Effect of confinement on phase-separation processes in a polymer blend observed by laser scanning confocal microscopy
Effect of confinement on phase-separation processes in a polymer blend observed by laser scanning confocal microscopy
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DOI：
10.1103/physreve.67.021801
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发表时间：
2003-02-01
影响因子：
2.4
通讯作者：
Takahashi, M
中科院分区：
文献类型：
--
作者：
Jinnai, H;Kitagishi, H;Takahashi, M
结构自组装在其临界组成的聚合物共混物的旋节线分解的后期阶段已被探索的激光扫描共聚焦显微镜，特别强调的约束（维数）和优先润湿固体表面的组成聚合物之一的影响。氘代聚丁二烯和聚丁二烯（PB）的混合物，具有相对较窄的厚度（Dcongruent到55 μ m），在整个厚度的三维观察。在玻璃表面附近清楚地观察到润湿层的形成，而在试样的中间形成双连续结构。通过几个结构参数来量化相分离结构的全局和局部特征，例如，特征长度λ（m）（t）、结构因子S（q）、每单位体积的界面面积Sigma（t）、界面曲率的概率密度P（H，K;t）等（t是相分离时间）。从这些结构参数的时间演化，从双连续结构的自相似生长的偏差被发现发生在过渡时间，t（tr），在该时间的缩放厚度，D/λ（m），接近统一。局部特征最敏感地观察到自相似增长的分解，即，Sigma（t）和P（H，K;t）。另一方面，全局特性Lambda（m）（t）没有提供对维度影响的有用洞察。原来，双连续结构，最初增长的动力学自相似性，最终转化为一个“柱状”结构（在tcongruent tot（tr）），其中圆柱形PB丰富的域桥的上部和下部PB润湿层。
Structure self-assembling in the late stage spinodal decomposition of a polymer blend at its critical composition has been explored by laser-scanning confocal microscopy with particular emphasis on the effects of confinement (dimensionality) and preferential wetting of solid surface by one of the constituent polymers. A mixture of deuterated polybutadiene and polybutadiene (PB) with relatively narrow thickness (Dcongruent to55 mum) was observed in three dimensions over the entire thickness. Formation of a wetting layer was clearly observed near the glass surface, while a bicontinuous structure evolved in the middle of the specimen. Global as well as local features of the phase-separating structures were quantified by several structural parameters, e.g., characteristic length Lambda(m)(t), structure factor S(q), interfacial area per unit volume Sigma(t), probability densities of interfacial curvatures P(H,K;t), etc. (t is a phase-separation time). From the time evolution of these structural parameters, a deviation from the self-similar growth of a bicontinuous structure was found to occur at a transition time, t(tr), at which a scaled thickness, D/Lambda(m), approached unity. The breakdown of the self-similar growth was most sensitively observed by the local characteristics, i.e., Sigma(t) and P(H,K;t). On the other hand, the global characteristic, Lambda(m)(t), did not provide useful insight into the effects of dimensionality. It turned out that the bicontinuous structure, initially growing with dynamical self-similarity, eventually transformed into a "columnlike" structure (at tcongruent tot(tr)) in which cylindrical PB-rich domains bridge the upper and lower PB wetting layers.