Cotton Surface Research Articles

Enhancing durability of superhydrophobic surfaces via nanoparticle-induced bipolar interface effects and micro-nano composite structures: A femtosecond laser and chemical modification approach

Superhydrophobic coatings are vital in energy, aerospace, and chemical engineering, while their complex preparation and limited durability hinder widespread application. Therefore, inspired by the unique structures of hydrophobic cotton surfaces and mosquito eyes in nature, a durable aluminum alloy superhydrophobic surface is developed using a combination of femtosecond laser and chemical modification methods. Initially, porous microneedle micro-nanostructures are ablated on the surface of the aluminum alloy via femtosecond laser technology. Then, epoxy resin modified with γ-aminopropyl triethoxysilane (KH550) forms a covalently bonded intermediate layer. Finally, biphasic silicon dioxide (BP-SiO2) nanoparticles modified by hexadecyltrimethoxysilane (HDTMS) are used to construct the top hydrophobic layer. The covalent interface interactions between the aluminum alloy substrate and the intermediate layer, as well as between the intermediate layer and the top layer, significantly enhance the durability of the superhydrophobic surface. The prepared F-M@KH-EP/BP-SiO2 coating exhibits outstanding superhydrophobic properties, with a water contact angle (CA) as high as 168.56° and a sliding angle (SA) as low as 1.52° More encouragingly, the composite coating maintains its excellent water resistance even when subjected to harsh mechanical durability damage, including sandpaper wear, tape stripping tests, water drop and sand impact tests. Moreover, the prepared coatings maintain distinguished non-wettability in harsh operating conditions such as corrosive liquid environments, ultraviolet radiation, ultrasonic vibration, etc. Additionally, the coating demonstrates remarkable self-cleaning properties. Superhydrophobic surface durability is significantly enhanced by combining nanoparticle-induced bipolar interface effect and micro-nano structures. These findings provide theoretical reference for the design and application of durable superhydrophobic coatings.

Functional textile surface production by analysing the mechanical properties of cotton, bamboo and linen woven surfaces

In the textile industry, it is seen that the use of nanomaterials is increasing to meet the demands for long-lasting and sustainable products. This research aims to improve the mechanical properties of 1×1 plain weave cotton, bamboo and linen surfaces made of natural yarns by coating them with ZnO, TiO2 and SiO2 to provide sustainable natural life and create a sustainable functional textile surface. For this reason, coatings were made with nanoparticles and applied to textile surfaces. The blade (stripping knife) coating method with subsequent dosing was used when the coating agent was liquid with an appropriate viscosity value. The surface morphology of the treated fabric was characterized by SEM, EDS and FT-IR analysis. Mechanical properties were analysed by thickness, weight and tear strength tests and antibacterial activity against S. Aureus and E. Coli bacteria were tested. When the results were examined, it was determined that cotton, linen and bamboo surfaces, which did not have antibacterial properties except for E. Coli (49.56%), showed antibacterial properties (100%) in bamboo and linen after coating with ZnO and TiO2 , and in bamboo after coating with SiO2 . The coating material also caused different effects in terms of thickness, weight and strength change.

Eco-friendly activation of cotton textiles with LiNbO3 nanoparticles for enhanced self-cleaning and antibacterial performance

Cotton textiles play a universal role in everyday life, but they are prone to stain and serve as a primary channel for transmitting viruses and bacteria. The photocatalytic/antibacterial coatings are highly effective in addressing bacterial contamination on fabrics, although their efficacy diminishes with continuous use and washing. Here, insights are provided into the attachment of LiNbO3 on cotton surfaces using eco-friendly chemical activators to promote resistance to washing cycles, self-cleaning, and bactericide textiles. LiNbO3 nanoparticles were synthesized by low-temperature hydrothermal synthesis and directly applied to cotton fabric using immersion. The synthesized nanoparticles were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) N2 adsorption, diffuse reflectance for band gap determination, and Raman spectroscopy. A simple and effective impregnation method was used, promoting an ester-bond attachment between the cotton surface and the activators. Microscopy analysis (SEM) confirmed the successful deposition of the nanoparticles on cotton fabric. The LiNbO3 coating consisted of transparent layers and did not change the properties of cotton. Methylene blue stains are generally eliminated under UV light after 2 h using nanoparticles and activators. Antibacterial properties were evaluated under visible light through direct contact with bacterial suspensions and culturing. The coated cotton fabric that was activated with oxalic acid exhibited significant photocatalytic antibacterial activity against both Escherichia coli (gram-negative) and Staphylococcus aureus (gram-positive) bacteria, with bacterial reduction rate above 97 %, even after 10 washing cycles. This performance can be attributed to the effective coupling of LiNbO3 with oxalic acid in the cotton’s surface and its resistance to washing out. This study's novel synthesis and coating method offers an environmentally friendly, cost-effective, and straightforward approach for producing LiNbO3 self-cleaning and antibacterial surface-activated cotton.

