Panyukov Sergey, Rabin Yitzhak
Department of Physics, Bar-Ilan University, Ramat-Gan 52900, Israel.
Phys Rev E Stat Nonlin Soft Matter Phys. 2002 Jun;65(6 Pt 1):061803. doi: 10.1103/PhysRevE.65.061803. Epub 2002 Jun 21.
Phase separation in a polymer mixture with an off-critical composition is described by a Ginzburg-Landau Hamiltonian that contains both cubic and quartic terms in the deviation of composition from its mean value in the homogeneous phase. Our analysis suggests that when a blend is brought in the vicinity of the spinodal, the initial homogeneous phase becomes unstable against the formation of a metastable lattice of spherical droplets whose lifetime diverges in the limit of infinite molecular weight. The composition of the droplets approaches that of the background phase and their size diverges with the approach to the critical point, but the composition contrast is enhanced and droplet radii become comparable to polymer dimensions, away from criticality. The connection between our predictions and the results of recent neutron scattering experiments is discussed, and new experiments that could probe the proposed droplet lattice are proposed.
具有非临界组成的聚合物混合物中的相分离由金兹堡-朗道哈密顿量描述，该哈密顿量在组成偏离其均相平均值时包含立方项和四次项。我们的分析表明，当一种共混物接近旋节线时，初始均相相对于形成球形液滴的亚稳晶格变得不稳定，其寿命在无限分子量的极限下发散。液滴的组成接近背景相的组成，并且它们的尺寸随着接近临界点而发散，但组成对比度增强，并且液滴半径在远离临界点时变得与聚合物尺寸相当。讨论了我们的预测与最近中子散射实验结果之间的联系，并提出了可以探测所提出的液滴晶格的新实验。
