Multiple Washing Cycles Research Articles

Study of Graphene Oxide/Polymer Composite Membranes in Air Filtration of PM2.5

pollution, particularly the issue of fine particulate matter (PM2.5), which has emerged as a significant environmental and public health concern globally. It is particularly important to develop efficient, economical and sustainable air filtration materials to reduce the concentration of PM2.5. In this study, we investigated the potential application of some polymers such as polyvinylidene fluoride (PVDF), polyacrylonitrile (PAN) and polyaniline (PANI) composites with graphene oxide (GO) for efficient PM2.5 filtration. These composites were found to have excellent filtration performance, thermal stability. PVDF/ GO/PI nanofiber membranes maintained stable performance under repetitive filtration cycles and high temperature conditions. PAN/GO/PI nanofiber membranes exhibited good mechanical properties and stable cycling performance.PANI/GO composites took advantage of the unique properties of the conductive polymers, and in TGA experiments, they showed minimal mass loss. Their durability and efficiency remain high even after multiple wash cycles, highlighting their potential for practical applications.

Influence of curing temperature on shape memory performance of polyethylenimine‐based shape memory polymer coated cotton fabric

AbstractThis research investigates the effect of curing temperature on the shape memory behavior and coating adhesion of polyethylenimine‐based shape memory polyurethane (PEI‐SMPU) to cotton fabric. The study utilized a dip‐coating process to apply a PEI‐SMPU solution to cotton fabrics, followed by curing at temperatures ranging from 100 to 160°C. Scanning electron microscopy confirmed uniform coating, and significant adhesion, and surface roughness was substantially reduced as evidenced by atomic force microscopy. The fabric's shape memory performance improved with increasing cure temperature, exhibiting excellent recovery (90%) at lower SMPU concentrations (1%). The results indicated that the tear strength of the fabric decreased with increasing curing temperature, attributed to constrained yarn mobility due to increased SMPU cross‐linking. The study successfully correlates the thermal and mechanical properties of SMPU‐coated fabrics with the interaction between SMPU and fabric, emphasizing the preservation of their laundering durability after multiple wash cycles. These findings contribute to the development of smart textiles with improved performance and longevity.

Encapsulating Fe3O4 Nanoparticles and Carbon Dots in a Metal-Organic Framework for Magnetic Fluorescent Taggants.

Magnetic fluorescent composite nanomaterials have broad application prospects in the fields of biological imaging, anticounterfeiting identification, suspicious object tracking, and identification of latent fingerprints in forensic medicine. For an effective taggant, a clearly visible identifying mark is necessary to enable observers to capture labeling information quickly and accurately, even from a distance. The preparation method of magnetic fluorescent composite materials is complicated and usually needs different surface modification and assembly processes. The limited loading capacity of fluorescent materials also limits the fluorescence properties of the composite, so it is difficult to produce obvious fluorescence as a taggant to meet the requirements of visible labeling. In this study, a core-shell structure of a magnetic fluorescent composite was prepared by using the metal-organic framework ZIF-8 as the host of fluorescent materials and an encapsulation shell coated on the Fe3O4 nanoparticles. The porous ZIF-8 is beneficial for increasing the loading capacity of fluorescent materials to ensure the fluorescence performance of the composite materials. Further modification of the composite surface prevented the desorption of fluorescent materials from the pores of ZIF-8, enabling the samples to maintain good fluorescence properties even after multiple washing cycles. The preparation method is simple, rapid, and cost-effective, and the prepared magnetic fluorescent composite nanomaterial has high magnetic separation performance and fluorescence performance, making it a promising material for identification, marking, and tracking.

Salt removal from coal flotation product filter cakes using counter-current and displacement washing

Water reuse is a common practice to alleviate water scarcity concerns and mitigate their environmental footprint in coal processing facilities. Nevertheless, water reuse leads to the accumulation of various organic and inorganic substances, including salt and residual reagents in the processing water, potentially leading to the retention of soluble impurities within the coal product. Residual impurities may result in a reduction in the quality of coal products. Salt and moisture retention has become a common issue on-site, but there lacks a proper solution currently. To resolve this industrial problem, investigations were carried out for the effects of washing on removing inorganic impurities from the cake during filtration. Filter cakes were prepared from flocculated metallurgical coal in process water. Two washing methods were trialled namely counter-current washing and displacement washing. Regarding washing efficiency, counter-current washing tended to produce cakes with higher specific resistance, which caused longer filtration time. Displacement washing, however, showed increased filtration time, though to a lesser extent. In addition, washing with different washing liquid ratios for multiple wash cycles showed that the filtration time, specific cake resistance, and medium resistance increased with the number of wash cycles. The analysis of the filtrate indicated that utilising a strategy of displacement washing with a washing ratio of 1:20 yielded the most effective removal of salt. The filter cakes were analysed using the μCT imaging technique to gain insights into the pore structure of the cake at a microscopic level. There was a significant change in the cake structure, where the pore profile was more evenly distributed and smaller when the cake was washed by displacement washing.

