Surface characterization of sputter silver-coated polyester fiber

The present study concerns modification of surface of polyester fiber by magnetron sputtering using a silver (Ag) target. A detailed characterization of the silver-coated polyester fiber was investigated by scanning electron microscopy (SEM), X-ray diffraction technique (XRD) and X-ray photoelectron spectroscopy (XPS). The results revealed the remarkable changes in the surface morphology and microstructure of silver film on polyester fiber after sputtering for 10 and 30 min respectively. The SEM results showed that the silver particles were uniformly and densely deposited on the surface of polyester fiber. The XRD pattern of silver coated fabric showed that silver film is polycrystalline structure and dominated by the very strong (220) peak. Depth profiling results of silver coated fabric by XPS indicated that mainly metallic silver is existed throughout the whole depth region.     

Management of silver scurf (Helminthosporium solani) with fungicide seed treatments and storage practices

Thiabendazole insensitive strains ofHelminthosporium solani, the causal agent of silver scurf, make controlling the disease with seed treatment difficult. Potato tuber seed treatments and environmental storage management practices were investigated as means to minimize silver scurf. Fungicide seed treatments were evaluated for control ofH. solani; disease was evaluated during the growing season, at harvest, and after 5 months of storage. Silver scurf was observed on progeny tubers eleven weeks after planting. Fungicides that reduced silver scurf incidence and severity on the seed resulted in reduced incidence and severity of the disease in the progeny tubers at harvest and significantly lower disease ratings after storage. Only small increases in disease incidence (0-8%) were seen after storage. Thiophanate-methyl with mancozeb, Captan with mancozeb, and fludioxonil were among the most effective in reducing the incidence and severity of silver scurf on seed and in progeny tubers (Incidence on progeny tubers at harvest for these three treatments were 3%, 9%, and 8% respectively). Thiophanatemethyl alone was not effective for control of silver scurf (48% incidence compared to 43% incidence for the untreated control). Environmental conditions in storage affected disease development. Reduced humidity (85%) during the curing period (0–3 weeks after harvest) significantly reduced (11%) the surface area of tubers infected with silver scurf. Free moisture on the tuber surfaces during storage significantly increased (15%) tuber surface area infection.H. solani was shown to survive in soil and on some potato storage building materials for up to 9 months. The silver scurf disease of potatoes can be suppressed using effective seed treatment and storage management.     

The effect of alkali pre-treatment on formation and adsorption of silver nanoparticles on cotton surface

This study is an attempt to investigate the feasibility of alkali pre-treatment to activate surface hydroxyl groups of cellulose fibers in order to enhance the deposition efficiency of silver nanoparticles (AgNPs) onto cotton fabrics. Cotton samples were pre-treated with various alkali solutions containing different earth metal hydroxides (LiOH, NaOH, and KOH). The as-prepared samples were then treated with aqueous silver nitrate followed by reduction treatment with aqueous ascorbic acid, which caused in situ formation of AgNPs on fiber surfaces. The surface structure of the fabrics was characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) analysis, and colorimetric data. The amount of silver was measured by using inductively coupled plasma-optical emission spectrometer (ICP-OES). Antimicrobial activity was measured against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria. It was established that alkali pre-treatment had a substantial effect on the formation and adsorption of AgNPs on the fibers. Alkali pre-treated samples were homogeneously coated by AgNPs with high surface coverage. Alkali type had significant effect not only on the amount of AgNPs on the surface but also on its size. High antibacterial activity against both Gram-positive and Gram-negative strains was also demonstrated, even after 10 cycles washing.     

Comparative Performance of Copper and Silver Coated Stretchable Fabrics

The present work described the development of multifunctional, electrically conductive and durable fabrics by coating of silver and copper particles using a dipping-drying method. The particles were directly grown on fabric structure to form electrically conductive fibers. Particles were found to fill the spaces between the microfibers, and were stacked together to form networks with high electrical conductivity. The electrically conductive fabrics showed low resistance with high stretch ability. The utility of conductive fabrics was analyzed for electromagnetic shielding ability over frequency range of 30 MHz to 1.5 GHz. The EMI shielding was found to increase with increase in concentration of copper and silver particles. Furthermore, the heating performance of the copper and silver coated fabric was studied through measuring the change in temperature at the surface of the fabric while applying a voltage difference across the fabric. The maximum temperature (119°C for silver and 112°C for copper) were obtained when the applied voltage was 10 V. Moreover, the role of deposited particles on antibacterial properties was examined against pathogenic bacteria such as Staphylococcus aureus and Escherichia coli. At the end, the durability of coated fabrics was examined against several washing cycles. The fabrics showed good retention of the particles, proved by small loss in the conductivity of the material after washing.     

