Research Interests

The research theme of the Breedveld group is "Structure and Rheology of Complex Fluids", investigating the structure and mechanical strength of materials that are neither simple Newtonian fluids nor elastic solids. Complex fluids encompass a large variety of materials: food products, polymer melts and solutions, coatings, personal care products, biological fluids and gels, etc. The mechanical properties (viscoelasticity, shear viscosity) are controlled by the microscopic structure, which can be tuned by changing the interactions between molecular building blocks.

The interplay between microstructure and rheology is the focus of our work and the primary goal is to develop new experimental tools to investigate the rheological properties of soft materials on the microscopic scale. In particular, we aim to study structural changes induced by environmental conditions.

Experimental work in the group is centered around two rheological techniques: conventional macrorheology on a rheometer and microrheology, a recently developed technique to study complex fluids on the microscale. While macrorheology characterizes mechanical properties by deforming a fluid sample (0.5 to 10ml) in a rheometer, microrheology employs sub-micron particles as mechanical probes. The thermal fluctuations of these particles act as the driving force (~kT) and the resulting Brownian motion can be visualized via video-microscopy and analyzed to extract rheological information about the surrounding fluid (See Figure 1).

Figure 1. Microrheology: from movie of fluorescent tracer particle motion to sample rheology.

Projects

Under construction