Wool fiber as an In situ reducing agent towards ZnO-based surface modified fabric development: Durability assessment in the realm of textile applications

The development of a bio-inspired method to fabricate ZnO nanostructure-modified functional wool fabric represents a substantial challenge in the textile field. This article reports for the first time the use of wool as a reducing agent for the synthesis of ZnO nanoparticles. While previous studies have employed alternative natural reducing agents for surface modification of host materials, this investigation uniquely utilizes the host material, wool, as the reducing agent for in-situ ZnO nanoparticle synthesis. In addition to demonstrating the use of wool as a reducing agent, this literature uniquely reports the durability of the modified fabric, achieved through the use of trimethoxy methyl silane. This silane compound acts as a bridging agent, forming a strong interface between the wool fibers and the synthesized ZnO nanoparticles. This innovative approach enhances the adhesion and stability of the ZnO nanoparticles on the wool fabric, a key aspect that contributes to the overall durability and performance of the modified material. The in situ surface modification process employed a metal oxide precursor (zinc acetate dihydrate), capping agents (hexamethylene tetraamine, sodium carbonate, and sodium sulfate), and a coupling agent (trimethyl methoxy silane). The capping agents were used to control the reaction conditions, while the coupling agent was employed to improve the durability of the surface modification. The impact of three different capping agents on the corresponding synthesis process was assessed, and the findings revealed that the choice of capping agent helped to form ZnO nanoparticles with distinct morphologies. Analytical techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), dynamic light scattering (DLS), and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, were utilized to characterize the synthesized particles and the treated fabric. The XRD analysis coupled with SEM analysis confirmed the successful formation of ZnO nanoparticles. The ATR-FTIR spectroscopy provided evidence of the formation of Si-O-Zn and Si-O-C bonds, observed at around 920 cm−1 and 1040 cm−1 respectively. These spectroscopic findings indicate that the surface modification involving the silane compound has enhanced the durability of the ZnO-modified fabric. The covalent linkages between the ZnO nanoparticles, the silane compound, and the wool fibers, confirmed by SEM analysis before and after washing cycles, have enabled the durable attachment of the nanoparticles to the fabric surface, even after multiple washing cycles. The results suggest a novel pathway to use wool as a reducing agent for the surface modification of the same material. Detailed mechanistic insights into the surface modification process and the corresponding chemical interactions were also discussed.

Versatile Antibacterial and Antioxidant Bacterial Cellulose@Nanoceria Biotextile: Application in Reusable Antimicrobial Face Masks.

Despite considerable interest in medical and pharmaceutical fields, there remains a notable absence of functional textiles that concurrently exhibit antibacterial and antioxidant properties. Herein, a new composite fabric constructed using nanostructured bacterial cellulose (BC) covalently-linked with cerium oxide nanoparticles (BC@CeO2NPs) is introduced. The synthesis of CeO2NPs on the BC is performed via a microwave-assisted, in situ chemical deposition technique, resulting in the formation of mixed valence Ce3+/Ce4+ CeO2NPs. This approach ensures the durability of the composite fabric subjected to multiple washing cycles. The Reactive oxygen species (ROS) scavenging activity of CeO2NPs and their rapid and efficient eradication of >99% model microbes, such as Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus remain unaltered in the composite. To demonstrate the feasibility of incorporating the fabric in marketable products, antimicrobial face masks are fabricated with filter layers made of BC@CeO2NPs cross-linked with propylene or cotton fibers. These masks exhibit complete inhibition of bacterial growth in the three bacterial strains, improved breathability compared to respirator masks and enhanced filtration efficiency compared to single-use surgical face masks. This study provides valuable insights into the development of functional BC@CeO2NPs biotextiles in which design can be extended to the fabrication of medical dressings and cosmetic products with combined antibiotic, antioxidant and anti-inflammatory activities.

