Rosin acid and SiO2 modified cotton fabric to prepare fluorine-free durable superhydrophobic coating for oil-water separation

Gum Rosin in Medical and Pharmaceutical Applications: From Conventional Uses to Modern Advancements

Gum rosin and its derivatives have been used traditionally in coatings and adhesives and are now increasingly applied in diverse medical and pharmaceutical fields. Owing to its film-forming ability, hydrophobic nature, biocompatibility, and ease of chemical modification, gum rosin has emerged as a promising excipient for controlled drug release, targeted drug delivery, and other biomedical applications. This review summarizes the evolution of gum rosin applications, from its conventional roles to its modern utilization in nanocarriers, transdermal systems, and other advanced drug delivery platforms. In addition, we discuss the challenges related to allergenicity, brittleness, and excessive hydrophobicity and propose strategies (such as chemical modification and polymer blending) to overcome these issues. This review provides a reference framework for researchers developing new rosin-based materials in pharmaceutical sciences.

Photothermal Superhydrophobic Zinc Oxide Cotton Fabric Based on an Impregnation Method

Superhydrophobic materials have applications such as oil-water separation, antifouling, and antibacterial properties. At present, most of the manufacturing process of superhydrophobic coatings not only is costly but also causes pollution to the environment, which is not in line with the concept of green and sustainable development. In this work, we have prepared a superhydrophobic coating using green and environmentally friendly chitosan, nanozinc oxide, γ-aminopropyl triethoxysilane (KH550), and stearic acid. The prepared cotton fabric showed remarkable superhydrophobic properties. Under simulated sunlight, the surface temperature of the superhydrophobic cotton fabric can increase to 50 °C. The superhydrophobic surface sustained its superhydrophobic property after at least 80 tape peeling tests, 50 occurrences of sandpaper friction, 3.5 h of washing, and 24 h of high-temperature heat treatment. Besides, the coating can be utilized for oil-water separation and is reusable. The oil-water separation effectiveness of the coating reaches more than 95%. Therefore, this inexpensive and ecofriendly nanozinc oxide/chitosan-based superhydrophobic coating has remarkable application potential.

Superwettable Nanomaterials: Fabrication, Application, and Environmental Impact

The increasing global concerns over energy consumption, environmental pollution, and sustainable development have sparked intensive research interest in advanced surface engineering solutions. This perspective critically reviews the development of superwettable surfaces as promising candidates for addressing these challenges. We analyze three key architectures that enable different levels of liquid repellency: micro/nano hierarchical structures for superhydrophobicity, re-entrant features for superoleophobicity, and doubly re-entrant designs for superomniphobicity. Recent developments have demonstrated significant progress in creating more environmentally conscious surfaces, including fluorine-free superhydrophobic textiles that reduce water and energy consumption in maintenance, energy-efficient smart windows with switchable wettability for building temperature regulation, and marine protective coatings that minimize chemical pollution. These advances contribute to environmental sustainability through multiple pathways: reduced resource consumption, improved energy efficiency, and decreased chemical pollution. However, challenges remain in achieving long-term durability, cost-effective fabrication, and comprehensive understanding of environmental impacts. This perspective provides insight into the current state of the field while highlighting the critical balance between performance optimization and environmental considerations in the development of next-generation superwettable materials.

Synergistic enhancement of hydrophobicity and mechanical properties of cellulose paper by (3-glycidoxypropyl) trimethoxy and rosin

Cellulose-based paper is inherently poor in hydrophobicity and mechanical strength, limiting its practical applications in daily life such as packaging materials, water-resistant labels, and disposable tableware. This study aimed to develop an effective and eco-friendly strategy to address these limitations by enhancing the hydrophobicity and mechanical properties of cellulose paper. To achieve this, an internal sizing agent was prepared by combining (3-glycidoxypropyl) trimethoxy (GPS) with natural rosin. This sizing agent was applied to cellulose paper, and its effectiveness was evaluated. Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) confirmed the successful introduction of rosin and GPS into the cellulose fiber network, forming covalent bonds. The variation in the microstructure and surface elemental distribution of the sizing cellulose paper was further analyzed by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). Thermogravimetric analysis (TGA) was conducted to evaluate the improved thermostability of the sizing cellulose paper. These structural improvements, including covalent bond formation and gap filling, contributed to the enhanced hydrophobicity and mechanical properties of the paper. This study provides a convenient and cost-effective approach to enhancing the functional properties of cellulose paper, offering new possibilities for its practical applications in eco-friendly packaging materials, disposable paper products, and high-performance paper-based packaging.

