Preparation of Fe3O4@CA/BNNS/AgNP Magnetic Microspheres and Photocatalysis of Dyes.

In this work, sea urchin-like magnetic Fe3O4@CA/BNNS/AgNP composite microspheres were successfully prepared. The photocatalytic performance of composite microspheres for the organic dye rhodamine B (RhB) was systematically investigated under different conditions, and the catalytic degradation rate of RhB was as high as 95% within 60 min; after three cycles of recycling, the degradation rate of RhB was reduced by only 8%. The main active agents in the reaction are e- and •O2-. Fe3O4@CA/BNNS/AgNP microspheres prepared in this study exhibit photocatalytic and electrochemical properties, making them easy to separate. This work is not limited to the development of Fe3O4-based catalysts but also is expected to provide ideas for the research and progress of photocatalytic composite catalysts with electrochemical properties.

Preparation of Flower-like Nanosilver Based on Bioderived Caffeic Acid for Raman Enhancement and Dye Degradation.

In this study, a simple, green, and low-cost room temperature synthesis of broccoli-like silver nanoflowers (AgNF) with a particle size of about 300-500 nm was developed using plant-derived caffeic acid as a reducing agent and polyvinylpyrrolidone as a dispersant under ultrasound assistance. The flower clusters covered by small nanocrystals of 20-50 nm significantly enhance the electromagnetic field signals. AgNF was deposited on the surface of silicon wafers as a surface-enhanced Raman spectroscopy sensor for the detection of probe molecules such as rhodamine 6G (R6G) and malachite green with high sensitivity, homogeneity, and reproducibility. AgNF was deposited on cotton fabrics in the form of composites to catalyze the degradation of dye pollutants such as R6G, MG, and methyl orange in the presence of sodium borohydride. 0.1 g of AgNF/cotton fabric could assist 15 mmol/L NaBH4 to achieve over 90% degradation of various dyes as well as a high concentration of dyes in 12 min with good reusability and recyclability. The AgNF synthesized in this work can not only monitor the type and amounts of pollutants (dyes) in wastewater but also catalyze the rapid degradation of dyes, which is expected to be valuable for industrial applications.

Fabrication of Robust Superhydrophobic Polyester Fabrics with Photothermal Conversion and Oil-Water Separation Performance through Deposition of Natural Polyphenols.

Superhydrophobic polyester (PET) fabrics were created by increasing fabric surface roughness and decreasing surface energy through interactions between natural polyphenols, ferrous sulfate heptahydrate, and hexadecyltrimethoxysilane. The superhydrophobic fabric can be obtained with different natural polyphenols, including tannic acid, ferulic acid, gallic acid, guaiacol, and caffeic acid. Durability tests were carried out on the superhydrophobic PET fabric, investigating resistance to washing, rubbing, UV aging, acids, alkalis, and organic reagents. The results demonstrate the stability and versatility of modified PET in complex environments. The modified superhydrophobic PET fabric exhibited exceptional oil-water separation and self-cleaning properties, exhibiting a water contact angle of 161.3° and a sliding angle of 4°. In addition, the modified fabric demonstrated a remarkable photothermal conversion efficiency, with the surface temperature increasing from 29.1 to 72 °C in 300 s, and it maintained a degree of photothermal conversion capability even upon completion of four cycles. This study offers novel perspectives on extending the utilization of natural polyphenols for constructing durable, robust, and multifunctional superhydrophobic fabrics.

Effect of Polyol Molecular Structure on Fluidity, Surface Tension, and Printed Pattern Sharpness of Disperse Dye Inks.

