Chi-Jung Chang

Ultraviolet-Durable Superhydrophobic Zinc Oxide-Coated Mesh Films for Surface and Underwater–Oil Capture and Transportation

In this paper, we report a simple and an inexpensive method for fabricating superhydrophobic/superoleophilic mesh films from microstructured ZnO coatings. The microstructured ZnO coatings, which do not contain any fluorinated compounds, maintain their superhydrophobicity and superoleophilicity after ultraviolet irradiation and display environmental stability. Furthermore, those microstructured ZnO-coated mesh films exhibit good selectivity (even underwater) and excellent recyclability, making them promising candidates for many potential applications, including liquid-liquid separation, water treatment, and liquid transportation.

Fabrications and Applications of Stimulus-Responsive Polymer Films and Patterns on Surfaces: A Review

In the past two decades, we have witnessed significant progress in developing high performance stimuli-responsive polymeric materials. This review focuses on recent developments in the preparation and application of patterned stimuli-responsive polymers, including thermoresponsive layers, pH/ionic-responsive hydrogels, photo-responsive film, magnetically-responsive composites, electroactive composites, and solvent-responsive composites. Many important new applications for stimuli-responsive polymers lie in the field of nano- and micro-fabrication, where stimuli-responsive polymers are being established as important manipulation tools. Some techniques have been developed to selectively position organic molecules and then to obtain well-defined patterned substrates at the micrometer or submicrometer scale. Methods for patterning of stimuli-responsive hydrogels, including photolithography, electron beam lithography, scanning probe writing, and printing techniques (microcontact printing, ink-jet printing) were surveyed. We also surveyed the applications of nanostructured stimuli-responsive hydrogels, such as biotechnology (biological interfaces and purification of biomacromoles), switchable wettability, sensors (optical sensors, biosensors, chemical sensors), and actuators.

Ag-doped ZnO nanorods coated metal wire meshes as hierarchical photocatalysts with high visible-light driven photoactivity and photostability.

Ag-doped ZnO nanorods were grown on stainless-steel wire meshes to fabricate the hierarchical photocatalysts with excellent visible light driven activity and anti-photocorrosion property. Effects of Ag doping and the surface structure on the surface chemistry, surface wetting properties, absorption band shift, photoelectrochemical response, and photocatalytic decolorization properties of the hierarchical photocatalysts, together with the stability of photocatalytic activity for recycled photocatalysts were investigated. Ag doping leads to red-shift in the absorption band and increased visible light absorption. Nanorods coated wire meshes hierarchical structure not only increases the surface area of photocatalysts but also makes the surface hydrophilic. The photocatalytic activity enhancement and reduced photocorrosion can be achieved because of increased surface area, enhanced hydrophilicity, and the interaction between the metal wire/ZnO and Ag/ZnO heterostructure interface which can improve the charge separation of photogenerated charge carriers.

Improved photocatalytic performance of ZnO nanograss decorated pore-array films by surface texture modification and silver nanoparticle deposition

Immobilized photocatalyst was prepared by the growth of ZnO nanograss on the ZnO pore-array substrate. The surface morphology, optical and photocatalytic properties of the photocatalysts were studied. Nanograss decorated ZnO pore-array films exhibited improved performance on the photocatalytic degradation of methyl orange (MO) in aqueous solution under UV radiation. The photocatalytic activity of pore-array films can be tuned by changing the surface nanostructure of the porous photocatalyst. The enhanced photocatalytic activity of the nanostructured pore-array photocatalyst can be attributed to increased active surface area, improved diffusion of dye molecules among the nanostructured catalyst, and enhanced light absorption through the light-trapping effect. Besides, the degradation of MO using Ag/ZnO composite pore-array catalysts with different sizes and densities of the Ag particles on the surface of ZnO nanostructure was investigated.

Effect of Compositions and Surface Treatment on the Jetting Stability and Color Uniformity of Ink-Jet Printed Color Filter

UV curable jet inks were ejected by a bubble-jet cartridge onto a glass substrate and fixed by a UV curing reaction to prepare LCD color filters. The rheology of jet inks was adjusted by changing the surfactants and monomers, in order to achieve good jetting directionality, uniform drop size and excellent wetting on the glass substrate. The surface energy of the substrate was modified by plasma treatment. The printed aqueous UV curable ink tends to move toward the O2-plasma treated ribs and this causes them to swell. This lowers the nanoindentation hardness of the ribs and deteriorates the uniformity of the printed color strips. Both the surface smoothness and color uniformity of the color strips were improved tremendously when the substrates were treated by CF4 plasma.

