Durable Water Repellent Research Articles

Dual immobilization strategy for slippery surface to achieve durable anti-corrosion and excellent anti-icing

Aluminum alloys always suffer from the deficient corrosion resistance and anti-icing property. Slippery liquid infused porous surfaces (SLIPS) inspired by “Nepenthes” have exhibited great potential in corrosion protection and anti-icing. However, the rapid depletion of the infused lubricants often results in the unsatisfactory long-term protective performances of SLIPS. In this study, a dual immobilization strategy was employed to fabricate a slippery surface with robust lubricant layer. The active lubricants were infused in the nanopores of anodized aluminum oxide (AAO) and grafted on the surface of silanized phytic acid (PA) substrate support simultaneously. Due to the presence of infused and covalently grafted lubricants, the obtained slippery surface possessed excellent and durable water repellency and anticorrosion property. Throughout 21 days of immersion in the 3.5 wt% NaCl solution, the water sliding angle of the slippery surface was lower than 10° and the low frequency impedance of the slippery surface was higher than 2.0 × 106 Ω cm2. Moreover, the slippery surface also possesses self-healing capacities that can automatically seal the scratch and repair the protective performance within 24 h. Furthermore, the cooled water droplet can easily roll away from the slippery surface treated by low temperature freezing. The results suggest that the slippery surfaces prepared using dual immobilization strategy can effectively protect aluminum alloys from corrosion and icing. This study provides a novel insight into the design and construction of SLIPS with excellent durability, which can expand the applications of SLIPS in harsh environments.

Synthesis and Application of Silane-Modified Castor Oil-Based Waterborne Polyurethane as a Fluorine-Free and Durable Water Repellent

Synthesis and Application of Silane-Modified Castor Oil-Based Waterborne Polyurethane as a Fluorine-Free and Durable Water Repellent

Target and non-target analyses of neutral per- and polyfluoroalkyl substances from fluorochemical industries using GC-MS/MS and GC-TOF: Insights on their environmental fate

Novel and emerging per- and polyfluoroalkyl substances (PFAS) are a key issue of concern in global environmental studies. In this study, air, sediment, and wastewater samples were collected from areas in and/or surrounded by fluorochemical-related industrial facilities to characterize the contamination profiles of neutral and novel PFAS (n-PFAS) using a gas chromatograph-based target and non-target analyses. Fluorotelomer alcohols were predominant in the samples, accounting for 80 % of the n-PFAS, followed by fluorotelomer acrylates. Air samples collected proximate to the durable water repellent (DWR) facility had the highest concentration of n-PFAS, which was approximately two orders of magnitude higher than those found in others. Non-target analysis identified fluorotelomer iodides and fluorotelomer methacrylate in multiple matrices near DWR facilities, indicating significant contamination of n-PFAS. Levels of both C6- and C8-based PFAS reflected a shift in usage patterns from C8- to C6-based fluorochemicals. Matrix-dependent profiles of n-PFAS revealed that shorter-chain (e.g., C6) and longer-chain (>C8) PFAS were predominant in air and sediment, respectively, implying that air and sediment are mobile and secondary sources of PFAS. Untreated and treated industrial wastewater also contained n-PFAS and their transformation products. The findings shed light on our understanding of the multi-matrix distribution and transport of PFAS.

Durable water- and oil-repellent textiles without long- or short-chain perfluoroalkylated substances

For decades, the water and oil repellency of textiles was achieved using long-chain (CnF2n+1, n ≥ 7) perfluoroalkyl substances (PFAS). However, due to their proven bioaccumulative nature and toxic impacts on the environment and human health, these substances have been phased out of industrial production and/or legally banned in many countries. There is some evidence that a shorter carbon chain leads to less bioaccumulation and toxicity, and accordingly short-chain PFAS have been widely used as a replacement in recent years. Nevertheless, short-chain PFAS exhibit inferior surface properties due to their less crystalline and more loosely packed polymer chains, as compared to their long-chain counterparts. Moreover, surface properties become worse with decreasing chain length. Here we develop an alternative method for obtaining durable water and oil repellency on a nylon fabric using a liquidlike perfluoropolyether (PFPE) brush coating. The coating demonstrates excellent water and oil repellency, on par with the banned long-chain PFAS finishes, although its longest PFAS degradation product would have a chain length of L = 3, i.e. an ultra-short-chain PFAS. The PFPE-treated nylon exhibits superior surface properties compared to state-of-the-art, short-chain PFAS finished fabrics used in industry currently, even after laundering and 10,000 cycles of abrasion. The comfort of the treated fabrics is also maintained. The PFPE coatings developed here could replace the toxic, short-chain PFAS in use worldwide today.

