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Item type:Item, Conducting Ag/oligothiophene complex pastes through a simple quenching/chelation method(2014-08-14) ;Lu, Fang-Hsien ;Chang, Feng-Chih ;Mohamed, Mohamed-Gamal ;Liu, Tzeng-FengChao, Chuen-GuangThis paper describes a simple and environmentally friendly approach-a facile, one-pot, quenching/ chelation method-for the fabrication of a silver paste in the form of Ag/oligothiophene complex composites. These Ag/oligothiophene complex composites possess excellent conductivities of 1.8 x 10(4) S cm(-1) in the bulk state and 6.08 x 10(2) S cm(-1) in the form of thin films. We have used X-ray diffraction (XRD). X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) to characterize the microstructures of these novel Ag/oligothiophene complex composites.Item type:Item, Thermal properties and liquid crystallinity of side-chain azobenzene copolymer containing pendant polyhedral oligomeric silsequioxanes(2010-11-01) ;Wang, Xiao-Tao ;Yang, Ying-Kui ;Yang, Zhi-Fang ;Zhou, Xing-PingLiao, Yong-GuiVinylated polyhedral oligomeric silsesquioxane (POSS-M) was prepared by the reaction of POSS containing amine groups with acrylic acid. Azobenzene liquid crystalline copolymer (LCP-POSS) was then synthesized with 6.0 mol% POSS-M and 94.0 mol% acrylate monomer containing azobenzene liquid crystalline moiety (Azo-M) by free-radical copolymerization. Homopolymer of Azo-M (LCP) was also synthesized under the same conditions. Their thermal properties and liquid crystallinity were characterized by Thermal gravimetric analysis (TG), differential scanning calorimetry (DSC), Wide-angle X-ray diffraction experiments (XRD) and polarized optical micrographs (POM). The results showed that LCP-POSS has higher thermal stability and glass transition temperature than pure LCP due to the incorporation of the rigid cage-like POSS. Especially, LCP-POSS exhibits enantiotropic smectic and nematic liquid crystalline behaviors, its smectic-nematic transition temperature (T (SN)) and nematic-isotropic transition temperature (T (NI)) are higher than those of pure LCP, which may promote and extend its applications on stimuli-responsive materials and devices.Item type:Item, Removal of Hg2+ from Aqueous Solution Using a Novel Composite Carbon Adsorbent(2009-05-15) ;Chang, Yu-Hsin ;Hsieh, Kuo-Huang ;Chang, Feng-Chih ;應用化學系Department of Applied ChemistryA novel composite carbon adsorbent (GCA) has been prepared by immobilizing activated carbon and genipin-crosslinked chitosan into calcium alginate gel beads via entrapment and applied to the removal of mercury (Hg2+) ions from aqueous solution (e.g., drinking water). Two bead sizes and two mixing ratios of components were obtained and characterized. Batch experiments were performed to study the Uptake equilibrium and kinetics, of Hg2+ ions by the GCA. The Hg2+ adsorption capacity of GCA was found to be dependent of pH and independent of size of the adsorbent. The Hg2+ adsorption rate of GCA increases with decreasing its bead size. However, both adsorption capacity and rate of GCA for Hg2+ increase with increasing its chitosan content. Otherwise, it was shown that the GCA has higher Hg2+ adsorption capacity and rate than activated carbon, which might he caused by the incorporation of chitosan into the GCA. The maximum Hg2+ adsorption capacity of GCA was found to be 576 mg/g, which is over seven times higher than that of activated carbon. Our results reveal the uniform distribution of activated carbon and chitosan within the alginate gel bead and that Hg2+ ions can diffuse inside the bead. It also demonstrated the feasibility of using this GCA for Hg2+ removal at low pH values. The Hg2+ absorbed beads of the GCA can be effectivelY regenerated and reused using H2SO4. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 112: 2445-2454, 2009Item type:Item, Improved reliability from a plasma-assisted metal-insulator-metal capacitor comprising a high-k HfO2 film on a flexible polyimide substrate(2010-01-01) ;Meen, Jagan Singh ;Chu, Min-Ching ;Kuo, Shiao-Wei ;Chang, Feng-ChihKo, Fu-HsiangWe have used a sol-gel spin-coating process to fabricate a new metal-insulator-metal (MIM) capacitor comprising a 10 nm-thick high-k thin dielectric HfO2 film on a flexible polyimide (PI) substrate. The surface morphology of this HfO2 film was investigated using atomic force microscopy and scanning electron microscopy, which confirmed that continuous and crack-free film growth had occurred on the film surface. After oxygen (O-2) plasma pretreatment and subsequent annealing at 250 degrees C, the film on the PI substrate exhibited a low leakage current density of 3.64 x 10(-9) A cm(-2) at 5 V and a maximum capacitance density of 10.35 fF mu m(-2) at 1 MHz. The as-deposited sol-gel film