In the present study, density functional theory (DFT) has been used in simulating and calculating the molecular geometries of differently structured polyols (within a water phase), as well as the weak interactions between these polyols and the water molecules. Furthermore, low field nuclear magnetic resonance (LF-NMR) has been used in studying the transverse relaxation times of different polyols, in addition to their (20.00 wt %) fluidity in an aqueous environment. Moreover, the influence of polyols, with different molecular structures, on the ink fluidity, was also explored. A bubble pressure tensiometer was also used to characterize the surface tension of the aqueous polyol (20.00 wt %) solution, the sodium dodecyl sulfate (SDS, 0.50 wt %) solution, and the ink. This was made to clarify the influence of polyol and SDS on the surface tension of ink. In addition, the particle size, zeta potential, pH value, viscosity, and rheological properties of the ink, were also investigated. The resulting data showed that polyols have certain effects on the particle size, stability, and viscosity of the ink. The jetting performances of different polyol inks were, under certain conditions of the inkjet drive waveform, also explored. The results showed that the fluidity, viscosity, and surface tension of the ink will render a certain influence on the inkjet performances. The prepared polyol ink was thereafter used for polyester fabric printing, and the contour sharpness and color fastness of the printed fabric were accordingly evaluated. The data showed that the increase in ink viscosity, and decrease in fluidity, promote the improvement in contour sharpness. In addition, the printed fabric demonstrated an excellent color fastness.

Preparation of CS-LS/AgNPs Composites and Photocatalytic Degradation of Dyes.

Synthetic dyes are prone to water pollution during use, jeopardizing biodiversity and human health. This study aimed to investigate the adsorption and photocatalytic assist potential of sodium lignosulfonate (LS) in in situ reduced silver nanoparticles (AgNPs) and chitosan (CS)-loaded silver nanoparticles (CS-LS/AgNPs) as adsorbents for Rhodamine B (RhB). The AgNPs were synthesized by doping LS on the surface of chitosan for modification. Fourier transform infrared (FT-IR) spectrometry, energy-dispersive spectroscopy (EDS), scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) were used to confirm the synthesis of nanomaterials. The adsorption and photocatalytic removal experiments of RhB were carried out under optimal conditions (initial dye concentration of 20 mg/L, adsorbent dosage of 0.02 g, time of 60 min, and UV power of 250 W), and the kinetics of dye degradation was also investigated, which showed that the removal rate of RhB by AgNPs photocatalysis can reach 55%. The results indicated that LS was highly effective as a reducing agent for the large-scale production of metal nanoparticles and can be used for dye decolorization. This work provides a new catalyst for the effective removal of dye from wastewater, and can achieve high-value applications of chitosan and lignin.

Preparation of Natural Plant Polyphenol Catechin Film for Structural Coloration of Silk Fabrics.

Traditional textile dyeing uses chemical pigments and dyes, which consumes a large amount of water and causes serious environmental pollution. Structural color is an essential means of achieving green dyeing of textiles, and thin-film interference is one of the principles of structural coloring. In the assembly of structural color films, it is necessary to introduce dark materials to suppress light scattering and improve the brightness of the fabric. In this study, the conditions for the generation of nanofilms of catechin (CC) at the gas-liquid interface were successfully investigated. At the same time, environmentally friendly colored silk fabrics were novelly prepared using polycatechin (PCC) structural color films. In addition, it was found that various structural colors were obtained on the surface of silk fabrics by adjusting the time. Meanwhile, the color fastness of the structural colored fabrics was improved by introducing polyvinylpyrrolidone (PVP) to form a strong hydrogen bond between the fabric and catechin. PCC film is uniform and smooth, with a special double-layer structure, and can be attached to the surface of silk fabrics, giving the fabrics special structural colors. Through the thin-film interference formed between the visible light and the PCC film, the silk fabrics obtain bright, controllable, and uniform structural colors. This method is easy to operate and provides a new way of thinking for environmental-protection-oriented coloring of fabrics.

Preparation of polyphenol-structural colored silk fabrics with bright colors.

Conventional textile dyeing relies on the use of dyes and pigments, which can cause severe environmental contamination and waste a large amount of water. Structural coloring is one of the effective ways to achieve environmentally friendly coloring of textiles. In this work, three plant polyphenols with the same o-benzenetriol structure (tannic acid (TA), gallic acid (GA), and tea polyphenol (TP)) were selected as raw materials. Three plant polyphenols can quickly form nanofilms at the gas-liquid interface through a Schiff base reaction with polyethyleneimine (PEI) under mildly alkaline conditions, which were deposited to the surface of silk fabric, allowing precise control over the thickness of film by adjusting the time, resulting in various structurally colored silk fabric. This method for creating structural colors is not substrate-specific and enables the quick production of structural colors on various textile substrates. Furthermore, the structural color silk fabric based on plant polyphenol has antibacterial performance. This textile coloring method is simple, cost-effective and environmentally friendly, providing a new approach to eco-friendly textile dyeing.

