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

项目编号：CTS-0624446 PRINCIPAL调查员：Gary L.Lealinstittion：加州大学圣巴拉特分校有限浓度和表面活性剂对液滴在流动中结合的影响这笔赠款将促进对小型四辊磨机中液滴的流动诱导结合过程的研究，它允许控制一对液滴(下至5-10微米范围)在流动中碰撞时的位置和方向。该装置允许进行独特的实验，可以用来探索单个液滴水平上的合并过程，这导致了一些意想不到的结果，这些结果表明，当前用于预测混合和混合设备中液滴尺寸分布的标度类型理论存在重大缺陷。这项研究最初是为了更好地了解粘性流体在表面活性剂存在下的混合或乳化过程。目前的研究考虑了前人工作的两个重要扩展：(1)考虑非稀释浓度下液滴的合并，其中与周围其他液滴的相互作用有望发挥重要作用；(2)扩展现有的理论计算，以包括表面活性剂的影响，从而寻求理解最近获得的关于这个问题的数据。将表面活性剂效应的理论模拟与实验进行比较，不仅有助于更好地理解表面活性剂的作用，而且还将检验小分子模型对共聚表面活性剂的适用性。这项工作的预期实际意义最终是更好地预测混合过程的结果，以及如何通过体相和界面性质、两种体相流体的相对量的变化来改变混合过程，特别是如何根据相容剂的可控参数来优化过程。该项目的理论方面将与UCSB的IGERT计划的“复杂流体”小组在科学计算方面进行合作。PI还将利用加州大学伯克利分校MSERC在全国知名的外展计划，每年夏天至少聘请一名本科生参与拟议的实验研究。总之，粘性流体中有效的混合或乳化模型将在理解、优化和开发新型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.