Electrochemical polymerization of 1,10-decanedithiol in CH2Cl2 and additive effect of benzylmercaptan

Synthesis of polymers containing disulfide bonds in the main chain by electrochemical polymerization of 1,10-decanedithiol (DEDT) in dichloromethane (CH2Cl2) was investigated. The resulting poly(DEDT) was also investigated under constant current electrolysis. It is observed that the number-average molar mass (Mn) of the polymer increases as a function of time (i.e. as a function of the Faradaic charge passing through the circuit), as opposed to what was observed in acetonitorile (CH3CN). These results are attributed to the solubility of the product, poly(DEDT) of the reaction in CH2Cl2, while it is insoluble in CH3CN. In the polymerization of DEDT in CH2Cl2, the relation between the Mn of the polymer and Faradaic charge showed the features of a stepwise polymerization process (which proceeds by the stepwise reaction between the functional groups of the reactants). The cleavage of the disulfide bond in the polymer was found to take place mainly at the anode via an oxidation process. By the addition of benzylmercaptan (BzSH), the molar mass of the polymer could be regulated. The benzylthiyl group derived from BzSH could be introduced at the polymer chain end.