Biomimetic Plastronic Surfaces for Handling of Viscous Oil

Abstract

Unconventional deposits such as extra heavy oil and bitumen represent a steadily increasing proportion of extracted fuels. The rheological properties of viscous crude oil represents a formidable impediment to their extraction, transportation, and processing and have necessitated considerable retooling and changes to process design. In this work, we demonstrate that highly textured inorganic substrates generated by depositing ZnO nanotetrapods onto periodically ordered stainless steel mesh substrates exhibit viscous oil contact angles exceeding 150°as well as enable the facile gliding of viscous oil. Such functionality is derived as a result of multiscale texturation and porosity achieved within these substrates, which are characterized by trapping of plastronic air pockets at the solid/liquid interface. Further reduction of the surface energy has been achieved by constituting a helical highly ordered self-assembled monolayer of a perfluorinated phosphonic acid on the ZnO surfaces. Such structures are strongly ejected upon immersion in water with water contact angles in excess of 160°. The functionalized substrates demonstrate remarkable superoleophobic behavior toward viscous crude oil with contact angles reaching 156°and are furthermore stable to temperatures of 290 °C. The remarkable results evidenced here hold promise for deployment of these constructs in the handling of viscous oil in order to reduce losses associated with transportation from railroad cars, pipelines, and other oil-handling equipment.

Magnesium Nanocomposite Coatings for Protection of a Lightweight Al Alloy: Modes of Corrosion Protection, Mechanisms of Failure

“…The Mg/PEI nanocomposites represent a valuable addition to the scarce options available for protection of lightweight Al alloys. Future work will focus on delaying the kinetics of Mg activation through surface modification of the nanocrystals as well as the incorporation of the Mg/PEI coating modules within corrosion control systems additionally incorporating anodic passivation and a non‐wettable top coat . Under conditions that induce stress corrosion cracking, mechanical properties of the specific alloy, governed in substantial measure by the alloying elements and their influence on the microstructure, are expected to play a significant role.…”

Tortuosity but not Percolation: Design of Graphene Nanocomposite Coatings for the Extended Corrosion Protection of Aluminum Alloys

“…Future work will focus on inclusion of electroactive layers such as surface-passivated Mg nanoparticles to additionally impart cathodic protection 12,13 as well as application of recently developed omniphobic composite coatings to limit fluid interactions. 66 ASSOCIATED CONTENT Supporting Information. Raman spectra of UFG solutions, optical microscopy images of coating surfaces, nanoindentation results at different loading rates, and EIS data of 17 wt.% UFG/PEI coatings monitored across 100 days are included in the supporting information.…”

Hierarchically Textured Oleophobic Internal Coatings that Facilitate Drag Reduction of Viscous Oils in Macroscopic Laminar Flow

“…Obtaining a surface that is not wetted by a specific liquid requires defining surface topology in such a manner as to produce the plastrons whilst simultaneously minimizing interfacial interactions at the line-of-contact (three-phase boundary) through chemical functionalization. [2] Notably, the Cassie-Baxter regime represents a metastable state. Upon application of sufficient pressure, disruption of plastrons, or if there is a change in surface tension, the liquid can transition from the Cassie-Baxter to the Wenzel regime, engendering a substantial increase in wettability.…”

“…Designing an omniphobic surface therefore requires a substantial degree of multiscale texturation (thereby reducing the fractional surface area where the liquid contacts the solid surface), re-entrant geometric curvature, as well as a reduced surface energy at the perimeter of the plastrons in order to preclude wetting by water or oil. [2][3][4] Although a high contact angle is a necessary condition for drag reduction, this in itself is not sufficient for predicting reduction of the pressure drop in a system. This is most evident under the no-slip boundary condition in the laminar flow regime where the velocity profile of the liquid is typically assumed to approach zero at the solid/liquid interface and the loss in pressure is due to the frictional interaction between the individual planes of fluid.…”

“…In stark contrast to water, which has a high surface tension derived from hydrogen bonding as the primary intermolecular interaction, drag reduction of low-surface-tension oils represents a particular challenge as a result of the relatively weaker cohesive forces (derived from the predominantly van der Waals' interactions between hydrocarbons), which render oils much more amenable to spreading on surfaces with even moderate surface energies. [2][3][4] As such, while drag reduction of water and oil-in-water emulsions have been explored over several decades, macroscopic tubing with internally coated oleophobic surfaces are almost entirely unexplored despite their clear potential to minimize frictional forces for viscous oil flow. Here, we present a scalable approach to coating tubing interiors spanning several feet in length with a hierarchically textured surface that is rendered omniphobic after surface functionalization with a perfluorinated phosphonic acid.…”