Phase diagrams for block copolymer/homopolymer blends exhibiting LCST behaviour
Phase diagrams for block copolymer/homopolymer blends exhibiting LCST behaviour
复制标题
表现出 LCST 行为的嵌段共聚物/均聚物共混物的相图
DOI：
10.1016/0032-3861(96)81101-3
复制
发表时间：
1996
期刊：
影响因子：
4.6
通讯作者：
W. Zin
中科院分区：
文献类型：
--
作者：
Hwan;Chang;W. Zin
我们展示了均聚物 H 与嵌段共聚物 A—B 的二元共混物（或混合物）的相图，其中两种类型的链段 H 和 A 之间存在放热相互作用。在尝试构建相图时，我们扩展了预测此类二元共混物中相分离行为的方法，其中 H 与共聚物的其中一个嵌段在化学上相同，例如A.均聚物与嵌段共聚物的二元共混物分为两种不同的状态，即有序状态和无序状态。假设无序状态下的嵌段共聚物充当无规共聚物，则无序状态下的自由能变化可以通过包含添加均聚物的局部增溶的模型来估计，该模型是对Meier发起的限链模型的修改。为了确定给定温度下的共存相，我们检查了两种状态的相对稳定性（即混合物中每种成分的化学势）。由此可以得到H和A-B共混物的浓度-温度相图。从预测的相图中发现，该系统的放热相互作用大大增加了H在A域中的溶解度并影响相图的形状。
We present phase diagrams of binary blends (or mixtures) of a homopolymer H, with a block copolymer, A—B, in which there is an exothermic interaction between two types of segments, H and A. In trying to construct phase diagrams, we extend the approach of predicting phase separation behaviour in such binary blends where H is chemically identical with one of the blocks of the copolymer, e.g. A. A binary blend of a homopolymer with a block copolymer is divided into two distinct states, i.e. an ordered state and a disordered state. On the assumption that the block copolymer in the disordered state acts as a random copolymer, the free-energy change in the disordered state can be estimated by a model including the localized solubilization of added homopolymers, which is a modification of the confined-chain model originated by Meier. To determine coexisting phases under a given temperature, we examine the relative stabilities (i.e. the chemical potential of each component in the blend) of the two states. As a result, the concentration—temperature phase diagrams of blends of H and A-B can be obtained. From the predicted phase diagrams, it is found that the exothermic interaction of this system greatly increases the solubility of H into the A domains and affects the shape of the phase diagram.