Qufu Wei

Functionalization of textile materials by plasma enhanced modification

Textile materials are increasingly used in various industries. In these applications, the surfaces of textile materials play a key role, because a range of performance properties depends on surface characteristics. As with many other types of materials, the surface properties of textiles can be readily altered by the treatment of the materials with gas plasma, without impairment of their bulk mechanical properties. This article presents examples of new approaches to functionalization of textiles using plasma-enhanced modifications. Examples are given of the work on polyethylene terephthalate (PET) nonwoven materials. Micrographs, obtained by scanning probe microscopy (SPM) and environmental scanning electron microscopy (ESEM) are presented to demonstrate changes in the surface topography, surface chemistry, and surface wettability of PET nonwovens. The great potential for significant improvements in the properties of textiles by plasma-enhanced modification is highly promising.Textile materials are increasingly used in various industries. In these applications, the surfaces of textile materials play a key role, because a range of performance properties depends on surface characteristics. As with many other types of materials, the surface properties of textiles can be readily altered by the treatment of the materials with gas plasma, without impairment of their bulk mechanical properties. This article presents examples of new approaches to functionalization of textiles using plasma-enhanced modifications. Examples are given of the work on polyethylene terephthalate (PET) nonwoven materials. Micrographs, obtained by scanning probe microscopy (SPM) and environmental scanning electron microscopy (ESEM) are presented to demonstrate changes in the surface topography, surface chemistry, and surface wettability of PET nonwovens. The great potential for significant improvements in the properties of textiles by plasma-enhanced modification is highly promising.

AFM Characterisation of Technical Fibres

Technical fibres are designed and produced to create microstructures that give the fibre product its characteristic properties. The use of new tools is of importance in fundamental and practical research and development of versatile technical fibres for a variety of applications. This paper highlights the methodological approaches to exploring the nanostructures, properties, and dynamics of surfaces and interfaces of technical fibres using Atomic Force Microscopy (AFM). The examples presented include structure characteristics of nanofibre materials, nanostructure and properties of fibre surfaces, nanoscale level interactions at fibre interfaces, and dynamic nanostructure evolution of fibre surfaces under different conditions. In these areas, AFM is shown to be a useful and versatile tool to study nanostructures, to probe surface and interface properties, or to investigate the dynamic process at fibre surfaces and interfaces. AFM provides powerful tools for nondestructive characterisation of technical fibres.

Effect of temperature on structure, morphology and crystallinity of PVDF nanofibers via electrospinning

Abstract I nfluence of temperature on morphology, structure and crystallinity of Poly (vinylidene fluoride) (PVDF) nanofibers was investigated in this study. The Wehilmy technique and viscosity testing apparatus were used to evaluate the surface tension and viscosity of electrospun solutions at various ambient temperatures. Surface morphologies and diameters of nanofibers were examined by Field-emission Scanning Electron Microscopy (FE-SEM) and atomic force microscopy (AFM). It was found that the surface morphologies were obviously affected by ambient temperature. This dependence was attributed to the change of the properties of Poly (vinylidence fluoride) solutions with temperature. The thermal properties and crystal structures of the PVDF nanofibers electrospun at different temperatures were also studied by differential scanning calorimetry (DSC), and Xray diffraction (XRD). The results revealed that the crystallinity and thermal properties were improved by increasing the ambient temperature during electrospinning

Preparation And Characterizations Of Ptfe Gradient Nanostructure On Silk Fabric

Superhydrophobic materials have been extensively studied because of their wonderful array of properties and applications. In this study, normal and superhydrophobic surface of silk fabric have been prepared via deposition of different shapes of PTFE nanostructure using magnetron sputter coating. The effects of PTFE sputter coating on surface morphology and surface chemical properties were characterized using atomic force microscopy (AFM) and ATR-FTIR (attenuated total reflection-Fourier transform infrared spectroscopy). The wettability of the fabric was characterized through measuring the surface contact angle by drop shape analysis apparatus and dynamic contact angle by Wilhelmy technique. As evaluated by water contact angle measurements, all the treatments resulted in a significant enhancement in the hydrophobicity of silk fabric, while larger sputtering pressures brought bigger PTFE nanoparticles, which led to higher contact angles. The results have also revealed that alternant working pressures, could bring gradient nanostructures which generated both high contact angle and less contact angle hysteresis.

