Polyester textile functionalization through incorporation of pH/thermo-responsive microgels. Part II: polyester functionalization and characterization

A new approach to functionalize the surface of polyester textiles is described in this study. Functionalization was achieved by incorporating pH/temperature-responsive polyelectrolyte microgels into the textile surface layer using UV irradiation. The aim of functionalization was to regulate polyester wettability according to ambient conditions by imparting stimuli-responsiveness from the microgel to the textile itself. Microgels consisted of pH/thermo-responsive microparticles of poly(N-isopropylacrylamide-co-acrylic acid) either alone or complexed with the pH-responsive natural polysaccharide chitosan. Scanning Electron Microscopy, X-ray Photoelectron Spectroscopy, ζ-potential measurements, and topographical analysis were used for surface characterization. Wettability of polyester textiles was assessed by dynamic wetting, water vapor transfer, and moisture regain measurements. One of the main findings showed that the polyester surface was rendered pH-responsive, both in acidic and alkaline pH region, owing to the microgel incorporation. With a marked relaxation in their structure and an increase in their microporosity, the functionalized textiles exhibited higher water vapor transfer rates both at 20 and 40 °C, and 65% relative humidity compared with the reference polyester. Also, at 40 °C, i.e., above the microgel Lower Critical Solution Temperature, the functionalized polyester textiles had lower moisture regains than the reference. Finally, the type of the incorporated microgel affected significantly the polyester total absorption times, with an up to 300% increase in one case and an up to 80% decrease in another case. These findings are promising for the development of functional textile materials with possible applications in biotechnology, technical, and protective clothin

Topographical effects of 02- and NH3-plasma treatment on woven plain polyester fabric in adjusting hydrophilicity

Hydrophilisation of polyester textile materials has been investigated over the last twenty years using low-pressure and atmospheric plasmas. According to these studies, wettability and capillarity of fabrics can be significantly improved depending on the process gas used. In the present study, the effects of low pressure O2- and NH3- plasma on the morphology and topometry of fabrics on four different length scales, as well as the influence of the topographical changes of textile structures on the resulting water spreading and absorption rates were investigated. The results of the topographic characterisation using two non-contact optical methods and wettability measurements indicate that the modification of filament nano-topography cannot satisfactorily explain the drastic changes observed in wettability. Dimensional changes (relaxation and shrinkage) as well as changes in warp morphology and inter-yarn spaces are more decisive for inducing hydrophilicity in polyester woven plain fabrics than an increase in the surface nano-roughness of their filaments

Cooperative action of cellulase enzyme and carboxymethyl cellulose on cotton fabric cleanability from a topographical standpoint

In this study, the effect of cotton treatment with cellulose and carboxymethyl cellulose on soil release of three different types of fabric: woven plain, woven twill and knitted were systematically studied. A recent study of the effect of a cleaning cellulase enzyme on cellulose films has proven that this substance selectively attacks amorphous cellulose regions, consisting of small hills in a matrix of flat crystalline regions. According to our previous investigations, where carboxymethyl cellulose is present in the formula, the enzyme seems to drive soil release performance. However, the mechanism has not yet been sufficiently studied from the topographical standpoint. In the present study, topographical changes caused by the treatment with cleaning cellulase enzyme and carboxymethyl cellulose on the fabrics by conditioning while washing were analysed on three different length scales in order to interpret their cooperation on water and oil absorption mechanisms and, hence, on cleanability of cotton fabrics stained with liquid–solid, liquid and solid soils

Cleanability Improvement of Cotton Fabrics Through Their Topographical Changes Due to the Conditioning with Cellulase Enzyme

In this study, topographical changes of woven cotton fabrics conditioned with a cellulase enzyme during several wash–dry cycles are systematically studied. A recent study of cellulase enzyme effect on cellulose films has proven that this substance selectively attacks amorphous regions of cellulose, consisting of small hills in a matrix of flat crystalline regions. In another study, topographical changes caused by cotton treatment with cellulase by conditioning while washing were analysed on three different length scales in order to interpret their cooperation on water and oil absorption mechanisms and, hence, on the cleanability of cotton fabrics stained with liquid–solid, liquid and solid soils. In the present study, we emphasise the micro-topographical changes resulting from several wash–dry cycles by the application of mathematical methods to quantify the changes of yarn micro-surfaces. As a result, we present a conceptual model that describes how the topographical effect of washing and conditioning by cellulase enzyme improves the cleanability of woven plain cotton fabrics

Surface roughness and wettability of wool fabrics loaded with silver nanoparticles: Influence of synthesis and application methods

Hydrophilization of wool fabrics was performed by silver nanoparticles with different surface charge using three different methods: exhausting, pad–dry–cure and in situ synthesis. Dynamic wetting measurements and surface topography analysis were used to evaluate surface changes on wool fabrics. The wool samples in situ loaded revealed the highest fabric roughness and porosity, while the use of the pad–dry–cure method leads to the lowest fabric porosity, and its roughness values approximately were the same as those for samples loaded with the exhaustion method. The results revealed that loading silver nanoparticles with high surface charges onto wool fabrics via the exhaustion method can significantly improve the hydrophilicity of wool fibre surface. The possible reasons for this improvement are discussed

Improved Railway Track Irregularities Classification by a Model Inversion Approach

Over time railway networks have become complex Systems characterized by manifold types of technical components with a broad range of age distribution. De facto, about 50 percent of the life cycle costs of railway infrastructures are made up by direct and indirect maintenance costs. A remedy can be provided by a condition based preventive maintenance strategy leading to an optimized scheduling of maintenance actions taking the actual aswell as the expected future infrastructure condition into account. A prerequisite is, however, that the thousands of Kilometers of railway tracks are almost continuously monitored. Thus, a promising approach is the usage of low-cost sensors, e.g. accelerometers and gyroscopes, which can be installed on common in-line freight and passenger trains. Due to ambiguous data records a credible classification of railway track irregularities directly from these data is challenging. Alternatively to this pure data-driven approach, in this paper a novel hybrid Approach is presented. To this end, a simplified vehicle Suspension model is applied for the purpose of railway track condition monitoring by analyzing the dynamic railway track - Train interactions. The inversion of the model can be used to recalculate the actual inputs (irregularities) of the monitored system (rail surface) which have caused recorded System Responses (dynamic vehicle reactions and acceleration data, respectively). These recalculated inputs are a sound Basis of subsequent data-driven condition monitoring analyses. In this preliminary study, a classification algorithm is implemented to identify a simulated railway track irregularity automatically