Incorporation of ZnO and their composite nanostructured material into a cotton fabric platform for wearable device applications

Improved cotton fabrics properties using zinc oxide-based nanomaterials: A review

Zinc oxide nanoparticles (ZnO NPs) have gained significant attention in the textile industry for their ability to enhance the physicochemical properties of fabrics. In recent years, there has been a growing focus on the development of ZnO-based nanomaterials and their applications for cotton and other fabrics. This review paper provides an overview of the synthesis and diverse applications of ZnO-based nanomaterials for textile fabrics, including protection against UV irradiation, bacteria, fungi, microwave, electromagnetic radiation, water, and fire. Furthermore, the study offers the potential of these materials in energy harvesting applications, such as wearable pressure sensors, piezoelectric nanogenerators, supercapacitors, and human energy harvesting. Additionally, we discuss the potential of ZnO-based nanomaterials for environmental cleaning, including water, oil, and solid cleaning. The current research in this area has focused on various materials used to prepare ZnO-based nanocomposites, such as metals/nonmetals, semiconductors, metal oxides, carbon materials, polymers, MXene, metal-organic frameworks, and layered double hydroxides. The findings of this review highlight the potential of ZnO-based nanomaterials to improve the performance of textile fabrics in a range of applications, and the importance of continued research in this field to further advance the development and use of ZnO-based nanomaterials in the textile industry.

Free-Standing PVDF/Reduced Graphene Oxide Film for All-Solid-State Flexible Supercapacitors towards Self-Powered Systems

The development of polymer-based devices has attracted much attention due to their miniaturization, flexibility, lightweight and sustainable power sources with high efficiency in the field of wearable/portable electronics, and energy system. In this work, we proposed a polyvinylidene fluoride (PVDF)-based composite matrix for both energy harvesting and energy storage applications. The physicochemical characterizations, such as X-ray diffraction, laser Raman, and field-emission scanning electron microscopy (FE-SEM) analyses, were performed for the electrospun PVDF/sodium niobate and PVDF/reduced graphene oxide composite film. The electrospun PVDF/sodium niobate nanofibrous mat has been utilized for the energy harvester which shows an open circuit voltage of 40 V (peak to peak) at an applied compressive force of 40 N. The PVDF/reduced graphene oxide composite film acts as the electrode for the symmetric supercapacitor (SSC) device fabrication and investigated for their supercapacitive properties. Finally, the self-charging system has been assembled using PVDF/sodium niobate (energy harvester), and PVDF/reduced graphene oxide SSC (energy storage) and the self-charging capability is investigated. The proposed self-charging system can create a pathway for the all-polymer based composite high-performance self-charging system.

Cytotoxicity, Antioxidant, Antibacterial, and Photocatalytic Activities of ZnO-CdS Powders

In this work, ZnO–CdS composite powders synthesized by a simple chemical precipitation method were thoroughly characterized. The morphological, structural, compositional, photocatalytical, and biological properties of the prepared composites were investigated in comparison with those of the pristine components and correlated with the CdS concentration. ZnO–CdS composites contain flower-like structures, their size being tuned by the CdS amount added during the chemical synthesis. The photocatalytic activity of the composites was analyzed under UV irradiation using powders impregnated with methylene blue; the tests confirming that the presence of CdS along the ZnO in composites can improve the dye discoloration. The biological properties such as antioxidant capacity, antibacterial activity, and cytotoxicity of the ZnO, CdS, and ZnO–CdS composites were evaluated. Thus, the obtained composites presented medium antioxidant effect, biocidal activity against Escherichia coli, and no toxicity (at concentrations less than 0.05 mg/mL for composites with a low CdS amount) for human fibroblast cells. Based on these results, such composites can be used as photocatalytic and/or biocidal additives for photoactive coatings, paints, or epoxy floors, which in their turn can provide a cleaner and healthier environment.

Zinc Oxide for Functional Textile Coatings: Recent Advances

The use of ZnO for the functionalization of textile substrates is growing rapidly, since it can provide unique multifunctional properties, such as photocatalytic self-cleaning, antimicrobial activity, UV protection, flame retardancy, thermal insulation and moisture management, hydrophobicity, and electrical conductivity. This paper aims to review the recent progress in the fabrication of ZnO-functionalized textiles, with an emphasis on understanding the specificity and mechanisms of ZnO action that impart individual properties to the textile fibers. The most common synthesis and application processes of ZnO to textile substrates are summarized. The influence of ZnO concentration, particle size and shape on ZnO functionality is presented. The importance of doping and coupling procedures to enhance ZnO performance is highlighted. The need to use binding and seeding agents to increase the durability of ZnO coatings is expressed. In addition to functional properties, the cytotoxicity of ZnO coatings is also discussed. Future directions in the use of ZnO for textile functionalization are identified as well.

