Research progress and application in ionic conductive hydrogels for flexible pressure and strain sensors

Flexible pressure and strain sensors have attracted increasing attention with the rapid development of medical and electronic interconnection.Ionic conductive hydrogels demonstrate more potential for flexible electronics sensors because of their excellent physicochemical properties such as biomimetic structures， suitable mechanical properties， and excellent biocompatibility. The classification， preparation methods， characteristics of ionic conductive hydrogels，and their applications in flexible pressure and strain sensors were reviewed. First， the sensing modes of ionic conductive hydrogels in pressure and strain sensors were introduced. Then， according to the different conductive principles， they were divided into three categories：metal ion hydrogels， ionic liquid hydrogels， and polyelectrolyte hydrogels. Their applications and research progress in pressure and strain sensors were systematically introduced from synthesis methods， performance characteristics，and improvement methods.Their potential application prospects and development trends were analyzed. The current challenges were summarized and prospects were made. It was believed that ionic conductive hydrogels still have great exploration space and application potential in intelligent flexible sensing.