Enhancing the Robustness of Superhydrophobic Coatings via the Addition of Sulfide

Durable Photothermal Superhydrophobic Coating Comprising Micro- and Nanoscale Morphologies and Water-Soluble Siloxane for Efficient Anti-Icing and Deicing

Photothermal superhydrophobic coatings offer immense promise for anti-icing and deicing applications. However, achieving long-term passive anti-icing and active deicing in photothermal superhydrophobic coating remains a significant challenge. We introduce a durable photothermal superhydrophobic coating, coprepared from water-soluble polytrimethylsiloxane (PMATF) in synergy with cactus-inspired composite nanoparticles (MPCS), which is composed of MoS2, polydopamine (PDA), Cu nanoparticles, and octadecanethiol (18-SH). The PM-MPCS coating exhibits a maximum water contact angle (WCA) of 171.8° and retains a high WCA after 330 cycles of sandpaper abrasion and 210 cycles of tape peeling. Additionally, the PM-MPCS coating exhibits exceptional photothermal conversion ability. The PM-MPCS films attain a surface temperature of 86.9 °C, displaying a photothermal conversion efficiency of 77.4%. In anti-icing tests conducted at -15 °C, PM-MPCS significantly prolonged the freezing time; the freezing time of a 5 μL water droplet was extended to 43 min. The active deicing performance is similarly effective, with PM-MPCS melting a 5 μL ice sphere in 5.5 min. Furthermore, PM-MPCS exhibits a low ice adhesion strength of 6.0 kPa, enabling effective ice removal even after numerous freeze-thaw cycles. The exceptional anti-icing and deicing performance can be attributed to the synergistic effects of the composite nanoparticles, which minimize ice penetration and enhance the photothermal conversion capabilities of the particles. These findings underscore the potential of PM-MPCS as a viable candidate for advanced anti-icing and deicing applications across various industries.

Formation of Robust Polydimethylsiloxane Coatings on the Flexspline Material and Mechanism of the Tribological Property Improvement

Flexspline frictional degradation causes failure of harmonic drives. This study focused on the improvement of the flexspline tribological properties. Flexspline material 40Cr was modified with a robust polydimethylsiloxane (PDMS) coating. Etched and chemically modified films were utilized to enhance the organic PDMS coating-substrate link strength. Comparing modified and unmodified 40Cr, the surface friction coefficient decreased by 82.2%. Moreover, the modified 40Cr exhibited excellent load-bearing properties. The effects of speed and lubricant-coating interaction on the tribological properties were verified. This study provides an essential theoretical basis for improving the tribological performance of harmonic drives via soft coating modification.

Nanofiber Composite Coating with Self-Healing and Active Anticorrosive Performances

Synergetic self-healing anticorrosion behaviors, by forming a self-assembly protective layer and repairing coating passive barrier, exhibit great potential in handling the notorious metal corrosion phenomenon. Herein, we developed a nanofiber-supported anticorrosion coating with synergistic protection effects of both self-healing and active corrosion inhibition, via a facile electrospinning combined coating technique. Polycaprolactone (PCL) nanofiber integrated with 2-mecapobenzothiazole-loaded halloysite nanotubes (HNTs-MBT) is directly deposited on the surface of metal substrate, forming an interconnected fiber network framework. The encapsulated corrosion inhibitor MBT can be released by a pH-triggered manner to realize instant corrosion protections. Additionally, coating defects could be repeatedly repaired by continuous polymer fiber upon heat treatment and the anticorrosion efficiency effectively remained, even after three cycles of damage-healing. Moreover, the repaired coating also exhibited durable anticorrosion performance, mainly attributed to the synergetic effects of both thermal-triggered bulk healing and active corrosion inhibition. This type of dual-functional coating provides efficient anticorrosive performances and may show great promise in long-term corrosion protection.

Robust Superamphiphobic Coatings Based on Raspberry-like Hollow SnO2 Composites

Good mechanical and chemical stabilities are the key factors for the wide application of superhydrophobic surfaces. In this work, we first prepared raspberry-like hollow structured SnO₂ nanoparticles using a simple hydrothermal method, followed by an annealing step. Then, the intrinsic raspberry-like hollow SnO₂ nanoparticles were combined with hydrophilic SiO₂ nanoparticles to construct rough surfaces with suitable hierarchical structures, and 1H,1H,2H,2H-perfluorodecyltriethoxysilane (FAS-17) was used as a hydrophobic modifier of SnO₂, while epoxy resin was used as an adhesive to prepare a superamphiphobic coating with good stability and durability. Such a coating can be applied on various substrates using a simple spray-coating or drop-coating method. The water contact angle and diiodomethane contact angle of the coating could reach up to ∼165 and ∼151°, respectively. After various chemical and mechanical stability tests including hot water treatment, salt water corrosion, strong adhesive tape peeling, and kneading, the coatings still remained amphiphobic. The facile fabrication of the robust superhydrophobic coating has great potential for applications in real life and industrial production.