Sono-synthesis approach of reduced graphene oxide for ammonia vapour detection at room temperature

In this paper, we report the sono-synthesis of reduced graphene oxide (rGO) using polyethyleneimine (PEI), and its performance for ammonia vapour detection at room temperature. Graphene oxide (GO) and reduced graphene oxide (rGO) were prepared by sonication method by using low-frequency ultrasound under ambient condition and films were deposited by Doctor Blade method. The rGO, which has vapour accessible structure showed a good sensing response with a minimum detection limit of 1 ppm and the detection range from 1 ppm to 100 ppm. The sensing response was found to be 2% at 1 ppm and 34% at 100 ppm of ammonia and the developed sensor operated at room temperature. The sensor displays a response time of 6 s and a recovery time of 45 s towards 100 ppm of ammonia vapour. The source for the highly sensitive, selective and stable detection of ammonia with negligible interference from other vapours is discussed and reported. We believe reduced graphene oxide (rGO) could potentially be used to manufacture a new generation of low-power portable ammonia sensors.

Eco-friendly post-consumer cotton waste recycling for regenerated cellulose fibers

In this study, post-consumer cotton waste was chemically recycled to produce regenerated fibers using eco-friendly alkaline/urea solvent systems. Both white and colored cotton waste was shredded and hydrolyzed using sulfuric acid to reduce the molecular weight of the cotton fibers. Two solvent systems, i.e., sodium hydroxide/urea and lithium hydroxide/urea, were used to dissolve the hydrolyzed cotton to prepare solutions for fiber regeneration by wet spinning. The diameter, morphology, thermal properties, crystallinity, and tensile properties of the regenerated fibers were characterized by SEM, TGA, XRD, and tensile testing. Results showed that, using this recycling method, fibers with tensile properties comparable to current commercial regular rayon fibers made from wood pulp could be produced, and dyes in the original cotton waste could be conserved to produce fibers with intrinsic colors, thus eliminating the need for dyeing processes. This study demonstrated an economical upcycling method for post-consumer cotton waste with environmentally friendly solvents.

Activated carbon monoliths derived from bacterial cellulose/polyacrylonitrile composite as new generation electrode materials in EDLC

Bacterial cellulose (BC) gel is synthesized by static culture process at the interface between air and medium. The solvent-exchanged BC gel is incorporated into polyacrylonitrile (PAN) copolymer solution under heating at 90 °C and subsequent cooling gives bacterial cellulose-polyacrylonitrile composite (BC-PAN) monolith. The BC-PAN monolith is carbonized at 1000 °C with physical activation in the presence of CO₂ to obtain the activated carbon monolith, BC-PAN-AC, with large surface area and high microporosity. Unique morphologies are observed for BC gel which is propagated to the BC-PAN monolith and restored in BC-PAN-AC. The BC nanofibers remain entwined throughout the porous skeleton of the PAN backbone and the entangled structure helps in retaining the continuity of the matrix of BC-PAN-AC and reduce the grain boundary impedance for electrical conduction. Cyclic voltammetry shows that these activated carbons are good electrode materials in electric double layer capacitors (EDLC) with capability of high-speed charging and discharging.

Exploration of Wedelia chinensis leaf-assisted silver nanoparticles for antioxidant, antibacterial and in vitro cytotoxic applications

Green synthetic route of silver nanoparticles (AgNPs) has already been proved to be an advantageous over other physico-chemical approaches due to its simplicity, cost effectiveness, ecofriendly and nontoxicity. In this finding, aqueous Wedelia chinensis leaf extract (WLE) mediated synthesis of AgNPs was approached. Surface plasmon resonance (SPR) band at 408 nm preliminary indicated the formation of AgNPs, while TEM and XRD characterization confirmed the formation of spherically shaped and crystalline AgNPs with an average size of 31.68 nm, respectively. The plausible biomolecules in the aqueous leaf extract responsible for the reduction and stabilization of AgNPs were identified by FTIR analysis and found to be polyphenolic groups in flavonoid. Further, synthesized AgNPs was explored for different biological applications. Biosynthesized AgNPs showed significant free radical scavenging activity as compared to Wedelia leaf extract and antibacterial activity against clinically isolated test pathogens where Gram-negative bacteria were found more susceptible to AgNPs than Gram-positive one. In addition, in vitro cytotoxic response was also evaluated on hepatocellular carcinoma Hep G2 cell lines and showed a dose-dependent cytotoxic response with an IC₅₀ value of 25 μg/mL.