Synthesis and Characterization of ZnO Nanoparticles and Their Application on Cotton Fabrics to Obtain Superhydrophobic Surfaces

حضرت جسيمات أوكسيد الزنك النانوية ZnO (NPs) بطريقة كيميائية رطبة عند درجتي حرارة مختلفتين (30-90) ̊C باستخدام كلوريد الزنك كبادئ في وسط مائي. تم توصيف جسيمات أوكسيد الزنك النانوي المحضر باستخدام المجهر الإلكتروني الماسح (SEM) ,حيود الأشعة السينية (XRD) ، وطيف الأشعة تحت الحمراء (FTIR) ، أشارت أنماط الأشعة السينية الى بنية سداسية (wurtizte) بمتوسط حجم بلوري (19.5-23nm) لجسيمات أوكسيد الزنك المحضرة عند درجتي الحرارة (30-90 ̊C)على التوالي. أظهرت صور المجهر الالكتروني الماسح أنه مع زيادة درجة الحرارة ، تغير شكل جسيمات أوكسيد الزنك النانوي من الأسلاك النانوية إلى االشكل الكروي . لتصنيع قماش قطني فائق المقاومة للماء. تم غمر القماش في محلول غروواني لأوكسيد الزنك بتركيز (1٪) ,ثم تعديله لاحقًا بحمض الشمع . تم توصيف القماش القطني المعالج باستخدام المجهر الإلكتروني الماسح (SEM) واختبار زاوية التماس (CA) .أظهرت نتائج المجهر الالكتروني الماسح أن جسيمات أوكسيد الزنك النانوي المحضر عند(90 ̊C) خلق خشونة على سطح القطن أفضل من جسيمات أكسيد الزنك النانوي المحضرعند (30 ̊C). أظهرت نتائج اختبار زاوية التماس CA خصائص فائقة الكره للماء لعينات أوكسيد الزنك النانوي المحضر عند(90 ̊C) ، بينما أظهرت عينات أوكسيد الزنك النانوي المحضر عند(30 ̊C) خصائص كارهة للماء فقط بعد التعديل بحمض الشمع. تم استخدام تراكيز مختلفة من حمض الشمع لجعل سطح أوكسيد الزنك كارهاً للماء. أظهرت نتائج زاوية التماس (CA) أن القماش القطني المعالج بأوكسيد الزنك النانوي المحضر عند الدرجة (90 ̊C) المعدل ب 1٪ وزناً من حمض الشمع أظهر سطحاً فائق الكره للماء بزاوية تماس (CA=154̊ ).

Development of antibacterial and hydrophobic PVDF@ZnO coating on cotton fabrics by electrospinning method

Products with antimicrobial properties enhance personal comfort and hygiene by preventing bacterial infections. In this work, we developed an antibacterial and hydrophobic coating by combining zinc oxide (ZnO) nanoparticles with poly (vinylidene fluoride) (PVDF) through the electrospinning method, aiming for an enhanced cotton surface for textile applications. Initially, ZnO nanoparticles were synthesized and integrated uniformly within the PVDF, characterized by various analytical techniques. This study highlights the coating's remarkable antibacterial activity, evidenced by a significant inhibition zone diameter of 18 mm against Staphylococcus aureus and its enhanced hydrophobicity, with a contact angle of 136°. Additionally, it was found that the Higuchi model could describe the diffusion release of ZnO from the PVDF coating. The obtained result allows us to conclude that applying the electrospinning method to fabric coatings opens new avenues in the design of functional textiles, particularly antibacterial ones, as proved in this paper.

Electroless Copper Plating on a Cotton Surface: Effect of Metal Ion Ligand Stability Constant on Reduction Deposition.

