Contact Angle Research Articles

Development of novel, efficient, and environmentally friendly degradable Fe3O4@CNTs/PLA membranes, and recovery of inorganic particles

Conventional organic membranes are difficult to recycle and degrade after use, which brings a burden to the environment. Modified particles have a significant impact in improving membrane performance, but if not handled properly, it may also have a negative impact on the environment. To address the above problems, carbon nanotubes (CNTs) is firstly coated by Fe3O4, and then hybridized with polylactic acid (PLA) to prepare novel degradable Fe3O4@CNTs/PLA membranes under the assistance of magnetic field. The structure and properties of PLA membrane are effectively improved by regulating the content of Fe3O4@CNTs and their distribution in PLA membrane. The porosity and pore size increases, and the contact angle decreases from 77.2° to 65.1°. The pure water permeability demonstrates an increase from 127.5 L/m2/h/bar to 250.8 L/m2/h/bar, and the bovine serum albumin rejection are all kept above 85.0 %. Moreover, the flux recovery rate increases from 85.3 % to 94.2 %, and the anti-fouling property is improved. In addition, the performance of Fe3O4@CNTs/PLA membrane is relatively stable during service. After use, the PLA in the hybrid membrane can be degraded by protease, while the Fe3O4@CNTs particles can be recycled by magnet attraction and reused afterward. This research offers a viable approach for the development of novel, efficient and environmentally friendly degradable membranes, as well as introduces a new idea for the recovery and reuse of nanoparticles.

Preparation of superhydrophobic polyurethane sponge with photodegradation function and study on its oil-water separation performance

The surface of tetrapod-shaped zinc oxide whiskers (T-ZnOw) was hydrophobized by the sol-gel method, and then loaded onto the surface of polyurethane sponge by dip-curing method to prepare a superhydrophobic polyurethane sponge with photodegradation function. When the mass ratio of superhydrophobic tetrapod-shaped zinc oxide whiskers (ST-ZnOw) and polydimethylsiloxane (PDMS) was 0.5:1, the water contact angle of the sponge was 157.5°. After being soaked in acid and alkali corrosion solution, rubbed with sandpaper and heat treated, the sponge can still maintain excellent hydrophobic properties. The adsorption capacity for different oils and organic solvents is 12 to 35 times of its own mass. After repeated extrusion-oil absorption experiments, it can still maintain its good adsorption capacity and high hydrophobicity, showing excellent reusability. The continuous oil-water separation efficiency of the material for different oils and organic solvents is above 95%, and the separation efficiency for the emulsion prepared with span80 content of 0.1wt% is 99.84%. At the same time, the prepared material can degrade the organic dye methylene blue under ultraviolet light, with a degradation rate of 99.35%, showing excellent potential for degrading organic pollutants.

Preparation and characterization of mangiferin-loaded polylactic acid nanofiber mat with antioxidant and anti-browning properties for the development of food packaging products

In this study, antioxidant nanofiber-based food packaging material composed of polylactic acid (PLA) and mangiferin (MG) was produced to reduce food spoilage. To this end, MG was extracted from Mangifera indica and chemically characterized. In vitro assays for scavenging several radical ions showed excellent antioxidant properties of MG. Thereafter, MG was blended with PLA to form nanofibers (PLA-MG) using electrospinning. The Field Emission-Scanning Electron Microscopy (FE-SEM) images of the prepared nanofibers displayed defect-free homogeneous morphology with an average fiber diameter of 176.89 ± 61.97 nm. Fabricated nanofibers were physico-chemically characterized. From chromatography, mangiferin content in the PLA-MG fiber was found to be 40.55 ± 3.7 μg/mg of fiber. Contact angle measurements of the fabricated nanofibers showed the hydrophobic nature of PLA-MG nanofibers. PLA-MG nanofibers demonstrated a significantly higher antioxidant activity compared to PLA nanofibers (****p < 0.0001), as evidenced by their superior performance in DPPH, ABTS, and FRAP assays. Specifically, PLA-MG nanofibers exhibited 3676 ± 3.46 mg/100 g vitamin C equivalents in antioxidant activity (VCEAC) and 1866 ± 2.12 VCEAC in ABTS and DPPH radical scavenging assays respectively. Further, apples wrapped with PLA-MG nanofibers showed that the browning of the fruit decreased when compared with controls. The MTT assay and live-dead assay indicated that the fabricated nanofibers were cytocompatible with L929 fibroblasts. The results showed that the fabricated PLA-MG nanofibers can be an effective non-toxic food packaging material to increase the shelf-life of the food. Finally, PLA-MG nanofiber-coated food container production was demonstrated to be commercialized for the effective transportation of food.

