CAREER: Microstructural Dynamics in Solvent-Responsive Complex Fluids

Georgia Tech Research Corporation, Atlanta GA

Investigators

Abstract

PROPOSAL NO.: CTS-0547066 PRINCIPAL INVESTIGATORS: VICTOR BREEDVELD INSTITUTION: GEORGIA TECH. CAREER: MICROSTRUCTURAL DYNAMICS IN SOLVENT-RESPONSIVE COMPLEX FLUIDS The primary goal of the research is to develop and apply new experimental tools for real-time monitoring of the microstructure and rheology under variable solvent conditions (i.e. composition, ionic strength and pH). Such methods are currently unavailable and would have significant potential impact on improving the structure-property relations of complex fluids of practical importance. Examples include: drug delivery gels that must release their drug load within a limited time under narrowly defined pH conditions; consumer products, for which commercial success hinges on their mechanical properties and stability during ingestion (food) or application to salty skin (creams, shampoos); colloidal crystals, where the goal is to assemble ordered, defect-free arrays of colloids for optical and micro-separation applications. These are just a few cases where the functionality of complex fluids critically depends on our ability to predict and control their response to external stimuli, in particular structural rearrangements due to sudden changes in solvent composition. The lack of methodology to investigate these processes in detail is an important barrier in the development of new materials and is the main target of the proposed project. The research aims to provide experimental access to phenomena in complex fluids that are related to solvent-dependent molecular interactions by pursuing the following specific technological and scientific goals: (1) Development, optimization and calibration of new technology: dialysis cell for microscopy and microrheology; and (2) Application of the device in experimental studies that address important scientific issues in three areas: gel formation and break-up kinetics of solvent-induced hydrogels; dynamics of phase separation in polyelectrolyte-based hydrogels; and nucleation, growth and melting of charge-stabilized colloidal crystals. The work will have an immediate impact on the design and optimization of stimuli-responsive fluids in the pharmaceutical and consumer products industries by providing new quantitative tools to assess product performance and to guide product development. The program will also involve coordinated efforts to educate students at various levels of the educational system about 'complex fluids' and 'rheology'. In addition to graduate and undergraduate student research, the PI will initiate a new outreach effort for K-5 students that addresses specific standards of the Georgia K-5 science curriculum by using the 'supermarket science' of complex fluids; the outreach program is designed to ultimately impact a significant fraction of K-5 students in the metro-Atlanta school system, which includes large numbers of underrepresented minorities; the proposed approach offers an excellent opportunity to reach these students early on in their educational career. Co-funded by the EHR Research on Learning and Education Program.