Preparation of Nanoporous Poly(3-hexylthiophene) Films Based on a Template System of Block Copolymers via Ionic Interaction

A series of well-defined aniline-chain-end-functionalized regioregular poly(3-hexylthiophene)s (P3HT-NH2) and sulfo-chain-end-functionalized polystyrene (PS-SO3H) have been prepared based on quasi-living Grignard metathesis and living anionic polymerization, respectively. Block copolymers via ionic interaction. (P3HT-NH3+)-b-(PS-SO3(-))s, were successfully synthesized, simply by blending P3HT-NH2 with PS-SO3H in toluene. The thermal and optical properties of the block copolymers were investigated by differential scanning calorimetry (DSC) and ultraviolet visible (UV-vis) spectroscopy. The self-assembly behavior of the (P3HT-NH3+)-b-(PS-SO3-) thin film was observed by atomic force microscopy (AFM) and transmission electron microscopy (TEM). In addition, grazing incidence X-ray scattering (GIXS) analysis found the microphase separation of P3HT-NH3+ and PS-SO3- domains as well as the packing behavior of P3HT-NH3+ segments in block copolymer thin films. By exploiting the pH-sensitive ionic interaction, the PS-SO3- domains were selectively etched with ethyl acetate/triethylamine, cleaving the ionic interaction between P3HT-NH3+ and PS-SO3- segments. to obtain the target nanoporous P3HT-NH2, films. The porosity of the films was confirmed by AFM, scanning electron microscopy (SEM) and GIXS analyses.