Electrostatic self‐assembly dyeing of cotton fabrics

A new approach to the dyeing of cotton fabrics using an electrostatic self‐assembly method was evaluated. Cotton fabrics were pretreated with 2,3‐epoxypropyltrimethylammonuium chloride and cationic charges were produced on the fabric surfaces. For the dyeing of cotton fabric, reactive and acid dyes were used. Oppositely charged anionic reactive/acid dyes and cationic poly(diallyldimethylammonium chloride) were alternately deposited on the surface of cationised cotton fabrics. Ten multilayer films of dye/poly(diallyldimethylammonium chloride) were deposited on the cotton fabric surfaces using a padder. The build‐up of the multilayer films and the level of colour strength (K/S) achieved are discussed. Samples of cotton fabrics were also dyed with the same dyes, but using the exhaust method, and both types of dyed samples were compared. The washing, rubbing and light fastness properties were evaluated for the dyed fabrics.     

Modifying of Cotton Fabric Surface with Nano-ZnO Multilayer Films by Layer-by-Layer Deposition Method

ZnO nanoparticle–based multilayer nanocomposite films were fabricated on cationized woven cotton fabrics via layer-by-layer molecular self-assembly technique. For cationic surface charge, cotton fabrics were pretreated with 2,3-epoxypropyltrimethylammonium chloride (EP3MAC) by pad-batch method. XPS and SEM were used to examine the deposited nano-ZnO multilayer films on the cotton fabrics. The nano-ZnO films deposited on cotton fabrics exhibited excellent antimicrobial activity against Staphylococcus aureus bacteria. The results also showed that the coated fabrics with nano-ZnO multilayer films enhanced the protection of cotton fabrics from UV radiation. Physical tests (tensile strength of weft and warp yarns, air permeability and whiteness values) were performed on the fabrics before and after the treatment with ZnO nanoparticles to evaluate the effect of layer-by-layer (LbL) process on cotton fabrics properties.     

Durable UV-protective cotton fabric by deposition of multilayer TiO<Subscript>2</Subscript> nanoparticles films on the surface

Durable ultraviolet (UV)-protective cotton fabric has great application potential in outdoor cotton clothing. In this study, oppositely charged TiO₂ nanoparticles were deposited onto cotton fabric through the layer-by-layer self-assembly technique, resulting in multilayer films with UV-protective properties. The mechanism of the technology has been investigated through characterization of the structure and properties using different techniques including FTIR, UV–Vis spectroscopy, and a scanning electron microscope with an energy-dispersive X-ray spectrum. The results showed that TiO₂ nanoparticles distributed uniformly on the surface of cotton fibers. The TGA results indicated that the TiO₂ nanoparticles deposit on cotton fabrics had little effect on the thermal stability of cotton fabrics. The tensile strength and air permeability of the cotton samples were tested by a universal material testing machine and automatic ventilation instrument. The UV protection property of cotton fabric after assembled multilayer films was measured by an ultraviolet transmittance analyzer, and the laundering experiments were carried out to determine the durability of TiO₂ nanoparticles on cotton fabric. The results showed that the UV protection property of cotton fabrics after assembled TiO₂ nanoparticles was still maintained at a high level after five launderings.     

Dual responsive wool fabric by cellulose nanowhisker reinforced shape memory polyurethane

Shape memory wool fabrics having both temperature and moisture responsiveness were fabricated by a functional nanocomposite treatment comprising of shape memory polyurethane (SMPU) and cellulose nanowhisker (CNW). Water vapor permeability and sweat absorption properties were investigated under different temperature or relative humidity values to test smart comfort capabilities of the treated fabrics. Besides, felting shrinkage and weight loss of the fabrics after repeated washing cycles were investigated for end use performance. It was found out that the wool fabrics functionalized by nanocomposite treatments exhibited dynamic breathability and sweat absorption changing with temperature and relative humidity of body or environment. Moreover, nanocomposite application enhanced rigidity, tear strength, anti-felting and weight loss performances of the wool fabric. 20 wt% CNW concentration can be suggested for thermal comfort, mechanical and end use performance enhancements to obtain smart garments having dynamic responsiveness to both body physiological and environmental changes. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 137, 48674.     

