星形共聚高分子微相分离的DPD模拟

用耗散粒子动力学(DPD)模拟方法研究了两种不同类型四臂星形两嵌段共聚物(A)4(B)4和(AB)4的微相分离,得到了体心立方球状、六方圆柱、层状、多孔层状和双连续螺旋状等几种稳定的介观结构以及一些过渡态结构。结果表明:其微相分离行为在总体上与线性和环状两嵌段共聚高分子相类似,而(A)4(B)4比(AB)4更容易发生相分离。介观层次上的计算机模拟可以作为对理论研究的一种补充,从而能够提供更为详细的信息。

Dissipative Particle Dynamics Simulation of Microphase Separation for Star-Diblock Copolymer Melts

Dissipative particle dynamics(DPD) simulation method is applied to simulate the(microphase) separation behavior of two different four-arm star-diblock copolymers(A)_4(B)_4 and(AB)_4.(The p)hase diagrams are constructed according to the simulation results at different interaction parameters(between) A and B segments and the composition of the copolymers.It is shown that the phase diagrams(of m)ultiarm star-diblock copolymers are similar to those of the linear and cyclic diblock copolymers;i.e.,(the o)rdered three-dimensional mesoscopic structures,such as lamellae,perforated lamellae,bicontinuous(gyroid),hexagonal cylinders and body-centered-cubic spheres can be indentified in the parameter space. Some melted structures,such as micelle,liquid rod and random network phases have also been found in the phase diagrams,which can be regarded as transitional morphologies.Compared to(AB)_4,it is easier for(A)_4(B)_4 to begin phase-separating.One conclusion is that the molecular simulation on mesoscopic scale can be considered as an adjunct to relevant theory research.