Interplay between Smectic Ordering and Microphase Separation in a Series of Side-Group Liquid-Crystal Block Copolymers
作者:I. W. Hamley、V. Castelletto、Z. B. Lu、C. T. Imrie、T. Itoh、M. Al-Hussein
DOI:10.1021/ma0498619
日期:2004.6.1
spacer. A series of copolymers with different volume fractions of mesogenic block were prepared by atom transfer radical polymerization. Ordering of mesogens into a smectic phase is characterized by a period 3.5 nm. Glass transition temperatures and the clearing temperature for each sample were determined by DSC. Additional ordering occurs due to microphase separation of the block copolymer at a length
通过差示扫描量热法(DSC),偏振光显微镜,小角X射线散射(SAXS)和小角中子散射(SANS)整体研究了一系列侧基液晶嵌段共聚物的层级有序性)。二嵌段共聚物包含聚苯乙烯嵌段和带有通过十二烷氧基间隔基连接至主链的手性联苯酯介晶单元的聚(甲基丙烯酸甲酯)嵌段。通过原子转移自由基聚合制备了一系列具有不同体积分数的介晶嵌段共聚物。介晶进入近晶相的特征在于周期为3.5nm。通过DSC确定每个样品的玻璃化转变温度和澄清温度。SAXS和SANS证实,由于嵌段共聚物在22-27 nm的长度范围内发生了微相分离,因此出现了另外的有序排列。对于包含PS圆柱体的样品,发现有序无序过渡与近晶各向同性过渡一致。确定具有少数和多数液晶块的样品的六边形形态。值得注意的是,在强磁场存在下,可以通过缓慢冷却通过透明温度来取向包括在聚苯乙烯基质中的液晶(LC)圆柱体的形态。LC矩阵中PS块形成的圆柱体的逆形态没有以这种