Triple Corrosion Protection: Dual-Layer Coating with Simultaneous Superhydrophobicity, Intelligent Self-Healing, and Shape Memory

In this paper, a self-healing superhydrophobic smart two-layer coating, ZOA/SMP-S, was developed. ZIF-8 was surface hydrophobically modified by octadecylphosphoric acid (OPA) to obtain Z-OPA and then encapsulated with a corrosion inhibitor, AMT ( 2-Amino-5-mercapto-1,3,4-thiadiazole), to obtain the superhydrophobic nanocontainers, ZOA. ZOA was embedded into the SMP (shape memory coating) to obtain the smart coating, and Z-OPA was sprayed to obtain the second superhydrophobic coating. SEM showed that the scratch coatings were rapidly reduced by scratches after a simple heat treatment. The prepared composite coatings showed excellent performance in corrosion inhibitor release, immersion, superhydrophobicity, and self-healing experiments. The contact angle of the superhydrophobic coating reached 158.2°, and the sliding angle was 2.8°. The low-frequency impedance value |Z|f=0.01 Hz of ZOA/SMP-S is as high as 1.58 × 1010 Ω·cm2 after 40 days of immersion test, which indicates that the triple protection greatly enhances the corrosion resistance of the coating.

Eco-friendly self-cleaning coatings: fundamentals, fabrication, applications, and sustainability

Eco-friendly self-cleaning coatings have garnered significant attention due to their potential to address environmental concerns while offering remarkable properties. This review explores the dynamic field of such coatings, focusing on their fundamental principles, fabrication techniques, applications, and sustainability. The main findings of this review shed light on the fundamentals of a wetting phenomenon that underpins superhydrophobicity and self-cleaning, revealing how bio-inspired approaches and sustainable materials have enabled the development of sustainable coatings. This review is structured around the fundamental principles of superhydrophobicity, discussing the basic mechanisms and following different approaches to eco-friendly coatings, focusing on bio-inspired methods and sustainable materials. Next, detailed fabrication techniques are discussed to create such coatings followed by various applications across industries, emphasizing the real-world impact of eco-friendly coatings. The next section discusses the various advantages followed by investigating the environmental implications and discussing how these coatings contribute to sustainability. The review concludes with commercial superhydrophobic self-cleaning products, which reflect the current state of research, outlining the challenges, and providing insights into future directions and innovations in this field. By providing an in-depth analysis of their fabrication techniques, applications, and potential future directions, it serves as a valuable resource for researchers and engineers seeking to design eco-friendly superhydrophobic coatings.

Fluorine-free, superhydrophobic self-healing and UV-blocking cotton fabric for oil/water separation

The discharge of oily wastewater not only pollutes waters but also deteriorates our living environment. Superhydrophobic cotton fabric is considered as an important remedy material for oily wastewater cleanup due to outstanding advantages including low cost, high porosity and switchable wettability. However, the existing superhydrophobic fabrics cannot exhibit durable superhydrophobicity during real-life applications due to poor interaction between the coatings and fabric substrates. To address this issue, one-step strategy is proposed to fabricate superhydrophobic cotton fabric by immersion in a octa-[2-(carboxyl methyl thio) ethyl]-polyhedral oligomeric silsesquioxane/cerium dioxide/polydimethylsiloxane (POSS/CeO2/PDMS) coating. As expected, the finished cotton fabric exhibits robust superhydrophobic resistance to mechanical abrasion and chemical corrosions. Notably, the finished cotton fabric shows thermal self-healing superhydrophobicity even if undergone repetitive abrasion cycles and air plasma etching. It is proposed that the rising temperature accelerates the rotations of PDMS chains and the migrations of MAPOSS and CeO2, contributing superhydrophobic self-healing of the damaged cotton fabric. Meanwhile, the superhydrophobic fabric displays high oil/water separation efficiency even in strong acid and alkali environments. Additionally, the POSS/CeO2/PDMS coating improves mechanical, thermal and UV-blocking properties of the finished cotton fabric. This work will pave a way to exploitation and applications of novel multifunctional textiles.

