C, Zhao F, Sun X, Yang Z, Chen T, et al. A novel electromechanical actuation mechanism of a carbon nanotube fiber. Adv Mater,2012; 24(39): 5379-5384.
[126]Hanus MJ, Harris AT. Synthesis of twisted carbon fibres comprised of four intertwined helical strands. Carbon,2010; 48(10):2989-2992.
[127]Hohenberg P, Kohn W. Inhomogeneous electron gas. Phys Rev,1964; 136(3B): B864-871.
[128]Kohn W, Sham LJ. Self-consistent equations including exchange and correlation effects. Phys Rev,1965; 140(4A):A1133-1138.
[129]谢希德,陆栋.固体能带理论：复旦大学出版社；1998.
[130]Perdew JP, Chevary JA, Vosko SH, Jackson KA, Pederson MR, Singh DJ, et al. Atoms, Molecules, Solids, and Surfaces:Applications of the generalized gradient approximation for exchange and correlation. Phys Rev B,1992; 46(11): 6671-6687.
[131]徐光宪,黎乐民.量子化学：基本原理和从头计算法：科学出版社；2004.
[132]Heitler W, London F. Wechselwirkung neutraler atome und homoopolare.1927.
[133]Perdew J, Wang Y. Accurate and simple analytic representation of the electron-gas correlation energy. Phys Rev B,1992; 45(23):13244-13249.
[134]Qin Y, Jiang X, Cui Z. Low-temperature synthesis of amorphous carbon nanocoils via acetylene coupling on copper nanocrystal surfaces at 468 K:A reaction mechanism analysis. J Phys Chem B,2005; 109(46):21749-21754.
[135]Shirakawa H, Iklda S. Infrared spectra of poly (acetylene). Polym J,1988; 2(2): 231-244.
[136]Wang Z. Transmission electron microscopy of shape-controlled nanocrystals and their assemblies. J Phys Chem B,2000; 104(6):1153-1175.
[137]Saveliev AV, Merchan-Merchan W, Kennedy LA. Metal catalyzed synthesis of carbon nanostructures in an opposed flow methane oxygen flame. Combust Flame, 2003; 135(1-2):27-33.
[138]Wang W, Yang K, Gaillard J, Bandaru P, Rao A. Rational synthesis of helically coiled carbon nanowires and nanotubes through the use of tin and indium catalysts. Adv Mater,2008; 20(1):179-182.
[139]Qi X, Zhong W, Deng Y, Au C, Du Y. Characterization and magnetic properties of helical carbon nanotubes and carbon nanobelts synthesized in acetylene decomposition over Fe-Cu nanoparticles at 450℃. J Phys Chem C,2009; 113(36): 15934-15940.
[140]Shaikjee A, Franklyn PJ, Coville NJ. The use of transmission electron microscopy tomography to correlate copper catalyst particle morphology with carbon fiber morphology. Carbon,2011; 49(9):2950-2959.
[141]李酽,朱晨,蔡菊芳.纳米晶的结构形貌控制及生长机理研究.材料导报,2003；17(06)：9-11.
[142]Niu W, Zheng S, Wang D, Liu X, Li H, Han S, et al. Selective synthesis of single-crystalline rhombic dodecahedral, octahedral, and cubic gold nanocrystals. J Am Chem Soc,2008; 131(2):697-703.
[143]Radi A, Pradhan D, Sohn Y, Leung KT. Nanoscale shape and size control of cubic, cuboctahedral, and octahedral Cu-Cu2O core-shell nanoparticles on si(100) by one-step, templateless, capping-agent-free electrodeposition. ACS Nano,2010; 4(3):1553-1560.
[144]Lu C, Prasad KS, Wu H-L, Ho J, Huang MH. Au nanocube-directed fabrication of au-pd core-shell nanocrystals with tetrahexahedral, concave octahedral, and octahedral structures and their electrocatalytic activity. J Am Chem Soc,2010; 132(41):14546-14553.
[145]Jin M, Zhang H, Wang J, Zhong X, Lu N, Li Z, et al. Copper can still be epitaxially deposited on palladium nanocrystals to generate core-shell nanocubes despite their large lattice mismatch. ACS Nano,2012; 6(3):2566-2573.
[146]Chen Q, Richardson NV. Surface facetting induced by adsorbates. Prog Surf Sci, 2003; 73(4-8):59-77.
[147]Newton MA, Belver-Coldeira C, Martinez-Arias A, Fernandez-Garcia M. Dynamic in situ observation of rapid size and shape change of supported Pd nanoparticles during CO/NO cycling. Nat mater,2007; 6(7):528-532.
[148]Tao F, Dag S, Wang LW, Liu Z, Butcher DR, Bluhm H, et al. Break-up of stepped platinum catalyst surfaces by high co coverage. Science,2010; 327(5967): 850-853.
[149]McKenna KP, Shluger AL. Shaping the morphology of gold nanoparticles by CO adsorption. J Phys Chem C,2007; 111(51):18848-18852.
[150]Kobayashi H, Yamauchi M, Kitagawa H, Kubota Y, Kato K, Takata M. Atomic-level Pd-Pt alloying and largely enhanced hydrogen-storage capacity in bimetallic nanoparticles reconstructed from core/shell structure by a process of hydrogen absorption/desorption. J Am Chem Soc,2010; 132(16):5576-5577.
[151]Small MW, Sanchez SI, Marinkovic NS, Frenkel AI, Nuzzo RG. Influence of adsorbates on the electronic structure, bond strain, and thermal properties of an alumina-supported pt catalyst. ACS Nano,2012; 6(6):5583-5595.
[152]Zhang R, Khalizov A, Wang L, Hu M, Xu W. Nucleation and growth of nanoparticles in the atmosphere. Chem Rev,2011; 112(3):1957-2011.
[153]Yang M, Jackson KA, Koehler C, Frauenheim T, Jellinek J. Structure and shape variations in intermediate-size copper clusters. J Chem Phys,2006; 124: 024308/1-6.
[154]Jiang M, Zeng Q, Zhang T, Yang M, Jackson KA. Icosahedral to double-icosahedral shape transition of copper clusters. J Chem Phys,2012; 136: 104501/1-8.
