Controlled Fabrication of 3D Chiral Microwrinkles via Asymmetrical and Biaxial Bucklings. (10th April 2019)

• Record Type: Journal Article
• Authors: Hwang, Myonghoo; Kim, Changho; Kim, Jinwoo; Son, Jeong Gon; Yeom, Bongjun
• Is Part Of: Advanced functional materials. Volume 29:Number 29(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-04-10
• Subjects: bucklings -- chirality -- handedness -- microwrinkles; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.201808979
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Nano‐ and microsized chiral materials are receiving significant attention because of their unique characteristics, which include chiroptical activities and enantioselective interactions with living materials. However, the realization of chiral morphologies in such small‐scale materials has been an issue because of the complicated fabrication methods and limited material selection. In this study, a facile and reproducible method is developed for fabricating 3D chiral microwrinkles with twisted shapes by asymmetric and biaxial buckling. Soft polydimethylsiloxane (PDMS) substrates are asymmetrically stretched with angled biaxial strains and exposed to UV/ozone to prepare hard silica layers on top of the PDMS substrates to induce microwrinkles. The chiral shapes are controlled by changing the angle (θ) between the two strain axes and the UV/ozone exposure times ( t 1, t 2 ) in each stage of buckling. The 3D chiral microwrinkles are shaped like "fusilli pasta" and occupy an area of 1.5 cm × 1.5 cm. The patterned area can be easily scaled, and no innate chiral biomaterial is necessary. This method could be widely extended to the fabrication of diverse types of chiral materials for advanced optical and bio‐applications. Abstract : "Fusilli" shaped 3‐dimensional chiral microwrinkles are fabricated by asymmetric and biaxial bucklings in sequence. The handedness and shapes are finely controlled based on the optimization of the biaxial strain angle, UV/ozone exposure times, and sequences in two buckling stages. This facile method is accomplished without the use of any innate chiral biomaterials, and is adaptable to other artificial chiral materials.