Advanced hydrophobic cotton threads enhanced with graphene/SWCNT nanocomposites for exceptionally high electrical conductivity

This study investigates the fabrication and characterization of conductive threads using graphene and single-walled carbon nanotubes (SWCNTs), focusing on their application in wearable electronics and smart textiles. We employed the drop casting method to coat cotton threads with a polar solvent-based dispersion of graphene and SWCNTs, aiming to enhance their electrical conductivity and hydrophobic properties. Our results demonstrate that the electrical conductivity of these conductive threads significantly increases with the concentration of graphene and SWCNTs, reaching a peak conductivity of 68.75 S. cm−1 in threads coated with a SWCNT layer followed by a graphene layer. These threads exhibit metallic behavior across a broad temperature range (room temperature to 130 °C) and maintain electrical stability over an extended period. Additionally, varying degrees of hydrophobicity were observed among the different thread compositions. A washability study revealed that threads with a bilayer of SWCNT and graphene maintained higher electrical conductivity after multiple wash cycles compared to those fabricated with a mixed layer of these materials. This research not only highlights the potential of graphene and SWCNTs in developing advanced conductive threads but also addresses the challenges in scalability and reproducibility, paving the way for future innovations in smart textile applications.

Photothermal Janus fabrics enabling persistent directional sweat-wicking in personal wet-thermal management

Directional sweat-wicking by Janus fabrics has gained substantial attention in promoting personal wet-thermal management for optimal human comfort. During intense physical exercise, excessive sweating can cause the flooding of fabrics and weaken their wicking capabilities once the inner capillary channels are saturated. To address this issue, we develop a photothermal Janus fabric through a facile polydopamine (PDA) deposition followed by single-sided spray-coating of hydrophobic polydimethylsiloxane (PDMS). Such innovative fabrics enable directional sweat-wicking through a Janus structure and persistent removal of excessive sweat by solar-powered evaporation. Under sunlight, our photothermal Janus fabrics exhibit an enhanced evaporation rate, approximately twice compared with that of conventional Janus fabrics (∼1.143 ± 0.027 kg m-2h−1), making them suitable for high sweating rates during vigorous exercise. Furthermore, these fabrics help to maintain the skin temperature within the normal range, preventing hypothermia caused by profuse sweating. In addition, our photothermal Janus fabrics exhibit excellent washing durability even after multiple washing cycles, ensuring prolonged performance and safety.

Thermal resistance prediction of aerogel fabrics after repeated washing based on small-sample data

Aerogel fibers utilized in thermal protective apparel exhibit exceptional heat insulation capabilities; however, concerns arise regarding potential degradation due to the detachment of aerogel particles during repeated washing. Accurate prediction of aerogel fiber thermal resistance is critical for assessing hydrothermal aging in aerogel textiles, yet the precision of such predictions is significantly hindered by limited sample data and numerous uncertainties constrained by testing time and expenses. The present study endeavors to ascertain the optimal parameters dictating aerogel fabric thermal resistance post-washing and establish a prediction model based on these variables using small-sample data. Four aerogel fabric candidates were selected and subjected to multiple washing cycles (0, 1, 5, 10, 15, and 20 cycles). Gray relational analysis (GRA) was initially employed to prioritize the primary thermal resistance parameters, thereby identifying the interrelations among various factors and circumventing the unreasonable equal treatment of samples in conventional gray predictions. Subsequently, a discrete gray linear regression (DGLR) algorithm was proposed and validated to estimate thermal resistance using input from four principal fabric parameters: the fabric weight, thickness, air permeability, and surface temperature distribution coefficient. The findings revealed that the GRA-DGLR model achieved relatively high accuracy, closely aligning with the experimental results. Following repeated washing, aerogel fabric thermal resistance diminished, with the air permeability, weight, thickness, and surface temperature distribution coefficient ranked in descending order of significance. This investigation highlights the considerable impact of repeated washing on aerogel fabric thermal resistance and the efficacy of the GRA-DGLR model in estimating this parameter.

