Retrofittable Flexible Fabric Liners with Surface-Functionalized Electroless Nickel Coatings for Midstream Transportation of Bitumen

Increasing global energy demands have heightened reliance on unconventional fossil fuels such as heavy oil and bitumen. However, the rheological properties of these liquids make them challenging to handle and transport. Midstream transportation methods for heavy oil and bitumen encompassing rail cars, trucks, tankers, and pipelines, require extensive dilution with lighter oils and thermal jacketing to facilitate fluid flow. Designing surfaces that readily glide heavy oil would allow for much more efficient midstream transportation by reducing reliance on diluents, decreasing product loss, substantially diminishing maintenance from surface fouling, and alleviating the need for expensive thermal infrastructure. Surfaces that form plastronic air pockets based on reentrant curvature and appropriate surface functionalization show promise for heavy oil drag reduction. Here, we present the design of a superhydrophobic and superoleophobic coating integrated directly onto cotton fabric substrates that can be used to retrofit current midstream infrastructure to glide bitumen. A multiscale hierarchically textured surface is achieved by embedding polytetrafluoroethylene (PTFE) nanobeads within an electroless nickel alloy coating whose surface energy is further reduced by surface functionalization with 1<i>H</i>,1<i>H</i>,2<i>H</i>,2<i>H</i>-perfluorooctanephoshonic acid (PFOPA). The wettability of the coated fabric has been examined as a function of coating thickness and surface functionalization for water, light oil, and bitumen. Robust superhydrophobic and superoleophobic behavior is observed with contact angles approaching 162 ± 5° for water and 153 ± 5° for heavy oil. Furthermore, beyond droplet behavior on surfaces, these substrates readily glide bitumen upon immersion. The coated fabric is also thermally and mechanically robust, exhibiting an increase in break force by approximately 20 kN upon addition of the coating and thermal stability up to 250 °C. The surface-functionalized ultrathin electroless nickel coatings integrated onto fabric can be fashioned into different geometric configurations and used as liners in midstream transportation vessels for facile handling and transport of heavy oil. The results demonstrate a promising approach to alleviating some of the most challenging aspects of heavy oil use in the fuel mixes of modern economies.