The effective removal of fats, in the form of crystallized triacylglyceride (TAGs) lipids, from fabrics and other surfaces can be expensive both in time and energy, requiring high temperatures (330+ K) even with modern detergents.1 Recently. However, it has been shown that by employing nanodiamonds (NDs) in combination with an anionic surfactant (sodium dodecylbenzene sulfonate, SDBS) can lead to the removal of tristearin (TS), a model triacylglyceride, at room temperatures.1 While opening significant possibilities for the use nanoparticles in cold-water laundering products, the precise mechanism for the action of NDs and SDBS at the TS-aqueous interface is still uncertain. Molecular dynamics (MD) simulations of these systems can provide important information about the interaction of the different species at the atomistic level2, and give clues about how to optimize these ND/surfactant mixtures for improved performance. Despite its importance both biologically and industrially the aqueous interface of TAGs has not been investigated by molecular simulation. In this study the TS-aqueous interface is characterized over a range of temperatures via MD simulations of a TS bilayer in water. The lipids form an ordered gel phase, with the fatty tails packing in a hexagonal arrangement. In the presence of SDBS, the bilayer shows no sign of instability despite the ability of surfactant molecules to embed themselves with TS interface. However, in the combined presence of NDs and SDBS the structures of the TS bilayer are disturbed. We find that the surface chargen density on the NDs is a major factor in the complex interplay of the interactions between the different species. Our findings can provide guidance for the development of energy efficient schemes for the low-temperature removal of crystallized fats. [1] Cui, X., et al., Nanodiamond promotes surfactant-mediated triglyceride removal from a hydrophobic surface at or below room temperature, ACS Appl. Mater. Interfaces, 2012, 4, 3225-3252. [2] Hughes, Z.E. and Walsh, T.R., Tri-stearin bilayers: Structures at the Aqueous Interface and their Interaction with Sodium Dodecylbenzene Sulfonate, J. Phys. Chem. B, 2014, In submission

Low-temperature removal of crystallized fats: Investigation of nanodiamond adsorption on the disruption of the aqueous tristearin interface

249th National Meeting (2015)

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