High Stability Self-healing Flexible Conductive Films Based On Nanofibers

As the best substitute for indium tin oxide(ITO)electrodes,silver nanowires have excellent application prospects in the fields of optoelectronic devices such as solar cells,electromagnetic shielding,transparent heaters,and sensors.Currently,template method,electrochemical method,wet chemical method and polyol method are commonly used to synthesize silver nanowires,but these processes have obvious disadvantages,such as low conductivity,poor stability,high production cost,and low repetition rate.And with the development of flexible optoelectronic devices,higher and higher requirements have been put forward for its additional functions,such as self-repair and degradability.In order to solve these problems,this paper uses electrospinning to prepare a highly conductive and transparent silver nanowire network based on nanofibers,and combines it with a self-healing elastomer to prepare a flexible conductive film with self-healing function.The main research contents are as follows:(1)The process of preparing silver nanowires by electrospinning was improved by wet treatment,and a silver nanowire network with high transparency and high conductivity was prepared.The diameter of silver nanowires is concentrated in 150-200 nm,with high aspect ratio,smooth surface,highly integrated,dense and uniform characteristics,and has a light transmittance of up to 95% at 550 nm.(2)Polydimethylsiloxane(PDMS)is used as the skeleton,through condensation polymerization with 4,4'-methylene bis(phenyl isocyanate)(MDI)and isophorone diisocyanate(IPDI)A PDMS-MDI-IPDI elastomer with excellent transparency,stretchability and selfhealing properties was prepared by reaction,and the effect of different ratios of MDI and IPDI on its properties was studied.It is found that as the proportion of IPDI increases,the fracture strain and self-healing properties of the elastic film increase,but the mechanical properties of the film decrease.When the ratio of MDI to IPDI is 4:6,the elastic film has the best mechanical properties(the fracture strain is 757%,the Young's modulus is 0.27MPa),and the self-healing performance(the fracture strain repair efficiency reaches 85% after 48 hours).(3)A flexible conductive film with self-healing function was prepared by combining silver nanowires with self-healing elastomers.The effects of different silver nanowire mass densities on the optical and electrical properties,mechanical properties,stability and self-repairing properties of the composite film were discussed.The results show that when the silver nanometer mass is 0.7mg/cm2,the self-healing flexible conductive film has the best photoelectric performance(the light transmittance at 550 nm is 85%,the sheet resistance value is 0.42?/sq,and the quality factor(Fo M)is 897),Mechanical properties(tensile fracture strain is 824%,fracture energy is 1.52MPa),stability(cyclic tensile-release resistance change rate is stable at 0-0.8,and it has excellent electrical conductivity when placed at 80°C for 20 days),self-repair Performance(without external interference after 48 hours of self-repair,the mechanical performance recovery efficiency reaches 85%,after 24 hours of self-repair,the electrical performance is basically completely restored).