Preparation Of Functional Rubber Materials Based On Iontronic Sensing Mechanism And Application In Electronic Skin

Flexible pressure sensors have attracted much attention because of their simple preparation methods,abundant raw materials,good mechanical properties,and high sensitivity.Among them,the iontronic flexible pressure sensors based on ionic electrical double layer(EDL)interface capacitive sensing have attracted extensive researches for high sensitivity,low noise impact,and response to both static and dynamic stimuli.Pressure sensing capability is one of the basic and powerful functions of human skin,and various electronic skins have been developed to mimic the tactile function of human skin.However,the current electronic skins are basically flat film-like devices,which are attached to human skin or target objects,using their flexible and stretchable properties to achieve limited deformation.This method is difficult to achieve full-coverage tactile sensing for objects with curved surfaces.Based on the principle of iontronic flexible pressure sensing,an electronic skin with full-coverage pressure sensing was proposed via material modification and electrode design.The main research work is as follows.1.Construction of ionic rubber system:Modification of polydimethylsiloxane(PDMS).Organic electrolyte was added to PDMS and doped with fumed silica to make it have iontronic conductivity.The mechanical and electrical properties of the material were investigated by comparing the organic electrolyte content,fumed silica content,and surface roughness.Finally ionic rubber with the mass ratio of PDMS,organic electrolyte and fumed silica at 2:1:0.3 was prepared,with Young’s modulus of 1.1 MPa.On this basis,the resin electrode model was fabricated through 3D printing,and then coated with appropriate conductive silver paste into the groove,providing electrical conductivity.Integrating with the ionic rubber,it became an iontronic flexible pressure sensor with the sensitivity of 1.46n F/k Pa/cm~2,and the pressure response time and minimum resolution are 25 ms and 9.61 Pa respectively.2.Design and application of conformal electronic skin:A fingertip-shaped iontronic sensing conformal e-skin was prepared using the castability of ionic rubber and the advantages of 3D printing.The application tests of human pulse detection and shape recognition were conducted on the conformal electronic skin,which proved that the sensor of this structure can solve the problems of overlapping,missing areas,and inability to achieve full haptic coverage in the current electronic skin fitting process.