Microfluidics and Soft Matter

We develop and use simple experimental tools - often based on microfluidic devices - for studying the physical mechanisms that govern the properties and behavior of soft materials. 

Insight into even the most complex materials or problems can often come from surprisingly simple experiments

A particular focus of our activities is the measurement of mechanical properties of soft objects such as hydrogels, microgels, or biological cells. We are developing dedicated techniques for studying the viscoelastic response of microscopic soft objects, fluid transport in hydrogels and other porous materials, or swelling-deswelling processes in hydrogel materials.

Another important activity is the study of phoretic forces in colloidal suspensions, including our recent unraveling of the physical origins of so-called exclusion zone (EZ) formation, where colloidal particles in aqueous suspensions are observed to be repelled from certain surfaces over long distances. 

We are currently working on the development of new microfluidic devices that exploit this EZ formation effect. These systems could find use in applications such as separation/sorting of biological or synthetic colloidal objects, for anti-fouling in reverse osmosis and blue energy applications, and in water purification.

Further we work on the interplay between different phoretic forces, including diffusiophoresis (colloid migration in a salt gradient), diffusio-osmosis (fluid motion along a surface in a salt gradient), electrophoresis (colloid migration in an electric field), and electroosmosis (fluid motion along a surface in an electric field). We are envisaging applications in microfluidic sorting or in electronic paper displays.