Electroless plating facilitates the metallization of nonconductive substrate surfaces, and of note, the precise control of the bath stability constant influences the deposition process of metal particles. In this paper, trisodium citrate, potassium sodium tartrate, nitrogen triacetic acid, thiourea, and ethylenediamine tetraacetic acid disodium were selected as coordination agents, and the effect of the metal ion ligand stability constant on the reduction deposition was studied. Coordination bonds can be established between the Cu2+ and O/N/S particles in the ligand because paired electrons in O/N/S hybrid orbitals tend to occupy empty Cu2+ hybrid orbitals and establish coordination bonds. More importantly, the copper-potassium sodium tartrate ligand exhibits the lowest stability constant and lowest reduction barrier. As an exception, a consecutive Cu-plated coating with an excellent crystallinity property was deposited on the cotton surface when potassium sodium tartrate was used as the coordination agent in the plating solution. The deposition amounts are 55.2% and 74.1% after 1 and 4 h of electroless copper plating, respectively. The surface resistivity of Cu-plated cotton is 0.38 Ω/cm2, and additionally, the surface resistivity ratio before and after 1000 cycles fluctuated between 0.9 and 1.1, indicating that the Cu-plated cotton exhibits outstanding flexibility. In this paper, the deposition rate can be optimized by adjusting the copper particle ligand stability constant in the plating solution, aiming to achieve optimal results.

Optimisation of nitrogen plasma exposure time for surface modification of cotton fibre

Surface modification via plasma treatment is useful in improving textile-based wound dressing functionality. This study was conducted to optimise the nitrogen plasma exposure time and its effect on the cotton surface (CS) properties at a constant nitrogen flow rate of 20 sccm for 5 to 30 min. The optimisation was done by analysing the alteration in morphology, functional group composition, crystallinity phase, electrokinetic potential, and colour of CS as subjected to nitrogen plasma. CS experienced an etching effect due to the presence of microcracks on its surface, with its electrokinetic potential becoming less negative, ranging from -5.51 to –8.05 mV. Then, the nitrogen functional group was detected on CS ranging from 2.9% to 4.5%, with its whiteness index reduced to 8.67% compared to the pristine cotton. As a result, 20 min was selected as the optimum exposure time for surface treatment. An exposure time of 30 min showed an early sign of degradation, which reduced its crystallinity index by 11.1%. Apparently, the CS is activated as exposed to the nitrogen plasma and experiences slight changes in its molecular structure without affecting its bulk properties.

Exploring the Potential of Halotolerant Actinomycetes from Rann of Kutch, India: A Study on the Synthesis, Characterization, and Biomedical Applications of Silver Nanoparticles.

A tremendous increase in the green synthesis of metallic nanoparticles has been noticed in the last decades, which is due to their unique properties at the nano dimension. The present research work deals with synthesis mediated by the actinomycete Streptomyces tendae of silver nanoparticles (AgNPs), isolated from Little and Greater Rann of Kutch, India. The confirmation of the formation of AgNPs by the actinomycetes was carried out by using a UV-Vis spectrophotometer where an absorbance peak was obtained at 420 nm. The X-ray diffraction pattern demonstrated five characteristic diffraction peaks indexed at the lattice plane (111), (200), (231), (222), and (220). Fourier transform infrared showed typical bands at 531 to 1635, 2111, and 3328 cm-1. Scanning electron microscopy shows that the spherical-shaped AgNPs particles have diameters in the range of 40 to 90 nm. The particle size analysis displayed the mean particle size of AgNPs in aqueous medium, which was about 55 nm (±27 nm), bearing a negative charge on their surfaces. The potential of the S. tendae-mediated synthesized AgNPs was evaluated for their antimicrobial, anti-methicillin-resistant Staphylococcus aureus (MRSA), anti-biofilm, and anti-oxidant activity. The maximum inhibitory effect was observed against Pseudomonas aeruginosa at (8 µg/mL), followed by Escherichia coli and Aspergillus niger at (32 µg/mL), and against Candida albicans (64 µg/mL), whereas Bacillus subtilis (128 µg/mL) and Staphylococcus aureus (256 µg/mL) were much less sensitive to AgNPs. The biosynthesized AgNPs displayed activity against MRSA, and the free radical scavenging activity was observed with an increase in the dosage of AgNPs from 25 to 200 µg/mL. AgNPs in combination with ampicillin displayed inhibition of the development of biofilm in Pseudomonas aeruginosa and Streptococcus pneumoniae at 98% and 83%, respectively. AgNPs were also successfully coated on the surface of cotton to prepare antimicrobial surgical cotton, which demonstrated inhibitory action against Bacillus subtilis (15 mm) and Escherichia coli (12 mm). The present research integrates microbiology, nanotechnology, and biomedical science to formulate environmentally friendly antimicrobial materials using halotolerant actinomycetes, evolving green nanotechnology in the biomedical field. Moreover, this study broadens the understanding of halotolerant actinomycetes and their potential and opens possibilities for formulating new antimicrobial products and therapies.

