An Integrated Anti-Fouling and Anti-Corrosion Coating Enabled by rGO/AgNPs and Amphiphilic Networks

Marine corrosion and biofouling are challenges that affect marine industrial equipment,and protecting equipment with functional coatings is a simple and effective approach.However,it is extremely difficult to combine anti-corrosion and anti-fouling properties in a single coating.In this work,we combine reduced graphene oxide(rGO)/silver nanoparticles(AgNPs)with a hydrophilic polymer in a bio-based silicone-epoxy resin to create a coating with both anti-fouling and anti-corrosion properties.The excel-lent anti-fouling performance of the coating results from a ternary synergistic mechanism involving foul-ing release,contact inhibition,and a hydration effect,while the outstanding anti-corrosion performance is provided by a ternary synergistic anti-corrosion mechanism that includes a dense interpenetrating net-work(IPN)structure,a barrier effect,and passivation.The results show that the obtained coating pos-sesses superior anti-fouling activity against protein,bacteria,algae,and other marine organisms,as well as excellent anti-corrosion and certain self-healing properties due to its dynamic cross-linked net-work of rGO/AgNPs and the hydrophilic polymer.This work provides an anti-corrosion and anti-fouling integrated coating for marine industrial equipment.

Durable self-polishing antifouling Cu-Ti coating by a micron-scale Cu/Ti laminated microstructure design

Marine biofouling is a major issue deteriorating the service performance and lifespan of marine infrastructures.The development of a durable,long-term,and environment-friendly antifouling coating is therefore of significant importance but still a critical challenge in maritime engineering.Herein,we developed a Cu-Ti composite antifouling coating with micron-sized alternating laminated-structure of Cu/Ti by plasma spraying of mechanically mixed Cu/Ti powders.The coating was designed to enable controlled release of Cu ions through galvanic dissolution of Cu laminates from the Cu/Ti micro-galvanic cell in aqueous solution.Results showed that remarkable antifouling efficiency against bacterial survival and adhesion up to~100%was achieved for the Cu-Ti coating.Cu/Ti micro-galvanic cell was in-situ formed within Cu-Ti coating and responsible for its Cu ions release.The successive dissolution of Cu laminates resulted in the formation of micro-channels under Ti laminates near surface,which contributed to controlled slow Cu ions release and self-polishing effect.Thus,environment-friendly antifouling capability and∼200%longer antifouling lifetime than that of the conventional organic antifouling coatings can be achieved for the Cu-Ti coating.On the other hand,as compared to the conventional organic antifouling coatings,the Cu-Ti composite coating presented much higher mechanical durability due to its strong adhesion strength,excellent mechanical properties,and two orders lower wear rate.The present laminated Cu-Ti coating exhibits combination of outstanding antifouling performance and high mechanical durability,which makes this coating very potentially candidates in marine antifouling application.

Tyramine-enhanced zwitterion hyaluronan hydrogel coating for anti-fouling and anti-thrombosis

Zwitterions have aroused much interest to endow implantable medical devices with anti-fouling and anti-thrombosis performance,due to their ability to form a hydrated layer that can provide a good barrier against protein and cell adhesion. Herein,tyramine modified sulfobetaine-derived sodium hyaluronan(HST) hydrogel coating was fabricated, in which hyaluronan(HA)was used as polysaccharide skeleton to graft zwitterionic sulfobetaine, and tyramine was introduced as crosslinker to construct both the network of hydrogel and a strong covalent bond between coating and substrate. Hydrogel coating was prepared by spin coating or painting HST prepolymer solution under ultraviolet light irradiation. The obtained HST hydrogel coating shows good stability. Moreover, in addition to its outstanding anti-fouling performance and good biocompatibility, it can effectively prevent thrombosis in blood circulation ex vivo. This work offers a universal strategy to prepare a high-performance anti-fouling and antithrombosis coating, which is expected to promote the development of functional coatings for biomedical materials.

Zwitterionic-phosphonate block polymer as anti-fouling coating for biomedical metals

Antifouling ability and blood compatibility are critically important in the development of medical metallic implants for clinical applications.Here,we report the zwitterionic-phosphonate block polymer as a new type of high-efficiency antifouling coating for metallic substrates.Six block polymers(pSBMA-b-pDEMMP)with different segment lengths(nSBMA:nDEMMP=10:25,40:25,100:25,75:5,75:40,75:100)were prepared and anchored on titanium alloy(TC4)substrates.1H nuclear magnetic resonance(NMR)results clearly showed the precise preparation of the block polymers.XPS analysis and water contact angle measurement indicated the successful construction of the block polymer on TC4 substrates.The relationship between the antifouling performance of the polymer coating and the length of pDEMMP and pSBMA segments in the block polymer was established.Results showed that the polymer containing the pSBMA segment above 40 repeat units could significantly inhibit protein adsorption,platelet adhesion,bacterial adhesion and cell adhesion,while the pDEMMP segment above 5 repeat units is able to generate stable zwitterionic polymer coating on TC4 substrates.This ease of production and high-efficiency antifouling modification strategy elucidated here may find broad application for biomedical implants and devices in clinical applications.

The progress on antifouling organic coating: From biocide to biomimetic surface

The advancement in material science and engineering technology has led to the development of antifouling(AF) coatings which are cheaper, durable, less toxic, and safe to the environment. The use of AF coatings containing tributyltin compounds was prohibited at the beginning of 2003, this necessitated the development of environmentally friendly coatings. The fouling release coating(FRC) lacks biocides and has low surface energy, low elastic modulus with smooth surface properties, hence a better release effect to fouling organisms. Several functional coatings have been recently developed based on fouling release(FR) technology to combat the effects of biofouling. Here, we provide a brief overview of innovative technologies and recent developments based on FRCs, including silicone, modified fluorinated polymer,cross-linked coatings, amphiphilic copolymer coating, hydrogel coatings, and biomimetic coatings. We also highlight the key issues and shortcomings of innovative technologies based on FRCs. This may give new insights into the future development of marine AF coatings.

Environmentally friendly expanded graphite-doped ZnO superhydrophobic coating with good corrosion resistance in marine environment

Designing and fabricating the marine anti-corrosion materials without fluorine by superhydrophobic method is a huge challenge. In this study, an environmentally friendly composite coating was prepared by combing modified expanded graphite(EAG) with nano zinc oxide(ZnO). This coating showed superhydrophobic surface and good corrosion resistance. Fourier transform infrared spectroscopy(FITR), X-ray diffraction(XRD),and scanning electron microscopy(SEM) were used to characterize the materials in fabricating process of the coating. The properties of three composite coatings(ZnO,EAG, and EAG@ZnO) were analyzed, including surface roughness, water contact angle, corrosion resistance, selfcleaning and anti-fouling. The combination of ZnO and EAG caused a big water contact angle, leading superhydrophobic surface of the composite coatings. The electrochemical results showed that the superhydrophobic EAG@ZnO coating had a larger capacitive arc diameter and charge transfer resistance, indicating the enhanced anti-corrosion resistance. Meanwhile, the EAG@ZnO coating also showed good self-cleaning and anti-fouling performance according to solid and liquid pollutants tests.In addition, the mechanical properties and stability of the superhydrophobic EAG@ZnO coatings were evaluated by knife peeling and finger scratch tests. In summary, these superhydrophobic and anti-fouling EAG@ZnO composite coatings provide a potential application in marine corrosion and protection field.