나노 박막 전사를 위한 스마트 하이드로젤 접착필름

Abstract

Nanotransfer printing (nTP) is one of the most promising nanofabrication techniques for the development of emerging flexible optoelectronic and biomedical devices because it enables the formation of functional nanomembranes and materials on diverse unconventional substrates. However, studies on the smart, stimuli-responsive adhesives that can be utilized for the nTP have not been fully explored so far, and require further developments. Here, we present wet-responsive and biocompatible smart hydrogel adhesives that exhibit an actively-controllable, switchable and reversible adhesion based on hydration-triggered microscopic- and macroscopic shape reconfigurations of the adhesives for a simple and efficient nTP. The smart hydrogel adhesive exhibits a superior adhesion strength in the dry state. When the adhesive is exposed to water, a hydration-induced shape transformation of the nanostructures and a macroscopic film bending occur, switching the adhesion off with extremely high adhesion switching ratio (>7000). With these smart adhesion properties, the reconfigurable hydrogel adhesives enable transfer printing of diverse semiconducting and metallic nanomembranes on arbitrary substrates. We also demonstrate that the wet-responsive and reconfigurable hydrogel adhesives can be employed for the transfer printing of a nanocrack-based strain sensor onto a bovine eye.