Ultraviolet Protection Factor Research Articles

Preparation of Photochromic Microcapsules of Poly(methyl methacrylate)/Inorganic Metal Oxide Composite Shells with UV‐Resistant Properties and Application to Printing on Cotton Fabrics

AbstractTo further enhance the fatigue resistance of spiropyran‐based photochromic materials and to explore the functionality of organic–inorganic metal oxide microcapsule shell materials, cross‐linked (P(MMA‐PETA)) and homopolymer (PMMA) shells have been developed by cross‐linking TiO2 and hybridizing ZnO on a PMMA matrix. PMMA/TiO2 photochromic microcapsules and PMMA/ZnO photochromic microcapsules with ultraviolet (UV)‐absorbing function are prepared by successfully encapsulating spiropyran photochromic compounds using these two composite shells. The results show that both microcapsules exhibit a complete spherical core–shell structure with good UV resistance and thermal stability. The TG test underlines a 50% coating rate of PMMA/ZnO microcapsules on spiropyran photochromic material, with an optimal ZnO addition of 10% and particle size range from 2 to 8 µm, effectively blocking UV‐A and part UV‐B radiation. Further, a 75% maximal coating rate is observed for PMMA/TiO2 microcapsules on spiropyran with optimal TiO2 addition at 2–4%, a particle size of around 5 µm, diffusely reflecting 48% of UV rays. The photochromic fabrics prepared with PMMA/TiO2 microcapsules have better UV resistance, with a UV protection factor value of 59.48, and excellent fatigue resistance after at least 30 cycles of UV–visible light irradiation.

Inherent mosquito repellent-cum-multifunctional polyurethane for multifunctional coating of cotton fabric

Textile had evolved from simple apparel to multifunctional textiles due to increasing awareness and upgrading technology. For fulfilling modern demands, multifunctional textile became a vital area of exploration for textile research community, and polyurethane coated textile is a significant contributor to attain this position. The current work reports ethyl anthranilate-based durable inherent mosquito repellent polyurethane (Mos PU) with ultraviolet (UV) protective, antibacterial and waterproof-breathable properties for coating of textiles. The Mos PU was characterised using Attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and Gel permeation chromatography (GPC) techniques. The changes in the properties of cotton fabric with the varying add-on were also studied. Thermal properties of Mos PU and coated samples were studied using thermogravimetric analysis. The functional properties of the coated cotton fabrics were also assessed against repeated laundering. The bacteria adherence and quantitative antibacterial activity tests confirmed the antibacterial effect of coated surface on different bacterial strains, gram positive S. aureus and gram negative E. coli. Moreover, the prepared coated cotton fabric showed excellent mosquito repellency (100 %), appreciable water vapour transmission rate and excellent UV protection factor (UPF rating of 50+). The functional properties of the prepared coated samples were significant even after ten launderings.

Sustainable polylactic acid spunlace nonwoven fabrics with lignin/zinc oxide/water-based polyurethane composite coatings

In this paper, polylactic acid spunlace nonwoven fabrics were coated with lignin/zinc oxide/water-based polyurethane composite formulations, including five different ratios of lignin and zinc oxide, via a film applicator and thermally cured. The coated and thermally cured nonwoven fabrics were tested in terms of color values, tensile strength, abrasion resistance, ultraviolet protection, hydrophobicity, antibacterial activity, air, and vapor permeability properties. Characterization studies were conducted by FTIR, DSC, TGA, XRD, and SEM. The ultraviolet protection factor of 215.47 and a water contact angle of 90.27° were obtained with the fabric coated with WPU-1:5 formulation. Nonwoven fabric coated with the WPU-1:5 formulation showed evident antibacterial activity against S. aureus and E. coli bacteria as 89 % and 100 %, respectively. With the addition of lignin/ZnO into water-based polyurethane coating paste, PLA nonwoven fabric exhibited improved antibacterial activity, tensile strength, abrasion resistance, and ultraviolet light protection performance. However, composite coatings decreased air and vapor permeability and hydrophobicity of fabrics, but acceptable results were obtained. The results indicate that polylactic acid nonwoven fabrics, when treated with lignin/ZnO/WPU composite coatings, exhibit enhanced mechanical and functional properties, rendering them promising for applications in protective medical textiles.

