Mass Transport in Smectic Condensate Networks Revealed by Flow Imaging

Liquid-liquid crystalline phase separation (LLCPS) is known to generate complex morphologies in smectic systems, such as networks in which nodes of smectic discs are connected by filaments under tension. It is apparent that mass transport occurs in these smectic condensate networks, but the dynamics of such transport have not been elucidated. Here, we investigate these post-network formation dynamics in a 12OCB–squalane system by flow imaging. Tracer emulsion droplets are used for particle-image velocimetry (PIV), enabling quantitative resolution of flow fields and a mapping of mass transport pathways. Our flow-field analysis reveals three reproducible flow and mass transport modes: (i) symmetric, inward flow and mass transport toward network nodes; (ii) reverse transport, or outward flow, away from nodes, which can be induced by slight heating; and (iii) unidirectional flow that accompanies the retraction of a node. These modes are governed by a tunable interplay between liquid crystal elastic free energy and mass diffusion, which dictates the routing of material within the evolving filamentous network. We demonstrate that the system can be deterministically switched between these modes through precise temperature control. Furthermore, the cooling rate provides an additional handle, modulating the characteristic diffusion time and influencing the resultant transport phenomena. Our results establish a kinematic framework that advances the mechanistic understanding of anisotropic demixing in structured fluids.