In-situ grown SiO2 on amino-silane modified polyacrylonitrile nanofibrous membranes and its waterproof-breathable and light-shielding properties

Waterproof and breathable (W&B) materials with light-shielding properties are expected to provide new choices for outdoor clothing. Herein, SiO2@PAN nanofibrous membranes were fabricated by a facile and eco-friendly strategy. Firstly, amino-silane modified polyacrylonitrile (PAN-APS) nanofibrous membranes were prepared by electrospinning. Subsequently, a hierarchical rough structure and robust superhydrophobic surface were formed by a one-step in-situ growing SiO2 and coating with hexadecyltrimethoxysilane (HDTMS). The results showed that SiO2@PAN nanofibrous membranes displayed durable water repellency (the water contact angle above 150° and the sliding angle of about 5.3°), and high breathability (the air permeability of 47.23 mm/s and the moisture permeability of 3.92 kg·m−2·d-1). And SiO2@PAN nanofibrous membranes had a certain durability, which water repellency could maintain even after mechanical abrasion, or after 24 h of immersion in acid-base solutions with pH values of 1, 4, 7, 10 and 13. Moreover, SiO2@PAN nanofibrous membranes showed light-shielding properties. After 10 min exposure to sunlight irradiation, the surface temperature of SiO2@PAN membrane was about 10 °C lower than that of PAN membrane and 20 °C lower than the temperature of the surface without covering membrane. This work provides a promising candidate for protective clothing.

Assessment of the Barrier Performance of the Flourosilicone Treated Fabric Exposed to Pesticides Spraying to Chilli Crop at Laboratory Conditions

In this study, in view of development of protective clothing for pesticide sprayers in chilli crop, the suitable fabric polyester 67/cotton 37 with weight 157.7 GSM was selected. BOND-WR-12-A RTU was aqueous fluorosilicone durable water and oil repellent emulsion was used to treat the fabric by using different application parameters at the rate of 5 per cent concentration. As per Chowdhury, 2018 water repellent finish type and concentrations were very important parameters to obtain water repellent fabric having acceptable use properties. Later, the treated fabric was exposed to the selected pesticides like Phosphamidon, Monocrotophos and Dimethoate for for three exposures. By estimating the absorption and penetration behaviour of the treated and untreated fabrics, the performance of silicon finish was determined by using four factor with CRD and Heuristic method. From this result, the treated fabric had restricted the absorbency over control fabric and the Studies on barrier clothing, [1,2] suggested that blends of polyester cotton and polyester viscose showed better barrier performance with minimum penetration of pesticides than other blended fabrics. Hence it can be used in development of protective clothing for pesticide applicators in chilli crop or any other field crops where ever pesticides are used.

A novel method to produce sustainable wind resistant and water repellant fabric for outdoor sport clothing

Clothing production have adverse impact on the environment due to inefficient energy utilization during production processing, huge consumption of water and usage of harmful chemicals. Therefore, this work aims to develop a sustainable wind resistant and water repellant fabric through novel technology that reduces production processing steps for efficient energy consumption without compromising required functional performances without durable water repellency coatings (DWR) and application of fluorinated chemicals. This development aims to overcome the drawbacks associated with multiple production processing steps, hazardous chemicals, delamination, degradation, and reduction in vapor permeability due to adhesive layer, etc. In this work, the one-layer fabric was developed using polyester filament yarn on one surface and polyamide low melt yarn on another surface using plaited knitting technique. Further, the fabric was thermally processed at different conditions to create uniform barrier film through melting and flowing of polyamide yarns on fabric surface. The optimized and efficient thermal processing parameters were determined using Box-Behnken design as 120°C, 30 s and 0.5 MPa which yielded a fabric membrane with air permeability of 33.5 cm3/s/cm2, highest resistance to surface wetting with grade 5, exhibited hydrophobicity with water contact angle (WCA) of 120° and water vapor transmission rate of 875.7 (g/(m2·24 h)). Developed fabric also shows high abrasion resistant which would have increased clothing lifespan and comparable stiffness to commercially available wind stopper and water repellant fabrics.