Enhanced oil/water separation using superhydrophobic nano SiO2-modified porous melamine sponges

Recent advancements in functional sponge materials have garnered significant interest due to their efficacy and cost-effectiveness in oil spill remediation. This study introduces both silane coupling agent (methyltrichlorosilane and 3-aminopropyltriethoxysilane) and nano-SiO₂ particles into the melamine sponge framework via impregnation. Additionally, polydimethylsiloxane (PDMS) serves a crucial role in curing to fuse the substrate with the coating through robust covalent bonds. The modified sponges (SiMAPs) facilitate the formation of rough surfaces comprising hierarchical structures by the deposition of nano-SiO₂ particles, while the silane coupling agents and PDMS contribute to a reduced surface energy. These SiMAP sponges maintain high stability with a water contact angle of 162.6° and demonstrate an adsorption capacity ranging from 40 to 90 times their weight in oil or organic solvents. Furthermore, they achieve a separation efficiency exceeding 98% and an oil flux of 14.38 L/m2∙s in immiscible oil-water mixtures. Additionally, the sorption of trichloromethane reaches 88.1 g/g, and the separation efficiency for surfactant-stabilized emulsions containing diesel is 62.8%. Remarkably, the oil-water separation efficiency surpasses 99.8% in dynamic continuous oil-water separation cycles, as evidenced by 20 experimental trials. These results underscore the substantial potential of SiMAP-modified sponges for addressing oil pollution by enhancing oil-water separation.

Robust special wettability materials for oil-water separation: Mechanisms and strategies

Special wettability materials have been favored by researchers in recent years, and have played a great role in a variety of fields such as fog water collection, anti-fog, anti-icing, self-cleaning, etc. Especially in the field of oil-water separation, the frequent occurrence of offshore oil spills has seriously endangered the ecological environment. Inspired by nature, researchers have developed and manufactured a lot of bionic special wettability materials, which are expected to be effective in oil-water separation and solve the problem. However, the inherent fragility of these materials significantly limits their practical applications. There is an urgent need to fabricate special wettability materials with excellent mechanical and chemical stability through appropriate surface structure and composition design. In this review, the wettability theory and failure mechanisms of special wettability materials used for oil-water separation are reviewed, followed by a summary of test methods used to characterize durability. Methods to improve the durability of materials in recent years are described. Firstly, starting from the substrate material, the appropriate substrate material is selected according to the working environment. Secondly, micro/nano hierarchical structures can enhance the robustness and durability of materials. For coating-type materials, strengthening the bond between the substrate material and the coating is a common and effective strategy. Chemical bonds can be formed between them, and the binder can also be introduced. Moreover, endowing the material with self-healing properties is also an efficient approach. The final section summarizes the challenges in this field and offers an outlook, with the expectation of enabling large-scale, real-world applications.