Sustainable traditional natural dyeing practice in Daboya and Ntonso communities of Ghana

Purpose The purpose of this study is to investigate the physical, ultraviolet (UV), colour appearance and colour fastness properties of selected fabrics dyed with natural dyes from Daboya and Ntonso communities of Ghana. The study further highlights the rich cultural heritage of traditional dyeing from these two communities. Craftsmen in West Africa especially Ghana, have sustained the traditional dyeing methods to produce textile products for consumers. Design/methodology/approach In this study, two sample fabrics were purchased from craftsmen at Ntonso and Daboya communities in Ghana. These fabrics were analysed at the laboratory under standard test methods for their physical, UV, colour appearance and colour fastness properties. Findings Results showed that all the sample fabrics have good UV shielding performance (ratings above 50+). Daboya sample fabrics (dyed with indigo dyes) produced more colour stains than the sample fabrics from Ntonso (dyed with black “kuntunkuni” dyes). The K/Ssum value or colour yield reduced after washing but that alternatively increased the calculated ultraviolet protection factor. Practical implications Findings from this study exposed the unique UV performance of dyed traditional fabrics (using natural dyes) from Ntonso and Daboya communities in Ghana. This inspires and enforces the need for craftsmen to improve their production cycle to produce these fabrics in different sizes which provides the necessary UV shielding abilities for consumers in the wake of climate changes. Originality/value This study demonstrated that the natural dyeing process at the two communities produced relatively good UV and colour fastness properties of the sample fabrics. These eco-friendly dyeing practices have survived over time to maintain and promote the concept of sustainability within the textile and fashion industry in Ghana.

Pyrazole-vaniline Schiff base disperse azo dyes for UV protective clothing: synthesis, characterization, comparative study of UPF, dyeing properties and potent antimicrobial activity

From 5-amino pyrazole, azo disperse pyrazole dyes containing o-vanillin have been synthesized and characterized using elemental analyses and Spectroscopic techniques. All synthesized dyes have been effectively used on polyester fabrics as disperse dyes, and the performances of dyeing have been studied and evaluated. The dyes have good depth, brightness and good leveling properties. The fastness properties of the dyed samples have been thoroughly examined and assessed with regard to washing, perspiration, rubbing, and light fastness. Color representation, colorimetric data (L*, a*, b, C*, h, and K/S), and other multifunctional features have also been studied. The degree of exhaustion and fixation were attained. Additionally, the dyed fabrics were put through an ultraviolet protection factor test, with the findings demonstrating that these dyes provided superior UV protection. The synthetic dyes were tested in- vitro against different bacteria and fungi, all of the dyes shown a significant activity compared with the standard drug.Graphical abstract

EFFECT OF NATURAL DYES AND DIFFERENT MORDANT TREATMENTS ON ULTRA-VIOLET PROTECTION PROPERTY OF COTTON FABRIC

Natural dyes are eco-friendly, skin-friendly, have pleasing colours and other beneficial characteristics, such as UV protection property. In the present work, different natural dyes (onion skin, henna leaves, curry leaves, neem leaves and turmeric), along with a number of mordants (myrobalan, alum, ferrous sulphate and ferrous sulhate-myrobalan), were used to study their effects on colour strength and the ultraviolet protection factor (UPF) values of treated dyed cotton fabric. It was found that the highest colour strength (K/S) was achieved on ferrous sulphate-myrobalan treated turmeric dyed cotton fabric (75.45), followed by the samples dyed with onion skin (48.24), henna leaves (37.40), neem leaves (28.61) and curry leaves (25.96). The highest UPF value was found for ferrous sulphate-myrobalan pretreated curry leaves dyed cotton fabric (27.69), which indicated very good protection, whereas the ferrous sulphate-myrobalan pretreated onion skin dyed cotton fabric showed good protection (23.39), followed by those dyed with henna leaves (21.79), turmeric (19.48), and neem leaves (16.43).

