本文建立了基于推广蠕虫状链模型的自洽平均场理论, 结合优化计算区域形貌使得自由能极小的方法, 来探究嵌段共聚物的单链刚柔性对其微相结构应力应变行为的影响. 为了考虑半刚性链体系的各向异性形变, 我们将原有的蠕虫状链模型推广至非正交的仿射坐标系下, 并从理论和数值上证明了本文体系可以在柔性极限下回到现有的连续高斯链模型. 在数值结果方面, 我们观察到了从完全柔性链到刚性棒状分子的不同单链刚柔性, 对于微相结构偏离原始平衡态的弹性响应过程的显著影响. 由于不同刚柔性下高分子链对外力响应机理的显著差异, 一维层状相结构的拉伸-压缩应力应变关系呈现出非对称的特点; 而剪切形变下的二维六角排列柱状相结构的界面形貌和整体排布也有明显的偏差. 此外, 在无外力的情况下, 本文中的方法可被直接用于探索最优的计算区域形貌来松弛体系的内部应力, 以达到真正的平衡态结构.

A self-consistent field theory formalism based on the wormlike chain model is developed to investigate the stress-strain relation for mesostructures in diblock copolymers under the influence of chain rigidity, involving the adjustable simulation cell in the non-orthogonal coordinates by means of optimization of free energy. We discover the significant effect of the chain persistency broadly spanning from the Gaussian chain to the rigid rodlike chain on the elastic response of mesophases that deviate from the initial equilibrium structures. We analytically and numerically demonstrate that our current approach in the long chain limit recovers to the Gaussian-chain-based theory. Being ascribed to the distinct conformational behaviors for flexible chains and rigid rodlike chains, the tensile and compressive stresses applied to lamellae exhibit asymmetric deformation behaviors and the shear stress applied to the initial equilibrium hexagonal cylinders results in noticeable deviations in the shape and spatial arrangement of cylindroids for various chain rigidity values. For the zero stress, in addition, our approach can be straightforwardly utilized to explore the optimal size and shape of the simulation cell in order to achieve a stress free configuration of systems.