Superhydrophobic surfaces for the sustainable maintenance of building materials and stone-built heritage: The challenges, opportunities and perspectives

Bio-inspired superhydrophobic surfaces have demonstrated great potential for functional applications across a wide range of fields, including the surface maintenance of building materials. In the outdoor environment, the degradation of building materials, such as concretes, stones, bricks, tiles and mortars, poses severe structural, functional and aesthetic risks to the entire construction, raising growing concerns worldwide. Superhydrophobic surfaces are ideal multifunctional protective coatings, owing to the inhibition of liquid adhesion/penetration, spontaneous surface self-cleaning and hindering the adhesion of bacterial cells to surfaces. Yet, despite the appealing multi-functionalities and the large number of materials reported in recent years, several drawbacks that hamper wide production and application remain unresolved, e.g., poor chemical/mechanical/weathering durability, low transparency, insufficient antimicrobial effect in humid environments, toxic and environmentally unfriendly raw materials upon fabrication. In this review, the key bottlenecks identified after tentative applications are summarized underlying the underpinning mechanisms in depth. The newly proposed emerging strategies for addressing the specific limitations are then categorized and discussed in detail. Additionally, taking into account the physicochemical properties of building materials, the particular requirements concerning stone-built heritage conservation and the outdoor environment, the feasibility and the pros and cons of novel strategies are critically reviewed, outlining the future prospects of the field.

Flexible, breathable, and durable superhydrophobic cotton fabric modified by behenic acid, tung oil, and ZIF-8 with anti-icing and self-cleaning properties

Textiles with self-cleaning and anti-icing capabilities in cold climates are essential for outdoor workers and enthusiasts. Superhydrophobic modification of textile surfaces is effective in imparting these characteristics. Although there are numerous methods available for manufacturing superhydrophobic textiles, careful consideration is warranted for environmental concerns over fluorochemicals, stability of superhydrophobic coatings, and fabric breathability. In this work, we utilized biomass resources such as tung oil and behenic acid, along with zeolitic imidazolate framework (ZIF-8), to modify cotton fabrics, thereby creating an innovative behenic acid/tung oil/ZIF-8 modified cotton (BTZC) fabric with anti-icing and self-cleaning features. This material manifests a unique nanoflower-shaped surface morphology, demonstrating exceptional superhydrophobicity with a static water contact angle (CA) of 162° and a sliding angle (SA) of 2°. Moreover, BTZC excels in its thermal stability, breathability, and resistance to icing. Equally impressive is its robust stability, as evidenced through rigorous testing under continuous washing and abrasion, sustained high and low temperatures, extreme pH environments, and immersion in various chemical solvents. BTZC presents as a fluorine-free, durable, economically viable alternative for outdoor textile applications, marking substantial progress in the utilization of biomass and metal-organic framework materials in the textile industry and promising implications for value enhancement.

Develop a novel and multifunctional soy protein adhesive constructed by rosin acid emulsion and TiO2 organic-inorganic hybrid structure

Soy protein adhesives (SPI) exhibit broad prospects in substituting aldehyde-based resin due to the economic and environmental-friendly characteristics, but still face a challenge because of the dissatisfied bonding strength and terrible water resistance. Herein, prompted by organic-inorganic hierarchy, a multifunctional and novel soy protein adhesive (SPI-RAE-TiO2) consisting of rosin acid emulsion (RAE) and TiO2 nanoparticles (TiO2) were proposed. In comparison with original SPI, the dry and wet shear strengths of modified adhesive reached 2.01 and 1.21 MPa, respectively, which were increased by 130 % and 200 %. Furthermore, SPI-6RAE-0.5TiO2 was selected as the best proportion via the method of response surface methodology (RSM). What's more, SPI-6RAE-0.5TiO2 adhesive demonstrated prominent coating performance in both dry and wet surface conditions. Meanwhile, SPI-6RAE-0.5TiO2 adhesive possessed excellent mildew resistance and antibacterial ability with Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), reflecting the antibacterial rates 97.71 % and 98.16 %, respectively. In addition, SPI-6RAE-0.5TiO2 adhesive also exhibited the outstanding green features such as the reduction of formaldehyde pollution and greenhouse effect through Life Cycle Assessment (LCA). Thus, this work provided a novel and functional approach to design multifunctional, superior-property and low-carbon footprint soy protein adhesive.