Dendronized polymer as building block for layer-by-layer assembly: Polyelectrolyte multilayer films for incorporation and controlled release of water-insoluble dye

The multilayer films of the carboxylic acid terminated Fréchet-type dendronized polymer (denpol) and poly(diallyl-dimethylammonium chloride) (PDDA) were fabricated using the electrostatic layer-by-layer (LbL) assembly technique on planar substrates. The influence of pH and ionic strength of the polyelectrolyte dipping solutions on the fabrication of the PDDA/denpol multilayer films has been investigated in detail. AFM images showed that pH of the polyeletrolyte dipping solutions can obviously influence the surface morphology and roughness of the denpol layer in the multilayer films. We also use a preassembly method for incorporating water-insoluble molecule of pyrene into interior of denpol, and then fabricate the PDDA/pyrene-loaded denpol multilayer films. Moreover, we demonstrated that the loaded pyrenes can be released from the LbL films, which can be controlled by ionic strength of immersing solutions. Interestingly, the pyrene-released multilayer film can be used to reload pyrene when immersing the pyrene-released film into a saturated aqueous solution of pyrene.     

自组装聚电解质薄膜的低角度X射线衍射研究

采用静电自组装技术在单晶硅和石英玻璃基片上制备了阳离子聚电解质PDDA和阴离子聚电解质PS-119的多层复合薄膜,对薄膜作低角度X射线衍射分析,得到清晰的Kiessig衍射曲线,根据衍射曲线估算了薄膜的厚度。自组装PDDA/PS-119薄膜的层状结构特征不明显,聚电解质单层的厚度可以控制在1nm上下,双层的厚度可以控制在2nm左右,薄膜的总厚度与聚电解质水溶液的浓度有关,与薄膜的双层数成比例关系。     

Mothproofing of wool fabric utilizing ZnO nanoparticles optimized by statistical models

Wool with high strength, elasticity, and resiliency has good dye-ability and comfort however could be digested by keratinolytic enzymes. In this research, wool fabric pre-treated with BTCA and then treated with nano ZnO. The treated fabrics showed mothproofing activity against the larvae of carpet beetle, Anthrenus verbasci, as feeding protein fibers. The role of both BTCA and nano ZnO concentrations on mothproofing properties of the wool fabric were optimized using statistical model of response surface methodology (RSM). Mothproofing was investigated through assessing wool weight loss during feeding by A. verbasci. The analysis of variance (ANOVA) was utilized to obtain the optimum models for wool with mothproofing properties. The damages on the wool surface confirmed with scanning electron microscopy and digital camera images. Further transmission and absorbance spectra approved the UV protection properties of the nano ZnO treated wool in both UVA and UVB.     

Effect of in situ deposition of calcium carbonate in cotton fiber on its mechanical properties

In this study, in order to improve mechanical properties of cotton fabrics, nano-micro sized calcium carbonate (CaCO₃) was deposited in situ on cotton fabrics. The mechanical properties, surface morphology, crystalline index, infrared spectrum, thermal property, and wettability of the deposited fabrics were measured and discussed. The results showed that the breaking strength of cotton fabric increased by about 10% after in situ deposition of nano-micro calcium carbonate. After ultrasonic washing, the strength of cotton fabric deposited CaCO₃ was still increased by about 10%. The crystallinity of the cotton fabric deposited with calcium carbonate increased from 76% to 84%. The hydrogen bond between cellulose molecules and calcium carbonate was confirmed by infrared spectroscopy. The hydrophilicity and thermal properties of cotton fabric were not significantly influenced by calcium carbonate deposition. This provides a new idea for improving the mechanical properties of cotton fabric.     

ITO electrode modified by self-assembling multilayer film of polyoxometallate on poly(vinyl alcohol) nanofibers and its electrocatalytic behavior

Poly(vinyl alcohol) (PVA) nanofiber mats were collected on indium tin oxide (ITO) substrate by electrospinning method. A multilayer film composed of α-[P₂W₁₈O₆₂]⁶⁻ (abbr. P₂W₁₈), a polyoxometallate (POM) anion, and poly(diallymethylammonium chloride) (abbr. PDDA) was fabricated by layer-by-layer (LBL) self-assembly technique on the PVA/ITO electrode. The PDDA/P₂W₁₈ multilayer film could be unselectively or selectively deposited on the PVA/ITO electrode via changing the amount of PVA nanofibers on the ITO substrate. The scanning electron microscope (SEM) images showed that when the electrospun time was short the PDDA/P₂W₁₈ multilayer film was unselectively deposited on PVA nanofiber mats because the amount of PVA nanofibers was too little to cover most of the ITO substrate. However, when the electrospun time was long enough, the PDDA/P₂W₁₈ multilayer film was selectively deposited on PVA nanofiber mats because of the larger surface area and higher surface energy of PVA nanofibers in comparison with the flat ITO substrate. Growth process of the multilayer film was determined by cyclic voltammetry (CV). Electrocatalytic effects of the PDDA/P₂W₁₈ multilayer film unselectively and selectively deposited on the PVA/ITO electrode on NO₂⁻ were observed.     

