Synthetic Surfaces with Robust and Tunable Underwater Superoleophobicity

Abstract

Surfaces with extreme wetting properties are useful for the collection, manipulation, transport, and avoidance of aqueous and organic fluids of commercial and strategic importance. Two major obstacles to the deployment of synthetic non‐wetting materials in practical scenarios are their lack of mechanical durability and their susceptibility to fouling in contaminated or chemically complex media. Here, crosslinked and nanoporous polymer multilayers are reported that overcome these limitations and exhibit robust and tunable “underwater superoleophobicity”, or the ability to almost completely prevent contact with oils and other organic fluids when submerged in water. These entirely organic coatings mimic key chemical and structural features found on the scales of fish and other natural anti‐oil‐fouling surfaces, and are remarkably tolerant to physical, chemical, and environmental insults commonly encountered in natural and synthetic aqueous environments. This approach also permits facile manipulation and patterning of surface chemistry and, thus, tunable spatial control over other important aspects of interfacial behavior, such as underwater oil adhesiveness, that extend and expand the potential utility of synthetic anti‐oil‐fouling surfaces in aqueous, aquatic, and marine environments.

Slippery Liquid-Infused Porous Surfaces that Prevent Bacterial Surface Fouling and Inhibit Virulence Phenotypes in Surrounding Planktonic Cells

“…13,21,56–58 After film fabrication, these reactive multilayers were treated with n -decylamine to functionalize residual azlactones remaining in the films with hydrophobic alkyl groups (Figure 1A) 13,21,57 and render them more chemically compatible with silicone oil. 13,21 Infusion of silicone oil into the decylamine-functionalized multilayers yielded SLIPS that exhibited water droplet sliding angles of ≤ 10°, in agreement with our past studies (Table 1).…”

Slippery Liquid‐Infused Porous Surfaces that Prevent Microbial Surface Fouling and Kill Non‐Adherent Pathogens in Surrounding Media: A Controlled Release Approach

“…Our approach is based on SLIPS fabricated by the infusion of a hydrophobic liquid oil into nanoporous polymer multilayers [29] fabricated by reactive/covalent layer-by-layer assembly. [29–32] We demonstrate that (i) these polymer-based SLIPS can substantially prevent surface fouling, including biofilm formation, by several types of common fungal and bacterial human pathogens, and (ii) that biofilm formation on the SLIPS-coated surfaces of planar objects and polymer-based catheter tubes can be reduced further by using porous polymer matrices loaded with triclosan, a model and well-studied broad-spectrum antimicrobial agent. [33,34] We also demonstrate (iii) that the release of triclosan into surrounding media can be used to efficiently and effectively kill planktonic microorganisms present in surrounding media and thereby prevent biofilm formation on neighboring uncoated surfaces.…”

Covalently Crosslinked and Physically Stable Polymer Coatings with Chemically Labile and Dynamic Surface Features Fabricated by Treatment of Azlactone-Containing Multilayers with Alcohol-, Thiol-, and Hydrazine-Based Nucleophiles

“…We consider this possibility to be unlikely in view of the covalently crosslinked nature of these PEI/PVDMA multilayers and the chemical stability of the amide/amide crosslinks that are formed during assembly. 28 Additional support for the labile nature of the amide/ester bonds in these materials is 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 15 provided by the results of other experiments described below. We note here that the hydrolysis of these amide/ester bonds releases pyrenebutanol in a manner that is 'traceless' (that is, cleavage of the linker by hydrolysis occurs in a way that does not change the structure or the function of the originally immobilized molecule).…”

“…[18][19][20][21]24,26,28,42,52 Of particular note in the context of the work reported here, those prior studies reveal that when these covalent modifications are made to multilayers possessing nano-and microscale topographic features, this approach can also be used to design films that are superhydrophobic, 20,24,42,52 or extremely non-wetting to water [superhydrophobic surfaces are defined here as having advancing water contact angles (WCAs) >150°, with low water roll-off angles [53][54][55] ]. The functionalization of nanoporous PEI/PVDMA films ~3.…”