Study on the Effect of Chitosan Modification Technology on Antibacterial Properties of Textiles.

The chitosan is fixed in an amide group of activated carboxyl groups and biological primary amino groups of nonwoven PET for antibacterial properties. Uncoated materials have fewer wetting properties and are less biocompatible. The objectives of the study were to evaluate surface chemical compositions and biocompatibility, antibacterial, and hydrophilic properties of polyester fabrics grafted with chitosan oligomers and after being activated by atmospheric pressure plasmas. A 2% 14.8 mg/cm2 uncolored PET woven fabric was dissolved in chitosan solution. Atmospheric pressure plasmas were used to activate polyester fabrics grafted with chitosan oligomers on both sides. Cell proliferation assay was performed for the biocompatibility study. The American Association of Textile Chemists and Colorists method was used to measure the width of the antibacterial zone and the Japanese Industrial Standard was used to count the number of bacterial colonies. Chitosan-coated and -activated uncolored PET woven fabric showed fewer percentage free carbon (p < 0.0001), higher percentage free oxygen to free carbon ratio (p < 0.0001), higher percentage free nitrogen to free carbon ratio (p = 0.0453), and higher percentage free oxygen plus free nitrogen to free carbon ratio (p < 0.0001) than untreated PET woven fabric. The dynamic contact angle of a water droplet and the wicking time were shorter for chitosan-coated and -activated uncolored PET woven fabric than untreated PET weaved fabric (p < 0.0001 for all). Chitosan coating leads to PET woven fabric being higher biocompatible, wettable, and antibacterial than untreated PET woven fabric.

Preparation of Superhydrophobic Fabric Based on Dopamine and Michael Addition under Ultraviolet Light.

This work reports a simple, stable, and environmentally friendly method to prepare durable superhydrophobic surfaces. First, a polydopamine coating is formed by oxidative polymerization of dopamine to form a secondary reaction platform to provide reaction sites for subsequent experiments. We applied a polydopamine layer onto a fiber surface using the Michael addition-reaction-grafted tetrakis (3-mercaptopropionic acid) pentaerythritol ester, followed by the introduction of tetraallyl silane and (mercapto) methyl siloxane-dimethyl siloxane copolymer on the polydopamine by a thiol-ene click-reaction under ultraviolet light. The resulting superhydrophobic Nylon 56 fabric exhibited a 166° static contact angle as well as excellent stability. The surface morphology of all samples was observed by field emission scanning electron microscope, X-ray photoelectron spectroscopy and energy dispersion spectroscopy, and the elemental composition and surface chemical state of the samples were analyzed. It also had the ability of oil-water separation. Fabric with such benefits broadens the applicability and innovation of superhydrophobic textiles for environmental and industrial applications.

Robust and flexible smart silk/PEDOT conductive fibers as wearable sensor for personal health management and information transmission.

Flexible highly conductive fibers have attracted much attention due to their great potential in the field of wearable electronic devices. In this work, silk/PEDOT conductive fibers with a resistivity of 1.73 Ω·cm were obtained by oxidizing Ce3+ with H2O2 under alkaline conditions to produce CeO2 and further promote the in-situ polymerization of 3,4-ethylenedioxythiophene (EDOT) on the surface of silk fibers. The morphology and chemical composition of the silk/PEDOT conductive fibers were characterized and the results confirmed that a large amount of polythiophene was synthesized and deposited on the surface of silk fibers. The conductivity and electrochemical property stability of the silk/PEDOT conductive fibers were evaluated by soaping and organic solvent immersion, and the conductive silk fibers exhibited excellent environmental stability and durability. The silk/PEDOT conductive fibers show good pressure sensing and strain sensing performance, which exhibits high sensitivity, fast response and cyclability, and have excellent applications in personal health monitoring, human-machine information transmission, etc.

Glucose-Responsive Silk Fibroin Microneedles for Transdermal Delivery of Insulin.