Surface modification of textiles by glow discharge technique: Part II: Low frequency plasma treatment of wool fabrics with acrylic acid

In this study, wool fibers are modified by low frequency plasma polymerization of acrylic acid regarding to its' hydrophobic character due to cuticular cells at their surfaces. Variables of the plasma glow discharge processes were power (40–100 W) and exposure time (5–45 min). The effect of plasma modification in the performance properties of wool were investigated on the basis of hydrophilicity of wool, average wrinkle recovery angle, and breaking strength. The surface chemical structures of fabrics were examined with x‐ray photoelectron spectroscopy. The hydrophobic wool fabric became hydrophilic after all plasma treatments except one (40W–5 min). Average wrinkle recovery angle of the treated fabrics were between 157 and 178°, while that of untreated fabric was 180°. The treated fabrics had a little bit lower angles according to the untreated fabric. However, even the lowest value as 157° means that the fabric has a good crease resistance property. The breaking strengths of fabrics were increased up to 26% after the plasma treatments. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

防紫外超疏水织物的制备及耐久性评价

采用全纳米颗粒自组装的方法,在棉、锦纶和涤纶织物上制备了TiO_2/SiO_2薄膜,再经十六烷基三甲基硅烷修饰,得到了兼具抗紫外及超疏水功能的多种织物。自组装过程中分别以SiO_2和Ti_2溶胶为原料,逐层于聚电解质表面处理的织物上组装了TiO_2/SiO_2多层薄膜。经扫描电子显微镜(SEM)测试表明,膜层均匀沉积在织物纤维表面。接触角测试表明,疏水处理后表面水的接触角可达172°。紫外可见分光光度计测试表明,经TiO_2/SiO_2修饰后,织物在紫外光区的吸光度成倍提高。用耐老化、耐摩擦、耐水流喷射等耐久性试验评价了织物在使用过程中可能遇到的各种破坏,证明自组装再经疏水剂处理的织物具有良好的耐久性。     

Composite graphitic nanolayers prepared by self-assembly between finely dispersed graphite oxide and a cationic polymer

Chemical flaking of graphite has been performed by reacting natural graphite with a strong oxidizing agent, NaClO₃/HNO₃. The formed hydrophilic, negatively charged graphite oxide (GO) colloids can be dispersed in water which allows the deposition of thin GO/cationic polymer (poly(diallyldimethylammoniumchloride, PDDA) multilayer films on a glass substrate by wet-chemical self-assembly. The feasibility of the charge-regulated layer-by-layer deposition is demonstrated by mutual charge titrations of the film-forming species. Visible-light spectroscopy revealed progressive growth of the film thickness with the number of deposition of steps, while XRD and AFM showed that partially exfoliated, highly anisometric (aspect ratio >50) graphite oxide platelet aggregates were deposited with an average thickness of the stacked graphite oxide platelets of 10 carbon layers (7.4 nm). Reduction of multilayer assemblies of GO and PDDA on glass yielded a non-conductive turbostratic carbon nanofilm. The original, conductive graphite-like structure was restored by reduction with N₂H₄ and annealing at 400 °C which, by gradual ordering of the carbon crystallites, caused a significant decrease in the resistivity.     

Application of a biopolymer chitosan-poly(propylene)imine dendrimer hybrid as an antimicrobial agent on the wool fabrics

In this research, chitosan-poly(propylene)imine dendrimer hybrid (CS-PPI) was applied to wool fabrics; and weight gain and antibacterial properties of the grafted wool fabric by CS-PPI were investigated. A response surface methodology employed for optimization of the important factors such as pH, processing time, and CS-PPI and cross-linking agent (CA) concentrations. The physical properties showed sensible changes regardless of weight gain. The maximum weight gain was obtained when the wool fabrics were treated with pH 5, processing time 24 h, CS-PPI 20 %(owf) and CA 5 % over weight of fiber (owf). Scanning electron microscopy analysis showed the presence of foreign particles determinedly fixed to the surface of the wool fabric. Fourier transform infrared spectroscopy and differential scanning colorimetry revealed the grafting of CS-PPI onto wool fabric by forming novel chemical bonds between the wool and CS-PPI molecules. The treated wool fabrics showed broad-spectrum antimicrobial activity against gram-positive and gram-negative bacteria. Antimicrobial activities of the treated wool by CS-PPI at a concentration of 20 % over weight of fiber (owf) demonstrated 100 % bacterial growth inhibition, which was preserved more than 84 % even after being washed in 12 various conditions repeatedly. The grafted wool fabrics have antibacterial potential due to the antibacterial property of CS-PPI molecules. The mechanism of CS-PPI grafting onto wool fabric using CA was proposed. The findings of this study support the potential production of the new environmentally friendly textile fibers.     