Polyester metallisation with electroless silver plating process

In this paper, electroless silver plating process for polyester was reported. The electroless silver plating is basically divided into four stages including pre-cleaning, sensitisation, electroless silver deposition and post-treatment. As the electroless silver plating stage is the key stage in affecting the brilliant appearance and various functional properties such as conductivity and ultra-violet protection, we will study the effect of process variables, i.e. amount of silver nitrate (AgNO₃), concentration of ammonium hydroxide (NH₄OH), concentration of sodium hydroxide (NaOH) and process temperature, using increased amount of silver in fabric surface as an indicator, for optimising the electroless silver plating process for possible industrial application. Experimental results revealed that amount of silver nitrate (AgNO₃)=1.77×10^?3 mole; concentration of ammonium hydroxide (NH₄OH)=6.25 %; concentration of sodium hydroxide (NaOH)=0.008 g/ml and process temperature=25 °C can give the best electroless silver plating for polyester fabric. The surface characteristics of the electroless silver-plated polyester fabric were evaluated by scanning electron microscope, X-ray photoelectron spectroscopy and X-ray diffraction analysis. Meanwhile, the performance properties of the electroless silver-plated polyester fabric were measured by CIE L*, a* and b* values, conductivity as well as ultraviolet protection. The experimental results would be discussed thoroughly in this paper.     

Screen printed silver patterns on functionalised aramid fabric

In this work, a simple and low cost method based on screen printing is presented to synthesize a conductive silver pattern on aramid fabric. The aramid fiber was treated with (3-mercaptopropyl)-trimethoxysilane to introduce a tail mercapto group promoting the ordered binding of silver nanoparticles. SEM and AFM images indicated a uniform distribution of silver nanoparticles on fiber surface. FTIR and XRD patterns confirmed the silver layer on the fibers. Furthermore, the electrical property of conductive fiber was characterized by conductive AFM and a digital multimeter, the surface resistance of conductive fabric was as low as 0.20 Ω/cm. And single fiber tensile test indicated that the mild treating process has no significant influence on the mechanical properties of the fiber.     

Investigation of mechanical properties of developed antimicrobial PPsuture/Ag nanocomposite

In order to prevent surgical complications due to microbial infections, we have developed polypropylene suture grafted with silver nanoparticles (PPsuture/Ag nanocomposite) by a simple immersion procedure. Physical and mechanical properties of developed suture are investigated. Suture surface characteristics are examined by scanning electron microscopy (SEM) imaging and atomic force microscopy (AFM). Silver content on suture surface was determined by Inductively coupled plasma atomic emission spectroscopy (ICP-AES). The mechanical properties of developed antibacterial PP suture/Ag were studied. We note that proposed silver coating method has not affected mechanical performances of suture. Antimicrobial performances of PP suture/Ag nanocomposites against S. aureus and E. coli colonies were also investigated.     

Application of silver nanoparticles as an antibacterial mordant in wool natural dyeing: Synthesis,antibacterial activity,and color characteristics

Madder is a natural colorant which is commonly applied with metal salts as a mordant to improve its affinity to fibers and color fastness. Madder produces an insoluble complex or lake in the presence of metal ions on mordanted fabric. In this study, wool fabric was pretreated with AgNPs (silver nanoparticles) as a mordant, then dyed with madder. The wool fabric samples were examined by scanning electron microscopy (SEM) and their colorimetric characteristics were evaluated. The formation of spherical silver nanoparticle was confirmed using UV-Visible spectroscopy, SEM images, and elemental analysis. The average size of synthesized silver nanoparticles on the surface of wool fibers is around 73 nm. The dyed wool samples were pretreated with different concentration of Ag⁺ ions or AgNPs, which showed higher color strength value compared to untreated dyed wool fabric. This pretreatment also presented good antibacterial activity.     