Surface and bulk mechanisms in repeating treatment of solid surfaces by purified water

To decrease the negative impact of surfactants, the idea of using purified water in washing has been proposed. Previous studies showed that purified water facilitates the roll-up mechanism by promoting electrostatic interactions between the surface and the soil. However, washing mechanisms can be dependent on the amount of remaining soil.In this work we studied the removal of thin Vaseline films and thicker oil films from hydrophilic surfaces using multiple washing cycles at different temperatures. The Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) and gravimetric analysis were used for thin and thick films respectively. In QCM-D experiments most of the thin film was removed during the first two cycles, while following cycles did not substantially affect washing efficiency; increased temperature facilitated the washing process. Gravimetric analysis showed that the washing of thicker films can be divided into two regimes. During the first, exponential, regime the amount of oil on the surface is high and surface mechanisms, such as roll-up, dominate. Oil droplets are kinetically stabilized in purified water by electrostatic interactions. As the amount of oil on the surface decreases, the second, linear, regime is introduced. The removal of oil occurs by equilibrium bulk mechanisms, where electrostatic interactions are less important.

Kappaphycus alvarezii flours as an ingredient for seaweed‐enriched, rice‐based, snacks: raw algae pretreatment and physical properties of the dough and snacks

SummaryIn this work, the addition of pretreated Kappaphycus alvarezii flour to a rice‐based snack formulation was proposed as an alternative to producing algae‐enriched snacks adding value to this seaweed and improving the quality of the snacks. Dried algae were submitted to multiple washing cycles to allow the reduction of the natural salt concentration of the algae. After, algae were dried and milled to obtain flour. The flour was added in different concentrations (0%, 2%, 5%, and 10%) in the model formulation of rice‐based dough. Rice‐K. alvarezii snacks were produced by baking at 220 °C. The proximate composition of the raw and pretreated algae was determined, as well as the colour, texture, and microstructure of dough and snacks. The pretreatment efficiently allowed for a reduction of 78% of the initial content of sodium and an 85% reduction of potassium. The concentration of 5% and 10% of algae addition presented higher values of hardness and consistency of the dough and lower adhesiveness. At higher concentrations, the seaweed flour acts as a processing aid during the preparation steps of the snacks but does not influence the hardness of the final snacks. The pretreated K. alvarezii flour is an alternative for increasing the quality of rice‐based snacks while preserving the algae's potential health benefits.

Long-lasting superhydrophobic antibacterial PET fabrics via graphene oxide promoted in-situ growth of copper nanoparticles

In this paper, superhydrophobic polyethylene terephthalate (PET) fabric with excellent antibacterial activity was prepared via in-situ growing of copper nanoparticles (CuNPs) and subsequent modification with 1-octadecanethiol (DT). Graphene oxide (GO) and tannic acid (TA) were synergistically used as polyanionic electrolyte in layer-by-layer (LBL) assembly, where GO played a critical role. It significantly promoted the nucleation of CuNPs on the fabric surface through its great specific surface area and abundant functional groups, thus improving the loading capacity and distribution uniformity of CuNPs. The co-action of GO and TA at the same time enabled the loading fastness of CuNPs to be greatly improved, resulting in an extremely stable surface structure of the fabric. The modified PET fabric exhibited superhydrophobic property with a static water contact angle greater than 150° and showed outstanding anti-fouling, self-cleaning and water-proofing performances, which might decrease bacterial adhesion to the fabric surface. Besides, the modified PET fabrics had excellent antibacterial activity with 99% antibacterial efficiency against both E. coli and S. aureus. More remarkably, the prepared fabrics still retained excellent superhydrophobic performances and antibacterial properties after multiple washing cycles and rubbing cycles. It as well as possessed striking antistatic capability and UV-blocking performance, with the volume resistivity as low as 108 Ω·cm and the ultraviolet protection factor (UPF) up to 202. This work provides an innovative and scalable method for the design and preparation of durable functional PET textiles.

Durable Hydrophobic Polymer Coating on Silk Surface by Surfactant-aided Fluoro-monomer Polymerization Through Admicellar Technique

Inspired by the lotus-leaf water repellent attribute, the ‘queen of textiles’, silk has been modified through the simple admicellar polymerization technique. Thin polymer coatings were successfully designed and fabricated on silk surfaces using surfactant-aided polymerization of 1H, 1H, 2H, 2H-Perfluorodecyl acrylate. The nanostructured surface morphology was studied by SEM and EDX. The structural changes of the surface due to new bond formation after surface modification were studied by FTIR technique. The water drop stay time test and water contact angle (WCA) measurement indicated that a substantial degree of hydrophobicity has been imparted to the silk surface. The best WCA of the polymer-coated silk was found to be 140.1°. The modified (cured at 60 °C) silk was studied to check the durability and quality of the polymer coating. The thermal stability of the coating was also found to be remarkably good. The modified hydrophobic surface showed enthralling durability against multiple washing cycles and abrasion cycles.