Sequentially adsorbed electrostatic multilayers of polyaniline and azo polyelectrolytes

In this study, multilayer films composed of alternate polyaniline (PANI) and azo-polyelectrolyte (PNACN, PPAPE, PNANT or PNATZ) layers were fabricated through the electrostatic layer-by-layer self-assembly scheme. In the electrostatic adsorption process, PANI was used as the polycation and the azo polyelectrolytes were used as the polyanion. The multilayer growth was monitored by UV-vis spectroscopy and optical ellipsometry. The photoresponsive and electrochromic properties of the multilayer films were studied by UV-vis spectroscopy and electrochemical measurement. Results show that the multilayer films exhibit linear increases in both the absorbance and film thickness with the increase of the deposition cycles. The thickness contributed by each individual layer depends on the pH of the PANI and azo-polyelectrolyte dipping solutions. The multilayer films can show photoinduced dichroic properties contributed by the azo-polyelectrolyte layers, but the ability to form surface-relief-grating (SRG) upon Ar⁺ laser irradiation is relatively weak. The multilayer films possess the characteristic absorption bands related to the azo chromophores and PANI. As the location of the PANI bands depends on its oxidation states, the multilayer films can show sensitive electrochromic variation. For instance, the PANI/PNACN multilayer films can undergo a transition from transparent yellow-green through deep green to opaque black when the potential changes from −0.1 to 0.8 V. It is demonstrated that using the azo polyelectrolytes with different hues, enriched spectrum of the colors can be obtained by the electrochemical transitions. The multilayer films containing both photoresponsive and electroactive components can be expected for applications in optics, photonic devices and others.     

Surface modification of TiO2/SiO2 composite hydrosol stabilized with polycarboxylic acid on Kroy-process wool fabric

Self-cleaning of wool fabric has been of increasing interest due to availability and practicability. In this paper, two kinds of wool fabrics, including raw wool and Kroy-process wool fabric, were successfully modified by TiO₂/SiO₂ gel stabilized by 1,2,3,4-butanetetracarboxylic acid (BTCA) and citric acid (CA), respectively. The optimum concentration of carboxylic acids and TiO₂/SiO₂ gel was decided by the crease recovery angles and total color difference (ΔE) values, respectively. The results revealed that wool fabrics treated with BTCA and TiO₂/SiO₂ had better wrinkle resistance in comparison with CA and TiO₂/SiO₂ treated samples. The decomposition of stains was studied using UV irradiation and the presence of TiO₂/SiO₂ gel demonstrated obvious self-cleaning property, in which the color of wool fabric was unchangeable. The hydrophilicity of Kroy-process wool fabric increased relative to raw ones. In addition, Scanning Electron Microscope images demonstrated the layer of TiO₂/SiO₂ nanoparticles coated on treated samples. In general, the adhesion properties coated to the fabric surface showed a slight loss even at harsh processing conditions, however, the anti-UV properties obviously increased due to the decrease in the fabric porosity. And the linkages between carboxylic acid and wool fibers were illustrated using FTIR pattern.     

Fastness and dyeability improvement of wool fabric pretreated with oxalate derivatives

Wool fabrics were pretreated with calcium and sodium oxalate in acidic and alkaline pH media. The pretreated and untreated fabric samples were then dyed in the same bath with acid dyes by the exhaustion technique. The pretreated fiber sample surfaces were observed using a scanning electron microscope. The color strength and fastness properties of the fabrics were investigated. The results of the study showed that pretreatment with oxalate derivatives can be used as a means of improving the dyeability of wool fibers. As the dyed, pretreated wool fabrics had higher color strength and fastness results than the untreated wool fabrics, the mechanical properties were affected negatively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Guided assembly of nanoparticles on electrostatically charged nanocrystalline diamond thin films

We apply atomic force microscope for local electrostatic charging of oxygen-terminated nanocrystalline diamond (NCD) thin films deposited on silicon, to induce electrostatically driven self-assembly of colloidal alumina nanoparticles into micro-patterns. Considering possible capacitive, sp² phase and spatial uniformity factors to charging, we employ films with sub-100 nm thickness and about 60% relative sp² phase content, probe the spatial material uniformity by Raman and electron microscopy, and repeat experiments at various positions. We demonstrate that electrostatic potential contrast on the NCD films varies between 0.1 and 1.2 V and that the contrast of more than ±1 V (as detected by Kelvin force microscopy) is able to induce self-assembly of the nanoparticles via coulombic and polarization forces. This opens prospects for applications of diamond and its unique set of properties in self-assembly of nano-devices and nano-systems.     

