Structures and Dynamics of Polymer Hybrid Chains Studied by the Fluorescence Depolarization Method

1. 聚合物链局部运动弛豫时间与化学结构的关系。(1)对各种聚合物链的局部链动力学研究表明，聚合物链的局部运动受其侧基的体积、立体规则性等化学结构的强烈影响。(2)聚苯乙烯（PS）链端局部运动的弛豫时间是聚苯乙烯（PS）链中心弛豫时间的十分之一。弛豫时间的分子量依赖性表明，每个键的旋转势决定了弛豫时间，PS的最大局部运动规模小于200个键。(3)链中心的弛豫时间取决于PS链荧光探针邻近的链结构。(4)聚合物链端MD模拟较好地再现了局部运动弛豫时间对分子量的依赖关系，表明局部运动反映了链段的协同旋转运动。2. 聚甲基丙烯酸烷基酯单层聚合物链在空气/水界面的分子运动。局部运动受主链α -甲基的位阻和相邻侧基的相互作用控制。3. 聚合物凝胶中交联点的局部运动。作为聚甲基丙烯酸甲酯凝胶交联点的荧光探针表明，交联点的局部运动取决于聚合物凝胶的溶胀比，而不是交联点之间的分子量。4. LOST体系相分离温度附近聚合物链的局部运动。对于在主链上附着荧光探针蒽的聚乙基乙烯醚，我们观察到在约4处发生了异常增强的荧光猝灭。C在LOST下面：20。我们验证了在LOST下动态猝灭的机制是通过荧光探针与波动聚合物片段的碰撞而发生的，聚合物片段是荧光猝灭剂。

1. Relationship between relaxation times of local motion and chemical structures for polymer chains. (1) Study of local chain dynamics for various polymer chains revealed that the local motion is strongly influenced by their chemical structures such as bulkiness of side groups, stereoregularity. (2) The relaxation time of local motion of chain ends is one tenth of that of the center for polystyrene (PS) chain. The MW dependence of relaxation times shows that rotational potential of each bond determines the relaxation times and that the largest scale of local motion is less than 200 bonds for PS.(3) The relaxation time of the chain center depends on the chain structure adjacent to a fluorescent probe for PS chain. (4) The MD simulation of polymer chain end well reproduced the observed MW dependence of the relaxation time of local motion and it showed that the local motion reflects a cooperative rotational motion of chain segments. 2. Molecular motion of polymer chain in the monolayer made of poly(alkyl methacrylate)s at air/water interface. The local motion is governed by steric hindrance of alpha-methyl group of the main chain and adjacent interaction of side groups. 3. Local motion of crosslinking points in polymer gel. The fluorescent probe which acts as a crosslinking point for poly(methyl methacrylate) gel showed that the local motion of the crosslinking point depends on the swelling ratio of polymer gel, not on the MW between the crosslinking points. 4. Local motion of polymer chain in the vicinity of a phase separation temperature for LOST system. For poly(ethoxyethyl vinylether) in which a fluorescent probe anthracene is attached in the main chain, we observed that extraordinarily enhanced fluorescence quenching took place at ca. 4。C below the LOST : 20。C.We verified the mechanism that below the LOST a dynamic quenching takes place through the collision of the fluorescent probe with fluctuating polymer segments which are fluorescence quenchers.