Synthesis Of Diacrylate Ionic Liquid/polymer And Its Application In Sensing

Hydrogels could generate electrical signals due to structural changes when subjected to external forces or deformation,and can be used as conductive materials for the preparation of strain sensors and are widely used in fields such as health monitoring and electronic skin.The development and application of hydrogels are limited by the loss of flexibility due to the easy evaporation of water inside the material during use.Ionic gels are obtained by polymerization of ionic liquids with polymers,and are widely studied and applied for their excellent plasticity,good electrical conductivity and environmental stability.During the preparation process of ionic gels,the poor compatibility between the ionic liquid and the polymer network could affect their mechanical strength and transparency,and even lead to leakage of the ionic liquid,which will limit their further application.Therefore,in this paper,a diacrylate ionic liquid is synthesized and crosslinked with polymer chains to synthesize ionic gels with excellent properties such as stretchability,electrical conductivity and thermal stability,which can be applied to the assembly testing of wearable capacitive sensors and supercapacitors.The main research is as follows:(1)An EO@DAIL gel with stretchability and electrical conductivity was prepared by grafting the prepared diacrylate ionic liquid(DAIL)onto the molecular chain of EOEOEA polymer by light curing using ethoxyethoxyethyl acrylate(EOEOEA)as the base material.The introduction of the ionic liquid imparted good thermal stability to the EO@DAIL gels,which were able to be stored for a long time in different ambient temperatures.The mechanical properties and ionic conductivity of EO@DAIL were effectively improved compared to the gel EO without DAIL addition,allowing it to be used as a conductive element for the assembly of capacitive sensors.However,due to the poor transparency,adhesion and self-healing properties of the prepared EO@DAIL,the performance of the assembled capacitive sensors was average.(2)To address the deficiencies in the previous chapter,this chapter uses the lithium salt Li TFSI and ethanol to modify EO@DAIL,so as to prepare and obtain EO@DAIL@Li gels with good transparency,adhesion and self-healing properties.The synthesized EO@DAIL@Li has excellent mechanical properties,excellent self-healing properties and good thermal stability,and can be stored and used for a long time at both low temperature(-20°C)and high temperature(60°C),and can maintain the electrical conductivity at different temperatures.Due to the presence of a large number of active functional groups on the surface of EO@DAIL@Li,it is able to produce strong physical and chemical cross-linking with different material surfaces,thus providing high adhesion to various material surfaces.(3)Based on the previous study,the assembled capacitive sensor(ECS)with EO@DAIL@Li gel as the core component exhibits a wide working range and high sensitivity,capable of generating signal changes for different strains and applied to realtime monitoring of human motion,and even capable of generating corresponding signal changes for small movements generated by the human body(e.g.,swallowing,pulse).In addition,the flexible supercapacitor(ISC)assembled with EO@DAIL@Li gel as the electrolyte and graphene/filter paper film as the electrode can be bent and folded at will with high specific capacitance and good cycling stability,and the ISC series combination is capable of powering LED and electronic meters.The results show that EO@DAIL@Li gel has a promising application prospect in flexible wearable sensors and energy storage.