Surface Structure Of Fabric Research Articles

Review of directional liquid transport on surfaces with different structures

Directional liquid transport has many cutting-edge applications, such as fog collection, agricultural drip irrigation, biochemical microreactors, water harvesting, non-powered micro-drug delivery, thin-film lubrication etc. There are many surfaces or linear structures in the natural systems can occur directional transport of water. In this paper, two bionic structures inspired by natural structures and two artificially fabricated surface structures are presented and their flow laws and mechanical mechanisms are described. Thereby, it is analysed that surface-driven external forces, such as the gradient of surface energy and the gradient of Laplace pressure, and surface pinning in other directions are the key points to drive the directional flow of liquids.

Regulation of the fabric wet adhesion property through structural design of desirable scale: A theoretical suggestion

It is a universal phenomenon existing in both manufacture and everyday life that fabrics tend to adhere under wet condition. The phenomenon is closely related to the interaction of the fabric surface structure and the liquid. Among the complex structures and numerous varieties of fabrics, the features of typical fabric structures are employed to establish a geometrical model (including structural configuration of spherical protrusion, cylinder, loop, and pore) in order to investigate wet adhesion property under the existence of massive liquid media. Through mechanical analysis on material-liquid bridge system (consisting of fabric material, liquid bridge adhering to the material, and the solid-liquid interface), a quantitative computational theoretical model is built with parameters including critical distance [Formula: see text], radius of the structure R*, apparent receding contact angle [Formula: see text], wetted sphere angle [Formula: see text], and so on, finding the rules and proposing a series of preferred ranges of regulating structural parameters to effectively achieve desirable fabric wet adhesion property in different circumstances. The research findings could be applied to the scientific prediction and on demand regulation of fabric wet adhesion property. They are of great significance with regard to improving the convenience of fabric wet processing, application properties under wet environments, apparel health and comfort for human body, and so on.

Homopolymer-Assisted Fusions of Polymer Brushes and Block Copolymer Vesicles

The applications of materials are closely associated with surface structures and properties. Surface coassembly of block copolymers (BCPs) and polymer brushes is an effective method to fabricate surface structures with tunable properties. The surface coassembly approach not only provides a method for the fabrication of surface structures but also provides a method for the synthesis of hybrid materials with hierarchical nanostructures. In this research, polystyrene (PS)-assisted fusions of PS brushes on silica particles and BCP vesicles in a surface coassembly process are studied. The concentrations of BCP and PS homopolymer are two key parameters in the fusion process. When the BCP concentration is held constant at 3 mg/mL, with an increase in PS concentration, aggregation of silica particles and the fusions of polymer brushes and BCP vesicles are observed. When the BCP concentration is kept at 8 mg/mL, large hybrid compound structures composed of silica particles and the fused vesicles are formed. In the surface coassembly process, the addition of PS leads to an increased volume percentage of the solvophobic component in the system. To reduce the surface energy and the unfavorable contact between the solvent and PS, silica particles with PS brushes and BCP vesicles are fused into large compound structures. A variety of hybrid materials with hierarchical macro-/mesostructures can be fabricated by using this method.

Investigation of the flammability properties of a cotton and elastane blend denim fabric in the presence of boric acid, borax, and nano-SiO2

This study contributes to the field of flammable resistant textiles. Boric acid, borax, and nano SiO2 were added to a commercial finishing solution, separate solutions were prepared for each. The difference in this study is to improve the functional finishing processes of denim fabrics consisting of 99% cotton and 1% elastane. The aim is to draw attention to the flame-retardant performance improvements that can be created by a synergistic mechanism for textiles. Using TGA, LOI and vertical combustion tests for determining flame retardant effect were sufficient to achieve meaningful and precise results. Each chemical added to increase the flammability performance effect of the commercial finish solution entered the fabric surface structure, and the flammability performance of the commercial finish solution was improved by a simple and feasible method. Denim fabric can be made suitable for industrial textiles by flame retardant finishing process.

