Hexagonal Boron Nitride: The Thinnest Insulating Barrier to Microbial Corrosion

Abstract

We report the use of a single layer of two-dimensional hexagonal boron nitride (SL-hBN) as the thinnest insulating barrier to microbial corrosion induced by the sulfate-reducing bacteria Desulfovibrio alaskensis G20. We used electrochemical methods to assess the corrosion resistance of SL-hBN on copper against the effects of both the planktonic and sessile forms of the sulfate-reducing bacteria. Cyclic voltammetry results show that SL-hBN-Cu is effective in suppressing corrosion effects of the planktonic cells at potentials as high as 0.2 V ( vs Ag/AgCl). The peak anodic current for the SL-hBN coatings is ∼36 times lower than that of bare Cu. Linear polarization resistance tests confirm that the SL-hBN coatings serve as a barrier against corrosive effects of the G20 biofilm when compared to bare Cu. The SL-hBN serves as an impermeable barrier to aggressive metabolites and offers ∼91% corrosion inhibition efficiency, which is comparable to much thicker commercial coatings such as polyaniline. In addition to impermeability, the insulating nature of SL-hBN suppresses galvanic effects and improves its ability to combat microbial corrosion.

Ångström-Scale, Atomically Thin 2D Materials for Corrosion Mitigation and Passivation

“…MIC is a specific type of corrosion where metal deterioration occurs due to microorganisms' metabolic products (i.e., sulfate-reducing bacteria (SRB), sulfur-oxidizing bacteria). Some 2D materials such as graphene, GO, and hBN have exhibited good performance as MIC passivation coating of metals as well as antibacterial coatings [47][48][49][50][51][52][53][54].…”

“…Thus, hBN is inherently insulating and does not induce galvanic corrosion. A comparative experimental study between SLG and SL-hBN (i.e., single-layer hBN) on Cu showed that hBN can reduce the galvanic corrosion by nearly 400 times [49]. The galvanic corrosion current density (I g ) and galvanic potential showed a peak during the initial stage of corrosion for SLG (Figure 10a,b).…”

Multifunctionality and Mechanical Actuation of 2D Materials for Skin‐Mimicking Capabilities

“…The 2D material nanocoatings not only mimic the skin's barrier functions but also provide much better and more effective protection against the serious threats that can easily damage human skin. Therefore, 2D materials have attracted great attention in many barrier applications to: (1) impede the penetration of small molecules, (2) mitigate the diffusion of harmful biological substances, and (3) provide high flame resistance …”

“…d) Corrosion tests exhibit microbial corrosion resistance of SL‐hBN coatings. c,d) Reproduced with permission . Copyright 2018, American Chemical Society.…”

“…2D materials also served as high‐performance barriers against microbial corrosion. Chilkoor et al found that a single layer of hexagonal boron nitride (SL‐hBN) can effectively hinder the surface corrosion induced by the sulfate‐reducing bacteria . As shown in Figure c, SL‐hBN coating can serve as an impermeable barrier that prevents the penetration of metabolites generated by the dissimilatory sulfate reduction process.…”