Silicene/poly(N-isopropylacrylamide) smart hydrogels as remote-controlled switches

Smart hydrogels with good flexibility and biocompatibility have been widely used. The common near infrared (NIR) photothermal agents are facing a trade-off between good photothermal-conversion efficiency and high biocompatibility. Therefore, developing new metal-free photothermal agents with low cost, high biocompatibility and excellent phase stability is still in urgent need. In this study, we successfully combined poly(N-isopropylacrylamide) (PNIPAM) with the two-dimensional (2D) silicene nanosheets via the in situ polymerization method. Attributed to the thermal-responsive nature of PNIPAM and the excellent photothermal properties of 2D silicene, the obtained silicene/PNIPAM composite hydrogels exhibited dual thermal and NIR responsive properties. This smart hydrogel showed rapid, reversible and repeatable NIR light-responsive behaviors. The volume of this smart hydrogels can shrink significantly under NIR irradiation and recover to its original size without the NIR irradiation. Remote near-infrared light-controlled microfluidic pipelines and electronic switches based on obtained silicene/PNIPAM composite hydrogels were also demonstrated. This work significantly broadens the application prospects of silicene-based hydrogels in remote light-controlled devices.(c) 2022 Published by Elsevier Inc.

Automated summary

In this study, a smart hydrogel was developed by combining poly(N-isopropylacrylamide) (PNIPAM) with two-dimensional (2D) silicene nanosheets. The resulting silicene/PNIPAM composite hydrogel exhibited dual thermal and near-infrared (NIR) responsive properties, with rapid, reversible, and repeatable NIR light-responsive behaviors. This smart hydrogel holds potential for applications in remote light-controlled devices.