Fabrication of a flexible capacitor sensor with surface-fabric-structured conductive silicon rubber

With the development of electronic technology, wearable electronic products and electronic skin have become the emerging products in this world. In this study, two kinds of flexible plate capacitors were prepared by an optimized spraying process, whose electrode layers and dielectric layers were conductive silicon rubber and pure PDMS, respectively. The inner surface structure of the capacitors was fabricated with the aids of fabric backup. Initial capacitance and capacitance response of sensors with/without fabric surface structure were calculated and analyzed according to formulae of equivalent dielectric constant of composite dielectric layers and equivalent capacitance of the capacitor. Capacitance responses of the sensors to compressive pressure and tensile strain loads were further tested. In addition, the effect of spraying parameters, including spraying distance, plate area and resistance of the CSR with loads were evaluated on the response. The sprayed flexible capacitors were finally demonstrated its potential application in sensing field, such as water dropping, feet lifting and walking. Results indicate that the surface fabric structure of flexible sensors will improve its stability and sensitivity, which assure the sensors of a prospect of motion sensor.

An Objective Fabric Smoothness Assessment Method Based on a Multi-Scale Spatial Masking Model

Fabric smoothness appearance assessment plays an important role in the textile and apparel industry. It remains a challenging task to evaluate the fabric smoothness objectively. In the existing objective methods based on the image analysis, features describing the fabric surface structure were used widely without considering the fact that fabric smoothness is a subjective concept concerned by the human vision perception. This paper proposes an effective method to realize the objective fabric smoothness assessment by analyzing the relationship between the spatial masking effect in the human vision system (HVS) and the fabric smoothness perceived by the human. The spatial masking effect model was improved and extended into the scale space model to imitate the human perception of the fabric smoothness appearance. A set of features was extracted from the fabric images by the model and trained by the support vector machine (SVM) classifier. The method was tested on the fabric image data set, including 385 manually labeled specimens captured by the proposed image acquisition system, and reached 82.60%, 95.84%, and 100% accuracies under the errors of 0°, 0.5°, and 1°, respectively. In the experiments, based on the discussion of the effect of the system parameters, i.e., classification models, training data size, feature scales, and illumination direction number, to the performance of the proposed method, and a set of best system parameters was verified. The final assessment results of the proposed method were illustrated and outperformed the state-of-the-art methods for fabric smoothness assessment and a series of widely used deep learning methods. Promisingly, the proposed method can provide novel research ideas for the image-based fabric smoothness assessment that considering the human perception mechanism.

A Dirty Story: Improving Colloidal Monolayer Formation by Understanding the Effect of Impurities at the Air/Water Interface.

Colloidal monolayers are important tools to fabricate surface structures at the nanoscale. A typical monolayer fabrication strategy involves the self-assembly of colloidal building blocks at liquid interfaces, which are subsequently deposited on a solid substrate. Even though this process is well established, the resulting order of the particles within the colloidal monolayer differs between batches of colloidal particles and can even change with the age of the dispersion. In this study, we investigate the origins of this variation of monolayer quality for polystyrene particles synthesized by surfactant-free emulsion polymerization. We correlate the interfacial behavior of the colloidal particles at the air/water interface on a Langmuir trough with the resulting quality of the monolayer after transfer to a solid substrate. We identify surface-active impurities as a major cause for a disturbed self-assembly of the colloidal particles. These impurities form during the particle synthesis and consist of copolymers of styrene, the comonomer acrylic acid, and sulfonate species from the initiator. We show that they can be removed by cleaning protocols to increase the monolayer quality. However, our experiments demonstrate that the impurities reappear over time even for cleaned dispersions, indicating desorption from the surface of the colloidal particles. We identify strategies to avoid the presence of the impurities at the air/water interface or to inhibit their effect on the self-assembly process. These simple guidelines improve the quality of the resulting colloidal monolayer, which is a prerequisite for the reliable fabrication of high-quality surface nanostructures from colloidal templates.

Construction of Hierarchical Natural Fabric Surface Structure Based on Two-Dimensional Boron Nitride Nanosheets and Its Application for Preparing Biobased Toughened Unsaturated Polyester Resin Composites.

