Stretching and Bending of Azopolymer Nanorod Arrays via Laser-Induced Photo-Fluidization

Abstract

Regular arrays of anisotropic polymer nanomaterials have attracted great attention because of their unique properties and various applications such as solar cell devices, sensors, and supercapacitors. The control of the shape manipulation and tailored properties of individual polymer nanomaterials in arrays, however, remains a great challenging task. In this work, we demonstrate a versatile approach to fabricate elliptical and bent polymer nanorod arrays through laser-induced photo-fluidization of azobenzene-containing polymers (azopolymers). Ordered anodic aluminum oxide (AAO) membranes are used as templates for generating azopolymer nanorod arrays via a solvent vapor annealing-induced wetting method. After being released from the AAO templates and shone by linearly polarized lights, the nanorod arrays can be transformed into anisotropic nanostructures, driven by the trans-to-cis and cis-to-trans isomerization of the azobenzene groups in the azopolymers. Depending on whether the laser beam is shone at normal or tilt angles of incidence, elliptical or bent nanorod arrays can be prepared, respectively. The deformation degrees and water wettabilities of the nanorod arrays can be varied by changing the illumination times. This study reports a beneficial route to prepare ordered arrays of anisotropic polymer nanostructures for advanced applications.

Advancing Nanopore Technology: Anodic Aluminum Oxide Membranes with Anisotropic Pores through Controlled Stretching for Applications in Nanopatterning

“…The morphological results, as presented in Figure b–g, demonstrate that more elliptical concave structures are formed near the crack point. To analyze the shape transformation more quantitatively, the values of aspect ratio and circularity are also calculated, as displayed in Figure h,i; the aspect ratio is determined by dividing the long axis by the short axis of the elliptical concaves, and the circularity and aspect ratio are inversely related . The results show that the aspect ratios decrease as the distances from the cracking site increase, while the circularities increase.…”

“…To analyze the shape transformation more quantitatively, the values of aspect ratio and circularity are also calculated, as displayed in Figure 4h,i; the aspect ratio is determined by dividing the long axis by the short axis of the elliptical concaves, and the circularity and aspect ratio are inversely related. 57 The results show that the aspect ratios decrease as the distances from the cracking site increase, while the circularities increase. Therefore, it can be inferred that the greatest deformation and stretching occur at the cracking site because of the highest stress, resulting in the most significant changes in the concave structures.…”

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

“…39 application in wettability-controlled coatings via laser-induced photofluidization of azobenzene side-chain polymers. 40 Zhang et al synthesized a novel photoresponsive polymer with enhanced mechanical properties and photohealing ability by introducing a long hexamethylene spacer and a long nhexadecyl tail into the azobenzene-containing side chain. 32 In addition, different azobenzene side-chain polymers and copolymers were also used to fabricate smart surfaces for applications in information storage, sensors, and lightresponsive soft photonics along with microfluidic devices.…”

“…Huang et al formulated high-performance smart adhesives by using small molecule azo compounds as photoswitches, which exhibit visible-light-controlled reversible photochemical crystal–liquid transitions . Ho et al presented a versatile strategy of preparing anisotropic polymer nanorod arrays for potential application in wettability-controlled coatings via laser-induced photofluidization of azobenzene side-chain polymers . 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 .…”