多尺度模擬在奈米膠粒的粒間作用研究(1/2)

Abstract

本研究主要目的在發展奈米膠粒粒間作用研究所需的多尺度模擬之理論方法與 軟體工具。第一年研究的主要內容包括：（1）膠體顆粒的粒間作用機制與其數值 模型之探討，（2）隨機布朗運動機制與離散元素模擬之整合。 在微觀的尺度下，顆粒的表面作用力主宰著顆粒與顆粒間的交互作用。而顆 粒與顆粒的粒間作用力，可根據作用範圍分成：長距離、短距離和超短距離作用 力。本年度研究案釐清文獻中重要的粒間作用力及其相關理論，並實作相對應之 數值模型於離散元素模擬程式，探討這些作用力對顆粒運動行為的影響。 在懸浮液中，膠體顆粒的動態行為，亦受到溶液分子隨機碰撞所影響。本年 度研究案亦整合隨機布朗運動的機制於離散元素模擬，更適切地模擬膠體粒子在 溶液中的動態聚結行為。我們模擬鎳的電鍍溶液中奈米尺寸碳化矽（SiC）顆粒 之聚結行為。加入布朗運動的模擬，明顯增加粒子在溶液中的碰撞機率，因而提 高聚結率。

The main objective of this research is to develop multiscale modeling techniques and simulation toolkits for studying colloidal nanoparticle interactions. In the first year, we have studied: (1) inter-particle mechanisms and their corresponding numerical models for colloids, and (2) stochastic nature of Brownian dynamics and its integration with a deterministic discrete element method. Surface forces dominate the particle interactions under microscopic scales. From the cut-off distances, the inter-particle forces can be classified into the long-ranged, short-ranged and very-short-ranged interaction forces. In the first year, we have studied theories for these interaction forces and implemented the corresponding numerical models in a discrete element simulation. The effects of collisions with solvent molecules have also been studied in the first year. The stochastic nature of collisions has been incorporated through the machinery of Brownian dynamics. Integrating Brownian dynamics with a discrete element simulation improves the predictive abilities for colloidal particle dynamics. The nano-sized SiC particles in electro-plating solution were modeled. The simulation results indicated that Brownian dynamics primarily dominated the agglomeration processes of colloids.