Fabrication of Stable Liquid-like Wetting Buckled Surfaces as Bioinspired Antibiofouling Coatings by Using Silicon-Containing Block Copolymers

Inspired by animals with a slippery epidermis, durable slippery antibiofouling coatings with liquid-like wetting buckled surfaces are successfully constructed in this study by combining dynamic-interfacial-release-induced buckling with self-assembled silicon-containing diblock copolymer (diBCP). The core diBCP material is polystyrene-block-poly(dimethylsiloxane) (PS-b-PDMS). Because silicon-containing polymers with intrinsic characters of low surface energy, they easily flow over and cover a surface after it has undergone controlled thermal treatment, generating a slippery wetting layer on which can eliminate polar interactions with biomolecules. Additionally, microbuckled patterns result in curved surfaces, which offer fewer points at which organisms can attach to the surface. Different from traditional slippery liquid-infused porous surfaces, the proposed liquid-like PDMS wetting layer, chemically bonded with PS, is stable and slippery but does not flow away. PS-b-PDMS diBCPs with various PDMS volume fractions are studied to compare the influence of PDMS segment length on antibiofouling performance. The surface characteristics of the diBCPs─ease of processing, transparency, and antibiofouling, anti-icing, and self-cleaning abilities─are examined under various conditions. Being able to fabricate ecofriendly silicon-based lubricant layers without needing to use fluorinated compounds and costly material precursors is an advantage in industrial practice.

Research Progress on Low-Surface-Energy Antifouling Coatings for Ship Hulls: A Review

The adhesion of marine-fouling organisms to ships significantly increases the hull surface resistance and expedites hull material corrosion. This review delves into the marine biofouling mechanism on marine material surfaces, analyzing the fouling organism adhesion process on hull surfaces and common desorption methods. It highlights the crucial role played by surface energy in antifouling and drag reduction on hulls. The paper primarily concentrates on low-surface-energy antifouling coatings, such as organic silicon and organic fluorine, for ship hull antifouling and drag reduction. Furthermore, it explores the antifouling mechanisms of silicon-based and fluorine-based low-surface-energy antifouling coatings, elucidating their respective advantages and limitations in real-world applications. This review also investigates the antifouling effectiveness of bionic microstructures based on the self-cleaning abilities of natural organisms. It provides a thorough analysis of antifouling and drag reduction theories and preparation methods linked to marine organism surface microstructures, while also clarifying the relationship between microstructure surface antifouling and surface hydrophobicity. Furthermore, it reviews the impact of antibacterial agents, especially antibacterial peptides, on fouling organisms' adhesion to substrate surfaces and compares the differing effects of surface structure and substances on ship surface antifouling. The paper outlines the potential applications and future directions for low-surface-energy antifouling coating technology.

Thiol-triggered deconstruction of bifunctional silyl ether terpolymers via an SNAr-triggered cascade

While Si-containing polymers can often be deconstructed using chemical triggers such as fluoride, acids, and bases, they are resistant to cleavage by mild reagents such as biological nucleophiles, thus limiting their end-of-life options and potential environmental degradability. Here, using ring-opening metathesis polymerization, we synthesize terpolymers of (1) a "functional" monomer (e.g., a polyethylene glycol macromonomer or dicyclopentadiene); (2) a monomer containing an electrophilic pentafluorophenyl (PFP) substituent; and (3) a cleavable monomer based on a bifunctional silyl ether . Exposing these polymers to thiols under basic conditions triggers a cascade of nucleophilic aromatic substitution (SNAr) at the PFP groups, which liberates fluoride ions, followed by cleavage of the backbone Si-O bonds, inducing polymer backbone deconstruction. This method is shown to be effective for deconstruction of polyethylene glycol (PEG) based graft terpolymers in organic or aqueous conditions as well as polydicyclopentadiene (pDCPD) thermosets, significantly expanding upon the versatility of bifunctional silyl ether based functional polymers.

Nucleophilic Aromatic Substitution of Pentafluorophenyl-Substituted Quinoline with a Functional Perylene: A Route to the Modification of Semiconducting Polymers

A systematic study of the influence of the chemical substitution pattern of semiconducting polymers carrying side chain perylene diimide (PDI) groups is presented. Semiconducting polymers based on perflurophenyl quinoline (5FQ) were modified via a readily accessible nucleophilic substitution reaction. The perfluorophenyl group was studied as an electron-withdrawing reactive functionality on semiconducting polymers that can undergo fast nucleophilic aromatic substitution. A PDI molecule, functionalized with one phenol group on the bay area, was used for the substitution of the fluorine atom at the para position in 6-vinylphenyl-(2-perfluorophenyl)-4-phenyl quinoline. The final product was polymerized under free radical polymerization providing polymers of 5FQ incorporated with PDI side groups. Alternatively, the post-polymerization modification of the fluorine atoms at the para position of the 5FQ homopolymer with the PhOH-di-EH-PDI was also successfully tested. In this case, the PDI units were partially introduced to the perflurophenyl quinoline moieties of the homopolymer. The para-fluoro aromatic nucleophilic substitution reaction was confirmed and estimated via ¹H and ¹⁹F NMR spectroscopies. The two different polymer architectures, namely, fully or partially modified with PDI units, were studied in terms of their optical and electrochemical properties, while their morphology was evaluated using TEM analysis, revealing polymers of tailor-made optoelectronic and morphological properties. This work provides a novel molecule-designing method for semiconducting materials of controlled properties.