Non-fluorinated durable water repellent and stain resistant coating

Fluorinated materials have been broadly used in the industry of water repellent and stain resistance. Because fluorinated materials have low surface tension, and the coatings could easily be manufactured as water-repellent and stain-resistant, fluorinated materials dominate the market for breathable waterproof textiles. However, these materials had substantial health hazards because of the toxicity of fluorinated materials. Moreover, many governments also regulate fluorinated materials for health reasons. As a result, non-fluorinated materials replacing fluorinated materials have become a trend in the industry. As a result, many companies are actively looking for solutions for non-fluorinated water-repellent and stain-resistant materials. This literature review will give a comprehensive understanding of water-repellent properties, materials surfaces, and stain-resistance properties, materials, and surfaces.Moreover, this review would also include reviews of natural water repellent and stain repellent. Furthermore, this review will also talk about the theories behind the materials. Additionally, the fabrication process limitation and future outlook will be discussed in this review.

Multifunctionalization and Increased Lifespan of a Worsted Wool Fabric

A lack of dimensional stability of worsted fabrics when laundering leads to a rapid increase in wool textile waste. Dry cleaning is thus highly recommended; however, it requires solvent(s), which are not eco-friendly. The aim of this study was to produce a machine-washable, 100% worsted wool woven as an outer fabric for men’s suit jacket that is also water-repellent in order to reduce the number of washes required during use. Chemical treatments were applied through successive paddings, using a blend of aqueous dispersion of polyurethane and polysiloxane (PUPX) for shrink-proofing/dimensional stability, followed by a second blend of an aqueous emulsion of fluorotelomer methacrylate and paraffin/hydrocarbon waxes (C6PW) polymers for water-repellency. The dimensional change of the finished fabric did not exceed 2%, meeting Woolmark requirements AW-1. Zeta potential measurements confirm that the fabric coated with PUPX has an overall anionic nature, which allows the good adhesion of the successive cationic C6PW polymer blend used in the second padding. Additionally, Scanning Electron Microscopy (SEM) analysis confirmed the good adhesion of the first blend (PUPX) to the wool fiber surface and inter-fiber bonding. After the application of (C6PW) resin, the fabric exhibited durable water repellency with a 5/5 spray test rating after 10 washes and dimensional stability, as well as high resistance to wear and abrasion, while retaining a soft feel and good flexibility.

Fate of Per- and Polyfluoroalkyl Substances from Durable Water-Repellent Clothing during Use.

To make outdoor clothing water- or dirt-repellent, durable water-repellent (DWR) coatings based on side-chain fluorinated polymers (SFPs) are used. During use of outdoor clothing, per- and polyfluoroalkyl substances (PFASs) can be emitted from the DWR to the environment. In this study, the effects of aging, washing, and tumble drying on the concentration of extractable PFASs in the DWR of perfluorohexane-based short-chain SFPs (FC-6 chemistry) and of perfluorooctane-based long-chain SFPs (FC-8 chemistry) were assessed. For this purpose, polyamide (PA) and polyester (PES) fabrics were coated with FC-6- and FC-8-based DWRs. Results show that aging of the coated fabrics causes an increase in concentration and formation of perfluoroalkyl acids (PFAAs). The effect of aging on the volatile PFASs depends on the type of fabric. Washing causes a decrease in PFAA concentrations, and in general, volatile PFASs are partly washed out of the textiles. However, washing can also increase the extractable concentration of volatile PFASs in the fabrics. This effect becomes stronger by a combination of aging and washing. Tumble drying does not affect the PFAS concentrations in textiles. In conclusion, aging and washing of fabrics coated with the DWR based on SFPs release PFASs to the environment.

Preparation and Application of Fluorine-Free Finishing Agent with Excellent Water Repellency for Cotton Fabric.

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.

Review of Non-Fluorinated Durable Water Repellent and Stain-Resistant Materials and Their Future development

Materials with superhydrophobic surfaces have significant values in industrial applications for the reason that these materials usually has the abilities of self-cleaning and stain-resisting. Currently, most superhydrophobic materials are fluorinated ones because fluorinated groups contribute to decreasing the surface energy and surface tension of materials. Nevertheless, toxicity of fluorinated materials prevents them from being widely used in some industrial areas. Thus, this paper aims to have a review of methods used to fabricate non-fluorinated materials with superhydrophobic surfaces. This work introduces both the advantages and disadvantages of fluorinated materials and displays the reasons why materials can be superhydrophobic. In addition, hierarchical structures and re-entrant structures are shown in this passage and methods of making these structures are listed. Besides, this paper presents some methods to fabricate structures which contribute to superhydrophobization. Furthermore, some non-fluorinated materials are listed and their abilities of repelling water and stains are displayed, consisting of silanes, organic materials, and inorganic materials. At last, this paper illustrates current limitation of non-fluorinated materials and their future developments.