A Fluorine-Free Superhydrophobic Cotton Fabric Prepared by a Green and Energy-Saving Method Is Used for Long-Lasting and Efficient Oil-Water Separation

Oil pollution poses a major threat to the ecosystem. Therefore, it is necessary to develop a material that can separate oil and water efficiently. Fabrics have a wide range of applications due to their economic simplicity and degradability. However, the existing methods of preparing superhydrophobic fabrics are complicated and energy-consuming, which are difficult to meet the concept of green and sustainable development. Moreover, various modified fabrics are less stable in harsh environments and do not have the ability to efficiently separate oil and water over a long period of time. In this paper, superhydrophobic zirconium dioxide (ZrO2) obtained from the modification of stearic acid was loaded onto the fabric surface using the adhesive properties of PDMS, resulting in the preparation of superhydrophobic/superoleophilic STA-ZrO2 fabrics. The fabric is made without involving time-consuming and energy-consuming heating, and it offers efficient oil-water separation, good stability and excellent recyclability. Truly in line with the concept of sustainable development.

Stable and Durable Superhydrophobic Cotton Fabrics Prepared via a Simple 1,4-Conjugate Addition Reaction for Ultrahigh Efficient Oil-Water Separation

Superhydrophobic materials used for oil-water separation have received wide attention. However, the simple and low-cost strategy for making durable superhydrophobic materials remains a major challenge. Here, this work reports that stable and durable superhydrophobic cotton fabrics can be prepared using a simple two-step impregnation process. Silica nanoparticles are surface modified by hydrolysis condensation of 3-aminopropyltrimethoxysilane (APTMS). 1,4-conjugate addition reaction between the acrylic group of cross-linking agent pentaerythritol triacrylate (PETA) and the amino group of octadecylamine (ODA) forms a covalent cross-linked rough network structure. The long hydrophobic chain of ODA makes the cotton fabric exhibit excellent superhydrophobic properties, and the water contact angle (WCA) of the fabric surface reaches 158°. The modified cotton fabric has good physical and chemical stability, self-cleaning, and anti-fouling. At the same time, the modified fabric shows excellent oil/water separation efficiency (98.16% after 20 cycles) and ultrahigh separation flux (15413.63 L m-2 h-1) due to its superhydrophobicity, superoleophilicity, and inherent porous structure. The method provides a broad prospect in the future diversification applications of oil/water separation and oil spill cleaning.

Engineering superhydrophobicity: a survey of coating techniques for silicone-based oil-water separation membranes

Oil spills in the ocean and the release of contaminated wastewater from industries cause significant harm to the ecosystem and water sources. To tackle this environmental problem, oil-water mixture separation has been the subject of extensive research over the past few decades. Improving oil absorbents is crucial in removing organic contaminants from wastewater produced by industrial activities. To this end, there is an increasing need for materials that can efficiently and flexibly recover oils from contaminated ocean waters, industrial wastewater, and other sources. Silicones are often used for this purpose because of their exceptional mechanical and thermal durability, as well as their low toxicity. The materials produced from silicones, such as foam, sponge, or substrate, exhibit excellent oil-absorbing properties (maximum oil absorption range, 23.2-77 g/g) and outstanding compression cycles. This article review highlights the advancements in the manufacturing of silicone-based products that have been extensively researched for oil-water separation. Understanding the interdependencies that determine the structure, performance, and manufacturing strategy is essential to producing selective oil absorbents with more commercial potential in the future. Recycling of silicones has also become increasingly important as a goal for the circular economy.

Supercritical CO2 extrusion foaming of highly open-cell poly(lactic acid) foam with superior oil adsorption performance

