We study the physical principles underlying soft materials such as membranes, fluid interfaces, colloids, emulsions, and powders. These materials surround us, play important roles in biology and technology, and raise many questions that challenge our current understanding of physics. Our experiments probe the relationships among inter-particle forces, structure, and dynamics of many-bodied systems — relationships that are central to condensed-matter physics. Currently, our work principally focuses on soft interfaces.

We also apply new fundamental insights to develop materials that literally assemble themselves or that adapt to conditions in useful ways. Much of our work is inspired by the amazing capabilities of biological systems, which we seek to mimic in synthetic materials. Self-assembled materials have unique adaptive, mechanical, optical and electronic properties that create new opportunities for foods, inks, coatings, personal protection, disease prevention, nanofabrication and other areas.

If you are a graduate student or a postdoc, check out the UMass Summer School on Soft Solids and Complex Fluids every year in June.

Current research areas

Membranes with nanoparticles, proteins or polymers

Inspired by living cells, can we design new responsive, shape-adapting materials? Can physical principles help explain viral infection or motility in cells? To answer to these questions, we experiment with lipid vesicles and particles of various shape. Discoveries include vesicle-based solid gels, a new route to triggered response, and some amazing self-destruction pathways! (Chris Oville, Rui Cao (PhD '20), Rob Keane (BS, '20), Sarah Zuraw-Weston (PhD '20)).

Amplifying molecular response in membranes

Light-responsive amphiphiles make light-activatable membranes with fascinating behavior and potentially powerful new application as triggerable materials or protective films for delicate surfaces. We study basic mechanisms using pipette aspiration - a remarkably powerful probe of individual vesicles. (Arash Manafirad, Chris Oville).

Fluid interfaces and contact lines

What sets the contact angle of a droplet on a surface? How do particles bound at a fluid interface interact with each other? Our work builds on our recent discovery that contact angle hystersis depends on interface curvature (not just chemistry and topography) - a new twist in a very old problem. We also study aging of curved contact lines and mechanics of 'particle rafts' at interfaces. (Ash Abraham, Mingzhu Cui, Rishabh Jain, Eric Lyons; Zach Curtis (BS '20), Rob Keane (BS '20), Wei He (PhD '18))

Electrically charged powders

Why are dry powders so susceptible to charging? What determines their discharge and flow properties? Why do dry powders with a net charge become rigid and cohesive? We study these questions with macro- and micro-scale measurements of granular media and contact electrification. Electrostatic charge at solid and fluid interface are ubiquitious and inspire new physics questions. (Sumner Gubisch, Oscar Said Hernandez-Daguer, Samantha Maragioglio; Rob Keane (BS '20), Jeremy Laprade (BS '19)).