A new multifunctional flame-retardant coating for cotton fabric to enhance smoke suppression, and UV shielding properties

Turmeric powder (TP) is used in the textile industry as a colouring agent, but its impact on the flammability properties of textiles wasn’t investigated. In this work, new coatings containing TP and TP with melamine polyphosphate (MPP) were utilized to enhance the thermal stability, flame retardancy, colour strength (K/S), and UV-protection factor (UPF) of cotton fabric (CF). Flammability tests indicated that TP alone failed to prevent flame spread in the fabric, and it increased the emission of toxic gases, especially CO and CO2. In contrast, the MPP/TP coating was able to put an end to the spread of a flame in CF, and the samples achieved self-extinction. The value of the limiting oxygen index (LOI) of CF was 18.2%, and it enhanced in MPP/TP containing samples to be 37.8%. K/S and UPF values showed that MPP/TP coatings improved the K/S and UPF values of CF to 2.9 and 290, respectively. Additionally, they lowered the toxic gases produced during CF combustion and the maximum specific optical density (Dsmax) of CF. The new coatings improved the char residue production in treated samples at 750 °C compared to CF, according to the thermogravimetric analysis (TGA) data. Untreated and treated samples' mechanical and physical characteristics were measured and compared. Analysis of smoke toxic gases and inspection of char remained following the smoke density test revealed that MPP/TP coating enhanced the flame retardancy of CF in both the condensed and gas phases.

Dyeing performance of wool fabric with natural pigment from Cordyceps militaris

As a sustainable and ecological dye resource, the biomass materials are receiving more and more attention. In this work, the pigments in Cordyceps militaris were extracted and applied for dyeing wool fabrics, and the various properties were investigated. The extracted pigments and dyed wool fibers were analyzed and characterized by ultraviolet–visible (UV-Vis) spectroscopy, Liquid Chromatography-Mass Spectrometry (LC-MS) and Fourier Transform Infrared (FTIR) spectroscopy. The single-factor experiments were used to screen and optimize the dyeing process. Six metal mordants with different use order were compared with each other, and their possible mordanting mechanisms were proposed. The color fastnesses, UV resistance and antioxidant properties were evaluated after dyeing. The results showed that UV-Vis, LC-MS and FTIR analysis confirmed that the main components of C. militaris extract was lutein. The optimal dyeing process for the extract was as follows: dyestuff mass 200% (o.m.f.), dyeing temperature 90 °C, dyeing time 45 min, bath pH 5.0, Na2SO4 mass 0 g/L. Metal ions are added to form chelate bonds between the dyes and the fibers, further improving the color fastness. The dyed fabric exhibits excellent UV resistance and its UPF (Ultraviolet Protection Factor) value increases with the color yield. Meanwhile, the dyed wool fabric could exhibit up to 94.77% antioxidant activity. These results provide new insight for the application of C. militaris pigments on wool fabric.

Over dyeing of Lyocell fabric with natural indigo and rhubarb

In order to enrich the range of natural dye chromatography, this study used rhubarb to dye indigo dyed Lyocell fabric to obtain green Lyocell fabric. Firstly, the Lyocell fabric was dyed with indigo using a typical reduction method. The K/S and b* values of dyed fabrics were used as evaluation indicators to determine indigo concentration of 1.2 g/l before the over dyeing. The effects of rhubarb concentration, pH value, and dyeing temperature on the K/S value and color characteristic value of rhubarb dyed Lyocell fabric are discussed. The results showed that acidic solution, higher rhubarb concentration, and lower dyeing temperature were beneficial to obtain higher K/S and b* values for the rhubarb dyed Lyocell. Finally, these three factors were taken as independent variables in over dyeing, and the red-green value of dyed fabric was taken as response value for response surface analysis. The response surface analysis of three factors and three levels showed that the pH value of the dye solution had a significant impact on the a* value. The a* value of the dyed fabric decreased with the increase in rhubarb concentration and the decrease in the pH value and dyeing temperature. The optimization process suggested by the regression model statistical analysis was as follows: rhubarb concentration was 2.67 g/l, dye bath pH 3.5, and dyeing temperature 57°C. The verification result showed that a* value of the over dyed fabric was –10.75, which was close to the predicted value –10.98. The infrared results showed that the cellulose characteristic groups of the undyed and dyed Lyocell fabrics were almost same. The Lyocell fabric dyed with indigo and rhubarb showed a blue-green color, and 50+ ultraviolet protection factor. The washing color fastness of the over dyed Lyocell fabric was 2–3 and the rubbing fastness was above 3. This over dyeing method may enrich the chromatogram of Lyocell fabric dyed with natural dyes.