Addressing marine oil spills and industrial water pollution necessitates the development of eco-efficient oil-absorbing materials. With increasing concern for the environment, there is a consensus to decrease the use of petroleum-based polymers. Herein, lightweight poly(lactic acid) (PLA) blend foams with varying thermoplastic polyurethane (TPU) content were fabricated via a solvent-free, eco-friendly supercritical carbon dioxide (scCO2) extrusion foaming technology. The incorporation of TPU significantly enhanced the crystallization rate of PLA, with the semi-crystallization time of PT30 and PT50 blends at 105 °C exhibiting a reduction of 77.2 % and 47.9 %, respectively, compared to neat PLA. The resulting foams exhibited an open-cell structure with excellent selective oil adsorption capabilities. Notably, the PT30 foam achieved a remarkable maximum expansion ratio of 36.0, while the PT50 foam attained the highest open-cell content of 96.2 %. The PT50 foam demonstrated an outstanding adsorption capacity, spanning from 4.7 to 18.8 g/g for diverse oils and solvents, with rapid adsorption kinetics, reaching 94.9 % of the equilibrium adsorption capacity for CCl4 within just 1 min. Furthermore, the PT50 foam retained 95.2 % of its adsorption capacity for CCl4 over 10 adsorption-desorption cycles. This study presents a scalable and sustainable approach for large-scale production of high-performance, bio-based foams, facilitating efficient oil-water separation.

Multifunctional coatings fabricated from Chinese hemp-derived superhydrophobic micro-nanocellulose

Ecologically feasible strategies for constructing superhydrophobic surfaces offer versatile applications in waterproofing, self-cleaning, selective absorption, and corrosion protection. Herein, we prepared low-surface-energy branched-chain-enriched micronanorod (F@SiO2@MNC) by hydrolyzing silane coupling agent and modifying fluoropolymer using micro-nanocellulose extracted from waste straw (Chinese hemp). These rods were sprayed and adhered to various substrates precoated with a binder, resulting in superhydrophobic surfaces. F@SiO2@MNC addition allowed for the formation of stable spherical liquid droplets when in contact with different types of aqueous liquids. Furthermore, these surfaces demonstrated excellent self-cleaning, robustness, abrasion resistance, UV resistance, cycling stability, and other multifunctionalities. They significantly enhanced the mechanical properties of filter paper, effectively separated oil water mixtures, and improved the corrosion resistance of metals. Our proposed strategy represents a novel approach for developing multifunctional coatings assembled from micronanocellulose.

Bioinspired Multiscale Mineralization: From Fundamentals to Potential Applications

The wondrous and imaginative designs of nature have always been an inexhaustible treasure trove for material scientists. Throughout the long evolutionary process, biominerals with hierarchical structures possess some specific advantages such as outstanding mechanical properties, biological functions, and sensing performances, the formation of which (biomineralization) is delicately regulated by organic component. Provoked by the subtle structures and profound principles of nature, bioinspired functional minerals can be designed with the participation of organic molecules. Because of the designable morphology and functions, multiscale mineralization has attracted more and more attention in the areas of medicine, chemistry, biology, and material science. This review provides a summary of current advancements in this extending topic. The mechanisms underlying mineralization is first concisely elucidated. Next, several types of minerals are categorized according to their structural characteristic, as well as the different potential applications of these materials. At last, a comprehensive overview of future developments for bioinspired multiscale mineralization is given. Concentrating on the mechanism of fabrication and broad application prospects of multiscale mineralization, the hope is to provide inspirations for the design of other functional materials.

Superhydrophobic Al2O3/MMT-PDMS Coated Fabric for Self-Cleaning and Oil-Water Separation Application

This study introduces a novel superhydrophobic coating applied to the fabric surface through spray coating of the Al2O3/MMT nanocomposite and PDMS polymer to enhance the surface roughness and reduce the surface tension, respectively. The as-prepared coating exhibits a remarkable superhydrophobic property with a water contact angle (WCA) of ∼174.6° and a water sliding angle (WSA) < 5°. Notably, the fabric demonstrates a self-cleaning property through removing dust and dirt via adhering to water droplets. Moreover, the insignificant loss of WCA (3.2 and 1%) after exposure to alkaline and acidic media for 10 days verifies the promising chemical stability of the coated layer, whereas WCA > 160° after 24 h of immersion in various organic solvents further indicates the layer resistance. Besides, the layer sustains WCA of 174.5, 172.5, and 168.45° after 1 month of air exposure, ultrasonic washing, and 50 cycles of home laundry. The mechanical resistance of the fabric was verified by maintaining a WCA of 158.73° after 200 abrasion cycles. Also, the layer exhibits thermal resistance with <4.1% of WCA loss in the temperature range of -10 to 180 °C. Additionally, the superhydrophobic coating excels in oil-water separation, achieving >99% separation efficiency for various oils. These exceptional properties position the fabric for diverse applications, including protective clothing, outdoor gear, medical textiles, and sportswear, emphasizing its versatility and novelty in the realm of superhydrophobic materials.