It has been a big challenge to prepare the unsaturated polyester resin (UPR) composites with good fire safety, interfacial quality, and impact strength in an environmentally friendly way. In this study, to improve interfacial performance of fabric-reinforced UPR composites, nontoxic two-dimensional hexagonal boron nitride (h-BN) nanosheets were assembled on the surface of ramie fabrics, where sodium alginate acts as a green dispersant to disperse h-BN sheets during the process. Then, the biobased phosphorus-containing toughening agent (PCTA) was synthesized to simultaneously improve the impact strength and fire safety of the composite. With application of h-BN nanosheets-assembled fabric (AF) and 20 wt % of PCTA, the AF/UPR@PCTA20 composite presented the maximum 41.2% decrease in the value of peak heat release rate and a maximum 17.8% decrease in the value of total heat release, which also reached V-0 rating in the vertical burning test. Meanwhile, the AF/UPR@PCTA20 composite showed an obvious increase in limiting oxygen index, from 24.0 to 29.5% compared with RF/UPR. The flame retardant mechanism was investigated from gas phase and condensed phase. Furthermore, compared to neat RF/UPR composite, the AF/UPR@PCTA20 composite showed a significant 68.8% improvement in impact strength, implying an extreme toughening effect of PCTA on UPR composites. The research provides a viable green method for the development of environmentally friendly UPR composites in the future.

Enhancement of Colour Effects of Dyed-Yarn Mixed Fabrics Using Cramming Motion and Finer Polyester Yarns.

This paper reports the study of the effects of cramming motion implemented during weaving and finer weft yarns used on dyed-yarn mixed woven fabrics produced by using raw white warps and multicolored-wefts. The cramming motion was used to increase the dyed-weft yarns cover factor of fabric, and thus, to reduce the negative effect of white warp floats at the fabric face on the color attributes of fabric. The surface structure of fabric was characterized by using several key geometrical parameters that determined the resultant fabric color attributes. The effects of fabric structure and density, weft yarn count, and the introduction of black yarn on the fabric face layer on the fabric surface geometrical parameters, physical properties, as well as color attributes were investigated under the implementation of cramming motion on the fabric. The color attributes of fabrics using cramming motion and finer yarns were also compared to the fabrics without cramming motion. The experimental results indicate that the weft yarn density and cover factor of fabric face layer are increased by applying cramming motion and finer yarns for fabricating the blue-red and/or black mixed fabrics. Consequently, the fabric lightness can be further reduced for achieving a better color effect on colorful and figured woven fabrics mainly using dyed-wefts for color mixing.

Anti- and De-Icing Behaviors of Superhydrophobic Fabrics

This paper reports the application of superhydrophobic coatings on cotton fabrics and their functionalities for anti- and de-icing efficacy. Superhydrophobic cotton fabrics with different water-repellent properties have been achieved by decorating the surface of pristine cotton fibers with ZnO structures of varying sizes and shapes through an in situ solution growth process, followed by the treatment of the surface with low-surface-energy coating such as Teflon. The surface morphology of the treated cotton fabrics was characterized using scanning electron microscopy (SEM). The surface wettability of the treated fabrics was evaluated through the measurement of static contact angle (SCA), contact angle hysteresis (CAH), and sliding angle (SA) of a water droplet. The anti- and de-icing behaviors of the treated fabrics were evaluated through both static (sessile droplet) and dynamic (spraying) tests. The results show that the superhydrophobic fabric with a higher SCA and the lower CAH/SA has superior anti- and de-icing behaviors in both the static and dynamic conditions. Compared to hard substrates, the soft, flexible, and porous (air-permeable) superhydrophobic fabrics can lead to broader applicability of textile-based materials for the design and fabrication of anti- and de-icing materials. Furthermore, the multi-scale surface structures of fabrics (fibers, yarns, and weaving constructions) combining with the hierarchical micro-nanostructures of the ZnO coating provides an ideal platform for anti-icing studies.

One-step Maskless Fabrication and Optical Characterization of Silicon Surfaces with Antireflective Properties and a White Color Appearance.

We report a simple one-step maskless fabrication of inverted pyramids on silicon wafers by reactive ion etching. The fabricated surface structures exhibit excellent anti-reflective properties: The total reflectance of the nano inverted pyramids fabricated by our method can be as low as 12% without any anti-reflective layers, and down to only 0.33% with a silicon nitride coating. The results from angle resolved scattering measurements indicate that the existence of triple reflections is responsible for the reduced reflectance. The surfaces with the nano inverted pyramids also exhibit a distinct milky white color.

