Poly(sodium styrene sulfonate)s with low molecular weights were synthesized via reversible addition-fragmentation chain transfer polymerization(RAFT). Poly(3

4-ethylenedioxythiophene) aqueous dispersions were prepared with the low molecular weight PSS as the template. The structure and performance of PEDOT:PSS were investigated. The results from 1H nuclear magnetic resonance(1H NMR) showed that the PSS with molecular weight of 3900

4900

9600 and 18300 were successfully synthesized. Fluorescence spectrometry measurements showed that low molecular weight PSS prepared via RAFT can form micelles in water

and the critical micelle concentrations(cmc) were around 10-6g·ml-1. Four probe surface resistance tests showed that the conductivity of the PEDOT film were greatly improved when the low molecular weight poly (sodium styrene sulfonate) was used as the template

and the highest the conductivity of the PEDOT film was about 3 times of that of PEDOT film in which poly(sodium styrene sulfonate) produced via conventional free radical polymerization was used as the template. UV-vis spectra results illustrated that the transparency of PEDOT:PSS films decreased with the decrease of molecular weight of poly(sodium styrene sulfonate)

and this is mainly due to the phase separation between the RAFT reagent segment and PEDOT:PSS. Thermal stability test showed that the low molecular weight PSS has no obvious effect on the thermal stability of PEDOT.