PROPERTY ENHANCEMENT OF PIGMENT PRINTED POLYESTER FABRIC USING PLASMA TECHNOLOGY

Today, the customer is the king of the market and polyester fabric is in high demand as it is more economical and has many good properties when compared with other textile material. Polyester is claiming more than 75percent of the estimated 60 million metric tons of fibres consumed in man-made textiles in the apparel industry over natural fibres. Naseerali (2013) In this study the researcher has made an attempt to improve the absorbency of polyester fabric as well as to reduce its static charge. Air plasma technology was used to treat the surface of 100% polyester fabric at different time durations of 15, 30, 45, 60, 90, 120 minutes. The control and the surface modified fabrics were then printed with water- based pigments which are eco-friendly and without water based pigments which are commercially used. As most of the pigment printed samples get peeled off so it was plasma treated and then printed to evaluate the durability of the pigment prints. The UPF (ultra-violet protection factor) value of all the control and the modified sample were then evaluated to determine the ultraviolet radiation blockage or transmittance by fabrics intended to be used for UV protection. It was further found that better UPF value of the modified non water- based pigment at 90 minutes when compared to water based pigment samples and untreated samples. The fastness properties like rub and color fastness were observed with standard methods. In the rub fastness tests it was observed that the plasma treated with water based pigments for 30 minutes gave better dry rub fastness and it concludes that plasma treatment more than 30 minutes is not required because it gives a better results at 30 minutes. In the color fastness properties the water- based and non-water based pigment printing gave a better result at all-time durations than the control sample, so in concern of energy usage, treatment can be given for less time duration to have better quality products.

Effect of metal organic framework on crystallization and ultraviolet protection ability of biobased PA5,6

Because of metal organic frameworks high surface area and good compatibility with polyamide 5,6(PA5,6), HKUST-1 was chosen as a nucleating agent and UV resistant agent for PA5,6 to improve its performances. The addition of HKUST-1 improves the crystallinity and crystallization rate of PA5,6 by increasing the intramolecular hydrogen bonds in PA5,6. In addition, after the addition of HKUST-1, PA5,6 has low ultraviolet (UV) transmittance and good UV resistance (ultraviolet protection factor is 15+) because the reflection, absorption, and scattering of UV light are enhanced by the effects of HKUST-1. Therefore, HKUST-1 is good nucleating agent for PA5,6 and enhances its UV resistance.

Construction of Multifunctional Hierarchical Biofilms for Highly Sensitive and Weather-Resistant Fire Warning.

Multifunctional biofilms with early fire-warning capabilities are highly necessary for various indoor and outdoor applications, but a rational design of intelligent fire alarm films with strong weather resistance remains a major challenge. Herein, a multiscale hierarchical biofilm based on lignocellulose nanofibrils (LCNFs), carbon nanotubes (CNTs) and TiO2 was developed through a vacuum-assisted alternate self-assembly and dipping method. Then, an early fire-warning system that changes from an insulating state to a conductive one was designed, relying on the rapid carbonization of LCNFs together with the unique electronic excitation characteristics of TiO2. Typically, the L-CNT-TiO2 film exhibited an ultrasensitive fire-response signal of ~0.30 s and a long-term warning time of ~1238 s when a fire disaster was about to occur, demonstrating a reliable fire-alarm performance and promising flame-resistance ability. More importantly, the L-CNT-TiO2 biofilm also possessed a water contact angle (WCA) of 166 ± 1° and an ultraviolet protection factor (UPF) as high as 2000, resulting in excellent superhydrophobicity, antifouling, self-cleaning as well as incredible anti-ultraviolet (UV) capabilities. This work offers an innovative strategy for developing advanced intelligent films for fire safety and prevention applications, which holds great promise for the field of building materials.

