Multifunctional Superamphiphobic Cotton Fabrics with Highly Efficient Flame Retardancy, Self-Cleaning, and Electromagnetic Interference Shielding

Cellulose-Based Electromagnetic Functional Aerogels: Mechanism, Fabrication, Structural Design, and Application

Electromagnetic functional materials offer a promising solution to reduce impacts from electromagnetic pollution and interference, such as digital communications, national defenses, and military fields. Cellulose-based aerogels, featured with their hierarchical porous structure, high specific surface area, and surface activity, can be engineered to possess electromagnetic wave shielding and absorption capabilities through structural regulation, composition optimization, and material functionalization. Moreover, these cellulose-based aerogels exhibit remarkable renewability and biocompatibility, highlighting their significant potential in the field of electromagnetic functional materials. In this review, we stigmatically overview the state-of-the-art of cellulosic electromagnetic functional aerogels, which begins with elucidating the mechanisms behind electromagnetic interference shielding and microwave absorption. The material design based on the physical and chemical characteristics of cellulose aerogels is discussed. Furthermore, the hierarchical design strategies of the cellulosic electromagnetic functional aerogels are reviewed including macro-structures, micro/nanostructures, and supramolecular structures. Multifunctional applications of cellulose electromagnetic functional aerogels are presented, such as infrared and radar stealth materials, intelligent responsive electromagnetic devices, and radiation protection equipment. Finally, an up-to-date summary and an outlook on developing the cellulose-based electromagnetic functional aerogels are provided in the fields of electromagnetic interference shielding and microwave absorption, as well as outlining future research perspectives.

Ethanol-induced ammonium polyphosphate-silver gel paint: breaking the trade-off between conductivity, flame retardancy and adhesion in single-layer functional coatings

Electrical fires pose significant threats to the lives and property safety of people. Although utilizing coatings to impart conductivity and flame retardancy to materials is convenient and reliable, traditional layer-by-layer preparation methods have the limitations of cost, convenience and scalability. Therefore, a single-layer coating that simultaneously imparts excellent conductivity and flame retardancy to materials presents broader application prospects. And good adhesion of the coating is another essential aspect. However, the trade-off between conductivity, flame retardancy, and adhesion creates huge challenges in the development of such coatings. Here, we report an ethanol-induced ammonium polyphosphate-silver (APP-Ag) gel paint to completely address the above issues. High molecular weight APP served as both a flame retardant and an adhesive, while the coordinating action of phosphate groups ensured the effective dispersion of nanosilver, and the nitrogen-containing carbon layer formed from triethanolamine and ascorbic acid at high temperature significantly enhanced the conductivity of the coating by connecting the silver nanoparticles. The coated materials could exhibit an electrical conductivity of over 200 S m-1, with the limiting oxygen index (LOI) exceeding 60%. Meanwhile, the peak heat release rate (PHRR) and total heat release (THR) decreased by more than 30% compared to those of the untreated materials. Additionally, we utilized this gel paint to fabricate electric heating fabrics, motion sensors, and fire alarm devices. Finally, we have thoroughly explored the potential mechanisms of conductivity, flame retardancy, and adhesion of the gel coatings.

TA-APTES Coating Facilitated Secondary Reactions for Synthesis of Multifunctional Porous Melamine Sponge and Application in Wastewater Treatment

Secondary reactions induced by functional surface coating are of critical significance and have attracted substantial interest, as the surface coating can function as a versatile platform for designing multifunctional coatings by tailoring the surface performance. The surface coating incorporated tannic acid, and 3-aminopropyltriethoxysilane (TA-APTES) contains plentiful nanospheres with secondary reaction sites, which is favorable for surface modification. In this research, a TA-APTES coating with a unique hierarchical structure was grown in situ on the skeleton of a porous melamine sponge under mild conditions. The secondary reactions triggered by the TA-APTES coating were comprehensively employed to construct a multifunctional melamine sponge for various applications. The TA-APTES-coated melamine sponge was first immersed in silver ammonia solutions for the reduction of silver ammonia ions. The decoration of Ag NPs endowed the sponge with catalytic and antibacterial activity, which could be applied for dye reduction and bacterial disinfection in wastewater. The surface energy of the TA-APTES-coated melamine sponge was subsequently decreased by long-chain alkyl molecules. After the condensation polymerization reaction with octadecyltrimethoxysilane, the surface of the melamine sponge coated with TA-APTES was converted into a superhydrophobic state, making it suitable for efficient separation of oil and water mixtures. The prepared superhydrophobic sponge demonstrated remarkable water repellency and strong oil affinity with a water contact angle of 156.5° and oil contact angle of 0°. Significantly, the superhydrophobic sponge retained a relatively stable oil absorption capacity and separation efficiency after multiple recycling utilization. The proposed routine for fabrication and design of TA-APTES coating demonstrates the potential to develop a multifunctional porous melamine sponge in solving water pollution issues.