Direct Femtosecond Laser Surface Structuring with Optical Vortex Beams Generated by a q-plate

Creation of patterns and structures on surfaces at the micro- and nano-scale is a field of growing interest. Direct femtosecond laser surface structuring with a Gaussian-like beam intensity profile has already distinguished itself as a versatile method to fabricate surface structures on metals and semiconductors. Here we present an approach for direct femtosecond laser surface structuring based on optical vortex beams with different spatial distributions of the state of polarization, which are easily generated by means of a q-plate. The different states of an optical vortex beam carrying an orbital angular momentum ℓ = ±1 are used to demonstrate the fabrication of various regular surface patterns on silicon. The spatial features of the regular rippled and grooved surface structures are correlated with the state of polarization of the optical vortex beam. Moreover, scattered surface wave theory approach is used to rationalize the dependence of the surface structures on the local state of the laser beam characteristics (polarization and fluence). The present approach can be further extended to fabricate even more complex and unconventional surface structures by exploiting the possibilities offered by femtosecond optical vector fields.

Effects of azimuthal angles on laser interference lithography.

This paper discusses the effects of azimuthal angles on two-, three-, and four-beam laser interference. In two- or three-beam laser interference, periodic surface structures of lines or dots were obtained. In four-beam laser interference with the polarization mode of TE-TM-TE-TM, the modulation in a particular direction was formed and calculated. In the work, a He-Ne laser system was used to simulate two-, three-, and four-beam laser interference, and the interference pattern was detected by a CCD. A high-power Nd:YAG laser interference lithography system was set up to pattern silicon wafers. In the experiments, one azimuthal angle was changed every time to form interference patterns when polarization states were fixed and incident angles were equal. The experimental results have shown that the azimuthal angle affects the periods and feature sizes of the interference patterns and the fabricated surface structures, which are in accordance with the theoretical and computer simulation results.

Fabrication and quantitative roughness analysis of hierarchical multiscale polymer surface structures

Nature's functional surfaces are typically hierarchical multiscale structures. There are several techniques for producing such artificial structures on polymers but their mass production is not straightforward. We present here a simple and versatile method for manufacturing hierarchical multiscale polymer surface patterns. The microroughening technique permits the single-step production of multilevel three-dimensional surface architectures in a mechanically durable nickel mold. The molding technique is suitable for area-controlled fabrication of structures with various geometrical shapes on smooth and curved surfaces. The mold structures were transferred to polypropylene surfaces by means of injection molding. The fabricated surface structures were characterized by using a filtered power spectral density method which facilitated a quantitative study of the roughness distributions at different length scales of structure periodicities. Analysis showed that the microroughening technique is an appropriate tool for controlled production of surface roughness at a micro-nanometer scale. Roughness distribution values can be used for predicting surface structure-related properties such as wetting, and the distributions can also be simulated without an experimental preparation process. The work presents a suitable approach for mass production of hierarchical polymer surfaces at different length scales and provides a new route for designing surface structures with tunable wetting properties.

Engineering a biocompatible scaffold with either micrometre or nanometre scale surface topography for promoting protein adsorption and cellular response.

Surface topographical features on biomaterials, both at the submicrometre and nanometre scales, are known to influence the physicochemical interactions between biological processes involving proteins and cells. The nanometre-structured surface features tend to resemble the extracellular matrix, the natural environment in which cells live, communicate, and work together. It is believed that by engineering a well-defined nanometre scale surface topography, it should be possible to induce appropriate surface signals that can be used to manipulate cell function in a similar manner to the extracellular matrix. Therefore, there is a need to investigate, understand, and ultimately have the ability to produce tailor-made nanometre scale surface topographies with suitable surface chemistry to promote favourable biological interactions similar to those of the extracellular matrix. Recent advances in nanoscience and nanotechnology have produced many new nanomaterials and numerous manufacturing techniques that have the potential to significantly improve several fields such as biological sensing, cell culture technology, surgical implants, and medical devices. For these fields to progress, there is a definite need to develop a detailed understanding of the interaction between biological systems and fabricated surface structures at both the micrometre and nanometre scales.

Laser assisted fabrication of random rough surfaces for optoelectronics

Optical surface structuring shows great interest for antireflective or scattering properties. Generally, fabricated surface structures are periodical but random surfaces that offer new degrees of freedom and possibilities by the control of their statistical properties. We propose an experimental method to create random rough surfaces on silicon by laser processing followed by etching. A photoresist is spin coated onto a silicon substrate and then exposed to the scattering of a modified laser beam. The beam modification is performed by using a micromirror matrix allowing laser beam shaping. An example of tuning is presented. An image composed of two white circles with a black background is displayed and the theoretical shape of the correlation is calculated. Experimental surfaces are elaborated and the correlation function calculated from height mapping. We finally compared the experimental and theoretical correlation functions.

