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柔软的微环境是赋予液晶分子对外场快速响应的基本要求之一,但纯液晶材料却无任何力学强度,限制了其进一步应用.本文将粒径为150 nm的二氧化硅引入由向列相液晶4-正戊基-4′-氰基联苯(5CB)和凝胶因子亚苄基山梨醇(DBS)组成的液晶物理凝胶中,通过纳米Si O2与DBS的协同效应来凝胶液晶,大幅度提高了所形成的复合凝胶网络的储能模量.采用差示扫描量热仪(DSC)、偏光显微镜(POM)、场发射扫描电子显微镜(FE-SEM)、流变仪和液晶显示参数测试仪等手段研究了液晶复合凝胶的相转变行为、形貌结构、流变和电光特性.结果表明,固定DBS含量为2.0%(质量分数,下同)时,与未加纳米粒子的液晶凝胶相比,随着纳米Si O2含量的增加,复合凝胶网络由纤维织构转变为类似球晶织构,其储能模量G′呈先增后减的趋势,当Si O2含量为2.0%时达到最大值1.5×10~5Pa,其阈值电压和关闭时间最大增幅不超过1和2倍.当二氧化硅添加量仅为0.5%时,复合凝胶的G′即可达10~5 Pa,提高了1个数量级,其阈值电压和关闭时间也分别只增加了46%和63%.此研究为进一步拓展此类材料在自支撑电光器件等领域的应用提供了新思路.
The soft microenvironment is one of the basic requirements for the liquid crystal molecules to respond to the external field quickly, but the pure liquid crystal material does not have any mechanical strength, which limits its further application.In this paper, In the liquid crystal physical gel consisting of 4-n-pentyl-4’-cyanobiphenyl (5CB) and the gel factor benzylidene sorbitol (DBS), the liquid crystal is gelled by the synergistic effect of nano-Si O2 and DBS , Which greatly improved the storage modulus of the formed composite gel network.Using differential scanning calorimetry (DSC), polarized light microscope (POM), field emission scanning electron microscope (FE-SEM), rheometer and Liquid crystal display parameter tester and other means to study the phase transition behavior, morphology, rheological and electro-optical properties of the liquid crystal composite gel.The results show that the fixed DBS content of 2.0% (mass fraction, the same below) Compared with the liquid crystalline gel, with the increase of nano-Si O2 content, the composite gel network changed from fiber texture to spherulite texture, and the storage modulus G ’firstly increased and then decreased. When Si O2 content of 2.0% reached a maximum of 1.5 × 10 ~ 5Pa, the maximum threshold voltage and closing time increased No more than 1 and 2 times.When the amount of silica added is only 0.5%, the G ’of the composite gel can reach 10 ~ 5 Pa, increased by 1 order of magnitude, and the threshold voltage and closing time also increase only 46% and 63% respectively.This study provides new ideas for further application of such materials in the field of self-supporting electro-optic devices.