Durable antimicrobial activity of fabrics functionalized with zeolite ion-exchanged nanomaterials against Staphylococcus aureus and Escherichia coli

Cotton fabric finished with β-cyclodextrin: Inclusion ability toward antimicrobial agent

In order to impart barrier properties against microorganisms and blood to 100% cotton fabrics and 55/45% woodpulp/polyester spunlaced nonwoven fabrics, samples are treated with chitosan and fluoropolymers using the pad-dry-cure and pad-cure meth ods, respectively. Antimicrobial activity of the samples is analyzed quantitatively by measuring the number of colonies of Staphylococcus aureus. Blood repellency is as sessed with an impact penetration test using synthetic blood. Laundering durability of the finishes is measured, and scanning electron microscopy is used to evaluate changes in the fabric surfaces. To investigate the effect of finishing on the hand and air per meability of fabrics, the mechanical properties of the samples are measured by the KES-FB system. Samples treated only with chitosan show a high reduction rate in the number of colonies. Dual finished specimens treated with 1.1 % chitosan concentration also maintain over 90% reductions in the number of colonies. The blood repellency of dual finished nonwoven fabrics is superior to that of dual finished cotton. Dual finished cotton fabrics exhibited durable antimicrobial activity with repeated laundering. As regards mechanical properties, bending rigidity and shear rigidity increase when cotton and nonwoven fabrics are treated only with chitosan, but these properties decrease after the fluoropolymer treatment. Air permeability of the specimens decreases slightly after the dual finish.

The fluorine-containing finishing agents commonly used for water repellent modification of cotton textile surfaces have been banned in most countries and regions because they have been proved to be seriously harmful to human beings and the environment, while non-fluorine hydrophobic modification of textiles suffers from the defect of non-durable performance. In this study, we propose a durable, fluorine-free and environmentally friendly approach for hydrophobic modification of cotton textiles: firstly, macromolecular polyurethane hydrophobes with vinyl groups are synthesized; subsequently, electron beam (E-beam) irradiation is used to generate reactive radicals on the surface of cotton fabrics, which triggers the graft polymerization of vinyl-based polyurethane (VPU) hydrophobes on the surface of the fabrics, resulting in the formation of covalently bonded, solid polyurethane hydrophobic layers on the surface of the fabrics. The hydrophobicity of the grafted cotton fabric was significantly improved and remained virtually unchanged after 20 accelerated washing cycles (equivalent to 100 times of household washing), which can be attributed to the robust covalent bonding between the hydrophobic polyurethane groups and the cotton fabric, thereby ensuring long-term stability of the hydrophobic performance. The scanning electron microscope (SEM) characterization and mechanical property test demonstrated that the radiation grafting of the macromolecule urethane hydrophobes had a small effect on the micro-morphology and mechanical properties of the cotton fabrics. The results of air permeability and moisture permeability of textiles proved that the method in this study can give better hydrophobicity to cotton fabric without affecting its air permeability and moisture permeability.

A study on the functionalization of cotton and viscose fabrics to achieve bifunctional conductive and antibacterial properties was carried out; 0.5 wt% AgNW ethanolic colloid was prepared, and fabrics were dipped and dried in the colloid 1, 10 and 15 times. After one dipping, both fabrics remained nonconductive, and the surface resistance (Rs) of cotton was 4.9 × 1010 and of viscose 3.6 × 1011 Ω. Excellent conductivity properties were shown in cotton fabric after 10 dippings (20 Ω) and in viscose fabric after 15 dippings (46 Ω). The Ag content of these fabrics was 53.3 and 52.3% (SEM/EDX analysis) and 13.77 and 14.12% (TG/DTG analysis) for cotton and viscose, respectively. XRD analysis revealed the presence of AgNWs on the fabric surface. FTIR/ATR, Raman and TG analysis confirmed the effects of modifications. The AgNW layers on both fabric surfaces were resistant to abrasion. After 50 washes of the modified cotton fabric, Rs increased from 20 to 195 Ω. The AgNW layer was stable and the fabric still highly conductive. However, viscose fabric became nonconductive after two washes, and the surface resistance increased from 46 to 1.4 × 1011 Ω. The tensile strength of cotton modified with AgNWs increased by about 49% and for viscose decreased by about 27%. AgNW-modified cotton fabric showed a significant antibacterial effect against S. aureus and K. pneumoniae bacteria. The presented method is more suitable for cotton because the modified cotton fabric retains the mechanical and conductive properties even after many washes.

