Synthesis and electrochemical properties of new viologen polymers

New polymeric viologens containing tetra-, tri-, or diethylglycol links as 1,1'-substituents has been synthesized by the reaction of tosylated ethylglycols with dipyridine in N, N-dimethylformamide (DMF). Thin films of insoluble hexafluorophosphate salts of these polyviologens were examined using electrochemical technique, electrochemical quartz crystal microbalance (EQMB), and atomic force microscopy (AFM). The cyclovoltammetric results show that the composition of the polyviologen determines the kinetics of the redox reactions and the mode of the charge transport through the film. The charge compensation during the reduction process is accomplished by cation insertion, and vice versa during oxidation. However, the EQMB data indicate that some anion insertion during oxidation also takes place. Water movement during the redox processes was observed.