폴리아크릴아마이드/알지네이트 상호침투 고분자 망상구조 하이드로겔의 합성과 응용

Abstract

Hydrogels crosslinked into three-dimensional structures with hydrophilic polymer chains have been studied as an attractive platform material in the biomedical applications as a material with biocompatibility and high water content characteristics. In particular, hydrogels have been applied to soft sensors and actuators by taking advantage of excellent transparency and reversible swelling and shrinkage properties by water. However, conventional hydrogels are limited in their application range due to weak mechanical properties. Therefore, recent studies are being conducted to increase the mechanical strength of hydrogels. We synthesized tough hydrogels with an interpenetrating polymer network (IPN) structure composed of covalent crosslinked polyacrylamide and ionic crosslinked alginate. In present work, we designed a plasmonic sensor and a water-responsive actuator based on these hydrogels. We developed a plasmonic sensor for bromide based on these IPN hydrogel embedded with silver nanoprisms. This sensing platform is based on transparency of hydrogel and localized surface plasmon resonance (LSPR) properties of Ag nanoprisms with sharp tips. The Ag nanoprisms immobilized inside the hydrogel were stable and retained their unique LSPR properties over a long period of time. Also, we developed an actuator by applying that Alginate/PAAm IPN hydrogel reversibly shows swelling and shrinkage phenomena only by water. The prepared hydrogel actuator operates based on shape memory properties that respond to water due to ionic crosslinks that can be formed reversibly and hydrogen bonds between hydrophilic polymer chains. The hydrogel actuator developed in this study shows a fast operating speed of less than 1 minute and repeated use test results maintaining almost 100%. Therefore, we believe that the proposed polyacrylamide/alginate IPN hydrogel has advantages over conventional hydrogels in sensor and actuator applications.