Liquid crystalline cyclic tetramethyltetrasiloxanes containing coumarin moietiesElectronic supplementary information (ESI) available: characterisation data; textures of CS1 and CS8; table of layer spacings. See http://www.rsc.org/suppdata/jm/b3/b302857g/
作者:Yanqing Tian、Eiichi Akiyama、Yu Nagase
DOI:10.1039/b302857g
日期:——
A series of new cyclic tetramethyltetrasiloxanes with coumarin units were synthesized. By a comparative study with their related vinyl terminated precursors, the liquid crystalline properties of the cyclic tetramethyltetrasiloxanes were investigated. The results show that the thermal properties of the cyclic tetramethyltetrasiloxanes are stabilised through their increasing clearing temperatures and broadening mesophases. The thermal properties of the cyclic tetramethyltetrasiloxanes show that introduction of a tail group at the 3 position of the coumarin unit increases the thermal stability of the liquid crystalline order. Increasing the length of the tail group causes the clearing temperatures of the cyclic tetramethyltetrasiloxanes to decrease. The photochemical behavior of spin-coated films of the cyclic tetramethyltetrasiloxanes indicates the photo-crosslinking of the coumarin units in the thin films.
研究人员合成了一系列带有香豆素单元的新型环状四甲基硅氧烷。通过与相关乙烯基前体的比较研究,研究了环状四甲基四硅氧烷的液晶特性。研究结果表明,环状四甲基四硅氧烷的热性能通过提高清澈温度和拓宽介相而得到稳定。环状四甲基四硅氧烷的热特性表明,在香豆素单元的 3 位引入尾基可提高液晶阶的热稳定性。增加尾基的长度会降低环状四甲基四硅氧烷的清澈温度。环状四甲基四硅氧烷旋涂薄膜的光化学行为表明,薄膜中的香豆素单元发生了光交联。