Spinodal decomposition and collapse of a polyelectrolyte gel
- Celora, Giulia L.
- Hennessy, Matthew G.
- Münch, Andreas
- Waters, Sarah L.
- Wagner, Barbara
2010 Mathematics Subject Classification
- 74A30 80A22 34B15
2008 Physics and Astronomy Classification Scheme
- 83.80.Rs 83.10.Tv.
- Polyelectrolyte gel, phase separation, collapse
The collapse of a polyelectrolyte gel in a (monovalent) salt solution is analysed using a new model that includes interfacial gradient energy to account for phase separation in the gel, finite elasticity and multicomponent transport. We carry out a linear stability analysis to determine the stable and unstable spatially homogeneous equilibrium states and how they phase separate into localized regions that eventually coarsen to a new stable state. We then investigate the problem of a collapsing gel as a response to increasing the salt concentration in the bath. A phase space analysis reveals that the collapse is obtained by a front moving through the gel that eventually ends in a new stable equilibrium. For some parameter ranges, these two routes to gel shrinking occur together.