Tunable functional properties on polyester fabric using simultaneous green reduction of graphene oxide and silver nitrate

Here, a novel method is introduced to create tunable properties on the polyester fabric through diverse chemical modifications. The polyester fabric was primarily modified with NaOH or ethylenediamine to enhance the surface activity. This will produce diverse chemical groups on the polyester fabric surface including carboxylate, hydroxyl and amine groups. The fabric was treated with grahene oxide through exhaustion method. The silver nitrate was then added and simultaneously reduced with grapheme oxide using ascorbic acid and ammonia to produce reduced graphen oxide/silver nanocomposites (rGO/Ag) on the fabric surface. The synthesized nanocomposites were characterized by TEM and Raman spectra. The presence and uniform distribution of the nanocomposites on the fabric surface was also confirmed by SEM images and EDX patterns. The electrical resistivity was varied on the raw and modified polyester fabric due to the diverse formation of the graphene nanosheets network on the fabric surface. More Ag particles were formed on the surface of the alkali hydrolyzed polyester whereas more graphene nanosheets deposited on the aminolyzed polyester fabric. Also the hydrolyzed polyester fabric exhibited higher antibacterial properties with the lowest silver nitrate in the processing solution. The aminolyzed fabric showed a lower electrical resistance than the hydrolyzed and raw fabrics with the same amount of GO in the procedure bath. The aminolyzed polyester fabric indicated higher affinity towards GO produced higher antibacterial properties before reduction and without silver nitrate however lower electrical resistance obtained after reduction comparing with other samples.     

Low temperature suspension polymerization of methyl methacrylate for the preparation of high molecular weight poly(methyl methacrylate)/silver nanocomposite microspheres

In order to prepare high molecular weight poly(methyl methacrylate) (PMMA)/silver nanocomposite microspheres, methyl methacrylate was suspension-polymerized in the presence of silver nanoparticles at low temperature with 2,2′-azobis(2,4-dimethylvaleronitrile) as an initiator. The rate of conversion was increased by increasing the initiator concentration. When silver nanoparticles were added, the rate of polymerization decreased slightly. High monomer conversion (about 85 %) was obtained in spite of low polymerization temperature of 30°C. Under controlled conditions, PMMA/silver microspheres with various number-average degrees of polymerization (6,000–37,000) were prepared. Morphology studies revealed that except for normal suspension microspheres with a smooth surface, a golf ball-like appearance of the microspheres was observed, due to the migration and aggregation of the hydrophilic silver nanoparticles at the sublayer beneath the microsphere’s surface.     

Antibacterial properties of PLA nonwoven medical dressings coated with nanostructured silver

In this paper, magnetron sputtering was applied to deposit nano-structured silver films on the surfaces of polylactic acid (PLA) nonwovens, which were used in medical dressings. The influence of the coating thickness of the nano-structured sliver films on the antibacterial property of the nonwovens was studied. The antibacterial properties of the medical dressings were measured by shake flask test. The surface morphology of nano-structured silver films and the grain sizes of silver agglomerates were analyzed by atomic force microscope (AFM). Energy dispersive X-ray (EDX) was employed to analyze the surface elemental compositions. The study revealed that the antibacterial properties were improved as the film thickness increased. AFM images of the coated samples indicated that as the sputtering time prolonged, the film thickness was increased, the film became compacter, and the specific area of the film was also increased. Thus, the release rate of silver ions increased, leading to the improved antibacterial property. It was found that the reduction percentage of both tested bacteria-Staphylococcus aureus and Escherichia coli reached 100 % as the coating thickness exceeded 1 nm.     

