Fabrication And Properties Of Polymer-based Conductive Film

As an important component of flexible electronic devices,the flexible transparent conductive film is widely used in outdoor heating materials,electric heating devices,automobile deicing appliances and other fields due to its advantages of high electrothermal conversion rate,flexibility,and high electric heating temperature.At present,ITO(indium tin oxide)is the main material for the preparation of transparent conductive films.However,the drawbacks of ITO(e.g.,brittle nature,high cost and resource scarcity)and the complex preparation process of TCF limit the massive production and further application of TCF.Therefore,new alternative materials have been explored,in which the combination of carbon nanotubes(CNTs)with flexible matrix has been widely studied.Based on polyvinyl butyral(PVB)and thermoplastic polyurethane(TPU)as the matrix,single-walled carbon nanotubes(SWCNTs)as the conductive particles,through the independent design of roll to roll(R2R)spraying device,the continuous preparation of SWCNTs/PVB transparent conductive laminated film and SWCNTs/TPU transparent conductive film sensors,the main research contents and conclusions are as follows:(1)The fabrication and properties of SWCNTs/PVB interlayer film and transparent conductive trilayer film.This study provides a facile method to fabricate TCF at low cost.First,a large area of flexible and conductive SWCNTs/PVB interlayer film was successfully fabricated by R2 R spraying mothed.Then the interlayer film was used to fabricate trilayer film through vacuum-assisted hot pressing.Such prepared trilayer film is multifunctional because of its high conductivity,transparence,flexibility and mechanical self-recovery,etc.On one hand,the trilayer film can be used to fabricate flexible deicing window,which shows good deicing performance at a low voltage.On the other hand,the bending sensor fabricated with trilayer film shows remarkable stability,repeatability and durability.Furthermore,the bending sensor can be used to monitor the motion of fingers.This study provides a facile method to fabricate TCF based on commercial but low-cost materials,which is suitable for industrial manufacture and practical application.(2)The continuous fabrication and properties of crack-based SWCNTs/TPU bending sensor.SWCNTs/TPU conductive films were prepared by spraying SWCNTs aqueous dispersion onto TPU films by R2 R spraying mothed.With the increase of spraying cycles,the sheet resistance decreases greatly at first and then slowly.The results show that under the same bending strain,higher sheet resistance leads to larger change of resistance and unstable response.In order to obtain a large and stable resistance response,we selected TS4 as the sample to be used in the following work.For better bending sensing performance,we used finite element analysis to simulate the stress distribution on the surface of the film bending sensor when it works,and we hope to disperse the strain by introducing cracks.Then we prepared crack-based SWCNTs/TPU bending sensor simply by cutting method.Their bending sensing performance were measured,which is consistent with our results by finite element analysis simulation,transverse cracks can improve the bending sensing performance by making the resistance change more regularly.This shows that it is possible to control the conductive network by constructing microstructures,which is of great significance for the preparation of sensors with good performance using economical raw materials.