アゾベンゼン修飾界面活性剤を用いた無機ナノ粒子薄膜の作製と諸性質の検討

摘要

無機薄膜は有機薄膜と比較して耐候性が高く，太陽電池などの電子部品や，高い耐摩耗性・耐腐食性が要求される機械部品など，さまざまな産業で利用されている。これらの多くは真空系を用いる乾式法で作製されるため高コストであり，より簡便な薄膜作製技術が求められている。界面活性剤は臨界ミセル濃度（cmc）以上でミセルを形成し，有機化合物を分子状で可溶化または微粒子状で分散する。%Inorganic nanoparticle films (TiO_2, ITO, ZnO, Al_2O_3, and SiO_2)were prepared using the micelle disruption method by which a nonionic surfactant with an azobenzen group (AZPEG) was reduced electrochemically. The surfactant, which adsorbed onto the inorganic nanoparticles to disperse them in aqueous solution, was desorbed from nanoparticles by electrolysis of the surfactant micelles. Particle films are formed if the nanoparticles had sufficient hydrophobicity to attach to the electrode. The inorganic nanoparticles were treated with silane-coupling agents to impart hydrophobicity, and silane-coupling agents of the type affected the particle film formation because the particle hydrophobicity was changed with the silane-coupling agents of the type. The AZPEG concentration in particle dispersions played an important role in forming particle films: optimal AZPEG concentration to form particle films was present. The optimal AZPEG concentration increased continuously with increasing specific surface area of the inorganic nanoparticles. After the nanoparticles had covered the electrode surface, nanoparticle film growth proceeded because AZPEG diffused through spaces in nanoparticle films. It was then reduced on the electrode.