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Study of Dielectric Normal Mode Process in Semidilute and Concentrated Solutions of Polymers.

聚合物半稀溶液和浓溶液中介电简正模过程的研究。

基本信息

批准号：
60550628
负责人：
ADACHI Keiichiro
金额：
$ 1.15万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1985
资助国家：
日本
起止时间：
1985 至 1986
项目状态：
已结题

项目摘要

Generally, the data of dielectric normal mode process provide two informations, i.e. the mean square end-to-end distance < <r^2> > and the relaxation time <tau_n> for fluctuation of the end-to-end vector. Using this technique, we studied the concentration C dependence of < <r^2> > and <tau_n> in semidilute and concentrated solutions of cis-polyisoprene (cis-PI) and compared them with the static and dynamic scaling laws.In a <theta> solvent dioxane, < <r^2> > was found to be independent of concentration as expected, while in a good solvent benzene, we found four concentration regions differing in the C dependence of < <r^2> >, i.e., dilute (I), semidilute (II), semi-concentrated (II') and concentrated (III) regimes. In regime II, < <r^2> > changed in proportion to <C^(-1/5)> in harmony with the scaling theory. In region II', the C dependence of < <r^2> > was explained qualitatively in terms of the Edwards theory. Similar behavior was seen in solutions of cis-PI in n-hexadecane and 1-eicosene having a marginal solvent quality.Relaxation times <tau_n> were reduced to those in an isofriction state <tau_(n zeta)> using the data for solutions of low molecular weight cis-PI. <tau_(n zeta)> in benzene and dioxane were proportional to <C^(1.3)> and <C^(1.6)> , respectively. These dependences can be explained only qualitatively by the dynamic scaling theory proposed by de Gennes. The distribution of the relaxation times was affected little by excluded volume effect and the hydrodynamic effect.

一般来说，介电简正模过程的数据提供两个信息，即均方端到端距离<<r^2>>和端到端矢量波动的弛豫时间<tau_n>。利用该技术，我们研究了顺式聚异戊二烯 (cis-PI) 的半稀溶液和浓溶液中 < <r^2>> 和 <tau_n> 的浓度 C 依赖性，并将它们与静态和动态标度定律进行比较。在 <theta> 溶剂二恶烷中，发现 < <r^2>> 正如预期的那样与浓度无关，而在良好溶剂苯中，我们发现了四个浓度区域不同之处在于 < <r^2>> 的 C 依赖性，即稀释 (I)、半稀释 (II)、半浓缩 (II') 和浓缩 (III) 方案。在状态 II 中，< <r^2>> 按与 <C^(-1/5)> 的比例变化，与标度理论一致。在区域 II' 中，< <r^2>> 的 C 依赖性根据 Edwards 理论进行了定性解释。在具有边缘溶剂质量的顺式 PI 的正十六烷和 1-二十碳烯溶液中也观察到类似的行为。使用低分子量顺式 PI 溶液的数据，将松弛时间 <tau_n> 减少到等摩擦状态 <tau_(n zeta)> 下的时间。苯和二恶烷中的<tau_(n zeta)>分别与<C^(1.3)>和<C^(1.6)>成正比。这些依赖性只能通过 de Gennes 提出的动态标度理论定性地解释。弛豫时间的分布受排除体积效应和流体动力效应的影响很小。