Preparation And Properties Of Conductive Epoxy Resin Containing Deep Eutectic Solvent

As an important branch of wearable electronic products,flexible pressure sensors have huge potential for development in fields such as medical,health,and artificial intelligence due to their high sensitivity,high elasticity,fast response ability,and accurate measurement of pressure distribution information compared to traditional sensors.Among them,conductive epoxy resin materials have developed rapidly in recent years because they can simultaneously balance mechanical and electrical properties.The demand for conductive epoxy resin systems in semiconductor and other applications is gradually increasing.Conductive epoxy resin is a composite material formed by combining an epoxy resin matrix with different conductive fillers,with the primary purpose of adding a second conductive phase to the epoxy resin.Currently,there are two types: electronic conductive epoxy resin containing electronic conductor fillers such as carbon nanotubes,graphene,and metals,and ion conductive epoxy resin containing ion conductor fillers.The problem with electronic conductive epoxy resin is that the fillers tend to agglomerate,randomly distribute,and have weak interfacial interactions in the epoxy resin matrix,which reduces the transparency and mechanical properties of the epoxy resin.The problem with ion conductive epoxy resin is poor compatibility and leakage due to the polarity difference between the ion dopant and the epoxy resin matrix.To solve the problems in the conductive epoxy resin mentioned above,we innovatively introduced a green and environmentally friendly class of ionic liquid,deep eutectic solvents(DESs),into the epoxy resin matrix in a copolymerization manner and synthesized a curing agent BI-D400,which increased the elasticity of the epoxy resin.The resulting conductive epoxy resin has high elasticity,high mechanical properties,high stability,high transparency,and conductivity,which can be applied in the field of flexible pressure sensors.By designing the DESs,we have given the conductive epoxy resin good adhesion and self-healing properties.The research content of this paper is as follows:Firstly,a curing agent BI-D400 was synthesized using polyether amine D400 as the main chain,and a DESs was prepared using tetrabutylammonium chloride(TBAC)as the hydrogen bond donor.The DESs was copolymerized with hydrogenated bisphenol A type epoxy resin ST3000 and curing agent BI-D400,and five proportions of conductive epoxy resin were prepared by adjusting the content of DESs in the resin matrix.The successful synthesis was demonstrated through basic structure characterization and microstructure characterization.The conductive epoxy resin was tested for optical properties,mechanical properties,and conductivity,and it was shown to retain good mechanical properties of the epoxy resin,as well as good elasticity and electrochemical stability.It has great potential in the field of flexible pressure sensors.Secondly,a type of DESs was prepared by using hydroxyethyl acrylate(HEA)as the hydrogen bond donor,which was co-polymerized with epoxy resin matrix ST3000 and curing agent BI-D400 to produce four ratios of conductive epoxy resins by varying the content of DESs.The successful synthesis of the conductive epoxy resin was confirmed by structural and morphological characterization.The conductive epoxy resin was then tested for optical properties,mechanical properties,electrical conductivity,adhesion properties,and self-healing performance.Results showed that the conductive epoxy resin retained the good mechanical properties of epoxy resin,while also exhibiting good elasticity,adhesion properties,and electrochemical stability,and a sensitive and stable response to external pressure due to the introduction of metal coordination.Furthermore,the conductive epoxy resin exhibited good self-healing performance.The prepared conductive epoxy resin can be applied in the field of flexible pressure sensors.