Study On Fabrication And Thermoelectric Properties Of1-3Type PANI-PVDF Composites

Thermoelectric materials is an important energy conversion material,it has become a hot research topic in the field of materials science for its characteristic of without transmission components,reliable performance,long service life and environ-mental friendly.The conductive polyanline(PANI) is the representative of polymer thermoelectric materials,which electrical conductivity can be adjusted by controlling doping,in addition, it provides more simple synthesis and lower thermal conductivity compared with inorganic semiconductor materials, so the application of conductive PANI to thermoelectrical field is very attractive.But the pure PANI fabricated at present is not only difficult to process into complex shapes,also it can’t satisfy the requirements on performance testing(thermo-electric merit factor) of actual devices,therefore it greatly limit the development of conductive PANI to thermoelectrical field.To select good thermal stability and easily processing materials as matrix,and low-dimensional structure(fibrous) PANI as functionality to synthesize1-3type composite system,is expected to improve the processing and the merit factor.So it is significant that studying1-3type structure and its formation law systematically for gaining the relationship between structure and properties.This dissertation focuses on the porous matrix Poly(vinylidene fluoride)(PVDF) prepared by appropriate processes,through changing proton acidity and aniline contents,1-3type PANI-PVDF was successfully synthesized,besides its thermoelectrical properties were studied systematically.With the characteristics of good thermal stability,easily processing molding and surface modification,the porous PVDF is a good matrix for this purpose.The porous PVDF was prepared by diffusion-absorption method,and its specific surface area,pore size and distribution were affected by process parameters.In this paper,the main influence on matrix materials include water drip content,drip rate and various additives.Experimental result indicated that,PVDF obtained at water drip capacity of 100mL and water drip rate of4.5-5.5mL/min could meet the requirements of initial destination.At room temperature,PANI and PVDF could achieve a clean integration by in-situ polymerization and form1-3type structure PANI-PVDF which is better thermal stability and merit factor than pure poly-aniline.The experiment analysis show that,structure and property of systems were influenced by aniline content,proton acidity and temperature.There is a clear1-3type structure in PANI-PVDF when aniline content is15-20wt%, their merit factor will decrease firstly and increase then(Transition temperature is393K,consistent with the results of thermal gravimetric analysis)with temperature arise.besides pH=1is the best dopant concentration,15wt%is the optical aniline content,its thermoelectric performance is.Thermoelectric merit factor ZT≥8.234x10-3,and reaches3.986x10-2at438K.