One-step green synthesis durable flame-retardant, antibacterial and dyeable cellulose fabrics with a recyclable deep eutectic solvent

The development of cellulose fabrics with good flame retardancy and durability has been a primary concern for in firefighting clothing. A recyclable ternary deep eutectic solvent (TDES) was used to prepare surface ammonium phosphate-modified cellulose fabrics (SACF). The incorporation of ammonium phosphate groups notably enhanced the durable flame retardancy of cellulose fabrics. The limiting oxygen index (LOI) of SACF could reach 48 %, and remain at 33.5 % even after 50 laundering cycles (LCs). And the TDES can be recovered and reused for 5 cycles and the SACF still remains flame retardancy. It also exhibited excellent antibacterial properties (with an antibacterial rate of 99.79 % against E. coli) and dyeability with cationic dyes. Moreover, the flame-retardant of the SACF did not decrease after dyed and showed both condensed-phase and gas-phase flame-retardant mechanisms during combustion. This method for producing flame-retardant cellulose fabrics with recyclable TDES effectively reduces the use of chemical reagents and holds promise for application in eco-friendly manufacturing and firefighting garments.

Multilevel structural polylactic acid fabrics for flame retardancy, durability, and electromagnetic interference shielding

The integration of polylactic acid (PLA) fabrics with bio-based flame retardants and conductive MXene addresses the requirements for safe sustainable development and electromagnetic interference (EMI) shielding. The dehydration and carbonization of phytic acid (PA) and polyethylenimine (PEI) were facilitated by employing 3-glycidyl oxy propyl trimethoxsilane (GPTMS) as an organic crosslinking agent, which was covalently bonded to both the flame retardants and the MXene conductive layer. The prepared multifunctional PLA fabric, designated as PA-PEI-MXene-60, exhibits a high Limiting Oxygen Index (LOI) of 35.6 %, a damage length of 3.2 cm, a peak heat release rate (pHRR) reduction of 81.38 %, and total heat release (THR) reduction of 27.03 %, indicating exceptional flame-retardant properties. Concurrently, the MXene conductive layer provides outstanding EMI shielding performance. A subsequent hydrophobic treatment was applied using polydimethylsiloxane (PDMS) coatings, resulting in a water contact angle of 148.8°. Additionally, while the PLA fabrics exhibited remarkable EMI shielding effectiveness at 54 dB. Importantly, despite undergoing repeated bending and abrasion tests, these multifunctional PLA fabrics maintain relatively high EMI shielding efficiency, demonstrating commendable durability. This work significantly contributes to the research and development of bio-based, safe, durable multifunctional flame-retardant materials with EMI shielding capabilities.

Multifunctional Wearable Electronic Based on Fabric Modified by PPy/NiCoAl-LDH for Energy Storage, Electromagnetic Interference Shielding, and Photothermal Conversion

With the rapid advancement of electronic technology, traditional textiles are challenged to keep up with the demands of wearable electronics. It is anticipated that multifunctional textile-based electronics incorporating energy storage, electromagnetic interference (EMI) shielding, and photothermal conversion are expected to alleviate this problem. Herein, a multifunctional cotton fabric with hierarchical array structure (PPy/NiCoAl-LDH/Cotton) is fabricated by the introduction of NiCoAl-layered double hydroxide (NiCoAl-LDH) nanosheet arrays on cotton fibers, followed by polymerization and growth of continuous dense polypyrrole (PPy) conductive layers. The multifunctional cotton fabric shows a high specific areal capacitance of 754.72 mF cm-2 at 5 mA cm-2 and maintains a long cycling life (80.95% retention after 1000 cycles). The symmetrical supercapacitor assembled with this fabric achieves an energy density of 20.83 µWh cm-2 and a power density of 0.23 mWcm-2. Moreover, the excellent electromagnetic interference shielding (38.83 dB), photothermal conversion (70.2 °C at 1000 mW cm-2), flexibility and durability are also possess by the multifunctional cotton fabric. Such a multifunctional cotton fabric has great potential for using in new energy, smart electronics, and thermal management applications.