was completely oxidized when employing O2 plasma at a relatively low temperature (ca. 250 degrees C), thereby enhancing the electrical performance. We employed X-ray photoelectron spectroscopy (XPS) at both high and low resolution to examine the chemical composition of the film subjected to various treatment conditions. The shift of the XPS peaks towards higher binding energy, revealed that O-2 plasma treatment was the most effective process for the complete oxidation of hafnium atoms at low temperature. A study of the insulator properties indicated the excellent bendability of our MIM capacitor; the flexible PI substrate could be bent up to 10(5) times and folded to near 360 degrees without any deterioration in its electrical performance.Item type:Item, Highly reliable Si3N4-HfO2 stacked heterostructure to fully flexible poly-(3-hexylthiophene) thin-film transistor(2011-08-01) ;Meena, Jagan Singh ;Chu, Min-Ching ;Wu, Chung-Shu ;Chang, Feng-ChihKo, Fu-HsiangA new and fully flexible Si3N4-HfO2 stacked poly-(3-hexylthiophene) p-type thin film transistor (P3HT-TFT) was successfully fabricated on thin semi-transparent polyimide (PI) substrate. The success of the TFT manufacturing adopts: (a) very simple and cost-effective sol-gel spin-coating technique to obtain 10-nm high-k HfO2 as dielectric layer over fully flexible PI substrate; (b) 50-nm silicon nitride (Si3N4) as the most efficient passivation layer on top of HfO2 film; (c) bendable 30-nm P3HT channel film by spin-coating method. Current-electric field characteristics of HfO2 layer in metal-insulator-metal (MIM) and TFT configurations, with or without Si3N4 passivation layer, were carefully evaluated. The origin of unsatisfactory leakage current in MIM and TFT structures could be effectively suppressed by means of Si3N4 film as the efficient passivation layer. The bottom-gate TFT demonstrated the on-to-off ratio 2 x 10(4) for drain current, -1.9 V threshold voltage and good saturation mobility (0.041 cm(2) V (1) s (1)). The proposed devices were examined in convex and concave types of various radii of curvature (R-C) in order to explore the manufacturing feasibility and electrical reliability of the fully flexible TFT for practical applications. In addition, various folding times and environmental stability on aforementioned devices with respective to electrical performances were also evaluated. (C) 2011 Elsevier B.V. All rights reserved.Item type:Item, Plasma-enhanced flexible metal-insulator-metal capacitor using high-k ZrO2 film as gate dielectric with improved reliability(2010-08-01) ;Chu, Min-Ching ;Meena, Jagan Singh ;Cheng, Chih-Chia ;You, Hsin-ChiangChang, Feng-ChihWe demonstrate a new flexible metal-insulator-metal capacitor using 9.5-nm-thick ZrO2 film on a plastic polyimide substrate based on a simple and low-cost sal-gel precursor spin-coating process. The surface morphology of the ZrO2 film was investigated using scan electron microscope and atomic force microscope. The as-deposited ZrO2 film under suitable treatment of oxygen (O-2) plasma and then subsequent annealing at 250 degrees C exhibits superior low leakage current density of 9.0 x 10(-9) A/cm(2) at applied voltage of 5 V and maximum capacitance density of 13.3 fF/mu m(2) at 1 MHz. The as-deposited sol-gel film was completely oxidized when we employed O-2 plasma at relatively low temperature and power (30 W), hence enhancing the electrical performance of the capacitor. The shift (Zr 3d from 184.1 eV to 184.64 eV) in X-ray photoelectron spectroscopy of the binding energy of the electrons towards higher binding energy; clearly indicates that the O-2 plasma reaction was most effective process for the complete oxidation of the sol-gel precursor at relatively low processing temperature. (C) 2010 Elsevier Ltd. All rights reserved.Item type:Item, Immobilization of Layered double Hydroxides in the Fluidic System for Nanoextraction of Specific DNA Molecules(2010-01-01) ;Chen, Jem-Kun ;Chan, Chia-Hao ;Chang, Feng-Chih ;應用化學系Department of Applied ChemistryThe purpose of this study was to immobilize inorganic layered double hydroxides (LDHs) on the poly(methylmethacrylate) (PMMA) substrate as the media to extract the specific DNA molecules through fluidic system to enhance the efficiency of extract specific DNA molecules from extreme low concentration in sample solution. The encapsulated DNA molecules released through dissolve of LDHs by slight acid (PH=4-5) solution then amplified by polymerase chain reaction (PCR), process through the primers for E. coli cells. The results show that immobilized LHDs could be regarded as the specific DNA detector in the sample solution mixed biomacromolecules for rapid disease diagnosis through fluidic system.Item type:Item, Highly efficient drug delivery systems based