Matan Mussel (University of Haifa) | Kinetics of volume transition in polymer gels |
Abstract:
A gel is a soft material composed of a solid phase interpenetrated by a liquid phase. Gels are abundant in nature. We eat gels, we are made of gels, and we use gels for various applications from contact lenses to vodka jello shots. Many gel systems change their volume in response to changes in environmental conditions, such as temperature, solvent quality, and ionic content. For certain gel characteristics, these volume changes can be abrupt as the control parameter is varied. This nonlinear response has been adopted for various man-made applications, such as sensors, actuators, and drug-delivery carriers, and is also believed to play an important functional role in various biological systems. Understanding the transient changes is important in these cases, but equilibrium swelling models, widely used in polymer physics, do not provide kinetic and dynamic information. I will begin this talk with a broad introduction about basic properties and potential uses of gels, and then turn to discuss a theoretical approach to model transient changes in a gel exposed to a new ionic environment
at macroscopic time and length scales. I will demonstrate that a continuum multicomponent approach can be useful for semi-quantitative predictions. Compatibility is demonstrated in three aspects by comparing results with measurements made on sodium polyacrylate gels: (1) dynamics of gel swelling and deswelling, (2) ion partitioning coefficient, and (3) effect of crosslink density.
When: December 1, 2021 02:00 PM (Jerusalem).
Where: Multipurpose building, seminar room 223 as well as via Zoom (hybrid format).