A study of abrasion and frictional behaviour of nonwoven interlining produced with different coating methods

Interlinings are produced recently not only natural and synthetics fibers but also fiber sheet form in nonwoven production methods. During usage, the fabric wears out and because of this problem fabric surface structure deteriorates. As a result of, investigation of fabrics surface and frictional properties has been important before usage of garments. For this reason, a patented laboratory instrument was designed which is based on horizontal working principle of accessing friction coefficient of fibrous textile surfaces. The tested materials were nonwoven interlining materials produced by spunbond methods. Abrasion resistance of paste dot-CoPES nonwoven interlining material is lower than others because of softness handle. On the contrary, friction coefficients have been obtained higher values.

Automatic pattern recognition and color separation of embroidery fabrics

Currently, there is very little literature on automatic image recognition and classification of embroidery fabrics. In today’s embroidery industry, front-end pattern-making still relies greatly on labor, using pattern-making software to carefully depict patterns and images in different colors and regions. Hence, an image analysis system that can recognize colors, regions and patterns automatically is a critical technique of improving the competitiveness of the embroidery industry. In this paper, the mean filtering method, central-weighted median filtering method and morphological operation were employed to filter out the light variation on the embroidery fabric surface structure, and a genetic algorithm was applied to distinguish images of repeat pattern embroidery from that of nonrepeat pattern embroidery. If it is a repeat pattern, then a much smaller sized subimage would be searched in the original image for the same color components and spatial structure, which could lower the computing load of the entire image greatly and is expected to achieve the processing speed required in an online real-time system. As for nonrepeat pattern embroidery images, discrete wavelet transform was applied to acquire low-frequency subimages, which can retain important image features while improving the computing efficiency. Be it a repeat or nonrepeat pattern, after obtaining subimages, specific criteria were used to determine the exact number of clusters, and the weighted fuzzy C-means method was employed to run color separation and region separation. The experiment proved that, in regard to the color embroidery images of repeat and nonrepeat patterns, the method proposed in this paper succeeded in color and region separations with good result.

Sound Absorption Behavior of Knitted Spacer Fabrics

This paper presents an experimental investigation on the sound absorption behavior of knitted spacer fabrics. Both weft-knitted and warp-knitted fabrics were used in the study due to their different structure features. The weft-knitted spacer fabric used was composed of two varied plain knitted outer layers and one textured polyester multifilament spacer layer, and it was considered as a porous sound absorber. The warp-knitted spacer fabric used was made with mesh structure on the outer layers and monofilament yarn in the spacer layer, and it was considered as microperforated panel sound absorber. The noise absorption coefficients (NACs) of these two kinds of fabrics under both single and multilayer forms as well as their combinations were tested using a two-microphone impedance measurement tube. The results show that the fabric surface structure and thickness, spacer yarn type and their connecting ways, fabric combinations and their arrangement methods have significant effects on the sound absorbability. The results also demonstrate that good sound absorbability could be achieved by using knitted spacer fabrics if suitable fabric structures and combinations are used.

Effect of weight and apllied force on the friction coefficient of the spunlace nonwoven fabrics

Friction force that can be defined as the forces resisting relative to the movement between two surfaces contacting with each other plays an important role in textile industry. During usage, the fabrics continue to friction to the textile or the other surfaces and because of this problem fabric surface structure deteriorates. Therefore, most of the scientists have been designed different methods in order to estimate surface properties and friction of fabric before their usage. In this study, friction experiments have been performed by designed and manufactured two different systems which work as a horizontal platform and inclined plane. It has tried to investigate friction properties of polyester nonwoven fabric samples which are produced by spunlace methods (air laid and spunlace bonding) with different weights. While the selected fabric samples weight increase, it has been seen that a low friction force occurred because of more stable structure. And also, it has been observed that the higher vertical force (load) applied on the specimens the lower the coefficient of friction. These results shows that both measurement methods have similar tendencies based on the analyzed results.