Novel synthesis of PVA/NaCl hydrogel for reversible thermochromism

Abstract

Hydrogel is a three-dimensional network which contains a high water content. It is widely applied to numerous fields such as health care, architecture and agriculture by virtue of excellent biocompatibility, simple preparation method and proper mechanical properties. Functional modification on hydrogels affords special physical and chemical properties which further spans their applications. Herein we report a novel strategy to prepare temperature-sensitive compound hydrogel using polyvinyl alcohol (PVA) and NaCl as raw materials, and borax as the crosslinking agent. It is found that the temperature response characteristic can be well realized by the variational solubility of NaCl under different temperatures. That is, these PVA/NaCl hydrogels present white at low temperature while they become transparent when temperature rise. In addition, the higher NaCl content is, the faster color changes.