A Superhydrophilic, Light/Microwave-Absorbing Coating with Remarkable Antibacterial Efficacy

Abstract

Driven by the overuse of antibiotics, pathogenic infections, dominated by the rapid emergence of antibiotic resistant bacteria, have become one of the greatest current global health challenges. Thus, there is an urgent need to explore novel strategies that integrate multiple antibacterial modes to deal with bacterial infections. In this work, a Co­(Ni,Ag)/Fe­(Al,Cr)2O4 composite duplex coating was fabricated using template-free sputtering deposition technology. The phase constitution of the coating was estimated to be 79 wt % Fe­(Al,Cr)2O4 phase and 21 wt % of an Ag-containing metallic phase. The composite coating consisted of a ∼10 μm-thick porous outer-layer and a ∼6 μm-thick compact inner-layer, in which the outer-layer is composed of a densely stacked array of microscale cones. After exposure to ambient air for 14 days, the composite coating showed a wettability transition from a superhydrophilic nature to exhibit adhesive superhydrophobic behavior with a water contact angle of 142° ± 2.8°, but it reverted to its initial superhydrophilic state after annealing in air at 200 °C for 5 h. The absorption rate of the as-received composite coating exceeds 99% in a broad band spanning both the visible and NIR regions and showed a high photothermal efficiency to convert photon energy into heat. Similarly, the composite coating showed microwave absorption behavior with a minimum reflection loss value of 38 dB at 4.4 GHz. In vitro antibacterial tests were used to determine the antibacterial behavior of the composite coating against Escherichia coli and Staphylococcus aureus after 60 min of visible light irradiation. After this exposure, the as-prepared composite coating exhibited nearly 100% bactericidal efficiency against these bacteria. The antibacterial behavior of the coating was attributed to the synergistic effects of the superhydrophilic surface, the release of Ag+ ions, and the photothermal effect. Therefore, this composite coating may be a promising candidate to efficiently combat medical device-associated infections.

Photothermal Superhydrophobic Cotton Fabric Based on Silver Nanoparticles Cross-Linked by Polydopamine and Polyethylenimide

“…As a kind of renewable and clean energy, solar energy can greatly alleviate the energy crisis. Photothermal conversion materials can convert solar energy into renewable energy, which can be widely used in many fields such as energy storage, − photothermal deicing, − photothermal antibacterial, − seawater desalination, − and photocatalysis , to meet different needs. However, photothermal materials are easily polluted in outdoor environment, so it is imperative to develop self-cleaning photothermal materials. , Superhydrophobic materials are a kind of material with ultrahigh water contact angle (WCA), − which can effectively improve the cleanliness of the surface, so as to achieve good cleaning effect. , In addition, superhydrophobic photothermal materials have a bright prospect in a wide range of applications. − …”

Exploring multielement nanogranular coatings to forestall implant-related infections

“…In this perspective, the NPs loading amount and the relative elemental concentration inside the nanogranular building blocks are of paramount importance ( Hu et al., 2014 ; Benetti et al., 2017 ; Benetti et al., 2019 ) and are usually provided in µg/cm 2 for coatings obtained by physical deposition methods. Typical values for magnetron sputtered coatings are ranging from 75 µg/cm 2 for Ag supported on boron nitride ( Gudz et al., 2022 ), to 210 µg/cm 2 for a mixed Ag/TiAlVN compound ( Marín et al., 2022 ) and up to 2000 µg/cm 2 for AgCo/Fe(Al, Cr)2O 4 microstructure ( Xu et al., 2022 ). When atomic layer deposition is employed, the metal amount changes from 157 µg/cm 2 for Ag/TiO 2 nanostructures ( Nazarov et al., 2022 ) down to a few µg/cm 2 for AgNP deposited on a steel surface ( González et al., 2021 ).…”

Magnetically driven hierarchically ordered carbonyl iron@SiO2/Ni@Ag/silicone rubber composite film for enhanced electromagnetic interference shielding with ultralow reflection

“…, Fe, Co, Ni). 33,34 Among them, CI microparticles stand out due to their excellent magnetization properties and easy large-scale preparation. To broaden the effective absorption band of CI microparticles, SiO 2 nanoparticles could be coated on their surfaces to endow them strong dielectric loss and good chemical stability.…”

“…In general, good magnetism is a prerequisite for microparticles to serve as EMW absorbers, such as ferrites (e.g., CoFe 2 O 4 , Fe 3 O 4 ), 30,31 carbonyl iron (CI), 32 and metals (e.g., Fe, Co, Ni). 33,34 Among them, CI microparticles stand out due to their excellent magnetization properties and easy large-scale preparation. To broaden the effective absorption band of CI microparticles, SiO 2 nanoparticles could be coated on their surfaces to endow them strong dielectric loss and good chemical stability.…”