Influence of gaseous dielectrics on the wettability of Al-6061 alloy using dry μ-electrical discharge milling

Superhydrophobic surfaces are essential for applications such as self-cleaning and corrosion resistance. This study explores the fabrication of superhydrophobic surfaces on Al-6061 alloy using dry micro electrical discharge milling (μEDM milling) and investigates the effects of gaseous dielectrics on wettability under atmospheric conditions. Surfaces machined in an oxygen environment showed a surface area roughness (Sa) of 4.68 μm, 73.3 % higher than those machined in argon, attributed to enhanced metal oxide formation. Energy Dispersive X-ray Analysis (EDAX) indicated a significantly elevated O/Al atomic ratio of 0.80 for oxygen-machined samples, which was 73.9 % greater than argon-machined samples, suggesting the presence of hydrophilic compounds such as AlO(OH) and Al2O3. Additionally, X-ray Photoelectron Spectroscopy (XPS) revealed that Al2O3 peaks on oxygen-machined surfaces were broadened and shifted to higher binding energies, correlating with decreased contact angles and increased surface hydrophilicity. These results suggest that using oxygen as a dielectric in theelectrical discharge machining (EDM) process promotes oxide layer formation, resulting in hydrophilic characteristics, while machining in argon encourages organic adsorption and greater hydrophobicity. The findings of this research provide insights that can inform future efforts to tailor surface properties for advancements in aerospace, automotive, and biomedical engineering applications.

Multifunctional superhydrophobic sugarcane bagasse capable of efficiently separating oil-water mixtures and degrading MB

Biodegradable and low-cost superhydrophobic absorption materials are still urgently required for the removal of organic compounds from sewage. In this study, sugarcane bagasse (SCB), an abundant and readily available byproduct from sugarcane industries, was used as substrate to fabricate the superhydrophobic adsorbent through a facile dip-coating technique. Firstly, β-FeOOH particles were in-situ grown on the SCB surface, which was further decorated with SiO2 particles. Next, the modified SCB were coated with benzoxazine based on cardanol and dodecylamine (CD) followed by a thermal curing to obtain a superhydrophobic SCB (PC-D/β-FeOOH@SiO2/SCB) with a water contact angle (WCA) of 154°. PC-D/β-FeOOH@SiO2/SCB not only exhibited excellent oil absorption capacities in the range of 11.8 to 22.6 g/g for various organic solvents and oils, but also could successfully separate immiscible oil-water mixtures and emulsions with a separation efficiency of over 99.1 %. After 30 cycles of use, the absorption capacity of the modified SCB only displayed a slight decrease and its separation efficiencies for immiscible oil-water mixture, water-in-oil and oil-in-water emulsions are all more than 99.2 %, meanwhile, all these repeatedly used SCB still maintained a superhydrophobicity, demonstrating an outstanding reusability. Moreover, the WCA of PC-D/β-FeOOH@SiO2/SCB was still higher than 150o after 48 h of immersion in HCl, NaOH and NaCl solutions, exhibiting a satisfactory chemical stability. Besides, the prepared SCB also possessed a high photocatalytic degradation activity to methylene blue. Therefore, this work not only provides a sustainable and cheap superhydrophobic absorbent for wastewater treatment, but also presents a route for the better utilization of SCB.

