Sheetlike Side-Chain Liquid Crystalline Polyacetylenes Forming Monolayer Lamellae in Dilute Solutions
Sheetlike Side-Chain Liquid Crystalline Polyacetylenes Forming Monolayer Lamellae in Dilute Solutions
复制标题
稀溶液中形成单层片层的片状侧链液晶聚乙炔
作者：
研究了一系列疏水侧链液晶（LC）聚乙炔，即聚（5-{（4′-烷氧基-4-联苯基）羰基）氧}-1-戊炔)s (P-3,m (m) 5,7,9))在稀溶液中的自组装行为。通过调整溶剂性质，使其对侧链上的烷基尾部具有选择性，通过浊度、动态光散射、1h NMR和激发荧光各向异性测量来表征组装过程。利用原子力显微镜和广角x射线衍射研究了溶液中形成的P-3，m聚集体的形态和结构。实验结果表明，P-3，m聚合物在选择性溶剂中可形成单层片层。在片层中，P-3，m分子呈片状，彼此平行排列，其骨架位于片层中心，其烷基尾覆盖在片层的上下表面。片层厚度在很大程度上取决于分子片的宽度。当溶剂对尾部具有选择性时，P-3，m链可能发生形状硬化，变得更像片状。
Self-assembly behaviors of a series of hydrophobic side-chain liquid crystalline (LC) polyacetylenes, namely, poly(5-{((4'-alkoxy-4-biphenylyl)carbonyl)oxy}-1-pentyne)s (P-3,m (m ) 5, 7, 9)), were studied in dilute solutions. The assembly was induced by tuning the solvent property to be selective for the alkyl tails on the side chains, with the processes characterized by turbidity, dynamic light scattering, 1 H NMR, and excitation fluorescence anisotropy measurements. The morphology and structure of the P-3,m aggregates formed in the solutions were investigated using atomic force microscopy and wide-angle X-ray diffraction. The experimental results indicate that the P-3,m polymers can form monolayer lamellae in selective solvents. In the lamella, the P-3,m molecules are sheetlike and pack parallel to each other with their backbones located in the lamellar center and their alkyl tails covering the top and bottom lamellar surfaces. The lamellar thickness is largely determined by the width of the molecular sheet. When the solvent becomes selective for the tails, the P-3,m chains may undergo shape stiffening to become more sheetlike.