Photodeformable Azobenzene-Containing Polyimide with Flexible Linkers and Molecular Alignment

Abstract

Azobenzene-containing polyimides (azo-PIs) as photodeformable materials have attracted scientific attention in view of combining photoresponse and high performance (such as excellent mechanical and thermal properties). In the previously reported photodeformation of azo-PIs, polarized blue–green light was utilized to produce concerted motion of azobenzene moieties based on the mechanism of photoinduced reorientation. Herein, we explored a designed azo-PI undergoing photodeformation upon unpolarized light irradiation. The azo-PI film aligned by the hot-stretching process exhibited fast and reversible bending behavior under alternate ultraviolet (UV) and visible (vis) light irradiation, indicating the efficient nano-to-macroscopic propagation of molecular deformation of azobenzene. Besides, the aligned azo-PI film even bent in hot water (80 °C) and hot silicone oil (100 and 120 °C) with UV light irradiation.

Multi-photoresponsive triphenylethylene derivatives with photochromism, photodeformation and room temperature phosphorescence

“…[11][12][13][14][15][16] This reversible photoisomerization as photochemical driving force can result in a photodeformable property in some cases, demonstrating the double switch of color and shape under light stimulus. [17][18][19][20][21][22][23] It can be further optimized by the aid of a polymer matrix. [24][25][26][27][28][29][30][31] However, the photoluminescence property is seldom connected with these photoswitchable properties, because of the possible energy loss in photochromic and photodeformable processes.…”

One‐Pot Synthesis of Melt‐Processable Supramolecular Soft Actuators

“…Stimuli‐responsive liquid crystal elastomers (LCEs) are capable of performing fast and reversible actuation, and have readily been applied as soft actuators[ 1 , 2 , 3 , 4 , 5 ] in applications such as soft robotics,[ 6 , 7 ] smart textiles,[ 8 , 9 ] microfluidics, [10] and artificial muscles. [ 11 , 12 ] A macroscopic mechanical response arises from an ordered to less ordered state in the covalently cross‐linked network thermosets at the isotropization temperature ( T i ).…”

Electrospun Azo‐Cellulose Fabric: A Smart Polysaccharidic Photo‐Actuator

“…Recently, photo-actuation of non-liquid-crystalline polymers containing azobenzene under specific conditions has been also reported. [33][34][35] Although these azobenzene-containing polymers possess great photo-deformable effects in the form of their crosslinked or networked gels or films, there are some fundamental drawbacks for practical applications such as artificial muscles in soft robotics because of their weak mechanical strength and thermal resistance. Therefore, designing polymeric photo-actuators in other forms than gels or films is of great importance.…”