Controlled migration of oleic acid amide through adsorption on TS-1 zeolite for long-lasting anti-adhesive rubber composites

The adhesion of materials on the surface can affect the appearance, durability, and performance stability of rubber composites. Incorporating anti-adhesive additives into composites is an effective strategy to improve anti-adhesive properties, as these additives migrate to the surface to form an anti-adhesive layer. However, excessive migration rates can result in poor durability of the anti-adhesive layer and significant powder adhesion on the surface. This study prepared titanium silicate zeolite adsorbed with acid amide composite filler (OAA@TS-1) by adsorbing OAA onto the active sites of TS-1, which was then incorporated into natural rubber (NR). The adsorption effect reduces the migration rate of OAA within the rubber composite, allowing more OAA to remain in the matrix. Additionally, the adsorption is reversible, and the adsorbed OAA can overcome the adsorption through molecular thermal motion, which can migrate to the surface. After the anti-adhesive layer is worn, OAA can persistently migrate outward, effectively repairing the layer and enhancing the durability of the anti-adhesive properties. In comparison to rubber composites filled solely with OAA, the OAA@(TS-1) filled rubber composite exhibits a remarkable reduction of 55% in the amount of adherent powder on the composite surface and a 24% decrease in the coefficient of friction after three friction cycles. After slicing and leaving for 3 days, the contact angle increases by 18%. The long-lasting anti-adhesive rubber composite developed in this study demonstrates significant application potential in areas such as material conveyance and power transmission.

The effect of the modified starch with side chain on the morphology of copper particles and the antibacterial properties of starch/copper composite material

In this paper, corn starch was modified by acetylation, esterification and amination, and the effects of different modifications on the structure and physicochemical properties of starch were investigated. And starch/copper composite materials were prepared by adding copper salts to the different modified starch, and the influence of modified starch and their additive amount on the morphology of copper and the antimicrobial properties were discussed. The results showed that: the contact angle of the modified starch was about 50° and exhibited hydrophilic-hydrophobic transition; the esterified starch had the smallest heat weight loss; the different modifications caused damage to the structure of the starch, which changed from the original smooth surface to a rough and wrinkled surface; hexahedral morphology copper particles were obtained by replacing them with the modified starch; the antimicrobial effect of the prepared starch/copper composite materials were related to the modification mode of starch, in which aminated starch show the best antimicrobial effect. This study provides a theoretical basis for the selection of starch type in the preparation of starch/copper composite materials in the future, which can also be used as antimicrobial components in other applications.

Moisture‐Resistant Nanofiber Membrane Loaded with Copper‐Manganese‐Tin Oxides for Dust and CO Filtration in High Humidity Environments

AbstractThis study presents a novel protective membrane, (0.8MnCuSnOx‐NaCl)@M, designed for high‐efficiency filtration of dust particles and carbon monoxide (CO) gas offers superior moisture resistance, air permeability, and catalytic functionality in high‐humidity underground settings. The membrane, incorporating tin oxide‐doped CuMnOx into polyvinylidene fluoride (PVDF) fibers with sodium chloride (NaCl), achieves 99.99% air filtration efficiency, 323.68 mm s−1 air permeability, and 92.5% CO catalytic filtration efficiency. Concurrently, the membrane exhibited exceptional hydrophobicity, characterized by a substantial water contact angle of 116.7°, negligible water staining, and a high hydrostatic pressure rating of 2035 Pa, suitable for humid environments. Furthermore, the water absorption profile of the membrane featured a diminished hydroxyl vibrational band, accompanied by a sustained CO conversion efficiency, attesting to its resistance to moisture‐induced deterioration. Computational fluid dynamics (CFD) simulations further clarify the membrane's filtration mechanism, indicating its potential for selective CO and particle filtration. This study provides a reliable idea for the development of moisture‐resistant fiber membranes with high efficiency for filtration of dust and CO. and underscores the synergy of experimental and theoretical approaches.

Melt-Blown Polypropylene Membrane Modification for Enhanced Hydrophilicity.

