[19a-C103-1~12] 6.4 Thin films and New materials

▼ [19a-C103-5] Room Temperature Mineralization of Cyclosiloxane Supramolecule Monolayers toward Ultrathin Silica Films

〇Huie Zhu¹, Buket Akkus¹, Shunsuke Yamamoto¹, Jun Matsui², Tokuji Miyashita¹, Masaya Mitsuishi¹ (1.Tohoku University, 2.Yamagata University)

Keywords:Cyclosiloxane, Photo-induced mineralization, Supramolecules

A high-quality thin silica films have been increasingly important for current electronic industries, especially considering the mushrooming market of flexible electronics. The thermal oxidation method to fabricate SiO₂ is a general industrial way, however, it requires extremely high temperature near 1000 ^oC. All the flexible polymer substrates cannot sustain at such high temperature. Therefore, room temperature formation of silica thin layers at nanometer precision is on demand for further development of flexible electronics. 1,3,5,7-Tetramethylcyclotetrasiloxane (TMCS, [CH₃SiHO]₄) bearing four functional Si-H groups offer diverse opportunities to develop a wide range of inorganic-organic hybrid materials through the efficient hydrosilylation reaction between –Si–H and vinyl groups. The TMCS derivatives are possible precursors to form ultrathin silica film through photo-irradiation. In this study, an amphiphilic TMCS-derived supramolecule (TMCS-DDA) with eight amide groups bridging between the siloxane core and the peripheral alkyl chains has been demonstrated to exhibit superior two-dimensional monolayer formation properties at the air/water interface. The monolayers readily acted as two-dimensional buliding blocks with finely controllable thickness at several nanometer scale irrespective of substrate types and properties promising for surface treatment or silica coatings. Poto-irradiation of the monolayers in UV-ozone chamber at room temperature effectively induced the mineralization of the TMCS-DDA into inorganic silica coatings with controllable film thickness as sub-1 nm precision.