[155]Bell D, Sun Y, Zhang L, Dong L, Nelson B, Grutzmacher D. Three-dimensional nanosprings for electromechanical sensors. Sensor Actuat A-Phys,2006; 130: 54-61.
[156]Hu G, Nitze F, Barzegar HR, Sharifi T, Mikolajczuk A, Tai C-W, et al. Palladium nanocrystals supported on helical carbon nanofibers for highly efficient electro-oxidation of formic acid, methanol and ethanol in alkaline electrolytes. J Power Sources,2012; 209:236-242.
[157]Tang N, Zhong W, Gedanken A, Du Y. High magnetization helical carbon nanofibers produced by nanoparticle catalysis. J Phys Chem B,2006; 110(24): 11772-11774.
[158]Xie J, Sharma PK, Varadan V, Varadan V, Pradhan BK, Eser S. Thermal, raman and surface area studies of microcoiled carbon fiber synthesized by cvd microwave system. Mater Chem Phys,2002; 76(3):217-223.
[159]Chen X, Motojima S. Morphologies of carbon micro-coils grown by chemical vapor deposition. J Mater Sci,1999; 34(22):5519-5524.
[160]Motojima S, Asakura S, Hirata M, Iwanaga H. Effect of metal impurities on the growth of micro-coiled carbon fibres by pyrolysis of acetylene. Mater Sci Eng B, 1995; 34(1):L9-L11.
[161]毕辉,寇开昌,王召娣,王志超,张教强.石墨化对微螺旋炭纤维热氧化动力学的影响.新型炭材料,2009；(04)：364-368.
[162]Lin M, Tan JPY, Boothroyd C, Loh KP, Tok ES, Foo YL. Dynamical observation of bamboo-like carbon nanotube growth. Nano Lett,2007; 7(8):2234-2238.
[163]Mukhopadhyay K, Porwal D, Lal D, Ram K, Narayanmathur G. Synthesis of coiled/straight carbon nanofibers by catalytic chemical vapor deposition. Carbon, 2004; 42(15):3254-3256.
[164]Yang S, Chen X, Motojima S. Morphology of the growth tip of carbon microcoils/nanocoils. Diam Relat Mater,2004; 13(11-12):2152-2155.
[165]Rodriguez NM. A review of catalytically grown carbon nanofibers. J Mater Res, 1993; 8(12):3233-3250.
[166]Chen X, Yang S, Motojima S. Carbon nanocoils with changed coiling-chirality formed over Ni/molecular Sieves catalyst. J Mater Sci,2004; 39(9):3227-3233.
[167]Hanus MJ, MacKenzie KJ, King AAK, Dunens OM, Harris AT. Parametric study of coiled carbon fibre synthesis on an in situ generated H2S-modified Ni/Al2O3 catalyst. Carbon,2011; 49(13):4159-4169.
[168]In-Hwang W, Kuzuya T, Iwanaga H, Motojima S. Oxidation characteristics of the graphite micro-coils, and growth mechanism of the carbon coils. J Mater Sci,2001; 36(4):971-978.
[169]毕辉,寇开昌,张教强.螺旋炭纤维的研究进展.炭素技术,2006；(02)：23-28.
[170]Ren X, Zhang H, Cui Z. Acetylene decomposition to helical carbon nanofibers over supported copper catalysts. Mater Res Bull,2007; 42(12):2202-2210.
[171]Jian X, Jiang M, Zhou Z, Yang M, Lu J, Hu S, et al. Preparation of high purity helical carbon nanofibers by the catalytic decomposition of acetylene and their growth mechanism. Carbon,2010; 48(15):4535-4541.
[172]Jian X, Jiang M, Zhou Z, Zeng Q, Lu J, Wang D, et al. Gas-induced formation of cu nanoparticle as catalyst for high-purity straight and helical carbon nanofibers. ACS Nano,2012; 6(10):8611-8619.
[173]王凯.掺杂T-ZnO的制备与性能.西南交通大学硕士,2006.
[174]Jing L, Xu Z, Sun X, Shang J, Cai W. The surface properties and photocatalytic activities of ZnO ultrafine particles. Appl Surf Sci,2001; 180(3-4):308-314.
[175]Jeong S, Woo K, Kim D, Lim S, Kim JS, Shin H, et al. Controlling the thickness of the surface oxide layer on cu nanoparticles for the fabrication of conductive structures by ink-jet printing. Adv Funct Mater,2008; 18(5):679-686.
[176]Nakamura J, Uchijima T, Kanai Y, Fujitani T. The role of ZnO in Cu/ZnO methanol synthesis catalysts. Catal Today,1996; 28(3):223-230.
[177]王定川,简贤,朱俊廷,庞何苗,周祚万.热处理有机聚合物螺旋纤维制备螺旋炭纤维及其表征.功能材料,2012；(05)：576-578.
[178]Varadan VK, Varadan VV, Lakhtakia A. On the possibility of designing anti-reflection coatings using chiral composites. J Wave-Material Interaction, 1987; 2(1):71-81.
[179]Guire T, Varadan VV, Varadan VK. Influence of chirality on the reflection of EM waves by planar dielectric slabs. IEEE Trans Electromagn Compat,1990; 32(4): 300-303.
[180]Varadan VK, Lakhtakia A, Varadan VV. Propagation in a parallel plate waveguide wholly filled with a chiral medium. J Wave-Mater Interaction,1988; 3(4): 267-351.
[181]Tang N, Zhong W, Au C, Gedanken A, Yang Y, Du Y. Large-scale synthesis, annealing, purification, and magnetic properties of crystalline helical carbon nanotubes with symmetrical structures. Adv Fund Mater,2007; 17(9):1542-1550.
[182]Motojima S, Hoshiya S, Hishikawa Y. Electromagnetic wave absorption properties of carbon microcoils/pmma composite beads in W bands. Carbon,2003; 41(13): 2658-2660.
[183]Du J-H, Sun C, Bai S, Su G, Ying Z, Chenga H-M. Microwave electromagnetic characteristics of a microcoiled carbon fibers/paraffin wax composite in Ku band. J Mater Res,2002; 17(5):1232-1236.
[184]苟宇.聚苯胺纳米管的原位合成机理及电磁学性能研究.西南交通大学,硕士,2010.
[185]Whitby R, Fukuda T, Maekawa T, James S, Mikhalovsky S. Geometric control and tuneable pore size distribution of buckypaper and buckydiscs. Carbon,2008; 46(6): 949-956.
