Red-Light-Controllable Liquid-Crystal Soft Actuators via Low-Power Excited Upconversion Based on Triplet鈥揟riplet Annihilation

详细信息    查看全文

• 作者：Zhen Jiang ; Ming Xu ; Fuyou Li ; Yanlei Yu
• 刊名：Journal of the American Chemical Society
• 出版年：2013
• 出版时间：November 6, 2013
• 年：2013
• 卷：135
• 期：44
• 页码：16446-16453
• 全文大小：421K
• 年卷期：v.135,no.44(November 6, 2013)
• ISSN：1520-5126

文摘

A red-light-controllable soft actuator has been achieved, driven by low-power excited triplet鈥搕riplet annihilation-based upconversion luminescence (TTA-UCL). First, a red-to-blue TTA-based upconversion system with a high absolute quantum yield of 9.3 卤 0.5% was prepared by utilizing platinum(II) tetraphenyltetrabenzoporphyrin (PtTPBP) as the sensitizer and 9,10-bis(diphenylphosphoryl)anthracene (BDPPA) as the annihilator. In order to be employed as a highly effective phototrigger of photodeformable cross-linked liquid-crystal polymers (CLCPs), the PtTPBP&BDPPA system was incorporated into a rubbery polyurethane film and then assembled with an azotolane-containing CLCP film. The generating assembly film bent toward the light source when irradiated with a 635 nm laser at low power density of 200 mW cm^鈥? because the TTA-UCL was effectively utilized by the azotolane moieties in the CLCP film, inducing their trans鈥?i>cis photoisomerization and an alignment change of the mesogens via an emission鈥搑eabsorption process. It is the first example of a soft actuator in which the TTA-UCL is trapped and utilized to create photomechanical effect. Such advantages of using this novel red-light-controllable soft actuator in potential biological applications have also been demonstrated as negligible thermal effect and its excellent penetration ability into tissues. This work not only provides a novel photomanipulated soft actuation material system based on the TTA-UCL technology but also introduces a new technological application of the TTA-based upconversion system in photonic devices.