A new precursor for conducting polymer-based brush interfaces with electroactivity in aqueous solution

We present the synthesis of a novel conducting polymer (CP) incorporating both pyrrole and thiopheneunits in its monomer, which is also substituted with an initiator for grafting of sidechains by atom-transferradical polymerisation (ATRP). The precursor monomer for the CP macroinitiator, 2-(2,5-di(pyrrol-2-yl)thiophen-3-yl)ethyl 2-bromopropanoate) (PyThon) is very readily electropolymerised at low monomerconcentrations and low applied potentials. Density functional theory (DFT) predictions of ionisation potentialsand spin-charge distribution for PyThon are in good agreement with these experimental results.We present also the grafting of sidechains from electropolymerised PolyPyThon (PPyThon) to yield surfaceconfinedpolymer brushes. Functionalisation with polystyrene (PS), poly(2,3,4,5,6-pentafluorostyrene)(PFS) and poly(ethylene glycol) methyl ether acrylate (PEGMEA) is demonstrated and confirmed by FT-IRand water contact angle measurements. These PPyThon-based molecular brushes are electroactive inboth water and acetonitrile, and show evidence of changes in surface conformation related to the redoxstate of the CP. The growth of human fibroblasts on PPyThon films is also demonstrated, indicating goodbiocompatibility of the polymer. We conceive PPyThon-based molecular brushes as a substrate for electricalstimuli-responsive surfaces with application particularly in the biomedical field.