Melt-blown, an environmentally friendly technique, is widely used to create high-quality non-woven fabrics by extruding molten polymer resins into interlaced fibers. In the realm of biomedical textiles, its unique microstructure makes it ideal for filtration and wound dressings. Our study focuses on modifying the surfaces of polypropylene melt-blown membranes. An effective, one-step, suitable, and reliable method to graft a bioactive polymer, sodium polystyrene sulfonate-PolyNaSS, onto the membranes has been developed. The process involves UV irradiation to initiate direct and progressive growth of NaSS over the surface through radical polymerization. To assess the efficiency of the grafting, techniques like colorimetry, water contact angle measurements, Fourier-transformed infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) were used. Outcomes related to the grafting were demonstrated by a change in wettability and quantitatively calculated sulfonate groups. Subsequently, grafted PolyNaSS promoted cell adhesion, as evidenced by improved cell morphology. On grafted membranes, fibroblasts exhibited a stretched shape, while non-grafted ones showed inactive round shapes. These findings underscore the chemical and biological reactivity of polypropylene materials, opening exciting possibilities for various applications of melt-blown materials.

Starch-pectin smart tag containing purple carrot peel anthocyanins as a potential indicator of analogous meat freshness

Smart films of starch/pectin and purple carrot peel (PCP) containing anthocyanins were developed, characterized, and used as pH-responsive tags to monitor plant-based chicken analogous. This study innovates by incorporating PCP in the film solution both as an extract and as a powder, and the resulting tags were applied to a plant-based food. PCP powder <100-mesh was directly incorporated into the film-forming suspension. For powder >100-mesh, two extracts were tested: an aqueous solution and a 1 % NADES solution added to the film-forming suspension. Quantification of PCP anthocyanins by HPLC showed a higher extraction under acidic conditions (1664 mg C3G equivalents 100 g−1). Films with PCP presented greater light protection. Films with 15 % and 25 % PCP and those with added extract showed better tensile strength (3.0–3.6 MPa), elongation at break (16–20 %) and a water contact angle of 52°. All films responded to pH variations (1 to 14) and ammonia vapor and showed ΔE* values >5. After 3 days, films used as smart tags monitoring chicken analogous presented noticeable color differences for PCPNADES (55 ± 8) and 15%PCP (40 ± 1). PCP showed strong potential as a pigmenting agent in films, especially as an aqueous extract with NADES for use as pH-responsive tags in chicken analogous.

Innovative fabrication of eco-friendly bio-based foam from sugarcane bagasse and sodium alginate with enhanced properties and sustainable applications for plastic replacement

Foam materials possess notable features, including low density, high porosity, low thermal conductivity, and high impact resistance, making them extensively used in various sectors such as construction, transportation, water treatment, and packaging. However, the majority of commercial foam materials are derived from synthetic polymers based on fossil fuels, which raises concerns regarding health and ecology. In this work, we present a straightforward and scalable approach (physical cross-linking and common pressure drying) for fabricating a bio-based foam material using pulp fibers sourced from discarded sugarcane bagasse and sodium alginate extracted from seaweed. The resulting foam material exhibits low density (13.7–20.5 kg/m3), exceptional thermal insulation properties (thermal conductivity as low as 38.6 mW/mK), thermal stability (no deformation at 140 °C), and mechanical strength. After a basic silane modification, it also shows favorable water resistance (with a contact angle of 128°). Moreover, the foam material demonstrates remarkable degradation performance, with a degradation rate exceeding 93.8 % after 90 days of burial in soil. Therefore, this novel method offers a sustainable solution for eco-friendly foam production across various application domains.

