Surfactants are commonly use to control the formation and anti-agglomeration of clathrate hydrates. This presentation will discuss our recent simulation and theoretical studies of the adsorption of surfactants to the clathrate/water and clathrate/oil interface, and their impact on the rate of nucleation, wetting, and agglomeration of clathrate hydrates. We find that the clathrate/water interface is oleophilic, and strongly binds surfactants through insertion of their hydrophobic tails on the half-cages at the interface, driven by the entropy of hydrophoniv dehydration. We use nucleation theory to demonstrate that the strong adsorption of surfactants to the clathrate/water interface can increase the rate of nucleation of the clathrates by over 100 orders of magnitude, to reach the values determined in laboratory experiments. The adsorption of surfactants to the clathrate/oil interface, on the other hand, occurs through the hydrophilic end of the molecule and is driven by enthalpy. We discuss the ordering of alkanol surfactants at clathrate/alkane interfaces, their effect on the contact angle to water and oil, and the microscopic steps that lead to agglomeration.

How do surfactants control the nucleation and antiagglomeration of clathrate hydrates?

2019 Fall National Meeting

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