A Study On Preparation Of Novel PEDOT/PSS-HNTs Composite Films

To date poly(3,4-ethylenedioxythiophene)/poly(4-styrene sulfonate)(PEDOT/PSS) has become one of the most widely studied conducting polymers because of its merits of high conductivity, high transparency for visible lights, good stability and excellent processing performance. So it shows a good prospect of application in many fields, such as thermoelectric technology, conductive composite materials, organic transparent electrodes, solar cell, sensor capacitor and absorbing materials. On the other hand, Halloysite nanotubes(HNTs) are nature aluminosilicate nanotubes. HNTs have attracted great studies and attentions due to their characteristics such as large length-diameter ratio and surface area, environmental friendly, good mechanical properties and biocompatibility. HNTs are widely used in catalysts, adsorption materials, and so on.This paper is consisted of three parts in a viewpoint of experiments. First part is a study on preparation PEDOT/PSS-HNTs composite films by using PH1000(a commercial PEDOT/PSS dispersion) and HNTs. Second part is a study on improvement of the electrical conductivity of PEDOT/PSS-HNTs composite films by treating with formic acid and by doping ethylene glycol(EG). Last part is a study on improvement of the mechanical properties of PEDOT/PSS-HNTs composite films by doping water-soluble polymers such as polyethlene glycol(PEG), polyacrylamide(PAM), carboxymethocel(CMC) and polypyrrolidone(PVP).As-prepared PEDOT/PSS-HNTs composite films were characterized by FTIR, SEM, TEM, XRD, EDX, N2 sorption isotherm and the four probe conductivity measurement, respectively. The maximum conductivity is 0.58 S/cm and surface area is 63.7 m2/g when the content of HNTs is 75.5 wt%. The electrical conductivity of PEDOT/PSS-HNTs composite films was much improved by treating with formic acid or by doping 7 wt% EG. The conductivity of PEDOT/PSS-HNTs composite films was improved in two orders of magnitude to attain 47.5 S/cm for the formic acid-treatment and 47.2 S/cm for the 7 wt% EG-doping. On the other hand, the mechanical properties of PEDOT/PSS-HNTs composite films by doping polyethlene glycol(PEG), polyacrylamide(PAM), carboxymethocel(CMC) and polypyrrolidone(PVP), respectively, were analyzed by photos and electronic universal testing machine. The results showed that the bending and stretching properties of the PEDOT/PSS-HNTs composite films were evidently improved by doping 7 wt% PEG. As a result, the young’s modulus of PEDOT/PSS-HNTs-PEG composite film treated with formic acid was 0.22 GPa.