Eco-Finishing of Cotton with Chitosan and Giant Goldenrod (Solidago gigantea Aiton) Aqueous Extract for Development of Antioxidant and UV Protective Textiles

ABSTRACT Giant goldenrod (S. gigantea Aiton) is considered an invasive weed in Europe, Asia, Australia, and New Zealand. In this research, the untreated and chitosan-treated cotton fabrics were functionalized with goldenrod inflorescences aqueous extract, at room temperature and 95°C. Zeta potential of fabrics was determined as a function of pH and the results showed an increased isoelectric point from 2.50 to 5.25 and amphoteric character of the chitosan-treated sample. The antioxidant activity (AA) of extract and functionalized fabrics was determined using DPPH analysis, while color and ultraviolet protection factor (UPF) were determined spectroscopically before and after wash and lightfastness testing. The chitosan pretreatment and dyeing of cotton at higher temperature increased AA (from 41.19 ± 0.28 to 56.08 ± 0.25), UPF (from 33.05 to 51.59) and color strength (K/S) (from 1.74 to 2.21), providing dyed cotton with excellent UV protection and a free radical inhibition activity. The samples had good wash fastness in terms of color (ΔEab* < 1), but not in terms of UV protection (UPF value decreased after washing to 23.47). The overall lightfastness was good to excellent (the UPF values of chitosan and dyed samples did not change much after lightfastness test (UPF = 51.75).

Enhancing the color shade and depth of linen fabrics dyed with Caesalpinia sappan L. wood extract using metallic salt mordants

This study demonstrated natural dyeing of linen with a dye extracted from sappan wood (Caesalpinia sappan L.). Four metallic salt mordants, namely (NH4)2Fe(SO4)2, CuSO4, SnCl2, and AlK(SO4)2, referred to as Fe, Cu, Sn, and Al, respectively, were used to improve the dyeing properties. The influences of the pH, dye concentration, mordant type and concentration, and mordanting technique on the dyeing properties were investigated. Dyeing without mordants resulted in a reddish-brown fabric; however, different mordants produced a variety of color shades. In general, the mordant containing Fe yielded the highest color strength, generating a dark gray color very close to black. Crimson and magenta fabrics were obtained using Sn, and pink fabrics were obtained using Al. The samples with the Cu mordant showed a dark and dull purple color. The color strength due to post-mordanting was higher than those due to pre- and meta-mordanting. Dyeing and mordanting increased the ultraviolet protection factor (UPF) of the fabrics. Only the fabrics post-mordanted with Fe exhibited good ultraviolet protection (UPF 15). The concentrations of extractable heavy metals (Fe and Cu) were also determined.

An All‐Stretchable, Ultraviolet Protective, and Electromagnetic‐Interference‐Free E‐Textile

AbstractFlexible and skin‐mountable electronics have drawn tremendous research attention with the booming of smart medical systems and wearing technologies, however, their environmental adaptability to electromagnetic and solar radiation has long been neglected. Herein, a novel health monitoring e‐textile with robust ultraviolet (UV) protecting and strong electromagnetic interference (EMI) shielding performance is rationally developed on an ultraelastic and bilayered nonwoven textile. Via the respective incorporation of silver flake‐modified liquid metal (AgLM) and silver nanoparticles (AgNPs) on each side of a permeable substrate, a Janus sensing layer with electrophysiological monitoring function, Joule heating ability, and excellent EMI shielding capability (up to 38.5 dB in X band) is first fabricated. Elastic microfibers embedded with sensitive photochromic microcapsules are then in situ assembled on the bioelectric‐sensing layer, achieving a bilayered e‐textile with a reversible UV‐chromic property and an extraordinary UV protection factor (UPF) of 335.56. The developed all‐stretchable and UV‐EMI proof e‐textile is utilized as a safe and comfortable on‐skin electronic to provide point‐of‐care health regulation under complex UV/EMI radiative environments. Specifically, stable Joule heating performance and accurate monitoring of electrocardiogram (ECG) and surface electromyography (sEMG) are simultaneously obtained, demonstrating promising applications in multifunctional and robust wearing electronics.

