Immobilization of Polythiophene Chirality Induced by a Helix-Forming [beta]-1,3-Glucan Polysaccharide (Schizophyllan) through Sol-Gel Reaction

It is known that an achiral water-soluble polythiophene (PT-1) is chirally twisted by complexation with a natural helix-forming polysaccharide, shizophyllan (SPG). We found that the chirality can be immobilized by sol-gel reaction of tetraethoxysilane (TEOS) with benzylamine as a catalyst ("solution mechanism"), where SPG acts not only as a chirality inducer for PT-1 but also as a chemical glue to adsorb silica particles onto the composite surface. When a complex with amine-appended SPG (SPG-NH) was used as a template, the sol-gel reaction proceeded according to the "surface mechanism," where silica particles were formed mainly on the composite surface due to the catalytic effect of the covalently bound amino groups and thus the reaction conditions became milder. It was confirmed that under the "surface mechanism" the chemical and physical properties of the original PT-1/SPG-NH composite are maintained more efficiently.