The synergetic collecting effect of N-oleoyl sarcosine (N-OSS) and dodecylamine (DDA) on the selective flotation of spodumene from albite

In this study, N-OSS combined with DDA was examined as an novel collector. The collecting performances and their synergetic interaction mechanisms were investigated comprehensively. The micro-flotation results illustrated it exhibited excellent selectivity on separation without pre-activation. Contact angle tests revealed N-OSS/DDA could selectively enhance the hydrophobicity of spodumene, whereas, it barely affected that of albite. FTIR, SEM-EDS and Zeta potential revealed N-OSS/DDA might co-adsorb on spodumene surface rather than that of albite. XPS analysis and DFT calculations inferred the O1 2p orbitals of COO within N-OSS could bond with Al 3s orbitals and the NH3+ groups of DDA adsorbed onto the surface of spodumene via hydrogen bonding and electrostatic attraction. Meanwhile, the hydrogen bonding between N-OSS and DDA promoted the co-adsorption on spodumene surface. While N-OSS/DDA weakly adsorbed on the surface of albite through physical adsorption. N-OSS/DDA exhibited outstanding floatability, which maybe a good substitute for conventional collectors in future.

Influence of copper ion cross-linked CMC-PVA film on cell viability and cell proliferation study

In this study, films composed of carboxymethyl cellulose and polyvinyl alcohol were fabricated using the solution casting method. Citric acid (4 %) was employed as a cross-linking agent, while glycerol (3 %) as a plasticizer. Cupric chloride (CuCl2·2H2O) was used for cross-linking at concentrations 0.5 %, 1 %, and 3 % over different times. The cross-linking with copper ions led to a noticeable reduction in elasticity, with the breaking strain ranging from 17.9 %–52.9 %. The ion hydration phenomenon increased the contact angle and swelling ratio. Fourier-transform infrared (FTIR) spectroscopy confirmed esterification reactions and copper ion cross-linking with sodium carboxymethyl cellulose (Na-CMC). The films showed antibacterial activity against Staphylococcus aureus and Escherichia coli. The ion-released mechanism followed was the non-Fickian super case-II type. The concentration and duration of cross-linking significantly influenced cell viability and proliferation. FE-SEM analysis revealed that effective concentrations of CuCl2.2H2O were 0.5 % and 1 %, and cross-linking times were 5–15 min, facilitating cell attachment and proliferation. Films are non-adhesive with water vapor permeation 800–900 g/m2/day. These results indicate the potential use of the films in treating second-degree burn wounds with low to medium exudate levels. This study provides valuable insights into the development of copper-infused materials for advanced wound healing applications.

Synthesis of MNS@PDMS Emulsion for Enhancing Hydrophobicity in Cementitious Materials with Limited Strength Loss

Developing hydrophobic agents that minimize the strength loss of bulk hydrophobic cementitious materials (BHCM) remains a formidable challenge. Substances such as siloxanes can hinder cement mineral hydration and prevent the formation of an initial network structure during the early hydration stages. In this study, a novel hydrophobic emulsion in which polydimethylsiloxane (PDMS) wrapped with modified nano silica (MNS) is designed to enhance the hydrophobic property of cementitious materials while minimizing strength loss. The results show that BHCM exhibits good hydrophobicity (water contact angle 121.8°) while significantly reducing strength loss (decreased by 10.3%). The presence of MNS effectively shields PDMS from direct contact with cement minerals during the initial stages. Moreover, MNS can react with portlandite (CH) to generate C-S-H phase and optimize the pore structure of hardened cement pastes. This study contributes to promoting the structure-function integration of cement composites and achieving an extended service life for concrete.

Preparation of energy-efficient, environmentally friendly and high-strength biocomposites from wood fibre ultramicro self-composite cellulose matrices

