(7hr) Explore Colloidal and Interfacial Phenomena in Complex Fluids: From Isolated Fluid Particles to Their Close Packing Structures

Complex fluids are aqueous solutions of dispersed colloids (solids, drops, and bubbles) and solute species such as polymers and surfactants. The complexity is often characterized by diverse interactions among components in the solution and manifested in a wide range of colloidal and interfacial phenomena. While typically occurring at nano or micro scales, many of these phenomena can further impact macroscopic fluid properties, presenting topics that are of interest to both scientific studies and practical applications. The goal of my research is to obtain fundamental understanding of colloidal and interfacial phenomena in complex fluids and formulate rationales for engineering bulk material properties.

My research training involves utilizing microfluidic systems to study electro-kinetics and fluid dynamics of biopolymers and particle dispersions. As a graduate student advised by Prof. Victor Ugaz, I performed DNA gel electrophoresis in microchip, seeking enhanced performance of DNA separation by studying interactions between DNA molecules and hydrogel pore morphologies. My postdoctoral studies with Prof. Todd Squires examined particle migration in chemical gradients. I have learned and designed microfluidic devices, which enable versatile chemical gradients to be imposed and colloidal migration to be observed and measured. In particular, I am now studying, both experimentally and theoretically, convective fluid flows induced by surfactant gradients.

My future research will focus on behaviors of fluid particles (drops and bubbles) in dilute and concentrated emulsions. First of all, for individual particles in diluted emulsions, I will explore how interfacial mass transport and fluid flows are coupled at particle surfaces, particularly with the presence of multiple surfactants and anisotropic surface properties. Second, concentrated fluid particles in confined channels start to pack into denser configurations, forming unique structures involving islands of carrier fluids connected by thin liquid bridges. My particular research thrust is 1) to develop the capability to produce such structurers with robust properties by exploring the parameter space dictating the fluid particle packing process and 2) to exploit their applications. For example, thin bridges in the structure can be used to probe colloid dynamics (in confined spaces) and to enforce diffusion-dominated solute transport.

Teaching Interests:

As a future instructor, I see my job not only in imparting materials from textbooks, but also in helping students to develop the capability of acquiring knowledge independently and continuously. This requires a considerable shift from the conventional teacher-dominated concept to a more student-centered methodology. My teaching philosophy is therefore formulated to reflect my efforts to achieve this by focusing on three essential elements in teaching activities: 1) recognizing students as individual learners, 2) encouraging self-evaluations, and 3) promoting active learning.

My mentoring/teaching experiences include advising undergraduate in summer research program and serving as teaching assistant (numerical methods and heat transfer). In particular, I have developed considerable interests to integrate programming with teaching and research activities, thus addressing broader audiences. As an example, I programed an iPad app (“Brownian Dynamics,” available on Apple App Store) that allows people to interact with and visualize polymer structures in various environments.