CdO-Nanografted Superhydrophobic Hybrid Polymer Composite-Coated Cotton Fabrics for Self-Cleaning and Oil/Water Separation Applications

The current study presents a simple and cost-competitive method for the development of high-performance superhydrophobic and superoleophilic cotton fabrics coated with cadmium oxide/cerotic acid (CdO/CE)-polycaprolactone (PCL)- and cadmium oxide/stearic acid (CdO/ST)-polycaprolactone-grafted hybrid composites. X-ray powder diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy are used to characterize the CdO/CE-PCL and CdO/ST-PCL and polycaprolactone-modified cotton fabrics. Using an optical contact angle meter, the wetting behavior of corrosive liquids such as coffee, milk, tea, water dyed with methylene blue, strong acids (HCl), strong alkali (NaOH), and saturated salt solution (NaCl) on the CdO-CE/ST/PCL-modified cotton fabrics is assessed as well as the durability of CdO-CE/ST/PCL-modified cotton fabrics in corrosive liquids. Data obtained from the oil-water separation experiment indicate remarkable separation efficiency with oil purity values of ≥99.97 wt %, and high permeation flux values of up to 11,700 ± 300 L m-2 h-1 are observed for surfactant-stabilized water-in-oil emulsions via a gravity-driven technique. From the data obtained, it is concluded that the nano-CdO-grafted superhydrophobic hybrid polymer composite-coated cotton fabrics (CdO-ST/(CE)/PCL/CFs) can be utilized for self-cleaning and oil/water separation applications.

From rosin to novel bio-based silicone rubber: a review

Rosin is a characteristic natural renewable resource. In view of the unique hydrogenated phenanthrene ring skeleton structure of rosin, it can be designed and synthesized to modify silicone rubber for improving its mechanical properties, thermal stability, and other properties. In this paper, the research progress of silicone rubber modified by rosin and its derivatives is reviewed, including internal or surface modification of room temperature or high temperature vulcanized silicone rubber. The different chemical modifications and polymerization pathways to obtain bio-based silicone rubber (e.g. rosin-based silicone cross-linking agent, filler compound rosin-based silicone cross-linking agent, rosin-based polymer, and rosin quaternary ammonium salt bifunctional antibacterial coating) are discussed and its research prospect is reviewed. Overall, the present review article will provide a quantitative experimental basis for rosin to produce bio-renewable multifunctional silicone rubber to increase our level of understanding of the behavior of this important class of silicone rubber and other similar bio-based polymers.

Urchin-like fluorinated covalent organic frameworks decorated fabric for effective self-cleaning and versatile oil/water separation

Oil contamination and industrial organic pollutants emission have been a serious problem affecting the ecological and residential environment. Membrane-based separation shows great application prospect due to its low-cost, environmental-friendly and easy operation. Therefore, the development of efficient oil-water separation membranes is highly desirable. Herein, a fabric filter with superwettability was prepared by coating urchin-like fluorinated covalent organic frameworks (COFs) on fabric, which was well utilized in filtering immiscible oil-water mixture and surfactant-stabilized water-in-oil emulsion driven only by gravity for the first time. The as-prepared COF fabric filter (defined as fabric@u-FCOF) possessed many outstanding properties, including superhydrophobicity with the water contact angle of approximately 151.6°, satisfactory resistance for alkaline, acidic and saline environments, as well as superior mechanical durability under harsh conditions. Because of the super-micropore of fabric@u-FCOF and the nanopore in the COF coating, the obtained fabric@u-FCOF exhibited excellent performances in terms of separation efficiency and permeability, in which the oil flux was up to 16964 L·m-1·h-2 and separation efficiency for the mixed o-dichlorobenzene/water was higher than 99.4%. In addition, the fabric@u-FCOF also showed excellent self-cleaning performance due to the micro/nano hierarchical structure of its surface. These excellent properties make it an ideal candidate for applications of oil/water separation and water purification.

