Anti-marine biofouling adhesion performance and mechanism of PDMS fouling-release coating containing PS-PEG hydrogel

Introducing PES porous membrane to establish bionic autocrine channels: A lubricating, anti-wear antifouling coating

As a global challenge, marine biofouling is causing serious economic losses and adverse ecological impacts. In recent years, a variety of promising and environmentally friendly anti-fouling strategies have emerged, among which the excellent anti-fouling performance of bionic autocrine coatings has been recognized. However, bionic autocrine coatings still suffer from uncontrollable secretion behavior, poor mechanical stability, and poor abrasion resistance. Inspired from dolphin skin, this study establishes an antifouling system i-PDMS/PES coating with lubrication based on secretion channels and resistance to abrasion properties by coupling a polyethersulfone (PES) porous membrane to the surface of secretion substance- silicone oil-infused polydimethylsiloxane (PDMS) pre-polymer coating. The secretion behavior of the secreted substances on the coating surface, the tribological properties of the coating surface, and the adhesion properties of marine bacteria and benthic diatoms were explored. The results showed that the secreted substances were rapidly secreted on the surface of the i-PDMS/PES coating to form a continuous lubricating film, and at the same time had an efficient self-replenishing ability, thus that not only effectively reduces the friction coefficient of the coating, but also mitigates the mechanical damage of the coating surface during friction. In additional, the continuous lubrication film formed by autocrine secretion improves the antifouling performance of the coating. Considering the actual application environment of antifouling coatings in the ocean, this study proposes a new solution to the problem of the long-term effectiveness of antifouling coatings.

Sustainable Coating Based on Zwitterionic Functionalized Polyurushiol with Antifouling and Antibacterial Properties

Zwitterionic polymer coatings facilitate the formation of hydration layers via electrostatic interactions on their surfaces and have demonstrated efficacy in preventing biofouling. They have emerged as a promising class of marine antifouling materials. However, designing multifunctional, environmentally friendly, and natural products-derived zwitterionic polymer coatings that simultaneously resist biofouling, inhibit protein adhesion, exhibit strong antibacterial properties, and reduce algal adhesion is a significant challenge. This study employed two diisocyanates as crosslinkers and natural urushiol and ethanolamine as raw materials. The coupling reaction of diisocyanates with hydroxyl groups was employed to synthesize urushiol-based precursors. Subsequently, sulfobetaine moieties were introduced into the urushiol-based precursors, developing two environmentally friendly and high-performance zwitterionic-functionalized polyurushiol antifouling coatings, denoted as HUDM-SB and IPUDM-SB. The sulfobetaine-functionalized polyurushiol coating exhibited significantly enhanced hydrophilicity, with the static water contact angle reduced to less than 60°, and demonstrated excellent resistance to protein adhesion. IPUDM-SB exhibited antibacterial efficacy up to 99.9% against common Gram-negative bacteria (E. coli and V. alginolyticus) and Gram-positive bacteria (S. aureus and Bacillus. sp.). HUDM-SB achieved antibacterial efficacy exceeding 95.0% against four bacterial species. Furthermore, the sulfobetaine moieties on the surfaces of the IPUDM-SB and HUDM-SB coatings effectively inhibited the growth and reproduction of algal cells by preventing microalgae adhesion. This zwitterionic-functionalized polyurushiol coating does not contain antifouling agents, making it a green, environmentally friendly, and high-performance biomaterial-based solution for marine antifouling.