Effect of the coating of zinc oxide (ZnO) nanoparticles with binder on the functional and mechanical properties of cotton fabric

Preparation of hybrid nanoparticles to enhance the electrical conductivity and performance properties of cotton fabrics

An extract obtained from Coleus Ambonicus was applied on cotton fabric by means of the exhaust, micro encapsulation and nano encapsulation methods, and the antimicrobial activity of the finished fabric assessed quantitatively by the AATCC test method 100 against gram positive (staphylococcus aureus) and gram negative (Escherichia coli) microbes. The finish applied on the the samples using all three methods exhibit a good bacterial reduction percentage. The finish applied on the samples using all three methods possesses a higher bacterial reduction percentage against gram positive microbes than gram negative, even after washing. The method of washing conforms to ISO method 3. The wash durability of the antimicrobial activity was assessed by the bacterial reduction percentage after washing. The wash durability of the samples using the direct exhaust method was very poor and it lost its antimicrobial activity after 10 wash cycles. The wash durability of the samples using the micro encapsulated method shows antimicrobial activity up to 10 wash cycles, dropping gradually to very low levels at 20 wash cycles. The wash durability of the samples using nano encapsulation shows good antimicrobial activity against both gram positive and gram negative microbes even after 30 washes

Reactive cyclodextrin (RCD) based nanoemulsion and loaded with coconut oil in presence of Tween 80 emulsifying agent for development of antimicrobial medical cotton fabrics is the subject of current research. RCD based nanoemulsion was prepared at different stirring duration, viz, 2, 4, 6 and 24 h in presence of Tween 80. This was done in order to induce varieties in size and morphology of the nanoemulsion. The coconut oil encapsulated RCD based nanocomposite was precipitated as powder using centrifugation technique for 60 min at 4500 rpm and the resulted powder was investigated using TEM and SEM techniques. The images that provided by these techniques confirmed the nano-sized scale of the coconut oil loaded RCD nanocomposite. In addition, the entrapment efficiency of coconut oil loaded RCD based nanoemulsion after centrifugation was calculated and was found to more than 93 %; this is a proof for the successful inclusion of the coconut oil inside the cavity of RCD molecules. Moreover, the obtained RCD based nanoemulsions were applied to bleached cotton fabrics as per the pad-dry-cure method. The as treated cotton fabrics were monitored for nitrogen content, add-on, mechanical properties and morphology vis-a-vis those similarly treated fabrics but using the as prepared microemulsion of RCD loaded with coconut oil in absence of Tween 80. The morphological structure of cotton fabrics treated with the nanoemulsion in question was also examined using SEM technique. Moreover, the biological activity of the nanoemulsion finished fabrics before and after being submitted to 20 washing cycles was investigated against different types of bacteria and fungi as per the inhibition zone method. Results obtained signify: (i) deposition on the fabric of coconut oil loaded RCD nanoemulsion; (ii) the add-on of the nanoemulsion on the surface of cotton fabric is a manifestation of the stirring duration, proofing the formation of ultrafine oil nanoemulsion which penetrates the fabric surface; (iii) the finished fabrics display antimicrobial activity with clear excellent inhibition zone even after 20 washing cycles, indicating the protection of these fabrics for human beings from harmful microbes. In conclusion, the cotton fabrics treated with nanoemulsion of RCD loaded coconut oil is considered as an effective super antimicrobial medical textile against pathogenic microorganisms of both bacteria and fungus species.

Fortification of cotton fabrics with dithiocarbamate-metal complexes to prepare durable antimicrobial fabrics

We developed an isocyanate group containing quaternary ammonium salt (IQAS) as a potential antimicrobial finishing agent that can be stored in a high purity form for more than a year in dry environments to permit convenient transportation and storage. Additionally, we report a facile and eco-friendly finishing technique to fabricate durable antimicrobial cotton fabrics using IQAS as an antimicrobial finishing agent by a dipping–padding–drying process. IQAS was bound onto the surface of cotton fabrics by a covalent bond to obtain a cotton fabric with excellent bactericidal activity, tearing strength, breaking elongation, bending rigidity, water vapor permeability, surface roughness and smoothness. The antimicrobial rates of these fabrics reached 92.2% and 98.5% against gram-negative bacterium Escherichia coli and gram-positive bacterium Staphylococcus aureus, respectively, even after 50 laundering cycles. These values are much higher than the reference antimicrobial rates of AAA class antimicrobial fabrics, as well as those of conventionally finished cotton fabrics, indicating that the IQAS finished cotton fabrics maintained excellent antimicrobial activity even after long-term repeated launderings. Moreover, the results indicate that the IQAS-treated cotton fabrics could improve the breaking strength (increased by 13.5% in the warp direction and 20.3% in the weft direction), the bursting strength (increased by 11.9%), the air permeability (increased by 12.6%) and the hydrophilicity compared to untreated cotton fabrics. Additionally, our non-leaching antimicrobial cotton fabrics treated with IQAS were non-toxic and showed no skin stimulation. Therefore, IQAS and the antimicrobial finishing technique reported here have great potential applications in antimicrobial fabrics used in hospitals, hotels and other susceptible situations. An isocyanate group containing quaternary ammonium salt that permits convenient transportation and storage was developed as a potential antimicrobial finishing agent to fabricate excellent antimicrobial cotton fabrics with well-preserved physical properties and security using a dipping–padding–drying process.