Cross-Linking Strategies for Fluorine-Containing Polymer Coatings for Durable Resistant Water- and Oil-Repellency.

Functional coatings for application on surfaces are of growing interest. Especially in the textile industry, durable water and oil repellent finishes are of special demand for implementation in the outdoor sector, but also as safety-protection clothes against oil or chemicals. Such oil and chemical repellent textiles can be achieved by coating surfaces with fluoropolymers. As many concerns exist regarding (per)fluorinated polymers due to their high persistence and accumulation capacity in the environment, a durable and resistant coating is essential also during the washing processes of textiles. Within the present study, different strategies are examined for a durable resistant cross-linking of a novel fluoropolymer on the surface of fibers. The monomer 2-((1,1,2-trifluoro-2-(perfluoropropoxy)ethyl)thio)ethyl acrylate, whose fluorinated side-chain is degradable by treatment with ozone, was used for this purpose. The polymers were synthesized via free radical polymerization in emulsion, and different amounts of cross-linking reagents were copolymerized. The final polymer dispersions were applied to cellulose fibers and the cross-linking was induced thermally or by irradiation with UV-light. In order to investigate the cross-linking efficiency, tensile elongation studies were carried out. In addition, multiple washing processes of the fibers were performed and the polymer loss during washing, as well as the effects on oil and water repellency were investigated. The cross-linking strategy paves the way to a durable fluoropolymer-based functional coating and the polymers are expected to provide a promising and sustainable alternative to functional coatings.

Durable flame retardant and water repellent cotton fabric based on synergistic effect of ferrocene and DOPO

In order to endow cotton fabric better water repellency and flame retardancy, ferrocene formaldehyde and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) were introduced into cotton fabric through facile chemical reaction. The specific pyrolysis products of Fe@DOPO cotton tested by TG-IR was reduced obviously compare with pristine cotton. More importantly, the peak heat release rate and total heat release of the modified cotton fabric were decreased by 48.9% and 19.2%, respectively. Through the analysis of combustion mechanism, it was indicated that ferrocene and DOPO have synergistic flame retardant effect. In addition to the flame retardant, the waterproof property of Fe@DOPO cotton was also greatly improved, and the contact angle was 138°. After 12 times of washing, the limiting oxygen index (LOI) of as-prepared cotton was still 24%, indicating Fe@DOPO cotton had a good washing resistance. These excellent properties were expected to make the modified cotton fabric applied in many fields.

Imparting Water Repellency to Leather through an Organo Metallic Chromium Complex

Organometallic compounds are finding novel applications and benefitting mankind in many ways. The present work relates to the development of such compounds that shall be locally available, cheap, durable and compatible water repellent for leather. The work methodology is so that first there is selection of method of preparation in which the easiest and most economical method is selected. Suitable methods of applications are then elucidated. Finally, some necessary tests of performance are conducted. There are certain weak areas, which are highlighted.

Quantifying Water Repellency by Modifying Spray Test Method AATCC TM22 to Extend Test Duration Allowing Discrimination between Similarly Graded Fabrics

The AATCC TM22-2014 spray test (similarly BS EN ISO 4920:2012) is widely used to determine the water repellency of textiles. Given the ongoing move towards non-fluorinated chemistries to provide water repellent finishes on textiles, modifications to the spray test are suggested to discriminate between those which initially demonstrate similar repellency and aid in assessment of performance within laboratory textile testing. An extended shower duration of 60 minutes or 120 minutes is recommended, with additional calculations to objectively quantify surface wetting. This increased test period demonstrated differences in performance between repellent finishes with a 1.37 g mass difference between fluorinated and non-fluorinated chemistries after 120 minutes. Further quantification of repellent performance, as set out in this study, would determine the performance of non-fluorinated durable water repellent (DWR) chemistries and suitability for end use.