THE DESIGN INNOVATION WITH A BIOPHILIC APPROACH TO SUPPORT THE TEMPORARY CONVERSION OF STUDENT DORMITORY AS A COVID-19 ISOLATION SHELTER

The increasing number of Corona Virus Disease (COVID-19) cases in Bandung, Indonesia, in July 2021 resulted in a higher hospital bed occupancy rate. The conversion of two student dormitory buildings into isolation shelters is expected to accommodate COVID-19 patients who do not have rooms in the hospital. This requires specific planning and innovation, particularly for materials. This study has two objectives: first, to evaluate how long coronaviruses can remain active on different material surfaces. The data collection strategy was carried out through Systematic Review. The second research objective was to design a COVID-19 isolation room that uses materials that facilitate the healing process. Field surveys and traditional literature reviews were conducted for this purpose. This study found that the virus did not survive long on the surfaces of cotton and cardboard. Thus, the room design uses these materials and is considered a biophilic design. This study is expected to provide insights for academics and researchers in interior design and architecture regarding the knowledge of furniture materials that prevent viruses from surviving longer. In addition, it is expected to inspire interior designers to design rooms that can help the healing process using a biophilic approach.

Analysis of the Surface of Historic Fabric from the Auschwitz-Birkenau State Museum after Treatment with Ethanol Mist Used to Eliminate Microorganisms Harmful to Human Health.

the aim of the work was to present the changes occurring on the model and historical cotton surface of cotton resulting from disinfection with 90% ethanol mist. Samples of historical materials consisted of fabric elements from suitcases stored in A-BSM. A mist of 90% ethanol was applied for 15 s at a distance of 16 cm from the surface. The spectra of cotton samples before and after ethanol application were recorded using Fourier transform infrared spectroscopy (FTIR-ATR). Analyses of the surface layers were performed using X-ray photoelectron spectroscopy (XPS). the decontamination performed did not show any significant differences in the chemical composition and surface structure of cotton before and after the use of 90% ethanol mist. Ethanol mist, which eliminates microorganisms from the historical surface, does not cause significant changes to the surface of historical objects.

Bio-based phytic acid/amino acid complex coating for antimicrobial and flame-retardant cotton fabrics

Here, a novel multifunctional coating containing bio-based phytic acid (PA), L-glutamic acid (L-Glu), and trimesoyl chloride (TMC) is constructed by a simple soaking strategy, giving cotton fabrics excellent flame retardancy, washability, and antibacterial properties. The coating layer on the cotton surface was prepared via the electrostatic and hydrogen bonding between PA and L-Glu, accompanied by the interface polymerization between PA, L-Glu, and TMC. Among them, the limiting oxygen index value of the treated cotton fabrics (C2 and C2-TMC) was as high as 40 %. During the vertical flammability test, both C2 and C2-TMC cotton showed self-extinguished behavior with a short damaged length (≤50 mm). Remarkably, the LOI of C2-TMC sustained a high value (30 %) even after 300 laundering cycles, maintaining its self-extinguishing behavior in the vertical combustion test. Additionally, in the cone calorimetry test, peak heat release rate and total heat release of treated cotton were lower than control cotton. Surprisingly, after 30 or 60 laundering cycles, the C2-TMC cotton exhibited excellent antibacterial activity against Escherichia coli, Staphylococcus aureus, and Candida albicans due to the continuous exposure of PA and L-Glu. Moreover, the coating layer on the cotton surface had little impact on the mechanical properties and feel of the fabric.