on functional supramolecular polymers: In vitro evaluation(2016-03-15) ;Cheng, Chih-Chia ;Chang, Feng-Chih ;Kao, Wan-Yi ;Hwang, Shiaw-MinLiao, Li-ChuanThe novel concept of modifying and enhancing the properties of existing functional micelles through self-complementary interactions has significant potential. In this study, a practical approach to living polymerization of functionalized thermoresponsive monomers enabled the incorporation of self constituted multiple hydrogen bonded groups into micelles that have potential as supramolecular drug-delivery systems. Phase transitions and morphological studies in aqueous solution showed that the microstructure can be controlled to achieve well-defined vesicle-like micelles with respect to the strength of the hydrogen bond segment. Thus, the resulting micelles have a very low critical micellization concentration and very high loading capacity (16.1%), making the loading process extremely stable and efficient. Incorporation of the anticancer drug doxorubicin (DOX) affected the micellization process in aqueous solution and enabled fine-tuning of drug loading and precise control of drug release rate with excellent sensitivity. Release studies in vitro showed that DOX-loaded micelles exerted dose dependent cytotoxicity against human liver carcinoma (HepG2) cells at the physiological temperature of 37 degrees C. In addition, DOX-loaded micelles were efficiently endocytosed by the cancer cells, which may enable the micelles to serve as suitable vehicles for effective delivery of anticancer drugs to primary tumors and metastatic disease. This newly developed material may provide a potential route towards next-generation drug delivery vehicles. Statement of Significance A breakthrough innovation in water-based thermo-responsive polymers has enabled significant progress in developing smart stimuli-responsive nanocarriers by generating novel "supramolecular polymeric micelles" via self-complementary hydrogen-bonding interactions. These newly developed micelles exhibit extremely high micellar stability and drug loading capacity (up to 16%), excellent thermo-responsive behavior and precise control of drug release rate due to hydrogen-bond-induced physical cross-linking. In addition, doxorubicin-loaded micelles were efficiently endocytosed by the cancer cells, which allows them to serve as suitable vehicles for effective delivery of anticancer drugs to primary tumors and metastatic disease. Thus, this work provides a potential route for the development of next generation multifunctional nanocarriers that have improved safety and to increase the therapeutic efficacy of anticancer therapy. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.Item type:Item, Functionalized graphene nanomaterials: new insight into direct exfoliation of graphite with supramolecular polymers(2016-01-01) ;Cheng, Chih-Chia ;Chang, Feng-Chih ;Wang, Jui-Hsu ;Chen, Jem-KunYen, Ying-ChiehA novel urea-cytosine end-capped polypropylene glycol (UrCy-PPG) can self-assemble into a long-range ordered lamellar microstructure on the surface of graphene, due to the strong specific interactions between UrCy-PPG and graphene. In addition, the graphene composite produced exhibits a high conductivity (similar to 1093 S m(-1)) with a dramatic thermo-responsive ON/OFF resistance-switching behavior (10 consecutive cycles).Item type:Item, Supramolecular Assembly Mediates the Formation of Single-Chain Polymeric Nanoparticles(2015-10-01) ;Cheng, Chih-Chia ;Chang, Feng-Chih ;Yen, Hsiu-Che ;Lee, Duu-JongChiu, Chih-WeiA breakthrough innovation in water-based polymeric nanoparticles has enabled significant progress in mimicking the folding of natural proteins by generating novel "single-chain polymeric nanoparticles" (SCPNs) via supramolecular interactions. In this study, a practical approach to the living polymerization of functionalized oligo(ethylene glycol) methacrylate monomers allows the incorporation of self-constituted multiple hydrogen-bonded groups into physically cross-linked polymer networks, which enables the formation of highly functionalized SCPNs in an aqueous environment. The newly developed materials are particularly attractive from a practical point of view since they have a very low critical micellization concentration and uniform particle diameters of ca. 25 nm, making them extremely stable under dilute conditions. Concentration-dependent experiments showed that SCPNs formed at polymer concentrations up to 40 mg/mL with no significant change in morphology observed. Moreover, the formed SCPNs had a very high stability in an aqueous solution containing surfactant, suggesting potential for a wide variety of applications as a promising candidate nanocarrier for bioimaging, controlled release, and drug delivery systems.