A multi-functional coating on cotton fabric to incorporate electro-conductive, anti-bacterial, and flame-retardant properties

Multi-functional textiles have become a growing trend among smart customers who dream of having multiple functionalities in a single product. Thus, this study aimed to develop a multi-functional textile from a common textile substrate like cotton equipped with electrically conductive, anti-bacterial, and flame-retardant properties. Herein, a bunch of compounds from various sources like petro-based poly-aniline (PANI), phosphoric acid (H3PO4), inorganic silver nanoparticles (Ag-NPs), and biomass-sourced fish scale protein (FSP) were used. The coating was prepared via in-situ polymerization of PANI with the cotton substrate, followed by the dipping in AGNPs solution, layer-by-layer deposition of FSP and sodium alginate, and finally, a dip-dry-cure technique after immersing the modified cotton substrate into the H3PO4 and citric acid solution. The key results indicated that the fabric treated with PANI/Ag-NPs/FSP/P-compound exhibited a balanced improvement in all three desired properties as the electrical resistance was reduced by 44.44 % while showing superior bacterial inhibition against gram-positive bacteria (S. aureus) and gram-negative bacteria (E. coli), and produced dense-black carbonaceous char residues, indicating its flame retardant properties as well. Thus, such amicable developments made the cotton textile substrate a multi-functional textile, which showed potential to be used in medical textiles, wearable electronics, fire-fighter suits, etc.

In Situ Synthesis of Cu2O Nanoparticles Using Eucalyptus globulus Extract to Remove a Dye via Advanced Oxidation

Water pollution, particularly from organic contaminants like dyes, is a pressing issue, prompting exploration into advanced oxidation processes (AOPs) as potential solutions. This study focuses on synthesizing Cu2O on cellulose-based fabric using Eucalyptus globulus leaf extracts. The resulting catalysts effectively degraded methylene blue through photocatalysis under LED visible light and heterogeneous Fenton-like reactions with H2O2, demonstrating reusability. Mechanistic insights were gained through analyses of the extracts before and after Cu2O synthesis, revealing the role of phenolic compounds and reducing sugars in nanoparticle formation. Cu2O nanoparticles on cellulose-based fabric were characterized in terms of their morphology, structure, and bandgap via SEM-EDS, XRD, Raman, FTIR, UV-Vis DRS, and TGA. The degradation of methylene blue was pH-dependent; photocatalysis was more efficient at neutral pH due to hydroxyl and superoxide radical production, while Fenton-like reactions showed greater efficiency at acidic pH, primarily generating hydroxyl radicals. Cu2O used in Fenton-like reactions exhibited lower reusability compared to photocatalysis, suggesting deterioration. This research not only advances understanding of catalytic processes but also holds promise for sustainable water treatment solutions, contributing to environmental protection and resource conservation.

A molecularly engineered fully bio-derived phosphorylated furan-based flame retardant for biomass-based fabrics

With the increasing awareness of environmental protection, the demand for eco-friendly bio-derived flame-retardant for textiles has received increasing attention. In this work, a fully bio-derived phosphorylated furan-based flame retardant (FAP) was synthesized by the Schiff reaction of furan-based compounds (furfural and furfurylamine). To evaluate the application scope and flame retardant efficiency of FAP, cotton fabrics and PLA nonwovens were selected as biomass-based representatives of natural fiber materials and synthetic fiber materials, respectively. Significantly, based on the composition of furan ring, phosphorus and nitrogen containing components of FAP, excellent charring and flame retardant properties of coated cotton fabrics and PLA nonwovens can be expected. TGA results showed that the residual char of C-FAP-3 and P-FAP-3 were 39.7% (increased by 267.6%) and 16.7% (increased by 215.1%), respectively, higher than those of control cotton (10.8%) and PLA nonwoven (5.3%). Cone test results exhibited that the peak heat release rate (PHRR) and total heat release (THR) values of C-FAP-3 were sharply decreased by 69.4% and 37.8%, respectively. P-FAP-3 also displayed a significant reduction in PHRR, implying high flame retardancy of C-FAP-3 and P-FAP-3. Notably, through the weight gains of FAP coating on cotton and PLA as well as the final LOI and VBT results of the flame retardant treated fabrics, it can be preliminarily inferred that control cotton fabrics are more likely to achieve better flame retardant effects than PLA. Additionally, the facile synthetic strategy of fully bio-derived flame retardants is expected to promote the development of green flame retardant strategies for high-performance textiles.