Layer-by-layer self-assembly of collagen and chitosan biomolecules on polyurethane films

Polyurethane (PU) films used in wound dressing applications often have appropriate properties. Still, surface modification is necessary to increase the biocompatibility. In this research, the surface of the PU films was modified with collagen and chitosan biomolecules through layer by layer (LbL) self-assembly process. The PU films were synthesized from castor oil and hexamethylene diisocyanate. Then, they were treated with low-pressure nitrogen plasma to graft with poly(acrylic acid). Before performing the LbL process, the surfaces of the PU films were modified using three different reagents, including (A) NaOH solution, (B) EDC/NHS solution, or (C) hexamethylene diamine. Then, the collagen and chitosan deposited in three and five layers on the surface. The images of FESEM, confocal microscopy, and AFM showed that the best performance of the LbL deposition process was after the surface modification with hexamethylenediamine (HMDA). The MTT assay showed that the presence of these biomolecules had boosted the proliferation of fibroblast cells. Increasing the number of the deposited layer from three to five, decreased the cell viability and antibacterial activity of the films. The obtained results propose the modification with HMDA and the deposition of three layers of collagen and chitosan on the PU films to improve its biocompatibility.     

Modification of surface properties of wool fabric with linde type a nano‐zeolite

Wool is a naturally occurring composite fiber consisting of keratin and keratin‐associated proteins as the key molecular components. The outermost surface of wool comprises a lipid layer that renders the surface hydrophobic, which hinders certain fabric processing steps and moisture management properties of wool fabrics. In this study, Linde Type A (LTA) nano‐zeolite (a Na⁺‐, Ca²⁺‐, and K⁺‐exchanged type A zeolite) was integrated onto the surface of wool using 3‐mercaptopropyl trimethoxy silane as a bridging agent. The resultant surface morphology, hydrophilicity, and mechanical performance of the treated wool fabrics were evaluated. Notably, the surface hydrophilicity of wool increased dramatically. When wool was treated with a dispersion of 1 wt % zeolite and 0.2 wt % silane, the water contact angle decreased from an average value of 148° to 50° over a period of approximately 5 min. Scanning electron microscopic imaging indicated good coverage of the wool surface with zeolite particles, and infrared spectroscopic evaluation demonstrated strong bonding of the zeolite to wool keratins. The zeolite application showed no adverse effects on the tensile and other mechanical properties of the fabric. This study indicates that zeolite‐based treatment is potentially an efficient approach to increasing the surface hydrophilicity and modifying other key surface properties such as softness of wool and wool fabrics. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42392.     

Comparative electrochemical study of myoglobin loaded in different types of layer-by-layer assembly films

Four different types of layer-by-layer films were assembled on solid surfaces and designated as PDDA/{ZrO₂}_n, {PDDA/ZrO₂}_n, {PDDA/NP-ZrO₂}_n, and {PDDA/PSS}_n, where ZrO₂ stands for zirconia sol-gel formed by vapor-surface sol-gel deposition, NP-ZrO₂ represents ZrO₂ nanoparticles, PDDA is poly(diallyldimethylammonium), and PSS is poly(styrenesulfonate). When these films were immersed in myoglobin (Mb) solutions, Mb could be gradually “absorbed” or loaded into the films, and the Mb-loaded films at pyrolytic graphite (PG) electrodes demonstrated nearly reversible cyclic voltammetric (CV) responses for Mb Fe^III/Fe^II couple and good electrocatalytic property toward H₂O₂. The electrochemical and electrocatalytic activity of Mb in these films exhibited the sequence of PDDA/{ZrO₂}_n-Mb > {PDDA/ZrO₂}_n-Mb > {PDDA/NP-ZrO₂}_n-Mb > {PDDA/PSS}_n-Mb. Among the four types of films, PDDA/{ZrO₂}_n films, formed by repeated vapor-surface sol-gel deposition of ZrO₂ on PDDA surface, demonstrated better porosity and permeability, and thus could load more amounts of Mb from its solutions. Also because of the better porosity of PDDA/{ZrO₂}_n-Mb films, the small counterions in buffer solution could get into and out of the films more easily, also resulting in the better CV responses of the films according to the mechanism of electron hopping. UV-vis and FTIR spectroscopic studies suggest that Mb in these films essentially retains its native structure. The protein-loaded multilayer films are a novel kind of protein layer-by-layer films, which provide a new route to immobilize proteins and may provide a foundation for fabricating the third generation biosensors based on the direct electrochemistry of enzymes.