Start
Dec 18, 2014 - 17:00
End
Dec 18, 2014 - 18:00
Venue
Room 118 Creativity Hall Chemical Engineering
Event Type
Speaker
Dr. Sumedh R. Risbud Postdoctoral Associate Department of ChemicalEngineering Massachusetts Institute of Technology
Title
Colloidal suspensions: (micro-) separation and (crystalline) self-assembly
Abstract: In the first part of the talk I will discuss the hydrodynamic aspects of microfluidic size based separation of colloidal suspensions vis-a-vis "deterministic lateral displacement" a method that uses an array of cylindrical micro-posts for separation. I will discuss a theoretical model derived using the concept of a critical impact parameter. The critical impact parameter will be shown to be a macroscopic experimentally measurable length scale that captures the effect of microscopic short-ranged repulsive interactions such as surface roughness. In the second part of the talk I will present a new proposed technique for self-assembly of colloidal suspensions to form colloidal crystals based on time-periodic toggling of a short-ranged attractive potential. >From basic statistical mechanics it will be shown that there exist optimal operating conditions to reach a low-defect crystalline state the fastest. A relation of this highly out-of-equilibrium pathway to a crystalline state to a purely equilibrium thermodynamic theory (scaled particle theory) might be presented time permitting.Bio: Dr. Sumedh R. Risbud is a chemical engineer with expertise in fluid mechanics. He received his B. Tech. and M. Tech. in Chemical Engineering from Indian Institute of Technology Bombay (India) in 2008. In 2013 he received his Ph.D. in Chemical and Biomolecular Engineering from the Johns Hopkins University (USA) for his work on theoretical and computational investigation of particle motion at low/zero Reynolds number under the guidance of Prof. German Drazer (currently at the Department of Mechanical and Aerospace Engineering Rutgers University). His doctoral research culminated in his dissertation titled 'Particle-Obstacle Interactions at Low Reynolds number: Implications for Microfluidic Applications’. Currently he is working with Dr. James Swan at the Department of Chemical Engineering Massachusetts Institute of Technology as a Postdoctoral Associate where he is investigating the dynamics of field-assisted organization of colloids.