THEORY OF MICROPHASE SEPARATION IN BLOCK CO-POLYMERS
THEORY OF MICROPHASE SEPARATION IN BLOCK CO-POLYMERS
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DOI：
10.1021/ma60078a047
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发表时间：
1980-01-01
期刊：
影响因子：
5.5
通讯作者：
LEIBLER, L
中科院分区：
文献类型：
--
作者：
LEIBLER, L
开发了 AB 型非晶嵌段共聚物相平衡的微观统计理论。特别是，研究了均匀熔体中有序中间相的开始，并找到了微相分离的标准。该理论唯一相关的参数是乘积（是表征 AB 相互作用的弗洛里参数；N 是聚合指数）和 f（链中单体 A 的分数）。结果表明，在一定的临界条件下，均相共聚物熔体出现特定的不稳定模式；这宣告了微相分离转变（MST）。 MST 之后，应出现周期性等于不稳定模式波长且具有体心立方 (bcc) 晶格对称性的中间相。对于大范围的组合物，bcc中间相预计是亚稳定相。只有另外两种有序相，即六方中间相和层状中间相，可能在 MST 附近稳定。计算稳定区域并提供系统的相图。预测不同有序相之间的一阶转变。提出了一种新的参数测量方法，这对于理论验证至关重要。
A microscopic statistical theory of phase equilibria in noncrystalline blockcopolymers of type AB is developed. In particular, the onset of an ordered mesophase from a homogeneous melt is studied and a criterion of themicrophase separation is found. The only relevant parameters of the theory turn out to be the product(is the Flory parameter characterizing AB interactions; N is the polymerization index) and f, the fraction of monomers A in a chain. It is shown that under certain critical conditions a specific unstable mode appears in the homogeneous copolymer melt; this announces the microphase separation transition (MST). After the MST a mesophase with the periodicity equal to the wavelength of the unstable mode and with the symmetryof a body-centered-cubic (bcc) lattice shouldappear. For a large range of compositions a bcc mesophase is expected to be a metastable phase. Only two other ordered phases, a hexagonal mesophase and a lamellar mesophase, may be stable near the MST. The regions of stability are calculated and the phase diagram of the system is provided. First-order transitions are predicted between different ordered phases. A new method of measuring of the parameter, crucial for verification of the theory, is proposed.