Considering the diminishing forest as a natural resource, the efficient use of small-diameter shrubs is crucial for global sustainable development. This approach has significant potential to prevent wasting forest resources and reduce carbon emissions. However, small-diameter timber has inherent drawbacks, such as the looseness of this material, susceptibility to cracking and deformation, and low strength, all of which significantly impact its range of applications. In this study, an efficient, green method was developed to prepare adhesive-free biocomposites from discarded small-diameter shrubs via ultrasonic pretreatment and thermoforming. After the ultrasonic pretreatment, the flexural and tensile strengths of the biocomposites increased by 145% and 132%, respectively. Ultrasonic pretreatment separated and destroyed chemical bonds among the lignocellulosic biomass macromolecules through high-speed shear and microjets. This process significantly increased the amount of binding sites on the cellulose fibres, and further densified the cell walls through hot pressing. Moreover, the ultrasonic pretreatment may remove components of the wood flour that act as fillers or density enhancers, resulting in a reduction in the density of the biocomposite. Simultaneously, lignin acted as a binder and improved fibre bonding through both physical and chemical cross-linking, resulting in a dense cellulose structure with a three-dimensional lattice structure and a less hydrophilic surface, as evidenced by a water contact angle of 81.72°. In addition, the high-quality, binder-free biocomposites did not emit harmful gases such as formaldehyde. Hence, they are expected to become sustainable materials for building decoration and furniture applications in the future.

Preparation of Waterborne Polyurethane Coatings with Enhanced Mechanical Properties and Superhydrophobic Surface

Waterborne polyurethane (WPU) coatings are recognized for their environmental friendliness and non-toxic nature. However, the presence of abundant hydrophilic groups within their polymer networks often restricts their hydrophobicity and mechanical performance. In this study, we utilized two distinct diols to design the molecular structure of WPU, aiming to enhance its mechanical properties by optimizing microphase separation and crystallinity, achieving a tensile strength of 24.13 MPa and a strain of 1350%. The resultant WPU exhibited high cohesion and abundant hydrogen bonding sites, which contributed to its strong adhesion of 8.31 MPa. Moreover, inspired by the self-cleaning function of lotus leaf-micro-nipples, we made the surface superhydrophobic by micro-nano structure. The irregularly embedded structure was formed between the WPU and SiO2@hbp. The surfaces of WPU coatings formed the peak-valley structure similar to the lotus leaf, achieving a water contact angle of 162° and a sliding angle near 1°. Additionally, the self-cleaning property of the coatings was preserved after 200 cycles of friction, each with a single friction distance of 40cm. The environmental friendliness and excellent self-cleaning capabilities of the coating highlight its potential for practical applications and provide a valuable reference for developing waterproof self-cleaning coatings.

Rational design of static wetting on roughness-engineered heterogeneous surfaces

Surface roughness and chemical composition are crucial in controlling the static wetting properties of surfaces. Here, conventional surface structuring methods used in Si microfabrication are used as a reference to analyze the impact of precisely engineered surface roughness. The static wettability of rough chemically heterogeneous surfaces is experimentally studied through contact angle measurements and compared against computational simulations to categorize the wetting behavior of water droplets. Heterogeneous samples are observed to already show significant dependence on the surface fraction covered by each material. Furthermore, owing to the presence of a resist layer on top of the Si pillars, intermediate states between the Wenzel (W) and Cassie–Baxter (CB) models are observed. Consistent with these models, we find that local chemical modifications of microstructured surfaces are crucial for controlling their surface wettability properties. Additionally, a comparison of equivalent microstructures made of Si or polydimethylsiloxane (PDMS) reveals the quantitative impact of the hydrophilic/hydrophobic nature of the material on the evolution of the wetting properties with increasing roughness factors. While Si surfaces behave according to the W model, PDMS surfaces show intermediate wetting states at significantly lower roughness levels. Bubbles trapped beneath water droplets demonstrate the existence of intermediate states that cannot be defined by either the W or CB models. By combining experimental results with finite element simulations, we not only demonstrate wettability control through specific roughness and chemical modifications but also provide insight into how these parameters interact to accurately predict and adjust static wetting properties.

