Active and Janus Particles

Project ID
FG-417
Project Categories
Non-Life Science
NSF Grant Number
CBET-1055284
NSF Grant URL
http://www.nsf.gov/awardsearch/showAward?AWD_ID=1055284
Completed
Abstract
This career development plan combines the PI’s expertise in low Reynolds number hydrodynamics and colloidal suspensions to study the emerging field of complex fluids based on “two-faced” Janus particles—particles which have two distinct sides—that depending on their surface functionality could lead to novel material properties and aggregation/self-ordering abilities or to autonomous behaviors using on-board chemical motors operating far from equilibrium. This proposal presents research and educational activities designed to elucidate important aspects of reconfigurable complex fluids—active materials that could change and relax their structure with minimum or no external intervention using as precursors Janus and catalytically-driven colloidal particles. The research efforts are divided in two main tasks. The first one focuses in studying the motion, rheology, and structural organization of Janus particle suspensions guided by a combination of fluid flows and external forces. Different behaviors are expected depending on the interparticle force between the ‘Janus’ faces of the particles (e.g., hard sphere, attractive, soft). The second research task aims at understanding collective motion of catalytically-driven Janus particle suspensions. A simple ‘colloidal’ approach to autonomous motion via chemical reactions will be used and implemented based on classic multicomponent diffusion and depletion flocculation theory. Simple elementary dynamic units operating with specific rules and exploiting chemotaxis will be proposed as ‘elements’ for future reconfigurable materials. These efforts will be accomplished by Brownian/Stokesian dynamics simulations and experiments with collaborating partners. The education and outreach components of the plan aim to involve the participation and enhance the education of Hispanics from the K-12 to the graduate level. At the graduate level, it is proposed to create a graduate course entitled “Particle Dynamics in Anisotropic Colloidal Suspensions”. At the undergraduate level, the tasks aim at the inclusion of emerging topics on colloidal hydrodynamics to an existing fluid mechanics course and the development and implementation of autonomously-moving Janus particles related modules for advanced multimedia presentation techniques in the classroom. In addition, the education activities include workshops to help students strengthen their communications skills and improve their preparation for the GRE. At the K-12 level, this proposal includes demonstrations and activities related to reconfigurable complex fluids that will be implemented through the Science on Wheels program.

Use of FutureSystems
FutureGrid will be use to run Brownian/Stokesian dynamics simulation of colloidal suspensions. FutureGrid will become an important facility for our research group. We will run codes in serial and parallel depending on the need. Many of our task are long and must be repeated many times to obtain averaged values.
Scale of Use
A set of simulations on entire systems will be run and for each I'll need 30 days to do that. It could take longer depending on the size of our suspension.