Preparation And Thermoelectric Properties Of SWCNT/PANI Flexible Film Materials

Polyaniline(PANI)has become a hotspot in the research of organic thermoelectric materials due to its unique doping mechanism and good environmental stability.However,the thermoelectric properties of PANI are still low.In this paper,organic/inorganic thermoelectric composite films of PANI/SWCNT with flexible self-supporting were prepared by different preparation methods.The effects of post-treatment,solvent,PANI doping state,and SWCNT content on the thermoelectric properties of PANI composite films were investigated.Firstly,SWCNT/CSA-PANI composites were prepared by solution casting method.The effects of different CNT content and PANI with different polymerization time on the thermoelectric properties of the composite films were investigated.Studies have shown that the ordered arrangement of PANI molecular chains on the surface of carbon nanotubes provides an effective channel for the rapid transport of electrons under the action of solvent,so that the effect of PANI on the structure and properties of composites is much less than that of fillers.The power factor of films with 60wt%CNT reached?60?W·m-1·K-2 at room temperature and 100 ?W·m-1.K-2 at 410 K.Secondly,the SWCNT/CSA-PANI composite film was prepared by vacuum filtration,and the effects of pressure treatment,solvent(EtOH,DMF)and different preparation methods on the thermoelectric properties of the film were investigated.Studies have shown that the film structure is more stable and the electric properties are greatly improved after cold pressing.Different solvents have a great influence on the structure of the composite film.DMF solvent can partially dissolve the PANI,but EtOH cannot.so that A composite film material with three-phase structure(PANI film/PANI particles/SWCNT)was prepared by using DMF solvent because the SWCNT can be evenly packaged by the dissolved PANI.The composite films prepared by DMF solvent is more stable than EtOH.The composite films with doped PANI has high conductivity,but the Seebeck coefficient is still low.The performance of the film prepared by vacuum filtration is greatly improved compared to the casting method.At room temperature,the maximum power factor of the film prepared by EtOH and DMF solvent(90wt%CNT)reached 84.1?W·m-1·K-2 and 114.4?W·m-1·K-2.Finally,SWCNT/EB-PANI composite films were prepared by vacuum filtration,and the effects of different solvents and different CNT contents on thermoelectric properties were investigated.The results show that the structure and properties of the films prepared by DMF solvent are more stable;the thermoelectric performances of S WCNT/EB-PANI composite films are higher than that of SWCNT/CSA-PANI composite films,especially the Seebeck coefficient is greatly improved.At room temperature,the maximum power factor of the films prepared by EtOH and DMF solvent(90wt070 CNT)reached 144 ?W·m-1·K-2 and 207.3 ?W·m-1·K-2,respectively,and the maximum value reached 328 ?W·m-1·K-2 and 402 ?W·m-1·K-2 at 360 K,respectively.