FINAL REPORT FOR DE-FG02-03ER46071 ENTITLED, "UNDERSTANDING FOAM RHEOLOGY FROM THE MICROSCOPIC TO THE MACROSCOPIC SCALE"

Dennin, Michael

关键词: foams;   

DOI  :  10.2172/1033933
RP-ID  :  doe-ED46071-Final Report
PID  :  OSTI ID: 1033933

学科分类：凝聚态物理

美国|英语

来源: SciTech Connect

【 摘 要 】

This research effort is focused on understanding the mechanical response of foams, and other complex fluids, from the microscopic to the macroscopic level. The research uses a model two-dimensional system: bubble rafts. Bubble rafts are a single layer of gas bubbles with liquid walls that float on a water surface. The work involves studies of the macroscopic response of foam under various conditions of external forcing, mesoscopic studies of bubble motion, and systematic variations of the microscopic details of the system. In addition to characterizing the specific properties of the bubble raft, a second aim of the research is to provide experimental tests of various general theories that have recently been developed to characterize complex fluids. Primarily, the focus is on testing the proposed jamming phase diagram paradigm. This paradigm suggests that a general jamme state of matter exists and is common to a wide range of systems, including foam, colloids, granular matter, glasses, and emulsions. Therefore,we have extended our research in two directions. First, we have included studies of plastic bead rafts. These are systems of plastic beads floating on the air-water interface. The advantage of plastic beads is that they do not pop, so they can be studied for the much longer periods of time required to measure the slow dynamics associated with the jammed state. Also, they allow us to explore a different density regime than the bubbles. Second, to better understand the role of defects in jamming behavior, we have done a few experiments on the impact of defects on domain growth.