Shu-Chuan Liao

Improvement of Thermoplastic Polyurethane Nonwoven Hydrophilicity by Atmospheric Pressure Plasma Treatment with He and N2 Mixed Gases

Thermoplastic polyurethane (TPU) nonwoven has good mechanical properties for use in biomaterial. However, its inherent hydrophobic nature restricts its application. In this study, atmospheric pressure plasma treatment with He and N2 gases was employed to TPU nonwoven material to improve the surface hydrophilicity while retaining the hydrophobicility on the back side of the material. The surface wettability was measured by water contact angle analysis, and the surface chemical composition was analyzed by X-ray photoelectron spectroscopy (XPS). The surface morphology was examined using scanning electron microscopy (SEM). The experimental results reveal that oxygen-containing groups such as C–O and O–C=O are generated on the plasma-treated TPU surface, leading to improved wettablility of the material.

Surface Graft Polymerization of Acrylamide onto Plasma Activated Nylon Microfiber Artificial Leather for Improving Dyeing Properties

To improve surface wettability and dye-ability of Nylon microfiber artificial leather, we apply oxygen plasma treatment and subsequently graft-polymerize acrylamide (AAm) on the surface. The surface properties of AAm-grafted Nylon microfiber artificial leather are characterized by FT-IR, SEM, ESCA and dyeing density (C.I.reactive Blue 4). The dyeing rate of AAm-grafted Nylon microfiber artificial leather, up-regulated with higher acrylamide grafting concentration, increases to 67.1 mg/cm 2 , and remains 66.4 mg/cm 2 after rinsed by water, showed better stability than that of control and oxygen plasma modified Nylon microfiber artificial leather. The water-absorptivity of s-graft acrylamide is five times than that of control. From the results, the efficiency and density of dyeing are both improved, indicating that plasma graft polymerization process could contribute to promote the absorption of dye on the artificial leather.

TEMPERATURE SENSITIVITY OF COMPOSITE HYDROGEL PREPARED BY SURFACE GRAFT POLYMER OF NIPAAm AND BAMBOO CHARCOAL POWDER

This study aimed at fabricating a new type temperature sensor device by taking advantages of electrical conductivity of bamboo charcoal powder and temperature sensibility of NIPAAm hydrogel. The resistance of such a composite device will be affected by temperature. Bamboo charcoal powders were first subjected to oxygen plasma treatment. The treated bamboo charcoal powders were then UV graft polymerization with N-isopropylacrylamide (NIPAAm) monomer solution to be immobilized on the electrode which had previously been modified with plasma of tetramethyltin (TMT) and O2 gas mixture. Using simple environment test to measure resistance, the LCST of bamboo charcoal powders mixed with NIPAAm hydrogel was found to be 31°C. At ambient temperatures higher than LCST, the electrode resistance decreases. The surface morphology of composite hydrogel was observed by SEM.

Plasma Polymerization of SnOxCy Organic-Like Films and Grafted PNIPAAm Composite Hydrogel with Nanogold Particles for Promotion of Thermal Resistive Properties

In this study, a new type of temperature sensor device was developed. The circular electrode of the thermally sensitive sensor was modified with tetramethyltin (TMT) and O2 plasma to form a thin SnOxCy conductive layer on the electrode surface. The nano-Au particles (AuNPs) were subjected to O2 plasma pretreatment to form peroxide groups on the surface. The thermally sensitive sensor made by mixing the treated AuNPs with N-isopropylacrylamide (NIPAAm) solution and then applying UV-induced grafting polymerization of the NIPAAm-containing solution onto the electrode substrate. The composite hydrogels on the electrode introduce thermo-sensitive polymeric surface films for temperature sensing. Using the ambient environment resistance test to measure the resistance, the lower critical solution temperature (LCST) of AuNPs mixed with NIPAAm hydrogel was found to be 32 °C. In common metallic materials, the resistance increased during environmental temperature enhancement. In this study, at ambient temperatures higher than the LCST, the electrode resistance decreases linearly due to the shrinkage structure with AuNPs contacting the circuit electrode.