[2]Su DS. Inorganic materials with double-helix structures. Angew Chem Int Ed, 2011; 50(21):4747-4750.
[3]Hanes CS. The action of amylases in relation to the structure of starch and its metabolism in the plant. Parts Ⅳ-Ⅶ. New Phytol,1937; 36(3):189-239.
[4]Watson J, Crick F. Molecular structure of nucleic acids:a structure for deoxyribose nucleic acid. Nature,1953; 171:737-738.
[5]Natta G, Pino P, Corradini P, Danusso F, Mantica E, Mazzanti G, et al. Crystalline high polymers of a-olefins. J Am Chem Soc,1955; 77(6):1708-1710.
[6]Nakano T, Okamoto Y. Synthetic helical polymers:conformation and function. Chem Rev,2001; 101(12):4013-4038.
[7]Yashima E, Maeda K, Iida H, Furusho Y, Nagai K. Helical polymers:synthesis, structures, and functions. Chem Rev,2009; 109(11):6102-6211.
[8]Yashima E, Maeda K, Furusho Y. Single- and Double-stranded helical polymers: synthesis, structures, and functions. Accounts Chem Res,2008; 41(9):1166-1180.
[9]Shinohara K, Aoki T, Kaneko T. Helical chirality of π-conjugated main-chain induced by polymerization of phenylacetylene with chiral bulky pinanyl groups: Effects of the flexible spacer and polymerization catalyst. J Polym Sci Pol Chem, 2002; 40(11):1689-1697.
[10]Eckhardt CJ, Peachey NM, Swanson DR, Takacs JM, Khan MA, Gong X, et al. Separation of chiral phases in monolayer crystals of racemic amphiphiles. Nature, 1993; 362(6421):614-616.
[11]Yashima E, Maeda K, Nishimura T. Detection and amplification of chirality by helical polymers. Chem-Eur J,2004; 10(1):42-51.
[12]Guo J, Yu L, Liu F, Guo R, Ma G, Cao H, et al. Effect of specific rotation of chiral dopant and polymerization temperature on reflectance properties of polymer stabilized cholesteric liquid crystal cells. J Polym Sci Pol Phys,2008; 46(15): 1562-1570.
[13]Yashima E, Maeda K. Chirality-responsive helical polymers. Macromolecules, 2007; 41(1):3-12.
[14]Green MM, Peterson NC, Sato T, Teramoto A, Cook R, Lifson S. A helical polymer with a cooperative response to chiral information. Science,1995; 268(5219): 1860-1866.
[15]Maxein G, Keller H, Novak BM, Zentel R. Opalescent cholesteric networks from chiral polyisocyanates in polystyrene. Adv Mater,1998; 10(4):341-345.
[16]Kauranen MM, Verbiest T, Persoons A, Meijer EW, Teerenstra MN, Schouten AJ, et al. Chiral effects in the second-order optical nonlinearity of a poly(isocyanide) monolayer. Adv Mater,1995; 7(7):641-644.
[17]Koeckelberghs G, Sioncke S, Verbiest T, Persoons A, Samyn C. Synthesis and properties of chiral helical chromophore-functionalised polybinaphthalenes for second-order nonlinear optical applications. Polymer,2003; 44(14):3785-3794.
[18]Motojima S, Chen Q. Three-dimensional growth mechanism of cosmo-mimetic carbon microcoils obtained by chemical vapor deposition. J Appl Phys,1999; 85(7):3919-3921.
[19]Yang S, Chen X, Motojima S, Ichihara M. Morphology and microstructure of spring-like carbon micro-coils/nano-coils prepared by catalytic pyrolysis of acetylene using Fe-containing alloy catalysts. Carbon,2005; 43(4):827-834.
[20]Motojima S, Hasixgawa I, Kagiya S, Andoh K, Iwanaga H. Vapor phase preparation of micro-coiled carbon fibers by metal powder catalyzed pyrolysis of acetylene containing a small amount of phosphorus impurity. Carbon,1995; 33(8): 1167-1173.
[21]Tang N, Wen J, Zhang Y, Liu F, Lin K, Du Y. Helical carbon nanotubes:catalytic particle size-dependent growth and magnetic properties. ACS Nano,2010; 4(1): 241-250.
[22]Gao PX, Ding Y, Mai W, Hughes WL, Lao C, Wang ZL. Conversion of zinc oxide nanobelts into superlattice-structured nanohelices. Science,2005; 309(5741): 1700-1704.
[23]Morito H, Yamane H. Double-helical silicon microtubes. Angew Chem Int Ed, 2010; 49(21):3638-3641.
[24]Xu F, Lu W, Zhu Y. Controlled 3d buckling of silicon nanowires for stretchable electronics. ACS Nano,2010; 5(1):672-678.
[25]Lin G-L, Tsai Y, Lin H, Tang C, Lin C. Synthesis of mesoporous silica helical fibers using a catanionic-neutral ternary surfactant in a highly dilute silica solution: biomimetic silicification. Langmuir,2007; 23(8):4115-4119.
[26]Zhang H, Wang C-M, Buck E, Wang L-S. Synthesis, Characterization, and manipulation of helical SiO2 nanosprings. Nano Lett,2003; 3(5):577-580.
[27]Zhang H, Wang C, Wang L. Helical Crystalline SiC/SiO2 Core-Shell Nanowires. Nano Lett,2002; 2(9):941-944.
[28]Motojima S, Ueno S, Hattori T, Goto K. Growth of regularly coiled spring-like fibers of Si3N4 by iron impurity-activated chemical vapor deposition. Appl Phys Lett,1989; 54(11):1001-1003.
[29]Jung JH, Kobayashi H, van Bommel KJC, Shinkai S, Shimizu T. Creation of novel helical ribbon and double-layered nanotube TiO2 structures using an organogel template. Chem Mater,2002; 14(4):1445-1447.
[30]Motojima S, Suzuki T, Noda Y, Hiraga A, Yang S, Chen X, et al. Preparation of helical TiO2/CMC microtubes and pure helical TiO2 microtubes. J Mater Sci,2004; 39(8):2663-2674.