Ultra-compact MXene fibers by continuous and controllable synergy of interfacial interactions and thermal drawing-induced stresses

Recent advances in MXene (Ti3C2Tx) fibers, prepared from electrically conductive and mechanically strong MXene nanosheets, address the increasing demand of emerging yet promising electrode materials for the development of textile-based devices and beyond. However, to reveal the full potential of MXene fibers, reaching a balance between electrical conductivity and mechanical property is still the fundamental challenge, mainly due to the difficulties to further compact the loose MXene nanosheets. In this work, we demonstrate a continuous and controllable route to fabricate ultra-compact MXene fibers with an in-situ generated protective layer via the synergy of interfacial interactions and thermal drawing-induced stresses. The resulting ultra-compact MXene fibers with high orientation and low porosity exhibit not only excellent tensile strength and ultra-high toughness, but also high electrical conductivity. Then, we construct meter-scale MXene textiles using these ultra-compact fibers to achieve high-performance electromagnetic interference shielding and personal thermal management, accompanied by the high mechanical durability and stability even after multiple washing cycles. The demonstrated generic strategy can be applied to a broad range of nanostructured materials to construct functional fibers for large-scale applications in both space and daily lives.

Commercial Janus Fabrics as Reusable Facemask Materials: A Balance of Water Repellency, Filtration Efficiency, Breathability, and Reusability.

Facemasks as personal protective equipment play a significant role in helping prevent the spread of viruses during the COVID-19 pandemic. A desired reusable fabric facemask should strike a balance of water repellency, good filtration efficiency (FE), breathability, and mechanical robustness against washing cycles. Despite significant efforts in testing various commercial fabric materials for filtration efficiency, few have investigated fabric performance as a function of the fiber/yarn morphology and wettability of the fabric itself. In this study, we examine commercial fabrics with Janus-like behaviors to determine the best reusable fabric facemask materials by understanding the roles of morphology, porosity, and wettability of the fabric on its overall performance. We find that the outer layer of the diaper fabric consisted of laminated polyurethane, which is hydrophobic, has low porosity (∼5%) and tightly woven yarn structures, and shows the highest overall FE (up to 54%) in the submicron particle size range (0.03-0.6 μm) among the fabrics tested. Fabric layers with higher porosity lead to lower-pressure drops, indicating higher breathability but lower FE. Tightly woven waterproof rainwear fabrics perform the best after 10 washing cycles, remaining intact morphologically with only a 2-5% drop in the overall FE in the submicron particle size range, whereas other knitted fabric layers become loosened and the laminated polyurethane thin film on the diaper fabric is wrinkled. In comparison, the surgical masks and N95 respirators made from nonwoven polypropylene (PP) fibers see over a 30% decline in the overall FE after 10 washing cycles. Overall, we find that tightly woven Janus fabrics consisting of a low porosity, a hydrophobic outer layer, and a high porosity and hydrophilic inner layer offer the best performance among the fabrics tested as they can generate a high overall FE, achieve good breathability, and maintain fabric morphology and performance over multiple washing cycles.

Effect of scouring and laundering on functional properties of natural colour cotton fabric

Natural color cotton is eco-supportive as they possess colour naturally in varied shades viz., brown, green, cream and other tints and shades of these colours. It has unique comfort and handle property which provides soothing to the wearer. A medium brown natural colour cotton fibre was spun into 20s count yarn on open end spinning and the pure colour cotton fabric was developed on handloom and subjected to scouring. The scoured natural colour cotton fabric undergone with multiple wash cycles and assessed for mechanical, functional properties, colour fastness to sunlight and washing properties. Results revealed that, the scoured natural color cotton fabrics at washing and sunlight was found to be increase in color strength and decrease in reflectance than the pure NCC fabric. After laundering at multiple washes, the scoured natural colour cotton fabric exposed to direct sunlight, it was found that the colour strength was significantly reduced and fabric became lighter, duller and yellower. However, the scoured natural colour cotton fabric subjected to washing and shade dried exhibited significantly greater K/S, which indicates the sample became darker, brighter and greener than the sample expose to direct sunlight. The natural colour cotton fabrics has better mechanical, functional and fastness properties can be suitable for production of diversified cotton products ranging from children garments to trendy outfits. Hence, the promotion of natural colour cotton fabrics is a sustainable approach for green environment.

