Hur, Jung Park, Hwaeun Oh, Hyeongsu Jeong, Sujin Cho, Jinhan Lee, Jonghwi Chung, Seungjun Hong, Yongtaek Son, Jeong Gon 2025-01-07T02:30:30Z 2025-01-07T02:30:30Z 2024-12-30 2025-02 0935-9648 https://pubs.kist.re.kr/handle/201004/151473 Stretchable devices, garnering increasing attention as next-generation form factors, have a crucial problem in that vertical contraction occurs during stretching, causing image distortion of stretchable displays and discomfort in skin-attached devices. Previous structural strategies to mitigate vertical contraction, such as auxetic reentrants and wrinkles, suffer from the drawback that their structure becomes visible during stretching. In this study, this issue is addressed by unidirectionally aligning nanoscopic cylinders within block copolymer elastomer films. Employing a shear-rolling process at high temperatures on thick films of polystyrene-block-polyisobutylene-block-polystyrene thermoplastic elastomers, macroscopic mechanical anisotropy is achieved, resulting in completely transparent and monotonically stretchable substrates devoid of vertical or depth distortion during deformation. Significantly, the unidirectional orientation of high-modulus cylindrical nanostructures induces macroscopic mechanical anisotropy with a modulus ratio exceeding five times. While the Poisson's ratio of conventional elastic materials hovers around approximate to 0.5, this mechanical anisotropy minimizes vertical contraction, yielding a Poisson's ratio below 0.07. Moreover, owing to the negligible size of the nanocylinders compared to visible-light wavelengths, the substrate can be monotonically uniaxially stretched while maintaining high transmittance without introducing distortions, surface undulations, or haziness, resulting in distortion-free stretchable substrates. English WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Fully Transparent and Distortion-Free Monotonically Stretchable Substrate by Nanostructure Alignment Article 10.1002/adma.202414794 1 Advanced Materials, v.37, no.6 Advanced Materials 37 6 Y scie scopus 001375808800001 2-s2.0-85211780110 Chemistry, Multidisciplinary Chemistry, Physical Nanoscience & Nanotechnology Materials Science, Multidisciplinary Physics, Applied Physics, Condensed Matter Chemistry Science & Technology - Other Topics Materials Science Physics Article BLOCK-COPOLYMERS POISSONS RATIO DENSITY MULTIPLICATION MECHANICAL-PROPERTIES PATTERNS GRAPHOEPITAXY ORIENTATION SHEAR-ROLLING PROCESS stretchable devices stretchable display stretchable transparent substrate zero Poisson`s ratio distortion-free substrate