Surface modification of polyester fibers by thermal reduction with silver carbamate complexes

In this study, the surface of polyester fiber was modified by means of thermal treatment with a silver carbamate complex. We used scanning electron microscopy (SEM), an X-ray diffraction technique (XRD), and X-ray photoelectron spectroscopy (XPS) to allow a detailed characterization of the silver-coated polyethylene terephthalate (PET) fibers. The results revealed remarkable changes in the surface morphology and microstructure of the silver film after thermal reduction. On SEM, the silver nanoparticles (AgNPs) were seen to be uniformly and densely deposited on the fiber surface. The XRD pattern of the silver-coated fiber indicated that the film has a crystalline structure. A continuous layer of AgNPs, between 30 and 100 nm in size, was assembled on the PET fibers. The PET/Ag composite was found to impart high conductivity to the fibers, with an electrical resistivity as low as 0.12 kΩ·cm.     

One-step continuous coating of silver nanoparticles on well aligned fibers of PAI/PTACM

Highly aligned ultrafine fibers of Poly (amide-co-imide) PAI (torlon)/Poly (trimellitic anhydride chloride-co-4, 4′-methylene dianiline) (PTACM) blends have been prepared by using mechano-electrospinning. Employing a mixed solvent system of DMSO and THF alongwith water coagulation bath as a medium, continuous fibers with improved mechanical properties have been obtained. The continuity of the fibers is strongly dependent on the solvent mixing ratio of DMSO and THF (6:4). Continuous fibers with the most uniform diameter are obtained when a 30 % of PAI and PTACM (1:1) resins by weight is used in the blending solution. The aligned fibers are further coated with silver nanoparticles using a one-step process by passing the electrospunned fibers through PEG solution and a silver precursor solution followed by reduction in a continuous process. The advantage of our method lies in a uniform silver coating on a single fiber that can be coated continuously on a larger length scale (～Km). The mechanical properties of these fibers are dramatically improved after their alignment. Better electrical conductivity is obtained for these fibers after they are coated with silver nanoparticles. The highly aligned silver decorated fibers utilizes a novel electroless continuous process using Polyethylene glycol (PEG), which shows good binding properties and can be used for various bio and electronic applications.     

Synthesis of silver nanoparticles with sericin and functional finishing to cotton fabrics

This research presents a novel strategy to fabricate multi-functional cotton textiles. In this study, silver nanoparticles-sericin (Ag NPS-sericin) hybrid colloid has been prepared using sericin as reducing agent and dispersing agent. Cotton fabrics was oxidized selectively with sodium periodate (NaIO₄) to generate oxidized cotton fabrics, and which has then been finished using Ag NPS-sericin hybrid colloid prepared to obtain multi-functional cotton textiles. The finished cotton fabric not only possessed excellent antibacterial activity, but also it was modified functionally by sericin protein, which endowed antibacterial cotton fabrics relatively smooth surface and good wear ability. Fourier transform infrared spectrogram confirmed that sericin protein was grafted onto cellulose fibers. Ag NPs were characterized by UV-Vis spectroscopy, transmission electron microscope (TEM) and X-ray powder diffraction (XRD). The results of SEM, X-ray photoelectron spectroscopy (XPS) and EDS confirmed that silver nanoparticles and sericin been loaded successfully on the surface of cotton fabrics. The antibacterial experiments showed bacterial reduction rates of S.aureus and E.coli were able to reach above 99 %. After washing 20 times, it showed still good antibacterial activity at over 95 % against S.aureus and E.coli.     

Surface characterization of aromatic thermotropic liquid crystalline fiber deposited by nanostructured silver

Nanostructured silver thin films were sputtered onto the aromatic thermotropic liquid crystalline fibers of Vectran by magnetron sputtering technology. Plasma treatment was used as pre-treatment in order to improve the deposition of the coating layer. Surface morphology of the coated fibers was examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). A full energy dispersive X-ray analysis (EDX) was used to detect the elemental composition of the material. Its conductivity and mechanical properties were measured and analyzed as well. The study revealed that a very thin conductive silver deposition exhibited high electrical conductivity as well as less influence on the mechanical properties of the pre-treated Vectran fiber. The plasma treatment could improved the deposition of the coating layer, but the surface roughness caused by plasma treatment also affected the surface conductivity. It was found that the surface resistivity could reach very low value of 1.66×10⁻³ Ω·cm after sputtering deposition for 30 min.     

