(400a) Three Dimensional Multiphasic Structures Via Vaporization Induced Phase Separation (VIPS)

Studies of bicontinuous interfacially jammed emulsion gels (bijels) have greatly expanded the possibilities of multiphasic systems. We have previously introduced the solvent transfer induced phase separation (STRIPS) method to prepare bijels from ternary mixtures of oil, water and co-solvent (ethanol). Although STRIPS enables continuous processing, the requirement of the outer aqueous phase limits their applications to liquid environments. Enabling production of bijels in air would further expand their applications in areas such as coatings and surface modification applications. In this work, we demonstrate a new method to produce three dimensional multiphasic structures, including bijels, via vapor-induced phase separation (VIPS). In VIPS, the evaporation of the co-solvent from a ternary mixture of oil, water and ethanol, induces phase separation. Particles present in the mixture attach to the interface and arrest the phase separation between water and oil. VIPS enables the fabrication of films and coatings via spreading or spraying particle-laden suspension onto a surface without the need for an outer aqueous phase. The structure of VIPs films on different substrates are characterized, and the influence of initial composition, substrate surface wettability and surrounding temperature are investigated.