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Cotton fabrics are popular for their excellent properties, but their wider application is always limited due to their disadvantages including lack of water repellency and easy pollution. In this pa...

Superhydrophobic cotton fabrics have been widely explored for their excellent properties, although there are still a few limitations in the practical applications for the reasons of poor environmental performance and short service life. In this study, the hexadecyltrimethoxysilane emulsion was prepared using O2-plasma and ultrasound for the superhydrophobic functional finishing of raw cotton fabric by immersion method. The prepared cotton fabrics showed a superior hydrophobicity with water contact angles larger than 156.0°, as well as an excellent self-healing ability. This self-healing ability was gained by simple heating treatment, which could restore the superhydrophobicity of the hydrophilic cotton fabric damaged by abrasion or O2-plasma treatment. The superhydrophobic cotton fabrics demonstrated excellent washing durability, which can withstand 50 times accelerated laundering cycles. Besides this, the superhydrophobic coatings also displayed fair chemical stability in strong acidic and alkaline solutions. The prepared nonfluorinated superhydrophobic cotton fabric with self-healing ability shows a potential for practical functional textile application.

The chiral ionic liquid CILTPT-MS [CH3(OCH2CH2)16CD]+[CH3SO3]− (CD = cinchonidine) is found to exhibit cloud point character. Due to this cloud point character, a CILTPT-MS-stabilized chiral nano-Pt catalyst is prepared and utilized to realize transfer in a H2O–1-pentanol biphasic system by simply changing the temperature. Therefore, a fluorine-free, thermoregulated phase-transfer catalysis system is developed and applied to the asymmetric hydrogenation of α-ketoesters with enantiomeric excess of >99% and excellent conversion. In addition, the chiral nano-Pt catalyst can be easily separated and reused efficiently.

Superhydrophobic self-cleaning surfaces are based on the surface micro/nanomorphologies and special chemical regents with low surface free energy. Such surface structures are highly susceptible to mechanical wear. Moreover, the use of fluorinated compounds is harmful to both human health and environment. Herein, a simple method based on spin coating and spraying is proposed to fabricate durable fluorine-free superhydrophobic surfaces. A glass substrate was coated with a layer of water-based paint via a simple spinning process. Due to the adhesive layer, modified SiO2 nanoparticles were strongly bonded to the glass substrate. After the coating was completely cured, the surfaces realized a water contact angle of 165.1° and maintained their water repellency after 50 abrasion cycles with sandpaper and 50 times of stripping test. No chemical reagents harmful for the environment were used.

The scientific fraternity and coating companies have researched and developed coatings with superhydrophobic features for a wide range of applications, varying from automotive, oceanic, pharmaceutical, and thermal and power sectors, over the preceding few years. The self-cleaning features of superhydrophobic surfaces exhibit pronounced dust repelling and lower dust adhesiveness qualities, along with incomparable water repellence for maritime, automotive, and pharmaceutical applications. The advancement of super-hydrophobic surfaces for averting the accrual of impurities on surfaces is an active space of exploration globally. A lesser hysteresis of contact angle leads to drops of water sliding effortlessly on such surfaces. The solid surfaces’ surface energy can be weakened by fixing materials of lesser surface energy on the exterior, which can be performed by the following dual methods; either by fixing materials of reduced surface energy straight onto the exterior of a substrate in the form of a coating of that material, or by fixing materials of less surface energy on the exterior of nano-architectural structures and then dropping the coating of those nanoscale materials on the exterior of the substrate. The generation of nanoscale irregularities on substrates by dropping nanostructure layers on surfaces makes it an attractive option since, usually, nanomaterials have a minimum of one dimension, ranging from 1 - 100 nm. The nanostructures’ sizes unveil exceptional physical and chemical characteristics, principally owing to their greater specific surface area to volume quotient. This review encompasses the non-fluorinated superhydrophobic coatings developed to date.

Environmental and health concerns are driving food packaging to reduce the use of poly- or perfluorinated compounds and petroleum-based polymers. Here, we successfully obtained good oil-proof paper by combining cellulose nanofibril (CNF) film with filter paper through film transfer. The process was not only facile but also did not require chemical reagents other than water. To achieve the kit number 12, the basis weight of the CNF film was 2.1 g/m2, which was much less than the amount required for coating. The calendering process further reduced the pores thus improving the oil resistance of the film transfer paper. At a calendering pressure of 20 N/mm, only 1.4 g/m2 of the CNF film was required for kit number 12. This study provides a new way for the application of CNF in the field of oil resistance.

