Liquid-liquid phase separation between jammed soft particles

The recent discovery of phase separated liquid droplets within living cells has led to a burgeoning interest in liquid-liquid phase separation (LLPS). These liquid droplets act as membrane-less organelles, performing biochemical functions by condensing a variety of biomolecules as they form and participating in intracellular signaling processes. The complexity of the cell's interior creates the need to understand LLPS within more complex environments than in simple mixtures of ideal polymers. In a recent example of such work, LLPS was studied within a crosslinked polymer network, where the network's elasticity was shown to modulate the size and the ripening of phase separated droplets forming within it. We see a need to extend such ideas to systems of jammed soft particles, as the cell's interior can exhibit the rheological properties of jammed matter. In this presentation, we will discuss our investigations of LLPS within jammed emulsions. We will show how the presence of jammed emulsion droplets influences the phase diagram of silicone oil mixtures that undergo LLPS near room temperature. The phase behavior will be connected to measurements of the interfacial tension between the phase separated liquids and to the yield stress of the jammed emulsions.