Two generations of poly (propylene imine) dendrimer with amino terminated groups (G2- and G5-PPI-NH2) were grafted on cotton cellulose fabric using cross linking agents (citric or glutaric acids). Fourier transform infrared (FTIR) spectroscopy identified ester groups which were formed between hydroxyl groups of the cotton fabric and carboxylic groups of the cross linking agents. Also, attenuated total reflectance-FTIR (ATR-FTIR) analysis confirmed formation of amide groups between the carboxylic groups of the cross linking agents and the amino end groups of the dendrimers. Nitrogen content (N-content) analysis revealed the presence of the dendrimers on the cotton fabric even after 5 washing cycles. In order to study the dispersion of the PPI dendrimers on the surface of the cotton fabric, field emission scanning electron microscopy (FE-SEM) was performed. The particle size distribution of the G2- and G5-PPI-NH2 aqueous solutions was also determined by dynamic light scattering (DLS) analysis. Antimicrobial activity of the PPI dendrimer aqueous solutions and the cotton cellulose fabric grafted with the dendrimers was evaluated both quantitatively and qualitatively against Gram-positive bacterium (Staphylococcus aureus), Gram-negative bacteria (Pseudomonasaeruginosa and Escherichia coli) and fungus (Candida albicans). The dendrimer grafted cotton cellulose fabric exhibited a 99 % reduction in bacterial counts against S. aureus, E. coli and C. albicans. The antimicrobial activities of the grafted cotton cellulose fabric with the PPI dendrimers were maintained even after 5 washing cycles.

The influence of 3, 10 and 50 washing cycles on the properties of cotton fabric and cotton-polyester blend in plain weave, was investigated in this study. In addition to the analysis of tensile properties in weft and warp directions and thickness, the number of particles produced in the dry state was also measured after 3, 10 and 50 washes. After washing, the entire effluent was analysed by determining the total suspended solids (TSS), the total solids (TS), the pH value and the conductivity. To determine the similarity of the observed wash cycles and properties of all processed samples, hierarchical cluster analysis (HCA) was performed. The fabric changes indicated by total wear in the warp direction after 50 washing cycles compared to unwashed ones amounting to 41.2% for cotton and 30.9% for cotton-polyester blend, may be attributed to the synergy of washing factors and raw material composition. Cotton fabric produced significantly more particles than cotton-polyester fabric in the dry state after the examined washing cycles in all size categories. A smaller number of released particles are in the larger size category >25 μm. The obtained TSS values confirm the degree of loading of the effluent with particulate matter from the analysed fabrics, since the detergent consists of water-soluble components. The HCA dendrograms confirmed that the release of particles during the first washing cycles is mainly determined by the structural properties of fabrics, while in the subsequent cycles the synergistic effect of chemical, mechanical and thermal effects in the interaction with the material prevailed.

Oil spill accidents on the sea and oily wastewater produced in daily life have posed serious threats to the environment. Therefore, there is an urgent need for a material that can effectively separate these mixtures using simple operations. Herein, an ecofriendly sandwich-structured coating with excellent superhydrophobic/superoleophilic properties was fabricated by in situ growth on copper mesh and cotton fabric substrates. Specifically, using the versatility of tannic acid (TA) film, including chelation and reduction with Cu2+, flower-like Cu2S@CuO can be in situ grown on a copper mesh or fabric surface. Then, the Schiff base reaction between TA and octadecylamine is used to hydrophobically modify the surface. Water contact angle (WCA) of the sandwich-structured TA-Cu2S-TA-ODA-coated copper mesh and fabric can reach 160.8 and 156.3°. The coated copper mesh can be folded into a miniature container to collect oil, with collection efficiency reaching 96.47%. And the collection efficiency can be above 90% even after 10 cycles, and its WCA is still 155°. Besides, it can quickly separate various oils. Even for highly viscous peanut oil, the separation efficiency and flux can reach 90.7% and 0.038 mL·cm-2·s-1, respectively, which are much higher than those reported by other similar studies. Furthermore, the coating can endow cotton fabrics with excellent UV-shielding performance compared to the original cotton fabrics. In particular, even after 100 tape peeling tests, 7 washing cycles, 1 h of continuous strong UV irradiation, or 24 h of organic solvent soaking, the sandwich-structured TA-Cu2S-TA-ODA coating still has superhydrophobic properties.

