CAREER: The Effect of Surface Roughness of Colloidal Forces: Prediction and Measurement

摘要 CTS-9702773 John Walz 表面粗糙度对胶体颗粒与表面间相互作用力的影响是一个非常有趣的课题。 在填充床过滤实验中，表面粗糙度经常被认为是预测和测量沉积速率之间差异的可能原因。 虽然已经开发了许多粗糙度模型，没有直接的实验测量的具体效果的粗糙度上的货车德瓦尔斯或表面之间的静电相互作用力已经获得。 本研究的目的是：（1）建立一个预测粗糙表面之间相互作用力的通用理论模型，其中粗糙度的数学描述与表面特征（例如，SEM显微照片，AFM轮廓）;（2）实验测量明确定义的粗糙表面之间的相互作用能量分布;和（3）测量表面粗糙度对流过填充床的颗粒的捕获率的影响。 将使用全内反射显微镜（TIRM）的光学技术获得能量分布测量。 测量粗糙度对长程二次能最小值和一次能垒的影响。 后者的实验是非常有用的，因为它是主要的能量势垒的高度，控制通过多孔介质传输的颗粒沉积速率。 所使用的实验程序将允许专门测量粗糙度对表面力的影响，包括有和没有流体动力学效应。 教育目标是改善杜兰大学化学工程系与当地石油和化学工业之间的关系。 这种改善的关系将，（1）为我们的学生提供更好的就业机会;（2）为我们的部门提供更多的财政支持;（3）改善为我们的学生提供的工程教育;（4）为支持当地化学工程界提供宝贵的资源。

ABSTRACT CTS-9702773 John Walz The effect of surface roughness on the interaction forces between colloidal particles and surfaces is a subject of great interest. Surface roughness is frequently given as a possible cause of the discrepancy between predicted and measured deposition rates in packed bed filtration experiments. Although numerous roughness models have been developed, no direct experimental measurement of the specific effect of roughness on the van der Waals or electrostatic interaction forces between surfaces has been obtained. The objectives of this research are to, (1) develop a general theoretical model for predicting the interaction forces between rough surfaces in which the mathematical description of the roughness is consistent with surface characterizations (e.g., SEM micrographs, AFM profiles); (2)measure experimentally the interaction energy profile between well-defined rough surfaces; and (3) measure the effect of surface roughness on the capture rate of particles flowing through a packed bed. The energy profile measurements will be obtained using the optical technique of total internal reflection microscopy (TIRM). Measurement of the effect of roughness on both the long range secondary energy minimum as well as the primary energy barrier will be made. The latter experiments are extremely useful since it is the height of the primary energy barrier which controls the rate of particle deposition in transport through porous media. The experimental procedure to be used will allow measuring specifically the effect of roughness on surface forces both with and without hydrodynamic effects. The educational objective is to improve the relationship between Tulane's chemical engineering department and the local oil and chemical industry. Such an improved relationship will, (1) provide better employment opportunities for our students; (2) provide increased financial support for our department; (3) improve the engineering education provided to our students; and (4) provide a valuable resource for supporting the local chemical engineering community.