Title: Effect of water-soluble vitamins on the structure and properties of poly(3,4-ethylenedioxythiopehene):poly(styrenesulfonate)

Authors: Shupeng Zhang, Yijie Xia and Jianyong Ouyang*

                 S. Zhang and Y. Xia contributed equally to this work.

Abstract: Intrinsically conducting polymers can have important application in biology because they can be conductive and have good biologicacl compatibility. Poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) has been the most popular conductive polymer in biological application due to its solution processability in water. PEDOT:PSS can be used as electrode materials or active materials of biological devices or circuits. It is important to study the effect of biomaterials on the structure and properties of PEDOT:PSS films. In this work, water-soluble vitamins that are biomaterials needed for organisms are used to treat PEDOT:PSS. They can significantly enhance the conductivity of PEDOT:PSS from 0.3 S cm^-1 up to higher than 1000 S cm^-1. The conductivity enhancement depends on the structure of vitamins. The highest conductivity enhancement was observed for PEDOT:PSS treated with vitamin B3. The vitamin-induced changes in the structure and properties of PEDOT:PSS were studied by UV-Vis absorption spectroscopy, temperature-dependence of resistance measurements, atomic force microscopy and cyclic voltammetry. The characterizations indicate that vitamins can induce phase segregation between PEDOT and PSS and the conformational change of the PEDOT chains. These discoveries are important to understand the application of PEDOT:PSS in biology and the development of new biological application of PEDOT:PSS.