Plasma Deposition and UV Light Induced Surface Grafting Polymerization of NIPAAm on Stainless Steel for Enhancing Corrosion Resistance and Its Drug Delivery Property

When stainless steel is implanted in human bodies, the corrosion resistance and biocompatibility must be considered. In this study, first, a protective organic silicone film was coated on the surface of stainless steel by a plasma deposition technique with a precursor of hexamethyldisilazane (HMDSZ). Then, ultraviolet (UV) light-induced graft polymerization of N-isopropylacrylamide (NIPAAm) and acrylic acid (AAc) in different molar ratios were applied onto the organic silicone film in order to immobilize thermos-/pH-sensitive composite hydrogels on the surface. The thermo-/pH-sensitive composite hydrogels were tested at pH values of 4, 7.4 and 10 of a phosphate buffer saline (PBS) solution at a fixed temperature of 37 °C to observe the swelling ratio and drug delivery properties of caffeine which served as a drug delivery substance. According to the results of Fourier Transformation Infrared (FTIR) spectra and a potential polarization dynamic test, the silicone thin film formed by plasma deposition not only improved the adhesion ability between the substrate and hydrogels but also exhibited a high corrosion resistance. Furthermore, the composite hydrogels have an excellent release ratio of up to 90% of the absorbed amount after 8h at a pH of 10. In addition, the results of potential polarization dynamic tests showed that the corrosion resistance of stainless steel could be improved by the HMDSZ plasma deposition.

UV-induced grafting polymerization of NIPAAm hydrogel and deposit of hydroxyapatites-like films on polymer surface by atmospheric plasma treatment

Surface graft polymerization can induce pure functional groups on surfaces which has a wide range of applications. In this study, helium atmospheric plasma treated (APT) (voltage: 12,00V, gas flow rate 0.4 l/min, glow distance 10mm) polyethylene terephthalate (PET) and thermoplastic polyurethane (TPU) nonwoven in order to activate the surface. Subsequently UV-induced surface graft polymerization of the temperature sensitive hydrogel N-isopropylacrylamide (NIPAAm) on the plasma activated material surface was performed and then deposition of hydroxyapatite (HA: Ca5(OH)(PO4)3) on treated samples were immersed in two separate solutions (Ca2+ and PO43− source) for 30 min in each solution percycle. The results showed that, APT He treated can improved the hydrophilicity on surface. Also could be successfully grafted poly (NIPAAm) gel on the polymer surface and deposit of Hydroxyapatites-like Films on polymer surface.

FABRICATION OF QCM TYPE SMOTHER DETECTION SENSOR BY PLASMA POLYMERIZING SnOx ORGANIC-LIKE FILMS AND SPIN COATING WITH POLY ETHYLENE GLYCOL

Quartz crystal microbalances (QCM) are transducers for chemical and biochemical sensing. The oscillation frequency of QCM is affected by the adsorbed mass on the surface. In this work, a new room temperature type gas sensor device fabricated by organically hybridized plasma deposition of tetramethyltin (TMT) and oxygen. Post treatment with poly ethylene glycol (PEG) was developed to detect the ambient environmental smother, and the responses of the fabricated sensor to smother detection were investigated. SnOxCy thin films on the sensor electrodes were obtained by plasma deposition from TMT and O2 gas mixtures at room temperature. A spin coating post treatment on the SnOxCy thin films turns into hydrophilic property. The response of the QCM sensor to the smother detection shows a frequency drop during the burning of candle and has good detection sensitivity with Δf equal to 2400 Hz. Repeated smother testing with the QCM type smother detection sensor also indicates the stability of the fabricated sensor.

A NOVEL METHOD TO EVALUATE PLASMA DEPOSITED SILICON OXIDE BARRIER FILMS BY WATER CONTACT ANGLE MEASUREMENT UNDER DC VOLTAGE APPLICATION (FOR CONFERENCE PUBLICATIONS FROM ACCS 2011)

In this study, organic silicon thin film was deposited on a comb type electrode substrate surface using hexamethyldisilazane (HMDSZ) plasma deposition technique to enhance voltage withstanding capability. The wettability, morphology and capability to withstand voltage were investigated by water contact angle (WCA) measurement, SEM observations, AFM and ampere meter analysis, respectively. The WCA of the substrate is 92.3° after the plasma deposition. As voltage is applied to the electrode, the WCA lowers to 76.4° and the resulting current flow is 0.078 mA. If the voltage is continually applied to the device, the organic silicon film on the substrate starts to peel off, accompanied with a sharp increase in current, which is an irreversible phenomenon. From the SEM and AFM analysis, the voltage withstanding capability of the device can be enhanced by prolonging the plasma processing time in order to obtain thicker thin film.