Facile Preparation of Durable and Eco-Friendly Superhydrophobic Filter with Self-Healing Ability for Efficient Oil/Water Separation

The superhydrophobic feature is highly desirable for oil/water separation (OWS) operation to achieve excellent separation efficiency. However, using hazardous materials in fabricating superhydrophobic surfaces is always the main concern. Herein, superhydrophobic filters were prepared via an eco-friendly approach by anchoring silica particles (SiO2) onto the cotton fabric surface, followed by surface coating using natural material-myristic acid via a dip coating method. Tetraethyl orthosilicate (TEOS) was used in the synthesis of SiO2 particles from the silica sol. In addition, the impact of the drying temperature on the wettability of the superhydrophobic filter was investigated. Moreover, the pristine cotton fabric and as-prepared superhydrophobic cotton filters were characterised based on Fourier-transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX) and contact angle (CA) measurement. The superhydrophobic cotton filter was used to perform OWS using an oil-water mixture containing either chloroform, hexane, toluene, xylene or dichloroethane. The separation efficiency of the OWS using the superhydrophobic filter was as high as 99.9%. Moreover, the superhydrophobic fabric filter also demonstrated excellent durability, chemical stability, self-healing ability and reusability.

Advancement in utilization of bio-based materials including cellulose, lignin, chitosan for bio-inspired surface coatings with special wetting behavior: A review on fabrication and applications

Natural bio-material surface with hydrophobic behavior (aqueous droplet to roll off from its surface) has inspired researchers to design sustainable artificial coatings with hydrophobic or superhydrophobic behavior. The developed hydrophobic or superhydrophobic artificial coatings are highly useful in various applications such as water remediation, oil/water separation, self-cleaning, anti-fouling, anti-corrosion and also in medical fields including anti-viral, anti-bacterial efficacy. In recent years, among various coating materials, bio-based materials derived from plants and animals (cellulose, lignin, sugarcane bagasse, peanut shell, rice husk, egg cell etc.) are applied on various surfaces in order to develop fluorine free hydrophobic coatings with longer durability by lowering the surface energy and increasing the surface roughness. This review summarized recent developments in hydrophobic/superhydrophobic coating fabrication methods, properties and applications with the use of different bio-based materials and their combinations. In addition, basic mechanisms behind the coating fabrication process and their durability under different environmental conditions are also discussed. Moreover, prospects and limitations of bio-based coatings in practical applications have been highlighted.

Advances in the research of carbon-, silicon-, and polymer-based superhydrophobic nanomaterials: Synthesis and potential application

With the rapid development of science and technology, superhydrophobic nanomaterials have become one of the hot topics from various subjects. Due to their distinct properties, such as superhydrophobicity, anti-icing and corrosion resistance, superhydrophobic nanomaterials are widely used in industry, agriculture, defense, medicine and other fields. Hence, the development of superhydrophobic materials with superior performance, economical, practical features, and environment-friendly properties are extremely important for industrial development and environmental protection. Aimed to provide a scientific and theoretical basis for the subsequent study on the preparation of composite superhydrophobic nanomaterials, this paper reviewed the latest progress in the research of superhydrophobic surface wettability and the theory of superhydrophobicity, summarized and analyzed the latest development of carbon-based, silicon-based and polymer-based superhydrophobic nanomaterials in terms of their synthesis, modification, properties and structure sizes (diameters), discussed the problems and unique application prospects of carbon-based, silicon-based and polymer-based superhydrophobic nanomaterials.