Molecular structures of siloxane materials should be highly controlled for achieving advanced functionalities. However, it is still difficult to precisely control the structure of siloxane materials by the sol–gel processing. In the present study, we focused on the silanol groups in the intermediate oligomers and resultant siloxane materials as a key structural unit for controlling the molecular structure. Thermal stability and chemical reactivity of silanol groups were found to be highly dependent on the steric effects of the surrounding side chains and siloxane skeletons. The present work suggests that controlling the steric effects around silanol groups in the intermediate oligomers allows modulating the crosslink density of siloxane skeletons. The selective molecular modification tunes the structure and chemical properties of the resultant siloxane materials.

应当严格控制硅氧烷材料的分子结构以实现高级功能。但是，仍然很难通过溶胶-凝胶工艺精确控制硅氧烷材料的结构。在本研究中，我们集中于中间低聚物中的硅烷醇基团和所得的硅氧烷材料，作为控制分子结构的关键结构单元。发现硅烷醇基团的热稳定性和化学反应性高度依赖于周围侧链和硅氧烷骨架的空间效应。目前的工作表明，控制中间低聚物中硅烷醇基团周围的空间效应可调节硅氧烷骨架的交联密度。