NOTE:  The Soft Matter Lab at Yale is closing and will re-emerge as the Laboratory of Soft and Living Materials at ETH in 2016.

Our research is focused on understanding and controlling the structure and dynamics of soft materials.   Soft materials encompass the bulk of living tissues as well as diverse engineered materials, from personal care products to energy-efficient electronic-paper displays.  Due to their accessible length and time scales, soft materials are great model systems for fundamental experiments in condensed matter physics. 

 Macroscopically, soft materials exhibit a mixture of fluid and solid properties, which are evident in familiar pastes, gels, and foams.  Microscopically, thermal fluctuations compete with interfacial and molecular forces to determine the dynamics of soft materials.  We investigate a variety of mechanical phenomena in soft materials including the basic physics of simple colloidal systems as well as the more complex mechanical properties of live cells and tissues. We are developing new methods to investigate the mechanics of these materials with a focus on mechanical singularities, which can determine the structural integrity and wetting of soft materials.
Self Assembly

The mechanical and optical properties of soft materials are typically determined by their structure at super-molecular scales, from a few nanometers to a few microns.  These structures can be highly organized, with a crystalline structure, or more loosely organized, with only short-range translational order.  Self assembly is the process through which soft materials spontaneously determine their own microstructure when only coarse macroscopic variables, like temperature and concentration, are controlled.  We engineer the self assembly of colloidal systems into new structures by synthesizing particles with novel geometries and surface chemistries.  We also study the self-assembly of biological nanostuctures at super-molecular length scales, with a focus on nanostructures that produce structural color.

Our investigations of soft matter are infused with optics. Not only is light a powerful tool for measuring and manipulating soft materials, but soft materials can also dramatically impact the flow of light.  We use quantitative light microscopy to measure the time-dependent structure of soft materials including colloids and live cells.  We use holographic optical tweezers to precisely apply forces to colloidal particles, which can be coupled to cells through surface functionalization.  We investigate structural colors in engineered colloids and biological soft materials.

Research Supported by:

Copyright Eric R. Dufresne, Yale University, 2011