Feiya Fu

Durable antimicrobial cotton textiles modified with inorganic nanoparticles

Numerous inorganic nanoparticles can impart antimicrobial properties to cotton textiles; however, the antimicrobial performance of the modified textile products is generally less durable. To solve this problem, accurate evaluation of the antimicrobial durability, and improved finishing techniques using inorganic nanoparticles are vital. In this review, it is demonstrated that a reliable description of durability consists of three factors: antimicrobial efficiency, its downtrend profile, and the loss of the inorganic NPs during the washing process. Based on a systematic evaluation of scientific publications, recent progress on antimicrobial cotton textiles modified using inorganic nanoparticles is summarized, with a focus on the durability. It was found that suitable polymer binders and the application of microwave or ultrasound are effective ways to improve the durability of antimicrobial fabrics. These findings will be helpful in designing durable new antimicrobial textiles using environmentally benign protocols.

Durable antibacterial cotton modified by silver nanoparticles and chitosan derivative binder

This article focuses on the functional finishing of textiles using silver nanoparticles (AgNPs) and chitosan derivative binder, which was synthesized by a modification of chitosan using α-ketoglutaric acid. The binder covalently linked to cotton fabric via esterification of the hydroxyl groups on the cotton surface, and tightly adhered to surface of the AgNPs by coordination bonds. As a result, the coating of AgNPs on the cotton fabric showed excellent antibacterial property and laundering durability. After 30 consecutive laundering cycles, the Ag content on the fabrics decreased to 37.6 %, but the bacterial reduction rates against both S. aureus and E. coli were maintained over 95 %. It has potential applications in a wide variety of fields such as sportswear, socks, and medical textile.

Silver-based, single-sided antibacterial cotton fabrics with improved durability via an l -cysteine binding effect

The main purpose of this work was to obtain durable antimicrobial cotton textiles functionalized with l-cysteine (Cys) and silver nanoparticles (Ag NPs). Cys molecules were covalently linked to cotton fibers via esterification with the cellulose hydroxyl groups, and the Ag NPs tightly adhered to the fiber surface via coordination bonds with the Cys thiol groups. As a result, the Ag NPs coating on the cotton fabric showed an excellent antibacterial function with an outstanding laundering durability. Even after 90 consecutive laundering tests, the modified cotton fabrics still showed satisfactory bacterial reduction rates against both Staphylococcus aureus and Escherichia coli, and the rates were are all higher than 94%. These findings will allow for broader applications of antimicrobial cotton textiles with a decreased safety risk and lower environmental impact due to the Ag NPs.

Surface modification by carboxymethy chitosan via pad-dry-cure method for binding Ag NPs onto cotton fabric

To obtain durably antimicrobial cotton fabric, carboxymethyl chitosan (CMC) was covalently linked to cotton fibers via an esterification with the cellulose hydroxyl groups, and the silver nanoparticles (Ag NPs) were adhered to the fiber surface by the coordination bonds with the amino groups of CMC. The finished cotton fabrics have an excellent antibacterial function and outstanding laundering durability. Even after 50 consecutive laundering tests, the modified cotton fabrics still show satisfactory bacterial reduction rates (BR) against both S. aureus and E. coli, which are all higher than 94%. These findings allow for broader applications of antimicrobial cotton textiles with a decreased safety risk and lower environmental impact arise from the Ag NPs.

Single-faced flame resistance of cotton fabrics modified via mist copolymerization

Cotton fabrics with single-faced flame resistance are successfully fabricated through a simple mist copolymerization process using pentabromobenzyl acrylate (PBBA) as the functional monomer. The co-monomers are methyl acrylate (MA), which can react with the hydroxyl groups of cellulose by transesterification, and divinyl benzene (DVB), a cross-linker. SEM images indicate that a very thin copolymer layer (the thickness is about 200 nm) was formed on the cotton fiber surface and the flame resistance tests show that the modified fabrics have an improved flammability with longer time to ignition (TTI), lower peak heat release rate (PHRR), lower total heat release (THR), and lower average mass loss rate (AMLR), when compared to the original cotton fabric. The modification also results in good wearing durability because the flame-retardant coating was covalently linked to the cotton fabric surface by many ester groups. Moreover, desired cotton characteristics such as tensile strength, water absorbency, vapor permeability and flexibility are mostly retained because the mist method gives a single-faced modification of the cotton fabrics.

