Development of hard particles simulator for detailed control of mesoscopic structure

本项目开发了一款针对一般形状硬粒子系统分子模拟的仿真软件。该项目分为三个子主题：1.；模拟器的开发2 .分散颗粒对材料中尺度结构的控制；模拟器在科学问题中的应用。以下是这三个子主题的结果。我们将模拟器命名为ESCARGOT，代表硬一般物体的平衡结构。该程序的模拟是基于粒子间的排斥相互作用。设计了由基本通用部分和扩展部分组成的程序体系结构。我们安排扩展部分针对应用程序的每个问题进行调优。模拟器的版本（Vex）号开发到5。我们决定在未来的开发中永远使用版本5的数据格式。为了利用分散颗粒控制材料的结构，我们研究了分散有机粘土的铁电聚合物PVDF。结果表明，粘土的分散影响了PVDF的结晶，所得样品对电场的电位移响应存在滞后。结果表明，少量的粘土含量诱导效果显著，表明应用的可能性。针对手性分子的液晶结构、聚合树脂的体积控制、体系尺寸对模拟结果的影响等问题进行了仿真测试。我们用硬排斥粒子表明，分子手性符号的改变会引起胆甾螺旋旋转符号的改变。我们指出，对于二聚分子体系，存在体积膨胀和体积收缩两种情况。针对系统尺寸对仿真结果的影响问题，以球棒系统为例进行了测试。对于该体系，我们指出在分子数45和90之间，模拟结果有显著的变化。

This project developed a simulation software that aims molecular simulation of system of hard particles of general shapes. The project was divided into three sub-themes: 1. Development of simulator 2. Control of mesoscale -structure of materials by dispersed particles, and 3. Application of the simulator for scientific problem. Following are results of these three sub-themes.1. We named the simulator as ESCARGOT which stands for Equilibrium StruCture of hARd General ObjecTs. Simulation of this program is based on repulsive interaction between particles. We designed the program architecture that consists of base general part and extension part. We arranged the extension part to be tuned for each problem of applications. Version (Vex) number of the simulator was developed to 5. We decide that data format of Ver. 5 is used forever for future development.2. For control of structure of materials by dispersed particles, we studied ferroelectric polymer PVDF in which organo-clay was dispersed. We indicated that dispersion of the clay affects the crystallization of PVDF and resultant sample shows hysteresis of responding electric displacement to electric field. We showed that small amount of clay content induces remarkable effect indicating application possibility.3. Simulator was tested for several problems: liquid crystal structure of chiral molecules, volume control of polymerizing resin, system size effect for simulation results, and so on. We indicated by using hard repulsive particles that change in sign of molecular chirality induce change in sign of rotation of cholesteric helix. We indicated for system of dimmerizing molecules that there are both cases of volume expansion and volume shrinkage. For the problem of system size effect for simulation results, we tested the case of system of spherical rods. For this system we indicated that remarkable change appears in simulation results between numbers of molecules 45 and 90.