Influence of Branching of Polythiophenes on the Microporosity

A chain growth polymerization of a branched polythiophene (BT) using a Pd(Ruphos) catalyst, as a promising route to synthesize microporous conjugated polymers with well-defined structures is reported. From N-2 adsorptions/desorption isotherm measurements, a Brunauer-Emmett-Teller surface area of 40.7 m(2) g(-1) is calculated for the BT, significantly higher than that of the linear poly(3-hexylthiophene) (P3HT) (25.7 m(2) g(-1)). The same trend is confirmed by simulations of the two polymer structures, from which a geometric surface area (SA(geo)) of 140 +/- 15.8 m(2) g(-1) is calculated for the BT, much more higher than for the P3HT with a SA(geo) of 6.7 +/- 7.1 m(2) g(-1). Moreover, the BT is soluble in common organic solvent and is readily processed in membrane with a CO2/N-2 selectivity up to 24.