A novel eco-friendly and durable superhydrophobic and flame-retardant cotton fabric with fluorine-free, halogen-free was prepared via step-by-step dip-coating and spraying technology. At first, common cotton fabric was impregnated in the flame-retardant ethoxysilane-terminated phosphate polyurethane. Afterwards, methanol mixture containing silica nanoparticles, methyl triethoxysilane, and dihydroxy-terminated polydimethylsiloxane was sprayed on the surface of the cotton fabric. Finally, a flame-retardant cotton fabric with micro-nano rough surface and low surface energy was formed. The resulting superhydrophobic and flame-retardant cotton fabric exhibited superamphiphobicity with the contact angle and sliding angle of 160° and 6°, respectively, while flame retardancy with limited oxygen index of 28.1%. and flame self-extinguishing. Furthermore, this superhydrophobic and flame-retardant cotton fabric showed robust superhydrophobicity and flame-retardancy after undergoing 1000 cycles of abrasion, 60 min of ultrasonic washing and 50 standard machine washing cycles, in sequence, indicating its potential as a multifunctional protective textile fabric. Additionally, the method proposed in this study can effectively solve durability and environmental problems currently faced by the coated fabric with superhydrophobicity and flame-retardancy.

We introduce a superhydrophobic surface that is composed of homogeneous polystyrene (PS) raspberry nanoparticles of around 50 nm diameter, via a convenient single-step scalable synthesis method. Th...

Recently, superhydrophobic surface on various type of substrates have attracted much attentions in electronics field. In this work, the classic Stöber method was used to prepare spherical silica particles with different particle sizes by adding different amounts of electrolyte (potassium chloride), giving rise to size distribution ranging from 300 nm to 2.55 yitm. Herein we constructed a micro-nano lotus-like structure in a facile way, achieving a superhydrophobic surface with using any Fluorine related chemicals. In the sense, the silica particles modified with HMDS were sprayed to prepare hydrophobic surface with contact angle up to 152.96° by increasing the frequency of sprays.

To develop a fluorine-free material of acidproof and breathable fabric, styrene–butadiene–styrene (SBS) blended with pitch was directly deposited on polyester/cotton blended fabric through electrospinning to fabricate a nanofibrous membrane composite fabric. Acrylic acid (AA) and methyl methacrylate (MMA) were used to graft SBS to improve compatibility between SBS and pitch, and the modified temperatures were set at 40°C, 60°C and 80°C. The effects of different grafting monomers and temperatures on the properties of SBS/pitch membrane composite fabrics were explored by Fourier transform infrared spectral analysis; morphological structures, acid-resistant properties and breathability (vapor permeability and air permeability) were also examined. The results showed that modified SBS/pitch membrane composite fabrics possessed good acid resistance and modest breathability. SBS-g-MMA/pitch (means SBS grafted by MMA) exhibited the highest acid resistance due to more evenly distributed beads than original SBS/pitch membrane composite fabrics and higher roughness than SBS-g-AA/pitch (means SBS grafted by AA) membrane composite fabrics. By systematically changing the grafting temperature, SBS-g-MMA/pitch membrane composite fabrics for which SBS was grafted by MMA at 80°C presented appropriate air permeability (120.5 mm/s), modest water vapor transport rate (13,656.45 g/(m2·d)), good tensile strength (1203 N) and bursting strength (616 N), and the best acid resistance (143°); meanwhile the acid penetration level reached level 3, which was attributed to the low surface energy caused by the fused ring from the pitch and the rough surface caused by the micro-beads in the nanofibers. The obtained modified SBS/pitch membrane composite fabric could be potentially applied in acidproof fabrics.

In this work, the hollow rectangular prism-like TiO2 (HRP-TiO2) mesocrystals with exposed {001} facets were synthesized via an in-situ hydrothermal process without introducing any additional hydrof...

Fluorinated compounds are exceptional to exhibit good as well as durable oil and water repellency. However, due to their adverse effect on human and ecology, these compounds are under immense press...