A simple strategy to significantly improve the anticorrosion and aging resistance of epoxy coatings by adding polyaniline modified multi-walled carbon nanotubes

Epoxy coatings are widely used for corrosion protection of metals, but under extremely harsh environments, the epoxy polymer chains such as the C-O bonds of epoxy ether and aromatic ether, and the -OH in the epoxy chain structure can also undergo aging and degradation, leading to the failure of the coating in service. How to extend the anti-aging capability of epoxy resins while maintaining their other properties unchanged has become a major challenge in the practical application of epoxy coatings. In this study, the polyaniline (PANI) modified multi-walled carbon nanotubes (MWCNT@PANI) were synthesized by polymerization in-situ and added to epoxy resin as an anti-aging filler. The various measurements have been adopted to characterize the composition and structure of MWCNT@PANI, and the anticorrosive performance of the composite coating for carbon steel were evaluated via salt spray, chemical aging and UV light aging. Results showed that the impedance value of the blank epoxy coating decreases by at least two orders of magnitude after the salt spray tests, and the contact angle decreases by about 30° and gradually changes from hydrophobic to hydrophilic, indicating a significant decline in corrosion resistance. In contrast, the composite coating confirmed the excellent anti-aging performance, while the impedance values increased by approximately 2-5 orders of magnitude compared to that in blank epoxy coatings, and remained around 1010 Ω·cm2. Given the dense encapsulation of MWCNT@PANI, the dispersion stability between the filler and EP can be improved, and the effective corrosion resistance performance was also supported by molecular dynamic simulation. Besides that, the ability of free radical quenching along with the labyrinth effect and hydrophobic interaction have also been investigated to explain the anticorrosion and anti-aging mechanism.

A bi-layer superhydrophobic coating with long-term anti-corrosion enabled by functionalized hexagonal boron nitride and PDMS-based polyurethane on Mg alloy

Two-dimensional (2D) nanocomposite coatings and superhydrophobic coatings are applied to retarding corrosion of Magnesium (Mg) and its alloys. However, stability of the delicate micro/nanostructure and corrosion durability are still intractable issues. In this work, a bi-layer superhydrophobic coating with excellent corrosion resistance has been successfully constructed on Mg alloy via a facile spray/spin assisted self-assembly technique. The polyurethane (PU) coating containing well-dispersed hydroxylated hexagonal boron nitride (OH-BN) nanoparticles acts as the barrier layer and “adhesive”, while the superhydrophobic modified h-BN (f-BN) nanoparticles serve as the water-repellent surface. In addition, the modifying agents containing dynamic disulfide bonds provide covalent bonding effect to construct a stable superhydrophobic surface. Hence, the obtained coating presents extreme non-wettability with an impressive static water contact angle (WCA) of 155° as well as possesses outstanding anti-water adhesion, anti-fouling and self-cleaning performance. Meanwhile, the designed coating shows excellent corrosion durability, which the value of |Z|f=0.01 Hz retains at 9.5 × 109 ohm cm2, higher than PU coating of two orders of magnitude. The developed coating shows promising potentials as a durable protective material for Mg alloy and other metals and alloys, shedding new lights on developing high-performance corrosion resistance technologies.

High acetone soluble organosolv lignin extraction and its application towards green antifouling and wear-resistant coating

Marine fouling poses significant challenges to the efficiency and longevity of marine engineering equipment. To address this issue, developing effective marine antifouling coatings is critical to ensure the economic viability, environmental sustainability, and safety of offshore operations. In this study, we developed an innovative green antifouling and wear-resistant coating based on lignin, a renewable and sustainable resource. Lignin is considered environmentally friendly because it is abundant, biodegradable, and reduces reliance on petroleum-based materials. The coating was formulated with a controlled hydrophilic-to-hydrophobic ratio of 2:8, leveraging lignin's unique properties. Applying lignin increased the water contact angle by 14.5 %, improving surface hydrophobicity and contributing to the coating's antifouling efficacy. Moreover, the mechanical strength of the coating was enhanced by approximately 200 %, significantly boosting its durability in harsh marine environments. Additionally, the friction coefficient was reduced by about 85 %, further preventing organism adhesion. These results demonstrate that lignin-based coatings offer a greener alternative to traditional antifouling solutions. The results of this study not only help advance antifouling coating technology but are also consistent with the broader goal of promoting environmental responsibility in marine engineering practice.