Preparation Of High Strength Self-wrinkling Hydrogel And Its Application In Sensor

Wrinkle exist widely in nature and give the subject unique properties by increasing extensibility or specific surface area.In recent years,due to the excellent performance of wrinkle,how to prepare and regulate artificial wrinkle has attracted extensive attention of researchers.With the in-depth study of wrinkle structure,it is found that most of the materials used to prepare wrinkle do not have biocompatibility,which limit its application in flexible sensors and biomedical fields.Hydrogel is a kind of flexible material with good biocompatibility,but the wrinkled hydrogel has poor mechanical properties and easily layered.In order to solve the above problems,this paper adopts soaking method to improve the mechanical properties of hydrogel,and systematically studies the control factors of hydrogel surface wrinkle,which is applied to 3D deformation and high sensitivity sensor parts.The results are as follows:1.Based on polyelectrolyte diffusion complexation strategy,high-strength polygonal wrinkle hydrogels and high-strength unidirectional ordered wrinkle hydrogels were prepared by three methods respectively,and various 3D shapes of hydrogels were prepared under control.Compared with previous studies,due to the increase of sacrificial bonds in hydrogels,the mechanical properties of hydrogels can be significantly improved by the three methods,with fracture strain up to 9000%,fracture stress up to 2.6 MPa and toughness up to 90 MJ/m³.This diffusion complexation strategy can be easily extended to different polyelectrolyte hydrogels,and due to the biocompatibility of the materials used,it is helpful to expand the application of pleated hydrogels in biomedical and tissue engineering fields.2.Based on Fe³⁺diffusion strategy,high strength hydrogels with multi-wrinkle structures were prepared by repeated pre-stretching and release method.The fracture stress of hydrogel can reach 2.15 MPa,the fracture strain can reach 3215%,and the toughness can reach 24 MJ/m³,these are superior to most previously reported wrinkle hydrogels.With the increase of wrinkle structure,the capacitance value and sensitivity of the capacitance sensor increased gradually.The sensitivity of the hydrogel with triple-wrinkle structure was330 times higher than that of the hydrogel with single-wrinkle structure.We also prepared a resistive sensor with triple-wrinkle structure and its sensitivity can reach 2.64,which can accurately monitor human behavior.The multi-wrinkle structure provides an effective and feasible scheme for the fabrication of ultra-high sensitivity flexible sensors.