Microneedles (MNs) have attracted great interest as a drug delivery alternative to subcutaneous injections for treating diabetes mellitus. We report MNs prepared from polylysine-modified cationized silk fibroin (SF) for responsive transdermal insulin delivery. Scanning electron microscopy analysis of MNs' appearance and morphology revealed that the MNs were well arranged and formed an array with 0.5 mm pitch, and the length of single MNs is approximately 430 µm. The average breaking force of an MN is above 1.25 N, which guarantees that it can pierce the skin quickly and reach the dermis. Cationized SF MNs are pH-responsive. MNs dissolution rate increases as pH decreases and the rate of insulin release are accelerated. The swelling rate reached 223% at pH = 4, while only 172% at pH = 9. After adding glucose oxidase, cationized SF MNs are glucose-responsive. As the glucose concentration increases, the pH inside the MNs decreases, the MNs' pore size increases, and the insulin release rate accelerates. In vivo experiments demonstrated that in normal Sprague Dawley (SD) rats, the amount of insulin released within the SF MNs was significantly smaller than that in diabetic rats. Before feeding, the blood glucose (BG) of diabetic rats in the injection group decreased rapidly to 6.9 mmol/L, and the diabetic rats in the patch group gradually reduced to 11.7 mmol/L. After feeding, the BG of diabetic rats in the injection group increased rapidly to 33.1 mmol/L and decreased slowly, while the diabetic rats in the patch group increased first to 21.7 mmol/L and then decreased to 15.3 mmol/L at 6 h. This demonstrated that the insulin inside the microneedle was released as the blood glucose concentration increased. Cationized SF MNs are expected to replace subcutaneous injections of insulin as a new modality for diabetes treatment.

Study on the mechanism of laccase-catalyzed polydopamine rapid dyeing and modification of silk.

Research on the polymerization of dopamine and its modification on the surface of materials has received extensive attention. In this work, the process of laccase catalyzing the rapid polymerization of dopamine and in situ dyeing of silk fabric were studied. The results showed that laccase catalyzed dyeing for 3 h under acidic conditions could achieve the dyeing effect of 24 h under an alkaline environment, and the enzyme catalyzed polydopamine showed better deposition uniformity on the substrate surface. According to molecular simulation analysis, dopamine oligomers were easily combined with the amorphous regions of silk fibroin, and dopamine oligomers and amino acids of silk fibroin could form hydrogen bonds and π-π stacking interactions. Dopamine oligomers could form intermolecular and intramolecular hydrogen bonds through amino groups and hydroxyl groups. In addition, dopamine oligomers would aggregate in the process of binding to silk fibroin and adsorbed to the surface of silk fibroin in the form of aggregates, and Michael addition reaction would also occur between dopamine oligomers and silk fibroin. Finally, the silk fabrics loaded with polydopamine were reacted with different kinds of metal salt solutions to form particles with different morphologies and crystal structures on the surface of the silk fibers, and the modified silk fabrics showed good hydrophobicity.

Preparation of Stable POSS-Based Superhydrophobic Textiles Using Thiol-Ene Click Chemistry.

In this study, a superhydrophobic fabric was synthesized by modifying the fiber's surface with dopamine-containing hydroxyl functional groups. Furthermore, we introduced mercapto-based functional groups by the hydrolysis of mercaptopropylmethyldimethoxysilane (MPMDS) and finally grafted POSS and mercaptans using a thiol-ene click reaction. These processes generated a superhydrophobic fabric with a static contact and a sliding angle of 162° and 8°, respectively. The superhydrophobic fabric's compact and regular micro-nano rough structure based on POSS and mercaptans provides stable fastness and durability, as well as high resistance to organic solvents, acid-base environments, mechanical abrasion, UV rays, and washing. Moreover, it can be used for self-cleaning and oil-water separation, and it has a wide range of applications in the coating industry.

Anti-Wrinkle and Dyeing Properties of Silk Fabric Finished with 2,4,6-Trichloropyrimidine.

