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采用可逆加成-断裂链转移(RAFT)聚合法,合成了系列具有刚性疏水胆固醇液晶元的聚甲基丙烯酸甘油酯-嵌段-聚甲基丙烯酸亚己基胆固醇酯(PGMA-b-PMA6Chol)两亲嵌段功能大分子.运用核磁共振(NMR)和凝胶渗透色谱(GPC)表征了其化学结构及分子量,并对其热性质、液晶相结构及相转变行为分别运用热台偏振光显微镜(POM)、热重分析仪(TGA)、示差扫描量热仪(DSC)和二维小角X射线散射(2D-SAXS)表征.采用纳米沉淀法研究了所得嵌段大分子的溶液自组装,动态光散射(DLS)和扫描电子显微镜(SEM)的研究发现溶液自组装聚集体为尺寸0.7～2.0μm的球形结构,其中含有较高刚性链段质量比例的嵌段大分子组装形成开口中空结构的聚集体,且其尺寸随着溶液温度的升高减小,呈现可逆温度变化响应性.结果表明刚性疏水胆固醇液晶单元和具有多羟基结构的亲水性甲基丙烯酸甘油酯的嵌段共聚可以调控该类嵌段大分子自组装及溶液聚集体形貌.
A series of PGMA-b-PMA6Chol esters with a series of rigid hydrophobic cholesteric liquid crystal elements were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization Which is a kind of block functional macromolecule.The chemical structure and molecular weight were characterized by NMR and gel permeation chromatography (GPC), and their thermal properties, liquid crystal phase structure and phase transition behavior were respectively analyzed by hot stage polarized light microscope POM, TGA, DSC and 2D-SAXS. The self-assembly of the resulting block macromolecules was studied by nano-precipitation method, Light scattering (DLS) and scanning electron microscopy (SEM) revealed that the solution self-assembled aggregates were spherical with size of 0.7-2.0 μm, and the block macromolecules with high rigid chain mass ratio assembled to form open hollow structure Aggregates and their size decreases with increasing temperature of the solution, showing a reversible temperature change response.The results show that the block copolymers of rigid hydrophobic cholesteric liquid crystal units and hydrophilic poly (methacrylic acid) glycerides with a polyhydroxy structure Such molecules to modulate the self-assembled block and a solution aggregate morphology.