[31]Li G, Jiang L, Pang S, Peng H, Zhang Z. Molybdenum trioxide nanostructures:the evolution from helical nanosheets to crosslike nanoflowers to nanobelts. J Phys Chem B,2006; 110(48):24472-24475.
[32]Davis WR, Slawson RJ, Rigby GR. An unusual form of carbon. Nature,1953; 171(4356):756-756.
[33]Baker RTK, Rodriguez NM. Carbon fiber structures having improved interlaminar properties.:United States Patents 1992, p. US0051449584A.
[34]Kim M, Rodriguez N, Baker R. The role of interfacial phenomena in the structure of carbon deposits. J Catal,1992; 134(1):253-268.
[35]Baker RTK, Harris PS, Terry S. Unique form of filamentous carbon. Nature,1975; 253(5486):37-39.
[36]Motojima S, Kawaguchi M, Nozaki K, Iwanaga H. Growth of regularly coiled carbon filaments by ni catalyzed pyrolysis of acetylene, and their morphology and extension characteristics. Appl Phys Lett,1990; 56(4):321-323.
[37]Motojima S, Chen X, Yang S, Hasegawa M. Properties and potential applications of carbon microcoils/nanocoils. Diam Relat Mater,2004; 13(11-12):1989-1992.
[38]Liu Y, Shen Z. Preparation of carbon microcoils and nanocoils using activated carbon nanotubes as catalyst support. Carbon,2005; 43(7):1574-1577.
[39]杜金红,苏革,白朔,孙超,成会明.螺旋形炭纤维的固相催化生长机制.中国科学E辑：技术科学,2003；(07)：604-608.
[40]Cheng J, Du J, Shuo BAI. Growth mechanism of carbon microcoils with changing fiber cross-section shape. New Carbon Mater,2009; 24(4):354-358.
[41]Bi H, Kou K, Ostrikov K, Wang Z. High-yield atmospheric-pressure CVD of highly-uniform carbon nanocoils using Co-P catalyst nanoparticles prepared by electroless plating. J Alloy Compd,2009; 484(1-2):860-863.
[42]Bi H, Kou KC, Ostrikov K, Yan LK, Zhang JQ, Zheng Ji T, et al. Unconventional Ni-P alloy-catalyzed CVD of carbon coil-like micro-and nano-structures. Mater Chem Phys,2009; 116(2-3):442-448.
[43]Lau K, Lu M, Hui D. Coiled carbon nanotubes:Synthesis and their potential applications in advanced composite structures. Compos Part B-Eng,2006; 37(6): 437-448.
[44]Lau K-t, Lu M, Liao K. Improved mechanical properties of coiled carbon nanotubes reinforced epoxy nanocomposites. Compos Part A-Appl S,2006; 37(10): 1837-1840.
[45]Li X-F, Lau K-T, Yin Y-S. Mechanical properties of epoxy-based composites using coiled carbon nanotubes. Compos Sci Technol,2008; 68(14):2876-2881.
[46]Fejes D, Hernadi K. A review of the properties and cvd synthesis of coiled carbon nanotubes. Materials,2010; 3(4):2618-2642.
[47]Biro L, Ehlich R, Osvath Z, Koos A, Horvath Z, Gyulai J, et al. Room temperature growth of single-wall coiled carbon nanotubes and Y-branches. Mater Sci Eng, 2002; 19(1):3-7.
[48]Wang J, Kemper T, Liang T, Sinnott SB. Predicted mechanical properties of a coiled carbon nanotube. Carbon,2012; 50(3):968-976.
[49]Lu M, Lau K, Xu J, Li H. Coiled carbon nanotubes growth and DSC study in epoxy-based composites. Colloid Surface A,2005; 257-258(0):339-343.
[50]Volodin A, Buntinx D, Ahlskog M, Fonseca A, Nagy JB, Van Haesendonck C Coiled carbon nanotubes as self-sensing mechanical resonators. Nano Lett,2004; 4(9):1775-1779.
[51]Hernadi K, Thien-Nga L, Forro L. Growth and microstructure of catalytically produced coiled carbon nanotubes. J Phys Chem B,2001; 105(50):12464-12468.
[52]Hou H, Jun Z, Weller F, Greiner A. Large-scale synthesis and characterization of helically coiled carbon nanotubes by use of Fe (CO)5 as floating catalyst precursor. Chem Mater,2003; 15(16):3170-3175.
[53]Kawaguchi M, Nozaki K, Motojima S, Iwanaga H. A growth mechanism of regularly coiled carbon fibers through acetylene pyrolysis. J Cryst Growth,1992; 118(3-4):309-313.
[54]苏革,杜金红,范月英,沈祖洪,康宁,成会明.用不同催化剂制备纳米炭纤维的生长机理.材料研究学报,2001；15(06)：623-628.
[55]李文军,徐海涛,郭燕川,陈丽娟.碳微线圈的气-液-固-固生长机理.物理化学学报,2006；22(6)：768-770.
[56]Qin Y, Li H, Zhang Z, Cui Z. Symmetric and helical growth of polyacetylene fibers over a single copper crystal derived from cupric (Ⅱ) tartrate decomposition. Org Lett,2002; 4(18):3123-3125.
[57]Qin Y, Zhang Z, Cui Z. Helical carbon nanofibers prepared by pyrolysis of acetylene with a catalyst derived from the decomposition of cupric (Ⅱ) tartrate. Carbon,2003; 41(15):3072-3074.
[58]Qin Y, Jiang X, Cui Z. Low-temperature synthesis of amorphous carbon nanocoils via acetylene coupling on copper nanocrystal surfaces at 468 K:A reaction mechanism analysis. J Phys Chem B,2005; 109(46):21749-21754.
[59]Zhou X, Cui G, Zhi L, Zhang S. Large-area helical carbon microcoils with superhydropho-bicity over a wide range of pH values. New Carbon Mater,2007; 22(1):1-5.
[60]Hanus M, Harris A. Synthesis, characterisation and applications of coiled carbon nanotubes. J Nanosci Nanotechnol,2010; 10(4):2261-2283.
[61]Shaikjee A, Coville NJ. The synthesis, properties and uses of carbon materials with helical morphology. J Adv Res,2012; 3(3):195-223.
[62]孙军海,周祚万,简贤.螺旋炭纤维的制备及其吸波性能研究进展.材料导报,2008；(01)：49-52.