Anti-candidiasis functional material for women’s cotton undergarments

The escalating incidence of Candida spp. infections among individuals with compromised immune systems is attributed to various factors, including broad-spectrum antibiotic usage, common health issues, and inadequate undergarments, requiring novel preventive measures. While the pathogenic mechanisms of Candida spp. infections remain incompletely understood, their virulence attributes and opportunistic nature challenge host defenses. In response, this research study introduces an innovative nanobiotechnological approach employing L-cysteine to develop nontoxic anti- Candida spp. textile materials. Cotton, an ideal material for women’s underwear, was functionalized with L-cysteine through an exhaustion procedure following activation with 2,2,6,6-tetramethylpiperidinyl-1-oxy free radical. The results demonstrated increased energy dispersive X-ray peaks corresponding to sulfur atoms in the functionalized cotton fabric, confirming that L-cysteine remained attached to the cotton surface even after washing cycles. Moreover, the cotton containing L-cysteine displayed morphology and mechanical properties similar to the nonfunctionalized cotton, indicating that the incorporation of L-cysteine did not impact the cotton properties. In addition, cotton functionalized with L-cysteine exhibited a significant reduction in yeast growth – 87.04 ± 1.90% for Candida albicans and 65.28 ± 3.03% for Candida parapsilosis – highlighting its potential as a class I medical device, particularly for preventing candidiasis in women’s medical underwear.

Durable, multifunctional cotton fabrics with in situ deposited micro/nanomaterials for effective self–cleaning, oil–water separation and antibacterial activity

The facile modification of cotton fabrics for excellent self–cleaning, oil–water separation, and antibacterial activity is of great interest for multifunctional requirements. Herein, a durable, robust, fluorine–free multifunctional cotton fabric was fabricated via in-situ growing zeolitic imidazolate framework-67 (ZIF-67) on the cotton surface, followed by depositing hydrophobic SiO2 (H-SiO2) nanoparticles synthesized via an improved Stöber reaction. Meanwhile, the abundant hydroxyls of the cotton fabrics provided the necessary ion interaction sites for the uniform deposition of micro/nanomaterials, confirmed by the visualized Raman imaging technology. The resultant H-SiO2/ZIF-67@cotton fabric exhibited superhydrophobicity with a water contact angle of 159° and versatile self–cleaning, antifouling, oil–water separation, as well as prominent antibacterial activity against S. aureus and E. coli. At the same time, the superhydrophobic cotton fabric possessed excellent durability and stability against harsh environments, including abrasion, washing, acid, base, salt, and organic solvents. This facile technique can be applied for large-scale production of multifunctional superhydrophobic cotton fabrics due to its easy operation, low cost, and environmental friendliness.

Controlled micro-scale ink droplet spreading on cotton fabrics via cellulose-based coatings for greener textile inkjet printing

Inkjet printing of cotton fabric is considered a cleaner, efficient and revolutionary technology in textile coloration industry. However, due to the good hydrophilicity of cotton fibers, ink droplet spreading was difficult to be prevented, causing the problems of poor image resolution, low dye utilization efficiency and reduced product quality. Hence, in this study, cellulose-based coatings were fabricated on the cotton surface to adjust the surface hydrophilicity and prevent ink droplet spreading. Results showed that, cellulose derivatives like hydroxypropyl cellulose (CMHPC) and hydroxyethyl methyl cellulose (HEMC) could form continuous and uniform cellulose film coatings on fiber surface. Because there are fewer hydrophilic side groups in HEMC structure, the hydrophilicity of cotton fabric and the ink spreading was effectively controlled. From microscope observation, the spreading lengths of a single droplet were significantly decreased by HEMC from 276.27 to 66.95 μm. The K/S values representing color depth were improved from 9.44 to 19.41. Furthermore, industrial application was conducted to verify the laboratory results, showing that higher image quality was obtained in practical application using HEMC. This work provides a more potential and greener application of cellulose-based coatings to promote the development of textile inkjet printing.