Kevlar® and Nomex® modification via 2,4-dihydroxybenzophenone anchoring improves water repellency and induces antibacterial and UV protection properties

Aramid materials, such as Kevlar® and Nomex®, are aromatic polyamides exhibiting excellent chemical and mechanical properties. Because of their demanding applications, it is essential to enhance their water repellency, their endurance to UV radiation, as well as their antibacterial properties, while simultaneously preserving or even strengthening their durability. The present work describes the successful modification of aramid materials, in a way that improves the final product, by inducing the desired properties without significantly affecting the existing ones. The synthesis of a model compound simulating aramid materials is carried out followed by thorough studies, thus leading to a better understanding of the behavior of aramid materials at the molecular level, as well as to their optimal modification conditions. Subsequently, the attachment of 2,4-dihydroxybenzophenone to Kevlar® and Nomex® fabrics, using epichlorohydrin as the anchoring moiety, along with detailed characterization, via IR and Raman spectroscopies, thermogravimetric analysis, and SEM imaging, are implemented. The wettability of the modified materials is determined by the water contact angle test, to probe their hydrophilicity or hydrophobicity. The antibacterial protection of the modified aramid materials is determined qualitatively against the Gram-negative bacterium E. coli DH5α and quantitatively according to an in situ method, using cyanobacterium Synechococcus sp. PCC7942. Moreover, the UV protection properties of the modified fabrics are studied by using the UV protection factor (UPF) and average UV-A and UV-B transmittance, while their ultimate strength is found well-preserved.

Assessment of UV Protection for Children's Summer Clothing.

Excess ultraviolet (UV) radiation exposure during childhood poses a particular long-term risk of developing skin cancer later in life however recent studies have called attention to the absorption of chemical sunscreen ingredients into the bloodstream with unclear significance.This has led to recommendations to consider sun protection in the form of clothing to reduce the need for sunscreen products. Ten brands of routine summer clothing not labeled as sun protective from five distributors marketed for children were identified with varying price ranges.Summer clothing items consisting of T-shirts and tops were evaluated for fiber composition, cost, and UPF testing was performed to determine UVA and UVB transmittance. Results: Around 88.2% of blended textile compositions compared to 60% of 100% cotton textiles offered adequate UV protection with an Ultraviolet Protection Factor (UPF) greater than 15. 58% of blended fabrics compared to 50% of cotton textiles offered a UPF greater than 30. There was no correlation between brand and cost with UPF values. Conclusions: In the absence of regulations for testing and labeling of all children's garments for UV protection, guidelines for the pediatric population for choosing clothing for the summer should reflect the information available to consumers that is easy to understand and more likely to result in higher UPF values.Based on fiber composition, blended textiles are more likely to have adequate UV protection compared to 100% cotton or 100% polyester.

Bio-derived phosphorous-nitrogen-silicon decorated halloysite nanotube towards enhancing flame retardant, UV-blocking and mechanical properties of poly(lactic acid)

Developing flame retardant and UV-blocking polylactide (PLA) with reinforced mechanical properties is important but challenging. Herein, bio-derived phytic acid was decorated on halloysite nanotube though silane grafting, ring-opening reaction with melamine and then electrostatic interactions with phytic acid. The obtained phopsphorous-nitrogen-silicon decorated halloysite nanotube (PNSiHNT) was incorporated into PLA to prepare PLA composites. The surface modification significantly improved the compatibility between PNSiHNT and PLA, and the flame retardant, UV-shielding and mechanical properties of the composites were enhanced. At 5% mass loading, the peak heat release and total heat release were reduced by 18% and 12% compared to pure PLA, respectively, superior to most phytic acid-based flame retardants. The relevant mechanism analysis showed that PNSiHNT can restrain the emission of combustible volatiles and promote the formation of protective char layer. Moreover, the flame-retardant PLA showed excellent UV-shielding ability with an ultraviolet protection factor (UPF) value of around 120. Due to the reinforcing effect of PNSiHNT and the strong interfacial interactions between PNSiHNT and PLA matrix, the PLA/PNSiHNT showed 77% and 116% increase in tensile strength and elongation at break compared to the bulk PLA. This study provides a strategy for designing bio-derived organic/inorganic systems for enhancing flame retardant, UV-blocking and reinforced PLA.

