Wang Maoxiang, Hu Wenbing, Ma Yu, Ma Yu-Qiang
National Laboratory of Solid State Microstructures, Department of Physics, Nanjing University, Nanjing 210093, China.
J Chem Phys. 2006 Jun 28;124(24):244901. doi: 10.1063/1.2203070.
We report dynamic Monte Carlo simulations of polymer crystallization confined in the cylindrical microdomains of diblock copolymers. The microdomains were prepared via spontaneous microphase separation from homogeneous melt, and the major component was then frozen in a vitreous amorphous state to make a hard confinement to the crystallization of the minor component. We found that during the isothermal crystallization at high temperatures, crystal orientations are dominantly perpendicular to the cylinder axis at the early stage of crystal nucleation and remain to the final state; while if the block junctions are broken before crystallization, crystal orientations are dominantly parallel at the early stage of crystal nucleation, and eventually other orientations take the place of parallel preferences. Analysis of bond orientations in the heterogeneous melts demonstrates the microscopic origin of oriented crystal nucleation.
我们报道了在二嵌段共聚物的圆柱形微区中受限的聚合物结晶的动态蒙特卡罗模拟。这些微区是通过从均相熔体中自发微相分离制备的，然后将主要组分冷冻成玻璃态非晶态，以对次要组分的结晶形成硬限制。我们发现，在高温等温结晶过程中，晶体取向在晶核形成的早期主要垂直于圆柱轴，并保持到最终状态；而如果在结晶前链段连接被破坏，晶体取向在晶核形成的早期主要是平行的，最终其他取向取代了平行偏好。对非均相熔体中键取向的分析揭示了取向晶核形成的微观起源。
