Phase separation in soft systems

The presence of a confining solid network fundamentally alters the phenomenology of phase separation by introducing an energetic cost associated with the network deformations induced by droplet formation and growth. It is now widely recognised that this additional energetic cost can inhibit the onset of phase separation, limit the size of phase-separated domains, and control domain morphology.

To establish a quantitative description of this process, we developed a thermodynamically consistent phase-field model that captures the competing effects of fluid-fluid interactions and elasticity, within a non-linear kinematic framework. We have since studied this model within the context of both synthetic gel networks and soft granular materials.

See here for a recorded talk I gave as part of the Porous Media Tea Time Talks series.

Recent experiments in synthetic polymer gels have demonstrated that when the size of phase-separated domains are comparable to the characteristic pore size of the network, a patterned phase with a well-defined length scale may emerge. We attribute this phenomenon to non-local elastic interactions, and have constructed a dynamic theory that explores how non-local interactions can arrest thermodynamic coarsening and drive the formation of stable patterned states.

Similar phenomena are also observed in other examples of complex systems that can be mapped to non-local interactions, such as electrostatic effects, active chemical reactions, and long-range membrane deformations.