Silk, a natural protein fiber, is widely used in the textile industry and biomedical materials for its excellent properties. However, its application in some fields is seriously restricted due to its poor anti-wrinkle behavior. In this study, 2,4,6-trichloropyrimidine (TLP) was used in the production of anti-wrinkle silk fabrics. The optimum finishing conditions were as follows: 3-g/L 2,4,6-trichloropyrimidine, 6-g/L NaHCO3, 8-g/L Na2SO4, finishing temperature of 65 °C, and finishing time of 40 min. The crease recovery angle of the finished fabric is 16-20% higher than the unfinished fabric, and the finishing process has a small effect on the whiteness of silk while achieving some degree of washing resistance. The morphology and chemical structures of the finished silk fabric were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. The K/S value of the finished silk fabric dyed with reactive dyes increased compared with the silk fabric only dyed, indicating that the dyeability of the finished fabric was improved. This technology provides a new method for fabricating silk color crease-resistant fabrics.

Fabrication of robust silver plated conductive polyamide fibres based on tannic acid modification.

A novel method for the preparation of silver plated conductive polyamide fibres (PA/Ag) based on tannic acid modification was reported in this work. The highly adhesive tannic acid was grafted onto the surface of sulphuric acid roughened polyamide fibres to sensitize the fibre. Then, the sensitized polyamide fibres were activated by low-concentration silver nitrate to form reactive centers. Chemical silver plating was finally carried out using silver ammonia solution with glucose. The surface morphology and chemical properties of the prepared polyamide fibres were analyzed and the surface resistance, fastness to washing, thermal decomposition properties, electrothermal properties, sensing properties and practical applications of the silver-plated polyamide fibres were also tested. The test results show that the prepared conductive fibres have excellent conductivity and stability, and have potential applications in flexible electronic devices and sensing fields.

Robust multifunctional superhydrophobic, photocatalytic and conductive fabrics with electro-/photo-thermal self-healing ability.

The fabrication of superhydrophobic and conductive fabrics that can conveniently and repeatedly restore the lost superhydrophobicity, caused by either the surface accumulation of trace organic contaminants or the chemical damage to surface components, remains challenging. Herein, we report a multifunctional superhydrophobic and conductive cotton fabric that integrates not only the photocatalytic activity for cleaning organic contaminants, but also the self-healing ability enabled by either electro-thermal or photo-thermal heating besides convection oven heating. The fabric was fabricated through the polydopamine (PDA)-assisted deposition of photocatalyst Ag/CdS and the subsequent thiol-Ag self-assembly. Either UV or visible light irradiation is able to decompose the surface organic contaminants, and the photocatalysis-induced slight damage on super water-repellency is curable by heating. The Ag layer endows the fabric with antibacterial property and conductivity along with the electro-/photo-thermal conversion ability, which offers relatively convenient ways of heating for curing the surface chemical damages caused by O2 plasma etching or accelerated washing. Of particular importance is that the fabric still shows super water-repellency even after 18 cycles of accelerated washing, which equals to 90 normal home laundering cycles. The combination of these multiple functions makes this fabric very promising for a wide range of wearable applications.

Performance of Washing-Free Printing of Disperse Dye Inks: Influence of Water-Borne Polymers.

Dye-containing wastewater discharge from the textile industry poses a serious pollution hazard that can be overcome by eliminating the washing step following the dyeing process. To study the washing-free printing of disperse dye ink, a number of water-borne polymers were selected and added to the ink, and the properties of the inks were discussed. By optimizing the ink formulation, printed fabrics with high color strength and color fastness were produced. The effects of the addition of polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), and polyethylene glycol (PEG) on the ink jetting performance and printing performance were intensively investigated. The migration-diffusion-fixation behavior of disperse dyes in inks on the polyester fiber was explored. The disperse dye ink with 0.075 wt.% PVA exhibited the strongest migration-diffusion effect. The PVA ink exhibited excellent jetting performance and printing color fastness, and the printing color strength was better than that of the PVP and PEG ink. The addition of PVA increased the difference between the solubility parameter of the disperse dyes and ink system, which improved the migration of disperse dyes from the ink system to the polyester fabric. Meanwhile, PVA could form a protective layer on printed fabrics because of its excellent film-forming properties at room temperature. The washing-free inkjet printing method developed in this study provides a theoretical basis for screening water-borne polymers and an environmentally friendly pathway for the printing of textiles.

Preparation of biomimetic non-iridescent structural color based on polystyrene-polycaffeic acid core-shell nanospheres.