Compatibilizing of cotton fabric with hydrophobic drug cover layer for anti-inflammatory performance with the implementation of ibuprofen

This paper presents active analgesic and anti-inflammatory dressings based on cotton woven material with surface functionalization enabling drug implementation. For this purpose, lactide was polymerized on the surface of cotton textiles to achieve better compatibility with hydrophobic drug and polylactide (PLA)-based macromolecules. Subsequently, ibuprofen-loaded PLA and PLA-PEG were implemented through the exhausting method. Such material was tested for cytotoxicity (toward L929 mouse fibroblasts) and anti-inflammatory activity (towards human Hs68 fibroblasts) based on the secretion of pro-inflammatory cytokines IL-1β and TNF-α. The results showed that the drug attachment and its performance are influenced by a combination of mercerization, bleaching and polylactide grafting, and the release of ibuprofen depends on the drug-loaded layer structure. Moreover, we show that cotton woven fabric with ibuprofen-loaded PLA and PLA-PEG cover layers had anti-inflammatory properties. These new dressings may open possibilities for developing prolonged analgesic and anti-inflammatory materials for wound healing or transdermal drug delivery.

Silica-Containing Phosphorus-Based Sol-Gel Finishing to Improve Flame Retardant Performance of Cotton Fabrics

In this paper, the sol-gel technique was used to design hybrid phosphorus-doped silica structures for improving the thermal stability and flame retardancy of cotton fabrics. To this aim, diethylphosphatoethyltriethoxysilane (DPTS) was employed as phosphate alkoxysilane in a multistep procedure that involved multiple layers (from 1 to 6) depositions. The multi-layer coatings were applied by padding using sols containing appropriate molar ratios of the precursor, anhydrous ethanol, catalyst, and hydrochloric acid. Moreover, the synergism P-N on flame retardancy of cotton was assessed by introducing 3-aminopropyltriethoxysilane (APTES) as an N-donor precursor in DPTS sols. The effects of the catalyst during the alkoxide reaction and the silica amount applied by sol-gel treatment on the thermo-oxidative behavior of the treated fabrics were deeply studied. The creation of the silica skeleton on the cotton surface and the interactions between the cellulosic fibres and the doped layer were investigated using FT-IR ATR spectroscopy. Moreover, thermal and thermo-oxidative stability, flammability properties, and combustion behavior of the sol-gel treated cotton fabrics were also studied, proving the effectiveness of the sol-gel coating in the fire protection of the cellulosic substrate.

Aerobic oxidation of aliphatic alcohol in cotton surface using epigallocatechin-3-gallate-iron (II, III) oxide (EGCG-Fe3O4) nanocatalyst from green tea extract

ABSTRACT This study involved the synthesis of epigallocatechin-3-gallate-Iron (II, III) oxide (EGCG- Fe3O4) nanocatalysts by reacting Fe2O3 with EGCG extracted from green tea (Camellia sinensis) aqueous extract. This environmentally friendly method was used as an alternative to traditional synthesis routes. The EGCG- Fe3O4 nanocatalysts were characterised using various techniques, including fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), BET Surface area analysis, analysis and vibrating sample magnetometer (VSM). The results showed that the Fe3O4 nanocatalyst absorption peak at 363 nm indicated the formation of the Fe3O4 nanocatalyst, while the EGCG absorption peak shifted slightly to 274 nm, indicating the formation of the EGCG nanocatalyst. The conversion of final product aliphatic aldehyde from aliphatic alcohol in cotton surface via a solvent free aerobic oxidation using EGCG-Fe3O4 nanocatalyst. The final product of aliphatic aldehyde was confirmed by 1H and 13C NMR. The molecular weight of the product was determined by mass spectral characterisation (EI-MS), which showed a molecular ion m/z of 72.06 (M+, 100%), which was confirmed by the molecular weight of isobutyraldehyde conforming to the molecular mass using EI-MS mass spectral analysis. This method has been used for aerobic oxidation of aliphatic alcohols in the textile and pharmaceutical industries and offers several advantages, including the use of environmentally friendly reaction conditions, reduced catalyst concentrations, high product yields, affordability, absence of solvents, and recovery and reuse of the EGCG-Fe3O4 nanocatalyst.