Antibacterial effect of carbon nanofibers containing Ag nanoparticles

Silver nanoparticles imbedded in polyacrylonitrile (PAN) nanofibers and converted into carbon nanofibers by calcination was obtained in a simple three-step process. The first step involves conversion of silver ions to metallic silver nanoparticles, through reduction of silver nitrate with dilute solution of PAN. The second step involves electrospinning of viscous PAN solution containing silver nanoparticles, thus obtaining PAN nanofibers containing silver nanoparticles. The third step was converting PAN/Ag composites into carbon nanofibers containing silver nanoparticles. Scanning electron microscopy (SEM) revealed that the diameter of the nanofibers ranged between 200 and 800 nm. Transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) showed silver nanoparticles dispersed on the surface of the carbon nanofibers. The obtained fiber was fully characterized by measuring and comparing the FTIR spectra and thermogravimetric analysis (TGA) diagrams of PAN nanofiber with and without imbedded silver nanoparticles, in order to show the effect of silver nanoparticles on the electrospun fiber properties. The obtained carbon/Ag composites were tested as gram-class-independent antibacterial agent. The electrosorption of different salt solutions with the fabricated carbon/Ag composite film electrodes was studied.     

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.     

Application of silver nanoparticles to cotton fabric as an antibacterial textile finish

A novel nano-silver colloidal solution was prepared in one step by mixing AgNO₃ aqueous solution and an amino-terminated hyperbranched polymer (HBP-NH₂) aqueous solution under vigorous stirring at room temperature. All results of Dynamic Light Scattering (DLS), Transmission Electron Microscopy (TEM) and UV/Visible Absorption Spectrophotometry indicated that silver nanoparticles had been formed in colloidal solution. Cotton fabric was treated with nano-silver colloid by an impregnation method to provide the cotton fabric with antibacterial properties. The whiteness, silver content, antibacterial activity and washing durability of the silver-treated fabrics were determined. The results indicated that the silver-treated cotton fabric showed 99.01 % bacterial reduction of Staphylococcus aureus and 99.26 % bacterial reduction of Escherichia coli while the silver content on cotton was about 88 mg/kg. The antimicrobial activity of the silver-treated cotton fabric was maintained at over 98.77 % reduction level even after being exposed to 20 consecutive home laundering conditions. In addition, the results of scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) confirmed that silver nanoparticles have been fixed and well dispersed on cotton fabrics’ surface and the major state of the silver presented on the surface was Ag⁰.     

Preparation of poly(acrylonitrile)-grafted silk fibers with antibacterial properties

This study is focused on investigating the feasibility of using silver(I) ions loaded poly(acrylonitrile)-grafted silk fibers as antibacterial dressing material. The optimum grafting conditions for ceric ammonium nitrate induced graft-copolymerization of acrylonitrile onto silk fibers were found to include initiator concentration of 35 mM, catalyst HNO₃ concentration of 0.40 M and initiation time of 10 min. The poly(acrylonitrile)-grafted silk fibers were loaded with silver(I) ions by equilibration method. The resulting fibers were investigated for their biocidal action against E. coli, by using zone inhibition and colonies counting method.     

Facile procedure for producing silver nanocoated cotton gauze and antibacterial evaluation for biomedical applications

We present a rapid, simple, convenient and cost-effective method for producing nanosized stable silver particles on cotton fibers with complete control of the silver loading level using a thermal reducing silver carbamate complex. Cotton gauze was coated with silver 2-ethylhexylcarbamate solution. Silver nanoparticles on the cotton gauze were characterized by energy dispersive X-ray spectroscopy and X-ray diffraction. Particle size and lattice image of the silver nanoparticles were studied by scanning electron microscopy. The antibacterial activity of the silver coated cotton gauze against Escherichia coli and Staphylococcus aureus, whole blood clotting and physical properties including vertical wicking test, water retention time and absorption of 0.9 % (w/v) saline were studied. Silver coated cotton gauze showed a faster blood clotting rate than the untreated cotton gauze. Cotton gauzes treated with two different silver concentrations (0.01 %, 0.1 %) showed slightly better saline absorption and they had better vertical wicking and water retention time than pristine cotton gauze.