[63]孙军海.螺旋纤维的制备与表征.西南交通大学,硕士,2008.
[64]Lee CJ, Lee TJ, Park J. Carbon nanofibers grown on sodalime glass at 500℃ using thermal chemical vapor deposition. Chem Phys Lett,2001; 340(5-6):413-418.
[65]Pan L, Zhang M, Nakayama Y. Growth mechanism of carbon nanocoils. J Appl Phys,2002; 91(12):10058-10061.
[66]Yang S, Chen X, Kusunoki M, Yamamoto K, Iwanaga H, Motojima S. Microstructure and microscopic deposition mechanism of twist-shaped carbon nanocoils based on the observation of helical nanoparticles on the growth tips. Carbon,2005; 43(5):916-922.
[67]Carneiro OC, Rodriguez NM, Baker RTK. Growth of carbon nanofibers from the iron-copper catalyzed decomposition of CO/C2H4/H2 mixtures. Carbon,2005; 43(11):2389-2396.
[68]Nitze F, Abou-Hamad E, Wagberg T. Carbon nanotubes and helical carbon nanofibers grown by chemical vapour deposition on C60 fullerene supported Pd nanoparticles. Carbon,2011; 49(4):1101-1107.
[69]Dong L, Yu L, Cui Z, Dong H, Ercius P, Song C, et al. Direct imaging of copper catalyst migration inside helical carbon nanofibers. Nanotechnology,2012; 23(3): 035702/1-7.
[70]Li X, Xu Z. Controllable synthesis of helical, straight, hollow and nitrogen-doped carbon nanofibers and their magnetic properties. Mater Res Bull,2012; 47(12): 4383-4391.
[71]Kuzuya C, In-Hwang W, Hirako S, Hishikawa Y, Motojima S. Preparation, morphology, and growth mechanism of carbon nanocoils. Chem Vapor Depos, 2002; 8(2):57-62.
[72]Chen X, Yang S, Takeuchi K, Hashishin T, Iwanaga H, Motojiima S. Conformation and growth mechanism of the carbon nanocoils with twisting form in comparison with that of carbon microcoils. Diam Relat Mater,2003; 12(10):1836-1840.
[73]Chen X, Takeuchi K, Yang S, Motojima S. Morphology and growth mechanism of single-helix spring-like carbon nanocoils with laces prepared using Ni/molecular sieve (Fe) catalyst. J Mater Sci,2006; 41(8):2351-2357.
[74]Yang S, Chen X, Kikuchi N, Motojima S. Catalytic effects of various metal carbides and Ti compounds for the growth of carbon nanocoils (CNCs). Mater Lett, 2008; 62(10-11):1462-1465.
[75]Zhang Q, Yu L, Cui Z. Effects of the size of nano-copper catalysts and reaction temperature on the morphology of carbon fibers. Mater Res Bull,2008; 43(3): 735-742.
[76]Chen X, Motojima S, Iwanga H. Vapor phase preparation of super-elastic carbon micro-coils. J Cryst Growth,2002; 237-239(3):1931-1936.
[77]Tang N, Kuo W, Jeng C, Wang L, Lin K, Du Y. Coil-in-coil carbon nanocoils:11 gram-scale synthesis, single nanocoil electrical properties, and electrical contact improvement. ACS Nano,2010; 4(2):781-788.
[78]Shaikjee A, Coville NJ. The role of the hydrocarbon source on the growth of carbon materials. Carbon,2012; 50(10):3376-3398.
[79]Shaikjee A, Coville NJ. The effect of substituted alkynes on nickel catalyst morphology and carbon fiber growth. Carbon,2012; 50(3):1099-1108.
[80]Li D, Pan L, Wu Y, Peng W. The effect of changes in synthesis temperature and acetylene supply on the morphology of carbon nanocoils. Carbon,2012; 50(7): 2571-2580.
[81]Khosravi M, Amini MK. Flame synthesis of carbon nanofibers on carbon paper: Physicochemical characterization and application as catalyst support for methanol oxidation. Carbon,2010; 48(11):3131-3138.
[82]Pramanik S, Kar KK. Synthesis of carbon nanofibers on hydroxyapatite by flame deposition. Fuller Nanotub Carbon Nanostr,2011; 19(7):605-616.
[83]Wang L, Li C, Gu F, Zhang C. Facile flame synthesis and electrochemical properties of carbon nanocoils. J Alloy Compd,2009; 473(1):351-355.
[84]Height MJ, Howard JB, Tester JW, Vander Sande JB. Flame synthesis of single-walled carbon nanotubes. Carbon,2004; 42(11):2295-2307.
[85]Akagi K, Piao G, Kaneko S, Sakamaki K, Shirakawa H, Kyotani M. Helical polyacetylene synthesized with a chiral nematic reaction field. Science,1998; 282(5394):1683-1686.
[86]Kyotani M, Matsushita S, Nagai T, Matsui Y, Shimomura M, Kaito A, et al. Helical carbon and graphitic films prepared from iodine-doped helical polyacetylene film using morphology-retaining carbonization. J Am Chem Soc,2008; 130(33): 10880-10881.
[87]Matsushita S, Kyotani M, Akagi K. Preparation of helical carbon and graphite films using morphology-retaining carbonization. Synthetic Met,2009; 159(21-22): 2198-2201.
[88]Iijima S. Helical microtubules of graphitic carbon. Nature,1991; 354(6348): 56-58.
[89]Hata K, Futaba DN, Mizuno K, Namai T, Yumura M, Iijima S. Water-assisted highly efficient synthesis of impurity-free single-walled carbon nanotubes. Science, 2004; 306(5700):1362-1364.
[90]Qu L, Dai L, Stone M, Xia Z, Wang ZL. Carbon nanotube arrays with strong shear binding-on and easy normal lifting-off. Science,2008; 322(5899):238-242.
[91]Yu M, Funke HH, Falconer JL, Noble RD. High Density, Vertically-aligned carbon nanotube membranes. Nano Lett,2008; 9(1):225-229.
[92]Lima MD, Fang S, Lepro X, Lewis C, Ovalle-Robles R, Carretero-Gonzalez J, et al. Biscrolling nanotube sheets and functional guests into yarns. Science,2011; 331(6013):51-55.