Influence of UV-Curable Compositions and Rib Properties on Ink-Jet-Type Color Filter Performance

UV-curable jet inks were ejected into a color area separated by barrier ribs, then fixed by UV curing reaction to prepare LCD color filter (CF). The widths of the color strip and rib were 90 µm and 20 µm, respectively. Either adding oligomer or increasing the amount of monomers can improve ink curability. By increasing the monomer content instead of incorporating the oligomer, the curing reactivity was elevated without deteriorating the pigment dispersion stability, jetting directionality and drop size uniformity. The drop formation behaviors were observed by the image-capture system. The ejected drops showed straight trajectory and uniform size without error and missing dots. The chemical resistance of the barrier ribs was improved to avoid collapse caused by ink corrosion.

Label-free DNA detection using two-dimensional periodic relief grating as a visualized platform for diagnosis of breast cancer recurrence after surgery.

In this study we fabricated a nanopillar array of silicon oxide, involving very-large-scale integration (VLSI) and reactive ion etching (RIE), as two-dimensional periodic relief gratings (2DPRGs) on Si surfaces. Thiolated oligonucleotide was successively immobilized on the thiol functionalized surfaces of 2DPRGs by disulfide bond as an optical probe to detect a human genomic DNA (hgDNA584), related to breast cancer recurrence after surgery, from a biological specimen. The oligonucleotide-bound 2DPRG alone produces insignificant structure change, but upon hybridization with hgDNA584 leads to a dramatic change of the pillar scale due to hgDNA584 filling inside the 2DPRG layers. The performance of the sensor was evaluated by capturing hgDNA584 on the oligonucleotide-bound 2DPRGs and measuring the effective refractive index (neff), resulting of color change from pure blue to red, observed by naked eyes along an incident angle of 20-30°. The surface-bound 2DPRG based assay with the chemoresponsive diffraction grating signal transduction scheme results in an experimentally simple DNA detection protocol, displaying attributes of both detection methodologies: the high sensitivity and selectivity afforded by 2DPRG probes and the experimental simplicity, and miniaturization potential provided by the diffraction-based sensing technology.

Bioconjugated Fluorescent Polymeric Nanoparticles for Imaging and Targeted Therapy of HER2-Overexpressing Cancer Cells

We report the development of Herceptin-conjugated fluorescent polymeric nanoparticles (PNp) probes. Synthesis of fluorescent conjugated polymer as the core, preparation of the core/shell PNp, the ability of immobilizing Herceptin on PNp, targeting and imaging of bioconjugated PNp toward HER2-overexpressing cancer cells, and therapeutic effect on cell cycle, together with the expression of apoptosis related proteins, were investigated. We have achieved active tumor targeting by rapid PNp-antibody binding to tumor-specific antigens. Besides, Herceptin-conjugated PNp can suppress the growth of HER2-overexpressing cancer cells.

Pultruded fibre-reinforced furfuryl alcohol resin composites: 1. Process feasibility study

Abstract Furfuryl alcohol (FA) prepolymer was developed to fabricate pultruded fibre-reinforced FA resin composites. FA monomer with p -toluene sulfonic acid was used to synthesize the FA prepolymer, which provided a good balance between processing parameters (including pot life, reactivity and wetting ability) and properties of the composites. The reactions occurring during synthesis of the FA prepolymers and the post-curing treatment were investigated by 1 H n.m.r. and i.r. spectroscopies. It was found that the mechanical properties of the composites increase with increasing die temperature or decreasing pulling rate. From the study on the mechanical properties of the composites, it was found that an optimum post-cure time exists when the post-cure temperature is above 200°C. It was also found that three kinds of reaction - crosslinking, chain extension polymerization and the transformation of the methylene ether linkage to a methylene linkage -occur during the post-curing treatment.

The biological stimuli for governing the phase transition temperature of the "smart" polymer PNIPAM in water.

A lack of sufficient knowledge regarding the behaviour of stimuli-responsive polymers to biological stimuli hinders the potential use of responsive polymers as biomaterials and medical devices. Hence, in this study, we demonstrate the impact of various globular proteins on the phase transition temperature of poly(N-isopropylacrylamide) (PNIPAM) in an aqueous solution through the use of fluorescence spectroscopy, dynamic light scattering (DLS), Fourier transform infrared (FTIR) spectroscopy and field-emission scanning electron microscopy (FESEM). Furthermore, we describe the molecular interaction of PNIPAM with proteins by the MolDock method. Our experimental and docking studies revealed that such proteins as α-chymotrypsin (CT), insulin (In) and haemoglobin (Hb) decreased the lower critical solution temperature (LCST) of the polymer, whereas succinyl-concanavalin A (SCA) increased the LCST of PNIPAM. The LCST changed upon increasing the concentration of protein from 0.5mg/mL to 1mg/mL. The thermoresponsive behaviour of PNIPAM can be significantly altered by the functional groups present in the protein. The findings of the present study can be used in the engineering of bioresponsive smart PNIPAM-based devices.