(425c) Water Wetting on Surfaces Under Fuel Oil Containing Surfactants and Its Implication for Coalescence Separation of w/o Emulsions

Several chemicals were deposited on glass slide as thin layers by spin-coating and their response to water wetting in both air and under fuel oils with various surfactants were studied. One chemical was found to behave dramatically differently than others and its unknown chemistry was thus revealed. This chemistry, when applied to a porous filter media for emulsified water separation from surfactant-rich fuel oils, gave rise to enhanced separation efficiency. Molecular structure analysis indicates this chemistry is unique as it provides in one molecule a hard hydrophobic segment and a soft hydrophilic segment, both of which are extremely important and favorable for coalescence separation. Such chemistry also leads to surprisingly intensive but reversible adsorption of surfactants from the fuel oil. As a result, when a new water droplet approaches the coating surface sitting with an early droplet or film, the surfactant molecules freshly assembling around the new water/oil interface are pulled away immediately, yielding ways for droplet confluence.