Electrodeposition and Thin Film Formation of Hyperbranched Poly(N-Vinylcarbazole) on Indium-Tin-Oxide Substrates

Thin films consisting of carbazole moieties are of current interest due to their various applications in optical and electronic devices. This study focuses on a new polymeric structure of carbazole and its ability to form films on conductive substrates. Hyperbranched poly(N-vinylcarbazole) (HPVK) was synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization in the presence of an initiator monomer, 2-(methacryloyloxy)ethyl, 4-cyano-4 (phenyl carbonothioylthio)pentanoate (CPP-HEMA). The hyperbranched polymer was then electrodeposited by cyclic voltammetry on indium-tin-oxide (ITO) substrates to afford the electroactive thin films. The films were analyzed by atomic force microscopy (AFM), UV spectroscopy and ellipsometry. These data were compared to the ones obtained using linear poly(N-vinylcarbazole) (LPVK). Effective electrodeposition on ITO substrates was proven by the peak observed at 430 nm in the UV spectrum and by the characteristic anodic and cathodic peaks present in the cyclic voltammogram. Furthermore, results showed that HPVK produced smoother, more homogeneous and thinner films with film thickness of 10 nm.