Development of photo-responsive flexible nano actuator for peristeric movement

在DMF中合成了主链上含有4，4‘-二氨基偶氮苯(DAA)的光响应性聚酰胺酸(PAA)和聚酰亚胺(PI)凝胶，并用扫描显微镜光散射法(SMILS)研究了光照射对PAA和PI凝胶的影响。以1，3，5-三(4-氨基苯基)苯(TAPB)为交联剂，对4，4‘-(六氟异丙基)苯二酸酐(6FDA)、4，4’-氧基二苯二甲酸酐(ODPA)、均苯四甲酸二酸酐(PMDA)三种不同类型的酰胺酸齐聚物进行了端交联改性。在PAA(OAA(6FDA/DAA)(4/3)-ν-TAPB)凝胶中，SMILS揭示了偶氮苯从纳米反式到顺式的光异构化所引起的网格尺寸变化从2.1nm0.83 nm，与偶氮苯在光照射下分子长度的变化相对应。此外，宏观上发现这种直径为0.2 mm的棒状聚酰胺酸凝胶在蓝光照射下可以快速而急剧地偏转，而在可见光照射下可以变得可逆地变直。通过在聚合物网络的主链中引入刚性芳环，实现了各向同性聚合物凝胶棒的光致宏观弯曲。通过制备聚酰胺酸管，研制了一种新型的柔性纳米光致蠕变驱动器。

Photoresponsive poly(amide acid) (PAA) and polyimide (PI) gels consisting of 4, 4' diamino azobenzene (DAA) in backbone were synthesized in DMF, and mesh-size changes induced by photoirradiation were investigated by using scanning microscopic light scattering (SMILS). Three different kinds of amide acid oligomers derived from 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), 4,4'-oxydiphthalic anhydride (ODPA), pyromellitic dianhydride (PMDA), were end-crosslinked with trifunctional amine, 1,3,5-tris(4-aminophenyl)benzene (TAPB). In the case of PAA(OAA(6FDA/DAA)(4/3)-ν-TAPB) gels, SMILS has revealed that mesh size change due to the photoisomerization of azobenzene from nanoscopically trans-form to cis-form amounts to be from 2.1 to 0.83 nm, and corresponds to the change in molecular length of azobenzene upon photo-irradiation. Moreover, it was found macroscopically that this poly(amide acid) gel in a rod shape with a 0.2 mm diameter can be deflected quickly and sharply by blue laser irradiation and becomes straight reversibly by visible light irradiation. This photo-induced macroscopic bending of isotropic polymer gel rods was realized by introducing rigid aromatic rings into main chains of the polymer network. Novel flexible nano actuator for peristaltic motion induced by photoirradiation was developed by fabricating poly(amide acid) tube.