Synthesizing Emulsions via Condensation

This thesis aims to explore condensed vapors' behavior (oil & water) on surfactant/nanoparticle interface solution and the possibility of emulsion formation by the aid of condensation. Emulsions are defined as a mixture of two immiscible liquids such that one of these liquids, called dispersed phase, is suspended as tiny droplets in another liquid called continuous phase. The current techniques for synthesizing emulsions can be broadly categorized as low and high energy methods concerning the amount of energy the particular technique consumes to break the dispersed phase within the continuous phase and generate tiny droplets. The energy required for droplet breakup depends strongly on the liquids' physical properties, such as surface or interfacial tension, viscosity, density, etc. Generating of droplets is considered as the first step in the formation process of emulsions. Since the mixture of two immiscible liquids is an energetically unfavorable thermodynamic process, the dispersed droplets intend to merge to decrease the system's free energy, giving rise to an unstable state, which subsequently results in emulsion separation. Therefore, emulsifiers and stabilizers are used to avoid coalescence events by providing kinetic stability leading to an increased emulsion's shelf life. This work aims to propose a new low-energy method of emulsion synthesis that does not require any shear stress for droplet formation by the aid of condensation, which is a thermodynamic process by which vapor-liquid phase change takes place. The first part of the research addresses one of the most challenging emulsion synthesis steps, breaking the drops to the nanoscale size. We show in detail how irreversible nanoparticle adsorption at the oil-air interface can lead to a small size water-in-oil emulsion (Pickering emulsion). In the wake of using condensation, the possibility of forming oil-in-water emulsion by condensation is also investigated by exploring nonionic and cationic surfactants' role on different modes of fragmentation exhibited by oil droplets condensing on a water-surfactant solution. This work highlights the distinct behavior between oil and water condensation, taking place on surfactant solutions. Finally, an emulsion-based icephobic coating composed of a copolymer is developed. The coating performance on delaying ice formation and decreasing ice adhesion strength is studied in detail, besides showing its other relevant applications.