[93]Jiang K, Li Q, Fan S. Nanotechnology:Spinning continuous carbon nanotube yarns. Nature,2002; 419(6909):801-801.
[94]Li QW, Zhang XF, DePaula RF, Zheng LX, Zhao YH, Stan L, et al. Sustained growth of ultralong carbon nanotube arrays for fiber spinning. Adv Mater,2006; 18(23):3160-3163.
[95]Shang Y, He X, Li Y, Zhang L, Li Z, Ji C, et al. Super-stretchable spring-like carbon nanotube ropes. Adv Mater,2012; 24(21):2896-2900.
[96]Motojima S, Asakura S, Kasemura T, Takeuchi S, Iwanaga H. Catalytic effects of metal carbides, oxides and Ni single crystal on the vapor growth of micro-coiled carbon fibers. Carbon,1996; 34(3):289-296.
[97]Chen X, Yang S, Motojima S. Morphology and growth models of circular and flat carbon coils obtained by the catalytic pyrolysis of acetylene. Mater Lett,2002; 57(1):48-54.
[98]Motojima S, Itoh Y, Asakura S, Iwanaga H. Preparation of micro-coiled carbon fibres by metal powder-activated pyrolysis of acetylene containing a small amount of sulphur compounds. J Mater Sci,1995; 30(20):5049-5055.
[99]Wen Y, Shen Z. Synthesis of regular coiled carbon nanotubes by Ni-catalyzed pyrolysis of acetylene and a growth mechanism analysis. Carbon,2001; 39(15): 2369-2374.
[100]Ma H, Pan L, Zhao Q, Zhao Z, Zhao J, Qiu J. Electrically driven light emission from a single suspended carbon nanocoil. Carbon,2012; 50(15):5537-5542.
[101]Wang G, Gao Z, Tang S, Chen C, Duan F, Zhao S, et al. Microwave absorption properties of carbon nanocoils coated with highly controlled magnetic materials by atomic layer deposition. ACS Nano,2012; 6(12):11009-11017.
[102]Kong XY, Ding Y, Yang R, Wang ZL. Single-crystal nanorings formed by epitaxial self-coiling of polar nanobelts. Science,2004; 303(5662):1348-1351.
[103]Snir Y, Kamien RD. Entropically driven helix formation. Science,2005; 307(5712): 1067-1067.
[104]Talapin DV, Lee J-S, Kovalenko MV, Shevchenko EV. Prospects of colloidal nanocrystals for electronic and optoelectronic applications. Chem Rev,2009; 110(1):389-458.
[105]Tao AR, Habas S, Yang P. Shape control of colloidal metal nanocrystals. Small, 2008; 4(3):310-325.
[106]Wang Y, Chen P, Liu M. Synthesis of well-defined copper nanocubes by a one-pot solution process. Nanotechnology,2006; 17(24):6000-6006.
[107]Kim MH, Lim B, Lee EP, Xia Y. Polyol synthesis of Cu2O nanoparticles:use of chloride to promote the formation of a cubic morphology. J Mater Chem,2008; 18(34):4069-4073.
[108]Xia Y, Xiong Y, Lim B, Skrabalak SE. Shape-controlled synthesis of metal nanocrystals:simple chemistry meets complex physics? Angew Chem Int Ed,2009; 48(1):60-103.
[109]Qin Y, Zhang Z, Cui Z. Helical carbon nanofibers with a symmetric growth mode. Carbon,2004; 42(10):1917-1922.
[110]Shi Y, Wang Y, Wang D, Liu B, Li Y, Wei L. Synthesis of Hexagonal Prism (La, Ce, Tb)PO4 Phosphors by Precipitation Method. Cryst Growth Des,2012; 12(4): 1785-1791.
[111]李晓辉,薛韩,张澜萃,朱再明.单核和双核酒石酸铜配合物的水热合成及晶体结构.化学试剂,2010；(06)：537-540.
[112]覃勇.螺旋碳纳米纤维的生长样式控制及其生长机理研究.中国海洋大学,博士,2005.
[113]Schmid RL, Felsche J. Thermal decomposition of Cu(Ⅱ)(C4H4O6)·3H2O and Co(Ⅱ)(C4H4O6)·2.5 H2O. Determination of mechanism by means of simultaneous thermal analysis and mass spectrometry. Thermochim Acta,1982; 59(1):105-114.
[114]Hansen PL. Atom-resolved imaging of dynamic shape changes in supported copper nanocrystals. Science,2002; 295(5562):2053-2055.
[115]Voorhees PW. The theory of ostwald ripening. J Stat Phys,1985; 38(1-2):231-252.
[116]Brailsford A, Wynblatt P. The dependence of Ostwald ripening kinetics on particle volume fraction. Acta Metallurgica,1979; 27(3):489-497.
[117]Ozawa T. Initial kinetic parameters from thermogravimetric rate and conversion data. Bull Chem Soc Jpn,1965; 38(11):1881-1886.
[118]Flynn JH, Wall LA. A quick, direct method for the determination of activation energy from thermogravimetric data. J Polym Sci Pol Lett,1966; 4(5):323-328.
[119]胡荣祖,高胜利,赵凤起,史启祯,张同来,张建军.热分析动力学.北京：科学出版社;2008.
[120]Malek J, Mitsuhashi T, Criado JM. Kinetic analysis of solid-state processes. J Mater Res,2001; 16(6):1862-1871.
[121]Kissinger HE. Reaction kinetics in differential thermal analysis. Anal Chem,1957; 29(11):1702-1706.
[122]Starink M. A new method for the derivation of activation energies from experiments performed at constant heating rate. Thermochim Acta,1996; 288(1): 97-104.
[123]Qi X, Deng Y, Zhong W, Yang Y, Qin C, Au C, et al. Controllable and large-scale synthesis of carbon nanofibers, bamboo-like nanotubes, and chains of nanospheres over Fe/SnO2 and their microwave-absorption properties. J Phys Chem C,2010; 114(2):808-814.
[124]Qi X, Ding Q, Zhong W, Au C-T, Du Y. Controllable synthesis and purification of carbon nanofibers and nanocoils over water-soluble NaNO3. Carbon,2013; 56(0): 383-385.
[125]Guo W, Liu C, Zhao F, Sun X, Yang Z, Chen T, et al. A novel electromechanical actuation mechanism of a carbon nanotube fiber. Adv Mater,2012; 24(39): 5379-5384.
