Fabrication, Structural Characterization, and Applications of Langmuir and Langmuir-Blodgett Films of a Poly(azo)urethane
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- 作者：Priscila Alessio ; Daniele M. Ferreira ; Aldo E. Job ; Ricardo F. Aroca ; Antonio Riul ; Jr. ; Carlos J. L. Constantino ; Eduardo R. Pé ; rez Gonzá ; lez
- 刊名：Langmuir
- 出版年：2008
- 出版时间：May 6, 2008
- 年：2008
- 卷：24
- 期：9
- 页码：4729 - 4737
- 全文大小：844K
- 年卷期：v.24,no.9(May 6, 2008)
- ISSN：1520-5827
文摘
The synthesis of a poly(azo)urethane by fixing CO2 in bis-epoxide followed by a polymerization reaction with anazodiamine is presented. Since isocyanate is not used in the process, it is termed "clean method" and the polymersobtained are named "NIPUs" (non-isocyanate polyurethanes). Langmuir films were formed at the air-water interfaceand were characterized by surface pressure vs mean molecular area per mer unit (
-A) isotherms. The Langmuirmonolayers were further studied by running stability tests and cycles of compression/expansion (possible hysteresis)and by varying the compression speed of the monolayer formation, the subphase temperature, and the solvents usedto prepare the spreading polymer solutions. The Langmuir-Blodgett (LB) technique was used to fabricate ultrathinfilms of a particular polymer (PAzoU). It is possible to grow homogeneous LB films of up to 15 layers as monitoredusing UV-vis absorption spectroscopy. Higher number of layers can be deposited when PAzoU is mixed with stearicacid, producing mixed LB films. Fourier transform infrared (FTIR) absorption spectroscopy and Raman scatteringshowed that the materials do not interact chemically in the mixed LB films. The atomic force microscopy (AFM) andmicro-Raman technique (optical microscopy coupled to Raman spectrograph) revealed that mixed LB films presenta phase separation distinguishable at micrometer or nanometer scale. Finally, mixed and neat LB films were successfullycharacterized using impedance spectroscopy at different temperatures, a property that may lead to future applicationas temperature sensors. Principal component analysis (PCA) was used to correlate the data.
-A) isotherms. The Langmuirmonolayers were further studied by running stability tests and cycles of compression/expansion (possible hysteresis)and by varying the compression speed of the monolayer formation, the subphase temperature, and the solvents usedto prepare the spreading polymer solutions. The Langmuir-Blodgett (LB) technique was used to fabricate ultrathinfilms of a particular polymer (PAzoU). It is possible to grow homogeneous LB films of up to 15 layers as monitoredusing UV-vis absorption spectroscopy. Higher number of layers can be deposited when PAzoU is mixed with stearicacid, producing mixed LB films. Fourier transform infrared (FTIR) absorption spectroscopy and Raman scatteringshowed that the materials do not interact chemically in the mixed LB films. The atomic force microscopy (AFM) andmicro-Raman technique (optical microscopy coupled to Raman spectrograph) revealed that mixed LB films presenta phase separation distinguishable at micrometer or nanometer scale. Finally, mixed and neat LB films were successfullycharacterized using impedance spectroscopy at different temperatures, a property that may lead to future applicationas temperature sensors. Principal component analysis (PCA) was used to correlate the data.