Superiority of Graphene over Polymer Coatings for Prevention of Microbially Induced Corrosion

Abstract

Prevention of microbially induced corrosion (MIC) is of great significance in many environmental applications. Here, we report the use of an ultra-thin, graphene skin (Gr) as a superior anti-MIC coating over two commercial polymeric coatings, Parylene-C (PA) and Polyurethane (PU). We find that Nickel (Ni) dissolution in a corrosion cell with Gr-coated Ni is an order of magnitude lower than that of PA and PU coated electrodes. Electrochemical analysis reveals that the Gr coating offers ~10 and ~100 fold improvement in MIC resistance over PU and PA coatings respectively. This finding is remarkable considering that the Gr coating (1–2 nm) is ~25 and ~4000 times thinner than the PA (40–50 nm), and PU coatings (20–80 μm), respectively. Conventional polymer coatings are either non-conformal when deposited or degrade under the action of microbial processes, while the electro-chemically inert graphene coating is both resistant to microbial attack and is extremely conformal and defect-free. Finally, we provide a brief discussion regarding the effectiveness of as-grown vs. transferred graphene films for anti-MIC applications. While the as-grown graphene films are devoid of major defects, wet transfer of graphene is shown to introduce large scale defects that make it less suitable for the current application.

Monolayer Graphene Coating of Intracortical Probes for Long‐Lasting Neural Activity Monitoring

“…Finally, graphene can also play the role of a diffusion barrier, preventing toxic release from the probe and acting as a corrosion protection for the metal‐based electrodes that could also contribute to reduce the immune reaction . Regarding the slow degradation of graphene, the presence of graphene should still prevent the surface ions to diffuse out of the implant during the paroxysm of the inflammation (i.e., during the first week), and thus allow a better healing around the probe.…”

Stress-transfer from polymer substrates to monolayer and few-layer graphenes

“…Besides its use as reinforcing filler, graphene is used as a coating in conventional materials for inducing multi-functionality 10 . Various graphene coated applications have been demonstrated such as gilding of large structures 4 and protection from corrosion 11 .…”

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

“…It has been demonstrated that, factoring in the growth-induced defects, transferring a 2D material can further deteriorate the 2D material structure (Figure 8) [18]. For example, researchers have found that as grown graphene on a rough metal substrate, if transferred to a target substrate, provides poor 2D material quality (i.e., higher defect density).…”

“…Organic and polymer coatings have a relatively large thickness (up to several microns), which could adversely affect thermal and electrical conductivity as well as the component dimensionality [17]. Many traditional polymer coatings are susceptible to microbial corrosion, high-temperature degradation, and have inherent porosity [14,18].…”

“…The transferred graphene exhibits higher defect density compared to in-situ grown graphene. Adapted with permission from ref [18]. under Creative Commons Attribution 4.0 International License.…”