Photoinduced deformation of amorphous polyimide enabled by an improved azobenzene isomerization efficiency

Abstract

Photodeformable azobenzene-containing polyimides (azo-PIs) have attracted attention due to their photo-response, good mechanical property, and thermal stability. The deformation principle of azo-PIs mainly depends on the accumulation of conformational changes...

Flexible Azo-Polyimide-Based Smart Surface with Photoregulatable Surface Micropatterns: Toward Rewritable Information Storage and Wrinkle-Free Device Fabrication

“…Similarly, the k tc values for trans−cis and cis−trans isomerization of different azo-PIs in the film state are calculated to be 0.064, 0.062, and 0.042 s −1 and 0.092, 0.072, and 0.068 s −1 , respectively (corresponding to the slope of the lines in Figure 6c,d), which are similar to those from previous works (Figure 6c,d and Table S2). 44,63 It is worth mentioning that the trans− cis and cis−trans isomerization rates of the azo-PI in the film state are lower than those of the solution state, which was due to the existence of strong intermolecular forces and steric hindrance in the solid film, which inhibited the isomerization of the azobenzene chromophores. 5,63 As a proof of concept regarding potential applications, this photoresponsive azo-PI surface can be used for rewritable information storage or wrinkle-free device fabrication.…”

“…Zhang et al synthesized a novel photoresponsive polymer with enhanced mechanical properties and photohealing ability by introducing a long hexamethylene spacer and a long n -hexadecyl tail into the azobenzene-containing side chain . In addition, different azobenzene side-chain polymers and copolymers were also used to fabricate smart surfaces for applications in information storage, sensors, and light-responsive soft photonics along with microfluidic devices. ,,, Recently, azobenzene main-chain polymers, such as azobenzene-containing polyimide (azo-PI), with excellent comprehensive performance have been used in the fabrication of smart soft actuators. − Although the light responsiveness of the azo-PI with different chain structures has been systematically researched, ,, the azobenzene main-chain polymers utilized for the fabrication of smart surfaces with photoregulatable surface morphology or photoswitchable optical properties have rarely been reported.…”

High Mechanical Strength and Multifunctional Microphase‐Separated Supramolecular Hydrogels Fabricated by Liquid‐Crystalline Block Copolymer

“…The light absorption coefficient of Azobenzene molecules at 365 nm was as high as 99%, and most of the light would be absorbed by Azobenzene molecules on the surface, so the shrinkage of the filamentous sample mostly occurred on the illuminated side. [ 57 ] Because only one side of the filamentous sample exposed to light contracts, the filamentous sample tends to bend in the direction facing the light. Meanwhile, the fracture stress of P(AM‐G)‐ b ‐PAzo 15 hydrogel decreased gradually with the increase of UV irradiation time (Figure S20, Supporting Information).…”

Shape‐Morphing Liquid‐Crystal polymers

“…Light is commonly used as a wireless stimulus for intelligent materials, which have the advantages of high temporal and spatial resolution. [22,[51][52][53][54][55][56][57][58] In light-responsive materials, light can trigger macroscopic morphing via the shape memory effect, inequivalent thermal strain, water desorption, changes in surface tension, phase transition and so on. In fact, the critical factor in realizing macroscopic morphing is to convert light energy into mechanical energy of materials.…”