[126]Hanus MJ, Harris AT. Synthesis of twisted carbon fibres comprised of four intertwined helical strands. Carbon,2010; 48(10):2989-2992.
[127]Hohenberg P, Kohn W. Inhomogeneous electron gas. Phys Rev,1964; 136(3B): B864-871.
[128]Kohn W, Sham LJ. Self-consistent equations including exchange and correlation effects. Phys Rev,1965; 140(4A):A1133-1138.
[129]谢希德,陆栋.固体能带理论：复旦大学出版社；1998.
[130]Perdew JP, Chevary JA, Vosko SH, Jackson KA, Pederson MR, Singh DJ, et al. Atoms, Molecules, Solids, and Surfaces:Applications of the generalized gradient approximation for exchange and correlation. Phys Rev B,1992; 46(11): 6671-6687.
[131]徐光宪,黎乐民.量子化学：基本原理和从头计算法：科学出版社；2004.
[132]Heitler W, London F. Wechselwirkung neutraler atome und homoopolare.1927.
[133]Perdew J, Wang Y. Accurate and simple analytic representation of the electron-gas correlation energy. Phys Rev B,1992; 45(23):13244-13249.
[134]Qin Y, Jiang X, Cui Z. Low-temperature synthesis of amorphous carbon nanocoils via acetylene coupling on copper nanocrystal surfaces at 468 K:A reaction mechanism analysis. J Phys Chem B,2005; 109(46):21749-21754.
[135]Shirakawa H, Iklda S. Infrared spectra of poly (acetylene). Polym J,1988; 2(2): 231-244.
[136]Wang Z. Transmission electron microscopy of shape-controlled nanocrystals and their assemblies. J Phys Chem B,2000; 104(6):1153-1175.
[137]Saveliev AV, Merchan-Merchan W, Kennedy LA. Metal catalyzed synthesis of carbon nanostructures in an opposed flow methane oxygen flame. Combust Flame, 2003; 135(1-2):27-33.
[138]Wang W, Yang K, Gaillard J, Bandaru P, Rao A. Rational synthesis of helically coiled carbon nanowires and nanotubes through the use of tin and indium catalysts. Adv Mater,2008; 20(1):179-182.
[139]Qi X, Zhong W, Deng Y, Au C, Du Y. Characterization and magnetic properties of helical carbon nanotubes and carbon nanobelts synthesized in acetylene decomposition over Fe-Cu nanoparticles at 450℃. J Phys Chem C,2009; 113(36): 15934-15940.
[140]Shaikjee A, Franklyn PJ, Coville NJ. The use of transmission electron microscopy tomography to correlate copper catalyst particle morphology with carbon fiber morphology. Carbon,2011; 49(9):2950-2959.
[141]李酽,朱晨,蔡菊芳.纳米晶的结构形貌控制及生长机理研究.材料导报,2003；17(06)：9-11.
[142]Niu W, Zheng S, Wang D, Liu X, Li H, Han S, et al. Selective synthesis of single-crystalline rhombic dodecahedral, octahedral, and cubic gold nanocrystals. J Am Chem Soc,2008; 131(2):697-703.
[143]Radi A, Pradhan D, Sohn Y, Leung KT. Nanoscale shape and size control of cubic, cuboctahedral, and octahedral Cu-Cu2O core-shell nanoparticles on si(100) by one-step, templateless, capping-agent-free electrodeposition. ACS Nano,2010; 4(3):1553-1560.
[144]Lu C, Prasad KS, Wu H-L, Ho J, Huang MH. Au nanocube-directed fabrication of au-pd core-shell nanocrystals with tetrahexahedral, concave octahedral, and octahedral structures and their electrocatalytic activity. J Am Chem Soc,2010; 132(41):14546-14553.
[145]Jin M, Zhang H, Wang J, Zhong X, Lu N, Li Z, et al. Copper can still be epitaxially deposited on palladium nanocrystals to generate core-shell nanocubes despite their large lattice mismatch. ACS Nano,2012; 6(3):2566-2573.
[146]Chen Q, Richardson NV. Surface facetting induced by adsorbates. Prog Surf Sci, 2003; 73(4-8):59-77.
[147]Newton MA, Belver-Coldeira C, Martinez-Arias A, Fernandez-Garcia M. Dynamic in situ observation of rapid size and shape change of supported Pd nanoparticles during CO/NO cycling. Nat mater,2007; 6(7):528-532.
[148]Tao F, Dag S, Wang LW, Liu Z, Butcher DR, Bluhm H, et al. Break-up of stepped platinum catalyst surfaces by high co coverage. Science,2010; 327(5967): 850-853.
[149]McKenna KP, Shluger AL. Shaping the morphology of gold nanoparticles by CO adsorption. J Phys Chem C,2007; 111(51):18848-18852.
[150]Kobayashi H, Yamauchi M, Kitagawa H, Kubota Y, Kato K, Takata M. Atomic-level Pd-Pt alloying and largely enhanced hydrogen-storage capacity in bimetallic nanoparticles reconstructed from core/shell structure by a process of hydrogen absorption/desorption. J Am Chem Soc,2010; 132(16):5576-5577.
[151]Small MW, Sanchez SI, Marinkovic NS, Frenkel AI, Nuzzo RG. Influence of adsorbates on the electronic structure, bond strain, and thermal properties of an alumina-supported pt catalyst. ACS Nano,2012; 6(6):5583-5595.
[152]Zhang R, Khalizov A, Wang L, Hu M, Xu W. Nucleation and growth of nanoparticles in the atmosphere. Chem Rev,2011; 112(3):1957-2011.
[153]Yang M, Jackson KA, Koehler C, Frauenheim T, Jellinek J. Structure and shape variations in intermediate-size copper clusters. J Chem Phys,2006; 124: 024308/1-6.
[154]Jiang M, Zeng Q, Zhang T, Yang M, Jackson KA. Icosahedral to double-icosahedral shape transition of copper clusters. J Chem Phys,2012; 136: 104501/1-8.
[155]Bell D, Sun Y, Zhang L, Dong L, Nelson B, Grutzmacher D. Three-dimensional nanosprings for electromechanical sensors. Sensor Actuat A-Phys,2006; 130: 54-61.
