Research Interests

My research interests fall into the general category of complex fluids. The systems that I have studied are colloids — mixtures of small, undissolved particles suspended in other surrounding substances. We have discovered that mixtures of silica particle in silicone oil, initially a viscous past, became a free-flowing liquid in about 2 weeks of time. Non-aqueous silica gels, similar to the ones we have studied, have wide industrial applications. For example, they are used as "fillers" for optical-fiber cables.  Silica is also the most widely used reinforcement agent for silicone rubbers. The interaction between silicone oil and silica, however, is not well understood on a molecular level. Our work therefore contributes to the understanding the properties of these systems from both a fundamental science and a practical application point of view.  My recent research projects are related to the study of silica gels.

1. Quantitative characterization of the silica/silicone oil system.  Namely, study how the viscosity of the silica/silicone mixture changes with time (the aging process).  

2. Investigation of the effects of additives like surfactants. Our preliminary investigation shows that surfactants slow down the aging process. A gel is formed when particles suspended in a fluid form a network due to colloidal interactions, and adding surfactants will change the way particles interact with each other. We need to obtain quantitative information about this process in order to gain insight into the mechanism responsible for the silicone/silicone oil gel-fluid transition.  

3. Electrical properties of silica suspensions. We want to measure how the dielectric properties of the mixture change with time. This involves measuring the dielectric dispersion (dielectric constant and conductivity as a function of frequency) of the suspensions, and monitoring the changes as the samples age.

Students who have finished two semesters of introductory physics courses are encouraged to contact me to arrange for independent studies courses (PHYS 250/350) or for summer research opportunities.