Caffeic acid (CA), as a natural plant-derived polyphenol, has been widely used in surface coating technology in recent years due to its excellent properties. In this work, caffeic acid was introduced into the preparation of photonic band gap materials. By controlling the variables, a reasonable preparation method of polystyrene (PS) @polycaffeic (PCA)-Cu(ii) core-shell microspheres was achieved: 1 mmol L-1 cupric chloride anhydrous (CuCl2), 3 mmol L-1 sodium perborate tetrahydrate (NaBO3·4H2O), 2 mmol L-1 CA and 2 g L-1 polystyrene (PS) were reacted at 50 °C for 10 min to prepare PS@PCA-Cu(ii) core-shell microspheres through rapid oxidative polymerization of CA coated PS of different particle diameters. The amorphous photonic crystal structure was self-assembled through thermal assisted-gravity sedimentation, resulting in structural color nanomaterials with soft and uniform color, no angle dependence, stable mechanical fastness and excellent UV resistance.

Fabrication of Superhydrophobic and Light-Absorbing Polyester Fabric Based on Caffeic Acid.

Caffeic acid (CA) was treated on the surface of polyester fabric (PET), and Fe2+ was used as an intermediate to form chelates with CA to increase the roughness of the polyester surface. With the addition of n-octadecyl mercaptan (SH), the mercapto group reacted with the carbon-carbon double bond of CA on the PET surface through enol click chemical reaction. Meanwhile, CA was polymerized under UV radiation, and thus CA-Fe-SH-PET was prepared. The introduction of SH with a long carbon chain reduced the surface energy of the PET, in order to endow the polyester fabric with a superhydrophobic/lipophilic function. Combined with XPS and FTIR tests, the new carbon-carbon double bond's binding energy and vibration peak were found on the fabric surface, indicating that CA was adsorbed on the PET fabric's surface. After adding SH, the double bond disappeared, demonstrating that SH and CA occurred a click chemical reaction and were grafted onto the PET fabric's surface. The water contact angle (WCA) of CA-Fe-SH-PET was about 156 ± 0.6°, and the scrolling angle (SA) was about 3.298°. The results showed that the modified polyester had a robust superhydrophobic stability in washing, mechanical friction, sun aging, seawater immersion, organic reagent, and acid-base erosion derived from the good adhesion of polymerized CA (PCA). At the same time, the modified polyester fabric had good self-cleaning, antifouling, and oil-water separation performance. It was found that the CA-Fe-SH-PET fabric had unique photothermal conversion characteristics, which can convert the absorbed ultraviolet light into thermal energy, providing a local warming effect due to rapid heating and improving the transmission speed of heavy oil (engine oil and diesel). The CA-Fe-SH-PET fabric can further prevent the transmission of ultraviolet rays, and the UV resistance of CA-Fe-SH-PET fabric is far higher than the UV resistance standard. The preparation method is simple, fast, efficient, and environmentally friendly, and it has better a potential application value in the oil-water separation field.

Degradation of textile dyes from aqueous solution using tea-polyphenol/Fe loaded waste silk fabrics as Fenton-like catalysts.

In this study, waste silk fabrics (SF) were modified with tea-polyphenols (TPs) and then iron (Fe2+). The modified silk fabrics (TP-SF/Fe) were characterized via Fourier-transform infrared (FTIR), energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) analysis. TP-SF/Fe was used in the Fenton-like removal of dyes (methylene blue, reactive orange GRN, and cationic violet X-5BLN) from aqueous solutions with catalyst-like activity. The effects of different catalyst samples, contact time, H2O2 concentration, initial dye concentration, and pH values on dye removal were investigated. The results showed that the dye removal percentages with the TP-SF/Fe-H2O2 sample reached 98%, 97%, and 95% in 5-40 min for methylene blue, reactive orange GRN, and cationic violet X-5BLN, respectively. Different thermodynamic and kinetic models were used to check the best fit of the adsorption data. The results indicated that the Freundlich isotherm and pseudo first-order kinetics models were the best fits. Moreover, it was also proved that TP-SF/Fe would be quite an effective and economical adsorbent for the treatment of textile dye wastewater. This work provides the basis for waste silk application in the removal of dyes from wastewater.