Fluorine-free foam fire extinguishing agents are environmentally friendly compared with aqueous film-forming foam fire extinguishing agents (AFFF). Design-Expert 11.0 software and the Box-Behnken design principle were used to optimize the foaming agent formulation which is the core of fluorine-free foam extinguishing agents and regression models of the expansion ratio (α), 50% drainage time (t50%) and surface tension (γ) were established. Furthermore, the optimal combination of foaming agent various factors (the mass fraction of APG0810, silicone surfactant, SDS and BS-12) were predicted by the regression models. The prediction results showed that when the mass fraction of APG0810, silicone surfactant, SDS and BS-12 were 2.0%, 0.242%, 0.116% and 0.349%, respectively, the comprehensive foaming agent performance was highest. The α, t50% and γ of the optimized foaming agent were 8.0, 376 s, and 24.1 mN/m, respectively. The fluorinefree foam fire extinguishing agent was prepared by compounding the optimized foaming agent with foam stabilizers and other additives, resulting in a surface tension of 24.3 mN/m and a spreading factor greater than zero. The, α, t50% and sealing time of the fluorine-free foam fire extinguishing agent were 7.6, 541 s, and 895 s, respectively, which were 8.6%, 16.1%, and 14% higher than commercial 6% AFFF.

The crystallization behavior and melt structure of the CaO–SiO2–B2O3-based fluorine-free mold flux were investigated. The results show that the crystallization of the mold flux was first inhibited and then promoted with the increase in Al2O3 content from 4 to 12 wt.%. However, it was enhanced by MgO in the range of 2–10 wt.%. The results of Fourier transform infrared spectroscopy and Raman spectroscopy showed that Al2O3 worked as a network former in the mold flux melt when its content was in the range of 4–8 wt.%, whereas it worked as the network breaker to provide O2− when its content was in the range of 8–12 wt.%. In addition, the combined effects from the charge compensation by Mg2+ and the network broken by O2− led to the increase in some typical T–O–T (Al–O–Al, B–O–B, etc.) and simpler structural units (Q0(Si), B–O− in the [BO2O−], etc.) when the MgO content was in the range of 2–6 wt.%. The continuous increase in O2− provided by the addition of MgO from 6 to 10 wt.% further depolymerized the network of the melt and finally caused fast crystallization.

Superhydrophobic coatings have received considerable attention owing to their potential applications. There has been an increasing demand for the construction of durable superhydrophobic coatings u...

Coated paper substrates are used for a wide range of applications. The biggest challenge that remains unsolved with regard to coated paper is its recyclability. Herein, we report a unique approach ...

Water repellency is a desired feature of fabrics for certain applications in textile industry such as water-repellent garments, tents, and umbrellas. Coating of fabrics with fluorocarbons or silicones followed by heat treatment is the general process to impart hydrophobicity even though the resulted water repellency is limited. In this study, we prepare a fluorine-free superhydrophobic coating from hydrophobic SiO2 nanoparticles that can be easily applied to common fabrics by simply spray coating, leading to superhydrophobic fabrics with a water contact angle of 172 degrees and a sliding angle of 3 degrees. The process to achieve extreme water repellency is simple and only involves a single step, and there is no need for further processes like annealing or heat treatment. The superhydrophobic coated fabrics display durability dependence on the texture of the underlying material, where coated chenille and nonwoven fabrics show robust mechanical durability against water impact, abrasion, and laundering. The ready availability of the coating materials, the simple process of application, and the robust mechanical durability of superhydrophobic fabrics show great potential for real-world applications.

The application of fluorocarbon surfactants in fire-fighting foam has been restricted due to their serious environmental hazards. Thus, it is necessary to develop the fluorine-free foam for fire-fighting and understand their characteristics from different perspectives compared with the fluorinated foam. The present study investigated foam stability, oil-film interaction, and fire extinguishing performance for fluorine-free and fluorinated foams. The results show that the adverse effect of oil on the stability of fluorinated foams is much less than that of fluorine-free foams. Besides, the trends in foam stability are not predicted by the entering, spreading, and bridging coefficients based on the measurement of surface and interfacial tensions. The differences in stability of fluorine-free and fluorinated foams are found to be consistent with the observation of oil-film interaction. Oil droplets destabilize the fluorine-free film by spreading over the film, whereas they tend to be rapidly expelled out of the fluorinated film in the form of oil lenses slightly affecting the film stability. Since the film is unstable in contact with oil, the fluorine-free foam cannot suppress the pool fire effectively at the expansion ratio of 6.8–7.2. By adjusting the foam expansion ratio, the fire extinction performance of the fluorine-free foam can be comparable to that of the fluorinated foam, and the burnback performance is significantly enhanced.

