Dynamics of Assembly of Colloidal Particles at Liquid Interfaces
Vinothan N. Manoharan
Associate Professor of Chemical Engineering and Physics
Some of the most difficult problems in condensed matter and biophysics today involve understanding how systems order themselves and why they sometimes fail to do so. Why do some liquids form glasses rather than crystals when cooled? How do proteins consistently fold into unique structures, given the myriad possible paths available to them? What are the forces between macromolecules, and how do those forces determine the structure of aggregates (and living things)? A related problem in materials science and nanotechnology involves preparing materials that organize themselves in three dimensions.
In my lab we use light scattering, optical microscopy, spectroscopy, synthesis and other experimental techniques to understand the physics of self-organization. For most of these experiments we use colloids, suspensions of particles typically about a micrometer in size. Because these particles are small enough to be buffeted about by Brownian motion, yet large enough that their motion is directly visible, they are extremely useful: they can be used as tracers to probe the internal dynamics of networks and fluids, as "handles" that can be attached to proteins and DNA so that these molecules can be manipulated with optical tweezers, and as generic model systems for understanding how random motion transforms disorder to order.