Gold nanoparticles (AuNPs) have attracted much attention and can be used as catalysts and biosensors. Scince AuNPs tend to aggregate in solvents, supporting materials are generally used as stabilizers. To achieve environment-friendly AuNPs catalysts for oxidation reactions, our group has recently reported the synthesis of hydrophilic-hydrophobic p-conjugated diblock copolymers, S-PDPrB-b-P3HT (SmHTn), containing sulfonic acid functionalized polyphenylene and poly(3-hexylthiophene), and hybrid gold nanoparticles (AuNPs/SmHTn). By using p-conjugated polymers for the supporting material, they have the potential to act as not only inhibitors of the aggregation but also redox mediators for the oxidation reaction. In this study, the relationships between the molecular weights of the supporting material and the catalytic reaction activity of the AuNPs/SmHTn catalysts were investigated. Diblock copolymers, SmHTns, were synthesized by the catalyst-transfer polycondensation method. The molecular weights of SmHTns were systematically controlled. The polymerization degrees, m and n, were calculated by 1H NMR and GPC measurements. Four kinds of diblock copolymers, S6HT13, S9HT22, S16HT32, and S19HT43, were obtained and used for the preparation of AuNPs/SmHTns by the reduction method with hydrazine. AuNPs/SmHTns were evaluated by XPS, STEM, and DLS measurements. SmHTns could support AuNPs in water. The particle size and shape of AuNPs were not dependent on the molecular weights of SmHTns. Alcohol oxidation reaction was carried out in aqueous solution using AuNPs/SmHTns as catalysts. The catalytic ability of AuNPs/SmHTns was affected by the molecular weights of SmHTns. AuNPs/SmHTns with low molecular weight SmHTns showed high oxidation efficiency. AuNPs/SmHTns with high molecular weight SmHTns could maintain catalytic ability after the recycling reactions. Although AuNPs showed a tendency to aggregate after the recycling reactions, AuNPs/SmHTns with high molecular weight SmHTns maintained the dispersed state.

Synthesis and catalytic reaction activity of gold nanoparticles/diblock ionomers (V): Effect of molecular weight

255th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.