One-pot fabrication of durable antibacterial cotton fabric coated with silver nanoparticles via carboxymethyl chitosan as a binder and stabilizer

In this article, durable antimicrobial cotton fabric was prepared by a one-pot modification process using a colloidal solution of silver nanoparticles (Ag NPs) stabilized by carboxymethyl chitosan (CMC). Due to coordination bonds between the amine groups of CMC and the Ag NPs and the ester bonds present between the carboxyl groups of CMC and the hydroxyl groups of cellulose, the Ag NPs were tightly immobilized onto the cotton fiber surface. As a result, the Ag NPs that were adhered on the cotton fabrics have uniform dispersion and small size, ranging from 10 nm to 80 nm. This provides the cotton fabric with remarkable and durable antibacterial activity against both S. aureus and E. coli. After 50 laundering cycles, the bacterial reduction rate (BR) for the modified cotton fabric remained over 94%. This method is simple, and it is particularly suitable for the industrial finishing process.

Thermally assisted self-healing behavior of anhydride modified polybenzoxazines based on transesterification

A self-healing polybenzoxazine is synthesized solely based on dynamic ester bonds. For this purpose, an anhydride (succinic anhydride) was added into bisphenol F derived benzoxazine monomer before thermocuring. Owing to the transesterification of newly formed ester bonds, the thermoset network behaves as a thermoplastic at 140 °C in the presence of Zn (Ac)2, and shows self-healing properties even after multiple damage-healing cycles. Furthermore, kinetics study indicates that the transesterification is a first-order reaction and the activation energy is about 135.4 kJ/mol. This study proposes a facile and economical way to prepare self-healing polybenzoxazine. It has promising applications in coating, adhesive, and other smart materials that rely on structurally dynamic polymers.

Excellent binding effect of L-methionine for immobilizing silver nanoparticles onto cotton fabrics to improve the antibacterial durability against washing

Silver nanoparticles (Ag NPs) have outstanding antimicrobial effects, but their weak adhesive force onto cotton fiber surfaces often causes undesired silver loss from antibacterial fabrics, diminishing antibacterial durability, and even leading to environmental and health risks. To improve adhesion of the Ag NPs, various strategies have been tried, but achieving long-term antibacterial effectiveness still remains challenging. Here, L-methionine is proposed as a binder reagent because it has low toxicity towards mammalian cells and has a methyl group to enhance its coordination ability. The antibacterial cotton fabric was fabricated via a very simple pad-dry-cure process: after dipping a cotton fabric in an L-methionine solution followed with heating for esterification, Ag NPs are formed via the reaction of silver nitrate with sodium borohydride. The resulting cotton fabric exhibits an excellent antibacterial property and laundering durability. Its bacterial reduction rates (BR) against both S. aureus and E. coli remained over 97% even after 90 consecutive laundering cycles. Moreover, the modification causes insignificant damage to cottons characteristics, such as tensile breaking strength, water absorptivity, and vapor permeability.

Three-dimensional cellulose based silver-functionalized ZnO nanocomposite with controlled geometry: Synthesis, characterization and properties

Cellulose based Ag-functionalized ZnO nanocomposite (AZC) films were prepared using a green and easy scale-up strategy. Firstly, ZnO embedded cellulose (ZC) nanocomposite was synthesized from a cellulose-NaOH/zincate/urea solution through a biomimetic approach. Secondly, Ag nanoparticles (NPs) with a mean diameter of 53.2 nm were efficiently deposited onto the surface of embedded ZnO in cellulose matrix under UV irradiation (16 w), yielding the multi-hybrid AZC film. Owing to the porous structure of cellulose substrate and its rich hydroxyl group, the NPs in the ACZ films displayed good stability. Because of the formation of Schottky barriers in the Ag-ZnO regions, the catalytic activity of ACZ films increased by 20 times when compared to that of ZC sample. Furthermore, the AZC films could completely inhibit both S. aureus and E. coli growth. This facile and eco-friendly approach is expected to pave the way for constructing multifunctional cellulose material for various niche applications.

Preparation of Copper Nanoparticles Coated Cotton Fabrics with Durable Antibacterial Properties

When copper nanoparticles (Cu NPs) were applied as an antimicrobial agent to finish cotton fabrics, there are two issues should be solved: the oxidization and the weak adsorbability onto cotton fiber surface. In the present work, we developed a new method that can achieve both immobilization and protection of the Cu NPs at the same time. As an effective binder, thioglycolic acid (TGA) was covalently linked to cotton fiber surface via an esterification with the hydroxyl groups of cellulose, then Cu NPs were introduced on the fabric surface in the presence of a protective reagent, citric acid. Due to the doubled stabilization acts of TGA and citric acid, the Cu NPs immobilized on the fabric surface showed an excellent antibacterial effect and outstanding laundering durability. Even after 50 consecutive laundering tests, the modified cotton fabrics still showed satisfactory antibacterial ability against both S. aureus and E. coli, which the bacterial reduction rates are all higher than 96 %. It is believed that this methodology has potential applications in a wide variety of textile productions such as sportswear, socks, and medical textiles.