The swelling and drying of a spherical gel

The event is taking part on the Tuesday, Feb 14th 2017 at 15.30
Theme/s: Pure and Applied Colloquia
Location of Event: Alan Turing 306
This event is a: Public Seminar

Swelling is a process in which a porous material spontaneously grows by absorbing additional pore fluid. Polymeric hydrogels are highly deformable materials that can experience extreme volume changes during swelling. This allows a small amount of dry hydrogel to absorb a very large amount of fluid, making hydrogels extremely useful in applications from moisture control to drug delivery. Here, we study the swelling and subsequent drying of a sphere of hydrogel. Despite the apparent simplicity of this problem, no model has yet shown satisfying agreement with experiments in terms of the dynamics of swelling and drying. We develop a dynamic model based on large-deformation poromechanics and we compare the predictions of the model with a series of experiments. We use the model and the experiments to study the dynamics of swelling and drying, and to highlight the fundamental differences between swelling and drying. Although we assume spherical symmetry, the model also provides insight into the transient patterns that form and then vanish during swelling, as well as the tendency of large spheres to fracture during drying.

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External Speakers

Chris MacMinn (University of Oxford)