Cotton fabrics modified with tannic acid/1-eicosanamine grafting layer for oil/water separation

The wettability of the surface of hydrophilic cotton fabrics was modified using a one-step protocol with tannic acid (TA) to provide its excess catechol groups to be grafted with 1-eicosanamine at pH 8.5 and room temperature with catalysts CuSO4/H2O2. The modification over the synthesis conditions revised the contact angles of water and diiodomethane droplets from 132.68 ± 0.49° to 143.95 ± 0.80° and from 100.08°±1.42° to 82.96 ± 1.38°, respectively. The corresponding dispersive of the so-yielded cotton surface ranged from 8.6 to 16.0 mJ/m2, and the polar components ranged from 0.08 to 2.7 mJ/m2, much lower than polytetrafluoroethylene. The modified cotton fabrics are omniphobic and can repel water and commercial oil products. The absorption tests revealed that the modified cotton fabrics absorbed 1.10 g hexane/g cotton by contacting hexane (top)-water (bottom) layers and absorbed 1.26 g hexane/g cotton by contacting water first for 30 s, then hexane for another 30 s. The modified fabrics reveal good absorption reusability as hexane absorbent is even pre-saturated with water. This conclusion is also valid for commercial unleaded gasoline #95 and diesel. A parametric study revealed that the added catalysts and prolonged reaction time would enhance the hydrophobicity of the surface. These modified cotton fabrics can absorb oil from water and oil spills. Mechanisms corresponding to this observation are discussed.

Preparation and properties of hydrophobic materials based on environmentally responsive low fluorine epoxy copolymer

Hydrophobic surfaces and super hydrophobic surfaces have been widely studied and applied to cotton, ceramics, glass and other surfaces, but less research has been done on environmentally responsive hydrophobic surfaces (ERHS). In this paper, the environmentally responsive low fluorine epoxy copolymer P(DMAEMA-r-TFEMA-r-GMA) was synthesized by traditional free radical polymerization and the obtained copolymer was applied to construct ERHS on the cotton fabric and wood/plastic composite (WPC). The effects of construction parameters (polymer concentration, pH value of impregnation solution, impregnation temperature, impregnation time, drying temperature and drying time) on the surface hydrophobic properties of cotton fabric and WPC were studied. L25 (56) orthogonal experiment scheme was selected to explore the optimal parameters of hydrophobic construction. The optimum construction conditions of ERHS cotton and ERHS WPC were as follows: polymer concentration of 10 mg/mL, impregnation time of 9 h, pH of 9, impregnation temperature of 50 °C and 60 °C, drying time of 6 h, and drying temperature of 120 °C. The maximum water contact angle (WCA) on the surface of ERHS cotton was 145°. After 15 times pH-stimulation circulations, the WCA changed in the range of 145° ± 5° to 120° ± 5°. After 10 times acid-base response circulations, ERHS cotton had good oil-water separation capacity, and the maximum oil-water separation rate varied from 99.82% to 98.24%. This hydrophobic modification had no effect on the thermal stability of cotton fabric. The maximum WCA of ERHS WPC was 135°. Under acidic conditions (pH=2), the water absorption rate of wood plastic was improved. The hydrophobic modification had little effect on the mechanical properties and thermal stability of WPC.

Molecularly imprinted polymer on cotton materials as substrates for smartphone-based image and distance-based analysis of Cu(II) in water samples.

Cotton fabric was used as a substrate for smartphone-based image analysis of Cu(II) in drinking water. To enhance its selective and specific binding sites on the cotton surface, a molecularly imprinted polymer (MIP) was introduced using color complexes of 4-(2-pyridylazo)resorcinol-Cu(II) (PAR-Cu(II)) as the template molecule, 3-aminopropyltriethoxysilane (APTES) as the functional monomer, tetraethoxysilane (TEOS) as the crosslinker and NH3 as the catalyst. After achieving optimum conditions, the obtained CF-MIP/PAR-Cu(II) presented a red color, which was changed to yellow upon the removal of Cu(II) with 1.5 M HCl. After using CF-MIP/PAR to detect Cu(II), the red, green and blue intensities of the images captured using a smartphone were analyzed using the ImageJ program. For the calibration curve plotted between Δgreen intensity and Cu concentration, the linear range was 0.10-1.0 mg L-1 with the best correlation coefficient (R2) of 0.999. The limit of detection (LOD) and the limit of quantification (LOQ) were found to be 0.038 and 0.11 mg L-1, respectively. To obtain a distance-based device, MIP-modified cotton thread (CT-MIP/PAR) with a four-channel design was used as an alternative device. The distance of red color development was measured after using CT-MIP/PAR to detect Cu(II). The linear range was 0.50-3.0 mg L-1 with an R2 of 0.997. The LOD and LOQ were 0.18 and 0.56 mg L-1, respectively. The proposed methods provide simple, portable and inexpensive devices with high accuracy and precision for the detection of Cu(II) in drinking water.