Studies on eco-friendly antibacterial agents based on bioactive ingredients extracted from natural products for textile application is gaining worldwide interest. In the current paper, an ethanolic extract of Pelargonium hortorum (Geranium) leaves was used to impart antibacterial finishing to cotton fabric. The bioactive compounds of the extract were identified. The extract was microencapsulated using eco-friendly wall shell material such as sodium alginate ormypro gum. The microcapsules forms were examined by light and TEM microscopes whereas the shape of microcapsules on the fabric surface was identified by SEM microscope. Cotton fabrics were treated with the microencapsulated extract by the pad-dry-cure method. Cotton samples treated with microencapsulated extract were post treated with citric acid or binder to fix the microcapsules on the fabric. The microencapsulated extract treated cotton showed antibacterial efficacy against both Escherichia coli(gram negative bacteria) (-ve) and Staphylococcus aureus (gram positive bacteria)(+ve). The treated fabric also showed anti-inflammatory efficacy. Effectiveness of finishing was accessed by determined numbers of washing cycles and the treated fabric retained an effective antibacterial property after 10 washing cycles. The effect of the treatments on the physio-mechanical properties of the treated fabrics was measured.

Effect of lipase on removal of lard from a cotton fabric by detergency was studied in detail by radioisotope and X‐ray microanalysis over 60‐min washing. Osmium tetroxide was used to label the soil for microscopy. Backscattred electron images were used to study residual soil present on and within the cotton fibers and in the interfiber spaces of the yarn bundle. Lard‐soiled samples had large deposits on the fabric surfaces; oil was present in the crenulation, secondary walls, and the lumen of the fibers. Relative concentrations of oil were determined for selected morphological locations within the fiber structure and at the fiber surface using X‐ray microanalysis. Specimens soiled with lard and tagged with osmium tetroxide immediately from the wash bath at 0, 5, 10, 20, and 60 min provide snapshots of the washing process. Within the yarn structure, domains with high oil concentration developed during washing. These domains were not adsorbed onto the fiber surfaces, but were contained within the twisted yarn structure. The inclusion of lipase “accelerates” the washing process with the dislodgment of the soil from the fiber surface being more complete for the yarn specimens washed with lipase for 20 and 60 min. The three main stages of the soil‐removal process—transport of water and detergent to the soil on the substrate, separation of soil and substrate, and transport of dislodged soil into the wash bath—were observed. Lipase functions in detergency by hydrolysis of triglycerides forming mono‐ and diglycerides and fatty acids that are more soluble in water, can undergo soap formation, enhance mesomorphic phase formation, and increase emulsification. The quantification of the mass of the residual oil is well‐defined using the radioisotope methodology. The effectiveness of lipase on removal of lard stains is observed at all points in the washing cycle (5, 10, 20, 60 min). Our data fit a classical kinetic description of the soil‐removal process described by an exponential decay, with the presence of lipase greatly increasing the rate of oil removal during the early period of washing (0 to 20 min). With the use of lipase in the washing bath, the amount of soil removal after 10 min is about the same as observed after washing 60 min with detergent only. Washing removes soil located on the fibers and yarns on the fabric surfaces early in the process and more completely. Soil that is located within the yarn structure is removed by washing but this requires more time, and lard removal from these interfiber capillaries is greatly enhanced by use of lipase. Washing does remove soil from within the cotton fiber, i.e. secondary wall and lumen, and this is also more complete with the use of lipase. After washing with a detergent for 60 min, the highest concentration of residual soil is in the lumen, although the concentration has been reduced by a factor of two. It appears that the lumen is the last region of the cotton fabric structure to be cleaned by laundering. The use of lipase in the wash bath increased the rate of soil removal for all locations with the cotton fabric and fiber structures.