The authors have demonstrated the thin-film properties and the ambipolar transport of a delocalized singlet biradical hydrocarbon with two phenalenyl radical moieties (Ph2-IDPL). The organic field-effect transistors (OFETs) based on Ph2-IDPL exhibit ambipolar transport with balanced hole and electron mobilities in the order of 10−3cm2∕Vs. The Ph2-IDPL film is an organic semiconductor with a low band gap of 0.8eV and has small injection barriers from gold electrodes to both the highest occupied molecular orbital and the lowest unoccupied molecular orbital. A complementary metal-oxide-semiconductor-like inverter using two identical Ph2-IDPL based ambipolar OFETs shows a sharp inversion of the input voltage with high gain.

A series of poly(arylene ether)s containing pendant superacid groups on fluorenyl groups were synthesized and their properties were investigated for fuel cell applications. Poly(arylene ether)s containing iodo groups were synthesized by the polymerization of 2,7-diiodo-9,9-bis(4-hydroxyphenyl)fluorene with difluorinated compounds such as decafluorobiphenyl, bis(4-fluorophenyl)sulfone, and bis(4-fluorophenyl)ketone, under nucleophilic substitution conditions. The iodo groups on the fluorenyl groups were converted to perfluorosulfonic acid groups via the Ullmann coupling reaction. The degree of perfluorosulfonation was controlled to be up to 92%, which corresponds to an ion exchange capacity (IEC) of 1.52 meq/g. The ionomers yielded flexible, ductile membranes by solution casting. The ionomer membranes exhibited a characteristic hydrophilic/hydrophobic phase separation, with small interconnected hydrophilic clusters (2-3 nm), which is similar to that of the benchmark perfluorinated membrane (Nafion). The aromatic ionomers containing superacid groups showed much higher proton conductivities than those of the conventional sulfonated aromatic ionomers with similar main chain structures. Fuel cell performance with the superacidic ionomer membranes was also tested.

Aromatic polymers containing perfluorosulfonic acid groups show well-developed and interconnected ionic clusters, and thus high proton conductivity at wide humidity range.