Influence of washing on textile material thermal properties under exposure of an open flame and heating ele-ment heat flow

Elevated temperatures are factors causing harm to human health and life. To ensure protection, various personal protective equipment is used, which includes special protective clothing. The article discusses the heat-shielding indicators of the safety of textile material. In order to determine the heat-shielding properties of the material, various types of exposure are used – convective heat from a heating element and an open flame. Fabrics of various raw materials and surface density are used for sewing special protective clothing. Five clothes were selected for the research. The research was held under the exposure of an open flame and convective heat of heating element with a comparable heat flux density equal to 80 kW/m². Also, research was held under influence of multiple wash cycles on radiant heat transfer index and heat transfer index.

Fabrication of multifunctional PET fabrics with flame retardant, antibacterial and superhydrophobic properties

The multifunctional polyethylene terephthalate (PET) fabrics with flame retardant, antibacterial and superhydrophobic properties were successfully fabricated by a simple coating approach to enhance the properties of PET fabrics and to make them extensively applicable in a number of fields. The composite coating was composed of ammonium polyphosphate (APP), polydopamine (PDA), PDMS-silica (PDMS-SiO2), and silver nanoparticles (AgNPs). ATR-FTIR spectra, XPS analysis, and SEM-EDS spectrometer were employed to investigate the morphological properties and constitution of these coatings. The flame retardant performance of the multifunctional PET fabrics was determined by LOI, vertical flame test (VFT) and cone calorimeter test (CCT). The results revealed that the APP@SiO2-PDA@Ag PET fabrics' LOI value reached 29.0 %, which was 9.5 % higher than that of pristine PET fabrics. Besides, the APP@SiO2-PDA@Ag PET fabrics could self-extinguish the fire quickly in the VFT. The peak heat release rate and total heat release of the APP@SiO2-PDA@Ag PET fabrics were 34 % and 26 % lower than those of the pristine one. Notably, the multifunctional PET fabrics had excellent antibacterial activity against E. coli and S. aureus. The multifunctional fabrics exhibited superhydrophobicity with a water contact angle (CA) greater than 150° and showed excellent self-cleaning and antifouling properties. More importantly, the multifunctional PET fabrics still retained excellent flame retardant performance and antibacterial properties after multiple washing cycles.

Multifunctionalized Cellulose Nanofiber for Water-Repellent and Wash-Sustainable Coatings on Fabrics.

A new synthetic route was developed to modify cellulose nanofiber for water-repellent coatings with great sustainability after multiple washing cycles. Multiple functional groups were grafted on 2,2,6,6-tetramethylpiperidine 1-oxyl radical (TEMPO)-oxidized cellulose nanofibers (TOCN) to achieve superhydrophobic performance and strong adhesion on cotton cloth. First, hexadecylamine (HDA) was used to modify TOCN surface into hydrophobic derivatives via amidation. The amidation-modified TOCN (AMT) were then grafted with a polyisocyanate cross-linking agent (PCA). The final multimodified TOCN (MMT) had hydrophobic alkyls and isocyanate groups on the surface. These surface functional groups were confirmed by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). After spraying the MMT suspension on cotton fabrics, the isocyanate groups would react with hydroxyl groups on cotton fibers, leading to a uniform conformal layer of MMT on fabric surfaces. The MMT coating showed great water repellence and washing sustainability. A large contact angle of 150° and a small sliding angle of ∼10° were observed. The superhydrophobic performance retained even after 10 laundry washing cycles. Several examples were also demonstrated to show the capability and the possibility of applying this coating material for water-repellent applications.

Dual responsive cellulose microspheres with high solid-state fluorescence emission

Materials that respond to multiple stimuli such as magnetic field and light are attractive for security and medical diagnostic applications. One of the major challenges in dual functional microspheres is that the presence of magnetic nanoparticles can quench fluorescence emission. Also, there is a probability of solid-state quenching due to the proximity of the fluorophore. We report here a facile approach to prepare cellulose microspheres with high solid-state fluorescence using 40 % tetrabutylammonium hydroxide (TBAH). The fluorescence quenching effect due to the presence of Fe3O4 nanoparticles and solid-state quenching due to aggregation of fluorophore was systematically investigated. Microspheres with the detectable magnetic response and fluorescence quantum yield as high as 0.57 (FMB 414) was obtained by optimizing the reaction conditions. Such a high quantum yield has not been reported before for dual stimuli-responsive fluorescent microspheres. The magnetic and fluorescent properties were found to be durable even after multiple washing cycles. These dual responsive cellulose microspheres can be added as security features to authenticate documents such as passports, degree certificates, currency notes, financial documents etc.