Nano zinc oxide for UV protection of textiles

This paper describes the effect on the fading of dyed polyester fabrics in artificial sunlight, when the Ultra Violet (UV) component of the radiation was blocked by coating the fabric with zinc oxide nanoparticles, dispersed in an acrylic polymer. Zinc oxide is photoactive and generates superoxide and hydroxyl radicals (Reactive Oxygen Species; ROS) when irradiated with UV in the presence of oxygen and water. The results for the four dyes studied show that different dye chromophores interact differently with ROS. Selection of dyes with anti oxidant properties or addition of other anti oxidants may reduce the adverse effects of ROS

Micro- and nano-characterization of membrane materials

The global warming has led to enormous challenges worldwide for a large variety of communities, particularly these associated to water and water treatment industry. Due to increasing scarcity of water resources, the development of new membrane materials and water treatment processes will play an important role in tackling this emerging problem. In this paper, the recent development in characterization of in particular, geometrical parameters of micro- and nano-membrane materials will be reviewed. Membranes with micro- and nano-pores have widely been used for ultrafiltration and nanofiltration. The structure of the pores and the surface of the pores/membranes may be optimized to achieve much improved flow rate in these micro-/nano-channels. Therefore, accurate characterization of porous structures will contribute significantly to the prediction of membrane performance. It will not only provide an insight into the new characterization methods but also the development of novel materials.

Natural rubber nanocomposite reinforced with nano silica

Inorganic nano fillers have demonstrated great potential to enhance the properties of natural rubber (NR). The present article reports the successful development of a NR nanocomposite reinforced with nano silica (SiO2). Its dynamic mechanical properties, thermal aging resistance, and morphology are investigated. The results show that the SiO2 nanoparticles are homogenously distributed throughout the NR matrix in a form of spherical nano-cluster with an average size of 80 nm when the SiO2 content is 4 wt%. With the introduction of SiO2, the thermal resistance and the storage modulus of NR host significantly increase, and the activation energy of relaxation of the nanocomposite, compared to the raw NR, increases from 90.1 to 125.8 kJ/mol.

Electroless synthesis of nano-structured gold particles using conducting polymer nanoparticles

In this study, gold nanoparticles were synthesized by electroless recovery of [AuCl4]− from an acidic aqueous solution using nano-structured conducting polymer, polypyrrole nanoparticles, as active surface. The formation of gold nanoparticles was confirmed by TEM, SEM and EDX measurements. The effects of the initial Au(III) concentration on the gold uptake was examined. The recovery capability and gold particle morphology prepared from polypyrrole nanoparticle were compared to that from cast PPy film counterpart.

Crystallographic analysis of nano-structured bainitic steels

A 0.79C-1.5Si-1.98Mn-0.98Cr-0.24Mo-1.06Al-1.58Co (wt%) steel was isothermally heat treated at 200 and 350°C bainitic transformation temperatures. The microstructure was consisted of bainitic ferrite lath and retained austenite for both heat treatment conditions. The crystallographic analysis revealed that the bainitic ferrite laths are close to the Nishiyama-Wassermann orientation relationship with their parent austenite. The isothermal bainite transformation temperature has a significant effect on the retained austenite characteristics and the variant selection of the bainitic ferrite laths. In general, a decrease in the isothennal bainite transformation temperature refined the bainitic structure and weakened the variant selection.

Nano related research in fibres and textiles

With the increasing hype surrounding what nanotechnology can actually deliver, research emphasis in this area needs to be placed on how nanotechnology can bring tangible benefits to existing industries and ordinary consumers. This paper gives selected examples of real world applications of nano-structured materials, including nano fibrous and particulate materials. It reviews recent research into nano-structured surface coating of textile substrates for enhanced functionalities, and the development of fine and uniform nanofibres for advanced applications. Emphasis has been placed on relevant research activities in the Centre for Material and Fibre Innovation at Deakin University, Australia. In the nano-structured surface coating area, several examples of enhancing fabric performance and functionality are provided, including silica coating for photochromic textiles, superhydrophobic surface coating and transparent ZnO coating to reduce colour fading of textiles exposed to UV radiation. In the nanofibre area, these activities include: elimination of beaded fibres without increasing the average diameter of the electrospun nanofibres, electrospinning of side-by-side bi-component nanofibres, new insight into the evolution of fibre morphology in electrospinning and the electrospinning technology itself.

Apatite formation on nano-structured titanium and niobium surface

Current orthopaedic biomaterials research mainly focuses on developing implants that could induce controlled, guided and rapid healing. In the present study, the surface morphologies of titanium (Ti) and niobium (Nb) metals were tailored to form nanoporous, nanoplate and nanofibrelike structures through adjustment of the temperature in the alkali treatment. The in vitro bioactivity of these structures was then evaluated by soaking in simulated body fluid (SBF). It was found that the morphology of the modified surface significantly influenced the apatite inducing ability. The Ti surface with a nanofiber-like structure showed better apatite inducing ability, than the nanoporous or nanoplate surface structures. A thick dense apatite layer formed on the Ti surface with nanofiberlike structure after 1 week soaking in SBF. It is expected that the anofibre-like surface could achieve good apatite formation in vivo and subsequently enhance osteoblast cell adhesion and bone formation in vivo.

Polymer coatings containing nano particles of zinc oxide for the UV protection of dyed polyester fabrics

The useful life of many outdoor textile products is limited by degradation caused by exposure to sunlight, in particular by the ultra violet component (below 400 nm). The degradation results in fading of colours and also loss of physical properties, such as tear strength and abrasion resistance. Degradation can be decreased with UV absorbers, often used in conjunction with antioxidants or free radical quenchers. The protection afforded by these organic compounds is, however, limited as they are ultimately destroyed by the UV radiation they absorb.
An alternative approach is to coat fabrics with a polymer containing an inorganic UV absorber, such as zinc oxide. The inherent stability of zinc oxide would be expected to provide a protective effect over a much longer period than can be achieved with an organic UV absorber. A possible disadvantage of zinc oxide when applied in a polymer film is that absorption and scattering of visible light can produce hazy films and, hence, an unacceptable change in fabric appearance.
This poster paper examines the possibility of using nano particles of zinc oxide dispersed in acrylic polymers for protecting dyed polyester fabrics against sunlight fading. Factors affecting both UV absorbance and film clarity will be discussed. The possibility will also be examined that the protective effect may be reduced in some circumstances by reactive oxygen species, generated by the interaction of UV with zinc oxide in the presence of air and water.

Development of a contact probe incorporating a bragg grating strain sensor for nano coordinate measuring machines

This paper presents a novel optical fibre based micro contact probe system with high sensitivity and repeatability. In this optical fibre probe with a fused spherical tip, a fibre Bragg grating has been utilized as a strain sensor in the probe stem. When the probe tip contacts the surface of the part, a strain will be induced along the probe stem and will produce a Bragg wavelength shift. The contact signal can be issued once the wavelength shift signal is produced and demodulated. With the fibre grating sensor element integrated into the probe directly, the probe system shows a high sensitivity. In this work, the strain distributions along the probe stem with the probe under axial and lateral load are analysed. A simulation of the strain distribution was performed using the finite element package ANSYS 11. Performance tests using a piezoelectric transducer stage with a displacement resolution of 1.5 nm yielded a measurement resolution of 60 nm under axial loading.