Synthesis and Application of Fluorine-free Environment-friendly Stearic Acid-based Oil and Water Repellent for Cotton Fabric

ABSTRACT 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 pressure. In this research, stearic acid which is a long-chain bio-based fatty acid is polymerized with a bio-based cross-linker citric acid in the presence of a catalyst. Stearic acid is a fluorine-free, environment-friendly, and nontoxic compound as compared to fluorinated compounds. Optimization of various parameters such as dosage of monomers, polymerization conditions, time, and temperature was carried out. The optimized recipe treated cotton fabric exhibited appreciable oil and water repellency and contact angle as well as the additional performance properties like crease recovery, soil resistance, antimicrobial performance, and shrinkage. Furthermore, the characterization of finished fabric was also carried out by SEM, EDX, XRD, FTIR, 1 H-NMR spectroscopy analysis.

Wettability, durability and corrosion properties of slippery laser-textured aluminum alloy surface under water impact

Laser textured aluminum alloy substrate was sprayed with hydrophobic SiO2 nanoparticles followed by the infusion of perfluoropolyether oil. The wettability and the corrosion properties were evaluated before and after the continuous water droplet impact tests. The results showed that the formation of composited pores consisting of micron-sized textured dimples and nano-sized porosities helps in enhancing the preservation of perfluoropolyether oil. The integration of textured micro-dimples endows durable water-repellency to the oil-infused SiO2 nanoparticle coating and the water contact angle stabilizes at a level of about 130° after the water droplet impact of 30 h. The micro-nano composited pores acted as oil reservoirs effectively prolong the life of lubricating oil layer, resulting in a superior corrosion resistance showing neither cathode nor anode currents against water droplet impact for 15 h.

The effect of weathering on per- and polyfluoroalkyl substances (PFASs) from durable water repellent (DWR) clothing

To assess the effects of weathering on per- and polyfluoroalkyl substances (PFASs) from durable water repellent (DWR) clothing, thirteen commercial textile samples were exposed to elevated ultra violet (UV) radiation, humidity, and temperature in an aging device for 300 h, which mimics the lifespan of outdoor clothing. Before and after aging, the textile samples were extracted and analysed for the ionic PFASs (perfluoroalkyl acids (PFAAs), perfluorooctane sulfonamide (FOSA)) and volatile PFASs (fluorotelomer alcohols (FTOHs), acrylates (FTACs) and methacrylates (FTMACs)). Results showed that weathering can have an effect on PFASs used in DWR of outdoor clothing, both on the PFAS profile and on the measured concentrations. In most weathered samples the PFAA concentrations increased by 5- to more than 100-fold, while PFAAs not detected in the original textiles were detected in the weathered samples. DWR chemistries are based on side-chain fluorinated polymers. A possible explanation for the increase in concentration of the PFAAs is hydrolysis of the fluorotelomer based polymers (FTPs), or degradation of the FTOHs, which are used in the manufacturing of the FTPs. The concentrations of volatile PFASs also increased, by a factor up to 20. Suggested explanations are the degradation of the DWR polymers, making non-extractable fluorines extractable, or the transformation or degradation of unknown precursors. Further research is needed to unravel the details of these processes and to determine the transformation routes. This study shows that setting maximum tolerance limits only for a few individual PFASs is not sufficient to control these harmful substances in outdoor clothing.

Superhydrophobic and breathable SiO2/polyurethane porous membrane for durable water repellent application and oil-water separation

Electrospun polyurethane membrane with porous structure could be used for waterproof and breathable applications, however, due to polar groups in the soft segment of polyurethane, water would easily permeate the membrane. The water repellency of polyurethane membrane could be improved by grafting hydrophobic silica particles onto the membrane to construct rough surface and low energy epidermis. Polyurethane membrane was chemically modified with 4,4′-methylenebis(phenyl isocyanate) to obtain a reactive group, which was then coupled with (3-aminoproyl) triethoxysilane. Thereafter, the treated membrane was added to the preparation solution of hydrophobic silica particles. Herein, the particles constructed the rough surface of the membrane, and hexadecyltrimethoxysilane endowed the membrane with hydrophobic epidermis. The resultant membrane exhibited significant hydrophobicity with high water contact angles (WCA) and low sliding angles (SA) to different aqueous solutions. Under cyclic stretching, the modified membrane displayed durable water repellency (WCA varied between 152.7 and 154.9°, SA fluctuated between 5.0 and 6.5°) and high breathability (8.4 kg·m−2·d−1). Furthermore, the hydrophobic membrane was superoleophilic and had high permeation fluxes for various oils. It could effectively separate (98.5%) the dichloromethane-water mixture over 30 separation cycles.