"The Effects of Finite Concentration and Surfactants on the Coalescence of Drops in Flow"

ABSTRACTPROPOSAL没有。项目名称：cst -0624446项目负责人：GARY L. leala研究机构：加州大学圣巴巴拉分校有限浓度和表面活性剂对流动中液滴聚结的影响这项资助将促进在微型四辊磨机中研究流动诱导液滴聚结的过程，当它们在流动中碰撞时，可以控制一对液滴的位置和方向（低至5-10微米范围）。该装置允许独特的实验，可用于探索单个液滴水平上的聚结过程，这导致了许多意想不到的结果，这表明当前用于预测混合和混合装置中液滴尺寸分布的缩放型理论存在重大缺陷。这项研究最初的动机是需要更好地了解黏性流体在表面活性剂存在下的混合或乳化过程。目前的研究考虑了先前工作的两个重要扩展：(1)一个是考虑非稀释浓度下液滴的聚结，其中与周围其他液滴的相互作用预计将发挥重要作用；(2)第二是扩展目前的理论计算，包括表面活性剂的影响，从而寻求理解这个问题最近获得的数据。表面活性剂效应的理论模拟与实验结果的比较不仅有助于更好地理解表面活性剂的作用，也将为共聚物表面活性剂小分子模型的适用性提供检验。这项工作的预期实际意义是最终为预测共混过程的结果，以及如何通过体积和界面性质的变化，两种体积流体的相对数量来改变它，特别是如何根据相容剂的可控参数来优化过程提供更好的基础。该项目的理论方面将与UCSB科学计算IGERT项目的“复杂流体”小组合作进行。PI还将利用UCSB的MSERC全国知名的外展计划，每年夏天至少吸引一名本科生参与提议的实验研究。总的来说，有效的黏性流体共混或乳化模型将在理解、优化和开发新的多组分聚合物材料方面发挥重要作用。

ABSTRACTPROPOSAL NO.: CTS-0624446PRINCIPAL INVESTIGATOR: GARY L. LEALINSTITUTION: UNIVERSITY OF CAL- SANTA BARBARAThe Effects of Finite Concentration and Surfactants on the Coalescence of Drops in FlowThis grant will facilitate a study of the process of flow-induced coalescence of drops in a miniature version of the 4-roll mill, that allows control of the position and orientation of a pair of drops (down to the 5-10 micron range) while they are colliding in a flow. This device allows unique experiments that can be used to explore the coalescence process at the level of the individual drops, and this has led to a number of unexpected results, which demonstrate significant flaws in current scaling type theories that are used for the prediction of drop size distribution in mixing and blending devices. This study was originally motivated by the need for a better understanding of the process of blending or emulsification processes for viscous fluids in the presence of a surfactant. The present studies consider two important extensions of previous work: (1) one is to consider the coalescence of drops at non-dilute concentrations where interactions with other surrounding drops are expected to play an important role; (2) the second is to extend current theoretical calculations to include surfactant effects, and thus seek to understand recently obtained data for this problem. Comparisons between theoretical simulations of surfactant effects and experiments will not only help to better understand the role played by surfactant, but will also provide a test of the applicability of the small molecule model for copolymer surfactants. The expected practical significance of this work is ultimately a better basis for predicting the outcome of a blending process, and how it will be modified by changes in the bulk and interface properties, the relative quantities of the two bulk fluids, and particularly how to optimize the process in terms of the controllable parameters of the compatibilizer. The theoretical aspects of this project will be carried out with the collaboration of the "complex fluids" group of the IGERT program at UCSB on scientific computing. The PI will also utilize the nationally well-known outreach program of the MSERC at UCSB to engage at least one undergraduate student each summer, to be involved in experimental studies that are proposed. In general terms, effective models for blending or emulsification in viscous fluids will play a major role in understanding, optimizing and developing new multi-component polymeric materials.