Waterproof and breathable membranes (WBMs) with simultaneous environmental friendliness and high performance are highly desirable in a broad range of applications; however, creating such materials still remains a tough challenge. Herein, we present a facile and scalable strategy to fabricate fluorine-free, efficient, and biodegradable WBMs via step-by-step dip-coating and heat curing technology. The hyperbranched polymer (ECO) coating containing long hydrocarbon chains provided an electrospun cellulose acetate (CA) fibrous matrix with high hydrophobicity; meanwhile, the blocked isocyanate cross-linker (BIC) coating ensured the strong attachment of hydrocarbon segments on CA surfaces. The resulting membranes (TCA) exhibited integrated properties with waterproofness of 102.9 kPa, breathability of 12.3 kg m-2 d-1, and tensile strength of 16.0 MPa, which are much superior to that of previously reported fluorine-free fibrous materials. Furthermore, TCA membranes can sustain hydrophobicity after exposure to various harsh environments. More importantly, the present strategy proved to be universally applicable and effective to several other hydrophilic fibrous substrates. This work not only highlights the material design and preparation but also provides environmentally friendly and high-performance WBMs with great potential application prospects for a variety of fields.

Aqueous film-forming foams (AFFFs) are widely used to extinguish liquid fires due to their film-forming properties. AFFF formulation historically contains per- and polyfluoroalkyl substances (PFASs) that can be very persistent and pose a health risk to biota and humans. Detailed analysis of the chemical composition of AFFFs can provide a better understanding on the potential environmental impact of the ingredients. In this study, a novel workflow combining target analysis, nontarget screening analysis (NTA), total fluorine (TF) analysis, and inorganic fluoride (IF) analysis was applied to disclose the chemical composition of 24 foams intended for liquid fires. Foams marketed as containing PFASs as well as fluorine-free foams were included. By comparing the sum of targeted PFASs and total organofluorine concentrations, a mass balance of known and unknown organofluorine could be calculated. Known organofluorine accounted for1% in most fluorine-containing AFFFs, and it was confirmed that the foams marketed as fluorine-free did not contain measurable amounts of organofluorine substances. Five fluorinated substances were tentatively identified, and non-fluorinated zwitterionic betaine compounds, which are considered to be replacement substances for PFASs, were tentatively identified in the organofluorine-free foams.

Water repellent is an important functional finish for cotton fabric. However, cotton fabrics often have poor washing resistance and other performances after actual finishing. In this study, based on the structural characteristics of cotton fiber and durability of water repellent, a cross-linked amino long-chain alkyl polysiloxane (CAHPS) was first prepared, and then reacted with modified silica. Finally, a chemically bonded organic–inorganic nanohybrid cross-linked polysiloxane (rSiO2–CAHPS) was fabricated. Furthermore, the rSiO2–CAHPS was emulsified to obtain a durable fluorine-free water repellent. The water repellent finishing for cotton fabric was carried out by the pad–dry–cure process. After finishing, the cotton fabric had good resistance to conventional liquids and excellent washing resistance, and still maintained good water repellency after 30 rounds of soaping. Moreover, properties including air permeability, mechanical property and whiteness are hardly affected after finishing. SEM and XPS characterization show that a layer of dense silicon film is formed on the surface of cotton fabric by rSiO2–CAHPS water repellent. The existence of nanosilica can improve the surface roughness of cotton fibers. The synergistic effect of fiber matrix, nanoparticles and CAHPS endows the fabric with a micro/nano-multi-scale micro-rough structure, which improves the water repellency of cotton fabric after water repellent finishing.

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A new type of superhydrophobic borneol-based polymeric coating has been prepared. The chemical composition of the polymer particles was analyzed by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, which showed that the polymer did not contain fluorine, which can effectively avoid the cytotoxic risk of fluorine. By dynamic light scattering, scanning electron microscopy, and static contact angle measurement, the contact angle of the prepared coating gradually increased with increasing diameter of the polymer particles, and a superhydrophobic coating surface was finally obtained. Interestingly, after dissolving the superhydrophobic sample with tetrahydrofuran and making it a normal hydrophobic sample, the antiadhesion performance for E. coli was greatly reduced, and it could not effectively prevent E. coli adhesion. In addition, a long-term antiadhesion study of bacteria was performed. The superhydrophobic borneol-based polymer coating showed long-term resistance to E. coli adhesion. Therefore, the excellent antibacterial properties and cell compatibility mean that this series of polymer materials has great potential in the field of biomedicine.

The fluorine-free metal–organic decomposition (FF-MOD) route is one of the table-top methods for the growth of high-quality superconducting YBa2Cu3O7−δ (YBCO) films due to its advantages of being e...