[156]Hu G, Nitze F, Barzegar HR, Sharifi T, Mikolajczuk A, Tai C-W, et al. Palladium nanocrystals supported on helical carbon nanofibers for highly efficient electro-oxidation of formic acid, methanol and ethanol in alkaline electrolytes. J Power Sources,2012; 209:236-242.
[157]Tang N, Zhong W, Gedanken A, Du Y. High magnetization helical carbon nanofibers produced by nanoparticle catalysis. J Phys Chem B,2006; 110(24): 11772-11774.
[158]Xie J, Sharma PK, Varadan V, Varadan V, Pradhan BK, Eser S. Thermal, raman and surface area studies of microcoiled carbon fiber synthesized by cvd microwave system. Mater Chem Phys,2002; 76(3):217-223.
[159]Chen X, Motojima S. Morphologies of carbon micro-coils grown by chemical vapor deposition. J Mater Sci,1999; 34(22):5519-5524.
[160]Motojima S, Asakura S, Hirata M, Iwanaga H. Effect of metal impurities on the growth of micro-coiled carbon fibres by pyrolysis of acetylene. Mater Sci Eng B, 1995; 34(1):L9-L11.
[161]毕辉,寇开昌,王召娣,王志超,张教强.石墨化对微螺旋炭纤维热氧化动力学的影响.新型炭材料,2009；(04)：364-368.
[162]Lin M, Tan JPY, Boothroyd C, Loh KP, Tok ES, Foo YL. Dynamical observation of bamboo-like carbon nanotube growth. Nano Lett,2007; 7(8):2234-2238.
[163]Mukhopadhyay K, Porwal D, Lal D, Ram K, Narayanmathur G. Synthesis of coiled/straight carbon nanofibers by catalytic chemical vapor deposition. Carbon, 2004; 42(15):3254-3256.
[164]Yang S, Chen X, Motojima S. Morphology of the growth tip of carbon microcoils/nanocoils. Diam Relat Mater,2004; 13(11-12):2152-2155.
[165]Rodriguez NM. A review of catalytically grown carbon nanofibers. J Mater Res, 1993; 8(12):3233-3250.
[166]Chen X, Yang S, Motojima S. Carbon nanocoils with changed coiling-chirality formed over Ni/molecular Sieves catalyst. J Mater Sci,2004; 39(9):3227-3233.
[167]Hanus MJ, MacKenzie KJ, King AAK, Dunens OM, Harris AT. Parametric study of coiled carbon fibre synthesis on an in situ generated H2S-modified Ni/Al2O3 catalyst. Carbon,2011; 49(13):4159-4169.
[168]In-Hwang W, Kuzuya T, Iwanaga H, Motojima S. Oxidation characteristics of the graphite micro-coils, and growth mechanism of the carbon coils. J Mater Sci,2001; 36(4):971-978.
[169]毕辉,寇开昌,张教强.螺旋炭纤维的研究进展.炭素技术,2006；(02)：23-28.
[170]Ren X, Zhang H, Cui Z. Acetylene decomposition to helical carbon nanofibers over supported copper catalysts. Mater Res Bull,2007; 42(12):2202-2210.
[171]Jian X, Jiang M, Zhou Z, Yang M, Lu J, Hu S, et al. Preparation of high purity helical carbon nanofibers by the catalytic decomposition of acetylene and their growth mechanism. Carbon,2010; 48(15):4535-4541.
[172]Jian X, Jiang M, Zhou Z, Zeng Q, Lu J, Wang D, et al. Gas-induced formation of cu nanoparticle as catalyst for high-purity straight and helical carbon nanofibers. ACS Nano,2012; 6(10):8611-8619.
[173]王凯.掺杂T-ZnO的制备与性能.西南交通大学硕士,2006.
[174]Jing L, Xu Z, Sun X, Shang J, Cai W. The surface properties and photocatalytic activities of ZnO ultrafine particles. Appl Surf Sci,2001; 180(3-4):308-314.
[175]Jeong S, Woo K, Kim D, Lim S, Kim JS, Shin H, et al. Controlling the thickness of the surface oxide layer on cu nanoparticles for the fabrication of conductive structures by ink-jet printing. Adv Funct Mater,2008; 18(5):679-686.
[176]Nakamura J, Uchijima T, Kanai Y, Fujitani T. The role of ZnO in Cu/ZnO methanol synthesis catalysts. Catal Today,1996; 28(3):223-230.
[177]王定川,简贤,朱俊廷,庞何苗,周祚万.热处理有机聚合物螺旋纤维制备螺旋炭纤维及其表征.功能材料,2012；(05)：576-578.
[178]Varadan VK, Varadan VV, Lakhtakia A. On the possibility of designing anti-reflection coatings using chiral composites. J Wave-Material Interaction, 1987; 2(1):71-81.
[179]Guire T, Varadan VV, Varadan VK. Influence of chirality on the reflection of EM waves by planar dielectric slabs. IEEE Trans Electromagn Compat,1990; 32(4): 300-303.
[180]Varadan VK, Lakhtakia A, Varadan VV. Propagation in a parallel plate waveguide wholly filled with a chiral medium. J Wave-Mater Interaction,1988; 3(4): 267-351.
[181]Tang N, Zhong W, Au C, Gedanken A, Yang Y, Du Y. Large-scale synthesis, annealing, purification, and magnetic properties of crystalline helical carbon nanotubes with symmetrical structures. Adv Fund Mater,2007; 17(9):1542-1550.
[182]Motojima S, Hoshiya S, Hishikawa Y. Electromagnetic wave absorption properties of carbon microcoils/pmma composite beads in W bands. Carbon,2003; 41(13): 2658-2660.
[183]Du J-H, Sun C, Bai S, Su G, Ying Z, Chenga H-M. Microwave electromagnetic characteristics of a microcoiled carbon fibers/paraffin wax composite in Ku band. J Mater Res,2002; 17(5):1232-1236.
[184]苟宇.聚苯胺纳米管的原位合成机理及电磁学性能研究.西南交通大学,硕士,2010.
[185]Whitby R, Fukuda T, Maekawa T, James S, Mikhalovsky S. Geometric control and tuneable pore size distribution of buckypaper and buckydiscs. Carbon,2008; 46(6): 949-956.
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