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

荧光去偏法研究聚合物杂化链的结构和动力学

基本信息

批准号：
09450359
负责人：
OHOKA Masataka
金额：
$ 6.14万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09450359/
关键词：
Fluorescence depolarization method Dynamic properties of polymer chains Nanosecond time region Local motion Relaxation time Thermosensitive polymer Molecular dynamics simulation Fluorescence probe 架橋点高分子鎖間相互作用高分子ハイブリッド鎖

项目摘要

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.

1.高分子链局部运动弛豫时间与化学结构的关系。(1)对各种高分子链的局部链动力学研究表明，其局部运动受其化学结构如侧基的膨松性、立构规整性等的强烈影响。(2)对于聚苯乙烯（PS）链，链端局部运动的弛豫时间约为中心弛豫时间的十分之一。弛豫时间的MW依赖性表明，每个键的旋转势决定的弛豫时间和局部运动的最大规模是小于200键PS。(3)链中心的弛豫时间取决于与PS链荧光探针相邻的链结构。(4)分子动力学模拟的聚合物链端很好地再现了所观察到的MW依赖的局部运动的弛豫时间，它表明，局部运动反映了合作的链段的旋转运动。2.聚甲基丙烯酸烷基酯单分子膜在空气/水界面上的分子运动。局部运动受主链α-甲基的空间位阻和侧基的相邻相互作用控制。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的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高分子链的局部运动。对于聚（乙氧基乙基乙烯基醚），其中荧光探针蒽连接在主链上，我们观察到，非常增强的荧光猝灭发生在约。4。下一篇：失去的：20 C.我们验证了在LOST以下通过荧光探针与作为荧光猝灭剂的波动聚合物片段的碰撞发生动态猝灭的机制。