Morphology, thermal and mechanical properties of PVAc/ TiO2 hybrid nanofibers

Abstract Organic/inorganic hybrid was successfully prepared by sol-gel technique, which consisted of polyvinyl acetate (PVAc) as organic segment and titanium dioxide (TiO2) as inorganic part. The PVAc/ TiO2 hybrid nanofibers were fabricated by electrospinning. The structures and properties of the hybrid nanofibers were investigated by transmission electronic microscopy (TEM), scanning electron microscopy (SEM), atomic force microscopy (AFM), thermogravimetric analyzer (TGA) and tensile testing. SEM observation revealed the fibrous structures of the hybrid nanofibers. AFM and TEM images indicated the surface morphology and inner structures of the hybrid nanofibers. It was found by TGA analysis that the thermal stability of pure PVAc nanofibers was enhanced by the increase of TiO2 phase. The breaking strength was increased while the breaking elongation was decreased as the TiO2 content increased.

Surface Funtionalization of Polymer Fibers by Sputter Coating

Polymer fibers are widely used in many industries, ranging from filtration, composites, tissue engineering, and electronics. The surface properties of polymer fibers are of importance in these applications. The surface properties of polymer fibers can be modified by different techniques. In this study, magnetron sputter coatings are used to generate functional nanostructures on polymer fiber surfaces. Conducting aluminum (Al) film, piezoelectric aluminum nitride (AlN) film, and ceramic film of aluminum oxide (Al2O3) are deposited onto polyethylene terephthalate (PET) fibers at low temperature. The surface topography and compositions of the funtionalized fibers are characterized by optical microscopy, scanning probe microscopy (SPM), and environmental scanning electron microscopy (ESEM). The observations by SPM reveal the different morphology of the fibers with different coatings. The examination by the ESEM equipped with a full energy dispersive X-ray (EDX) analysis indicates the change in the chemical compositions of the fiber surfaces.

Comparative studies of functional nanostructures sputtered on polypropylene nonwovens

Abstract Functional nanocomposite nonwoven materials were prepared by surface coating with copper and silver using magnetron sputter coating. The composite nonwoven materials with metallic nanostructures were analyzed and compared by means of atomic force microscopy, energy dispersive X-ray analysis and electrical and optical tests. The observations by atomic force microscopy revealed the formation of functional nanostructures on the fibre surfaces. It was found that copper had more compact structures on the fiber surface than silver under the same sputtering conditions. The transmittance analysis showed that the nonwoven substrates deposited with nanostructural copper showed better ultraviolet and visible light absorption than those coated with silver. The functional nonwoven materials coated with silver had lower electrical resistance than those coated with copper.

CHARACTERIZATION OF DYNAMIC WETTING OF PLASMA-TREATED PTFE FILM

Polytetrafluoroethylene (PTFE) has been increasingly used in many industries due to its low frictional coefficient and excellent chemical inertness. The surface properties of PTFE are of importance in various applications. The surface properties of PTFE can be modified by different techniques. In this study, PTFE film was treated in oxygen plasma for improving surface wettability. The effects of plasma treatment on dynamic wetting behavior were characterized using Scanning Probe Microscopy (SPM), Fourier transform infrared spectroscopy (FTIR), and dynamic contact angle (DCA) measurements. SPM observations revealed the etching effect of the plasma treatment on the film. The introduction of hydrophilic groups by plasma treatment was detected by FTIR. The roughened and functionalized surface resulted in the change in both advancing and receding contact angles. Advancing and receding contact angles were significantly reduced, but the contact angle hysteresis was obviously increased after plasma treatment.