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

通常，介电简正模过程的数据提供两个信息，即均方端到端距离&lt; &lt;r^2&gt; &gt;和<tau_n>端到端矢量涨落的弛豫时间。利用这一技术，我们研究了<tau_n>顺式聚异戊二烯（cis-PI）半稀溶液和浓溶液中&lt; &lt;r^2&gt; &gt;和&lt;&lt;r^2&gt;&gt;的浓度C依赖性，并与静态和动态标度律进行了比较，发现在二氧六<theta>环溶剂中，&lt; &lt;r^2&gt; &gt;与浓度无关，而在良溶剂苯中，我们发现&lt; &lt;r^2&gt; &gt;的浓度C依赖性存在四个不同的浓度区域，即：稀释（I）、半稀释（II）、半浓缩（II '）和浓缩（III）方案。在第二种情况下，&lt; &lt;r^2&gt; &gt;与&lt;C^（-1/5）&gt;成比例变化，与标度理论一致。在II '区，用Edwards理论定性地解释了&lt; &lt;r^2&gt; &gt;的C依赖性。顺式-PI在正十六烷和1-二十烷中的溶液也有类似的行为，<tau_n>而低分子量顺式-PI溶液的弛豫时间则缩短到等摩阻状态。在苯和二氧六环中，τ_（n ζ）分别与&lt;C^（1.3）&gt;和&lt;C^（1.6）&gt;成正比。这些依赖性只能用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斥体积效应和流体动力学效应的影响很小。

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.