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We study the physics of soft condensed matter, materials which are easily deformable by external stresses, electric or magnetic fields, or even by thermal fluctuations. These materials typically possess structures which are much larger than atomic or molecular scales; the structure and dynamics at mesoscopic scales determine the physical properties of these materials. The goal of our research is to probe and understand this relationship. We study both synthetic and biological materials; our interests extend from fundamental physics to technological applications, from basic materials questions to specific biological problems. The techniques we use include light scattering, optical microscopy, rheology, and microfluidics.

We sponsor an informal seminar every Wednesday -- the squishy physics and pizza night. To learn more and check the schedule of speakers, check out our Squishy Physics Talks webpage.

On our links page, we have listed the various instruments we use; we encourage people who have an interest in using these facilities to contact us to schedule experiments. In addition, there are links to tutorials we have written about our techniques.


We have four major research themes in our group:

  1. Soft materials: We investigate the properties and structure of soft materials such as colloids, emulsions, drops and gels. Our focus is on developing a fundamental understanding of the properties of these materials, as well as using the materials as models for the study of more complex phenomena. In addition, much of our work is motivated by potential technological applications.
  2. Biophysics: We use our expertise in soft matter to investigate the properties of biomaterials and of cells. We study the underlying physics of biopolymer networks to determine the origin of their mechanical properties. We also extend these studies to investigate the mechanical properties of living cells.
  3. Flow in porous media: We study multiphase fluid flow through porous media. We build model systems to study the fundamentals of the fluid flow, and we create new structures to control the flow and improve fluid collection. This work is motivated by resource recovery and water flow through the ground.
  4. Microfluidics: We have two different general research areas in our microfluidic effort. Both of them are focused on the study of multiphase flow, or drops, in microfluidics.
    • Material fabrication: We use our ability to precisely control fluid mixing with microfluidic devices to create structures that have new properties and that have potential for encapsulation and release applications. We also investigate the possibilities of scale up to make practical quantities of these materials.
    • High throughput biological experiments: We use our microfluidic devices to control aqueous drops in an inert carrier oil. Each drop is used as a reactor vessel for biological experiments, allowing us to perform billions of separate reactions, each with a volume of about a picoliter. This enables ultra-high-throughput screening of biological reactions or even of individual cells.

For updates about the website, please contact Liheng Cai.