In situ tailoring of Ag-doped-TiO2/TPMP/cotton nanocomposite with UV-protective, self-sterilizing and flame-retardant performance for advanced technical textiles

Herein, we present a novel approach to the development of a multifunctional, UV-protective, photocatalytic, antimicrobial and flame-retardant nanocomposite fabric surface. Using a sol–gel/hydrothermal approach, a phosphorus-based flame-retardant 3-(trihydroxysilyl)propyl methylphosphonate (TPMP) in combination with Ag-doped TiO2 was applied to the surface of cotton fibers for the first time, using an aqueous AgNO3 solution as the dopant. The modified cotton fabrics were characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDS) and X-ray diffraction spectroscopy (XRD) to confirm the successful application of Ag-TiO2 and TPMP on the cotton fabric by analyzing the surface morphology, chemical composition, chemical bonding and crystal structure. The functional properties of the modified cotton fabric were determined by measuring the UV protection factor (UPF), burning behavior and thermo-oxidative stability, as well as antibacterial activity against Escherichia coli and Staphylococcus aureus. The results show the formation of a unique nanocomposite matrix of TPMP–polysiloxane on the surface of cotton fibers with well-distributed Ag-TiO2. The formation of TiO2/Ag2O particles on the surface of cellulose fibers was also confirmed. The synergism between all components of the nanocomposite resulted in excellent UV protection in the UVA and UVB region, with a UPF of 50+, self-sterilizing activity against both tested bacteria and enhanced thermo-oxidative stability. Therefore, the novel approach proposed herein is promising for the development of multifunctional, protective surfaces for advanced technical textiles.

Boosting laccase activity by synergistic drive of near infrared laser, surfactant, and sodium chloride for healthcare coatings with UV resistance, anti-oxidation, and photothermal conversion

Natural enzymes as green and efficient biocatalysts are essential in constructing multifunctional organic coatings for meeting the green chemistry processes. Herein, the laccase activity was for the first time enhanced by synergistic drive of near infrared (NIR) laser, dodecyldimethyl (3-sulfopropyl) ammonium hydroxide internal salt (SDDAB), and sodium chloride (NaCl). The SDDAB activation on laccase activity is unpredictable, which is advanced compared with conventional predictable ones, including adding mediator and improving reactive temperature. The NaCl can again boost the laccase activity by 29.8 % in the presence of SDDAB. Moreover, NIR laser irradiation again promotes laccase activity by 16.3 % in laccase/SDDAB/NaCl. The total specific activity of laccase exhibits an improvement of 29.2 %, indicating an advancement compared with the activities decrease in immobilized and encapsulated laccases. The Vm of laccase has been improved to 150.9 %. Besides, the hydrogen bonds and van der Waals force between laccase and SDDAB have been verified. Thus, laccase/SDDAB/NaCl was adopted to catalyze the polymerization of gallic acid to create eco-friendly UV-resistant, antioxidative, and photothermal coatings for healthcare. The ultraviolet protection factor (UPF), free radical scavenging ability, and photothermal temperature are 126.28, 95.0 %, and 94.2 °C, respectively. The multifunctional coating not only exhibits the response of sunlight-like photothermal conversion, but also possesses the photothermal response mediated by NIR laser. With the intensity increase of NIR laser irradiation, the surface temperature of modified cotton fabric is gradually strengthened from 29.5 to 43.8 °C. The surface characteristic and chemical composition of the multifunctional coatings were investigated by modern technology. The smartphone was adopted to quickly detect the red, green, and blue (RGB) values for demonstrating the successful fabricating of composite coatings, compared with traditional K/S characterization. Briefly, this work provided a novel, feasible, and elegant idea to boost laccase activity, inspiring more scholars to create advanced organic coatings with natural enzyme as the high-performance green catalysts for meeting green chemistry processes.