Synthesis and polymerization of a new thiophene functionalized with both NLO-active chromophore and an alkylic self-plastifying chain

This paper describes a new easy and straight-forward synthetic pathway leading to a thiophenic monomer functionalized with a second-order NLO chromophore and with an alkylic plastifying chain, namely the 3-{6-[4-(4′-nitrophenylazo)-N-ethyl-N-phenylamino]hexyl}-4-hexylthiophene. The corresponding polymers obtained by direct oxidative polymerization and by post-polymerization functionalization of a polymeric precursor are soluble in common organic solvents even if their chromophore content is 100%. The final materials have been characterized by using 1H- and 13C-NMR spectrometry, FT-IR spectroscopy, SEC, DSC analysis and conductivity measurements. The thermal characteristics and the electrical behaviour of the “self-plastifying” polymers are comparable to those of the alkylthiophene/chromophorized-alkylthiophene copolymers, but the presence of the highest content in NLO chromophoric substituent in the new synthesized homopolymers makes them particularly interesting for optoelectronic applications.