Accessing the Thiol Toolbox: Synthesis and Structure-Activity Studies on Fluoro-Thiol Conjugated Antimicrobial Peptides

The para-fluoro-thiol reaction (PFTR) is a modern name for the much older concept of a nucleophilic aromatic substitution reaction in which the para-position fluorine of a perfluorinated benzene moiety is substituted by a thiol. As a rapid and mild reaction, the PFTR is a useful technique for the post-synthetic modification of macromolecules like peptides on the solid phase. This reaction is of great potential since it allows for peptide chemists to access the vast catalogue of commercially available thiols with diverse structures to conjugate to peptides, which may impart favorable biological activity, particularly in antimicrobial sequences. This work covers the generation of a library of antimicrobial peptides by modifying a relatively inactive tetrapeptide with thiols of various structures using the PFTR to grant antimicrobial potency to the core sequence. In general, nucleophilic substitution of the peptide scaffold by hydrophobic thiols like cyclohexanethiol and octanethiol imparted the greatest antimicrobial activity over that of hydrophilic thiols bearing carboxylic acid or sugar moieties, which were ineffectual at improving the antimicrobial activity. The general trend here follows expected structure-activity relationship outcomes like that of changing the acyl group of lipopeptide antibiotics and is encouraging for the use of this reaction for structural modifications of antimicrobial sequences further.

C1 Polymerization of Fluorinated Aryl Diazomethanes

A library of fluorinated aryl diazomethanes were polymerized using BF₃·OEt₂ as a catalyst. The polymerization of 2,3,4,5,6-pentafluorophenyl diazomethane was found to be controlled, permitted chain extensions, and facilitated access to a series of block copolymers. Moreover, the polymer chains grew in one carbon increments (so-called "C1 polymerizations") and, as such, afforded highly substituted polymers that featured aryl units pendant to every carbon atom of the backbone. The polymers were characterized using size exclusion chromatography, various spectroscopic techniques, and a series of static and dynamic contact angle measurements. Compared to less-substituted analogues that were prepared using typical C2 polymerization methodologies, the C1 fluorinated polymers were found to be more hydrophobic while maintaining a sufficient solubility to be processed into robust films.

Versatile polymer-based strategies for antibacterial drug delivery systems and antibacterial coatings

Human health damage and economic losses due to bacterial infections are very serious worldwide. Excessive use of antibiotics has caused an increase in bacterial resistance. Fortunately, various non-antibiotic antibacterial materials...

Synthesis, aqueous solution behavior and self-assembly of a dual pH/thermo-responsive fluorinated diblock terpolymer

The synthesis of fluorinated dual-responsive block terpolymers via sequential reversible addition–fragmentation chain transfer (RAFT) polymerization is presented.

Multifunctional Antibacterial Materials Comprising Water Dispersible Random Copolymers Containing a Fluorinated Block and Their Application in Catheters

Inhibiting the attachment of bacteria and the formation of biofilms on surfaces of materials and devices is the key to ensure public safety and is also the focus of attention and research. Here we report on the synthesis of multifunctional antibacterial materials based on water dispersible random copolymers containing a fluorinated block, poly(acrylic acid-co-1H,1H,2H,2H-perfluorododecyl acrylate) (PAA-co-PFDA), and poly(hexamethylene biguanide) hydrochloride (PHMB). PAA-co-PFDA copolymers were synthesized through a simple free radical polymerization. After lightly cross-linking of PAA-co-PFDA and complexation with PHMB, multifunctional antibacterial PAA-co-PFDA/PHMB complex nanoparticles were generated, which can form transparent coatings on various substrates. The resultant coating has aggregation-induced emission character which can be used to observe the uniformity of the coating on a catheter and has a potential application as a fluorescence probe. It has been demonstrated that the PAA-co-PFDA/PHMB complex nanoparticle coatings can resist bacterial adhesion in physiological environment and exhibit excellent antibacterial activity in infection environment. In vitro and in vivo experiments indicated that the PAA-co-PFDA/PHMB complex nanoparticle coated catheters exhibited excellent antibacterial activity and possessed good biocompatibility. This method is simple and scalable, which is important for future commercialization. The attractive multifunctional properties of the PAA-co-PFDA/PHMB complex nanoparticles, such as antifouling, antimicrobial, emission, and pH-responsive release character, have great potential application in a wide range of biomedical fields.

The para-fluoro-thiol reaction as an efficient tool in polymer chemistry

The current literature describing the application of the para-fluoro–thiol reaction in the realm of macromolecular chemistry and the future of this coupling strategy are discussed.

Biodegradation Studies of Novel Fluorinated Di-Vinyl Urethane Monomers and Interaction of Biological Elements with Their Polymerized Films

The monomeric components of resin composites in dental restorative materials are susceptible to hydrolysis in the oral cavity. The main objective of this study was to assess the bio-stability of fluorinated urethane dimethacrylates and determine the nature of fluoro-chemistry interactions with protein and bacterial adhesion (both sources of hydrolytic activity) onto cured resin. Degradation studies were performed in the presence of either albumin (in a mildly alkaline pH) or cholesterol esterase (CE). The surface chemistry of the polymers was assessed by water contact angle measurements, pre- and post- incubation with albumin. Adhesion of Streptococcus mutans to cured resin was investigated. The fluorinated monomers were more stable against degradation when compared to the commercial monomer bisphenol A-diglycidyl methacrylate (BisGMA). While fluorinated monomers showed hydrolytic stability with respect to CE, all fluorinated monomers underwent some degree of degradation with albumin. The fluoro-chemistry did not reduce protein and/or bacterial adhesion onto the surface, however post incubation with albumin, the fluorinated surfaces still presented hydrophobic character as determined by the high contact angle values ranging from 79° to 86°. These monomers could potentially be used to increase the hydrophobicity of polymeric composites and provide a means to moderate esterolytic degradation associated with the monomeric component of the polymers within the oral cavity.