Browsing by Author "Huang, Chih-Feng"

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A "Plug and Play" polymer through biocomplementary hydrogen bonding
(2008-10-01)
Cheng, Chih-Chia
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Huang, Chih-Feng
;
Yen, Ying-Chieh
;
Chang, Feng-Chih
;
應用化學系
This article describes a DNA-like polymer that exhibits the ability to self-assemble through hydrogen bonding. We synthesized poly[1-(4-vinylbenzyl)thymine] (PVBT) and 9-bexadecyladenine (A-C16) through an atom transfer radical polymerization (ATRP) and alkylation, respectively. Biocomplementary PVBT/A-C16 hierarchical supramolecular complexes formed in dilute DMSO solution through nucleobase recognition, that is, hydrogen bonding interactions between the thymine (T) groups of PVBT and the adenine (A) group of A-C16; evidence for this molecular recognition was also gained from dynamic light scattering studies. H-1 NMR titration studies in CDCl3 showed that T-A complexes formed rapidly on the NMR time scale with high association constants (up to 534 M-1). Moreover, FTIR spectroscopic, differential scanning calorimetry, wide-angle X-ray diffraction, and small-angle X-ray scattering analyses provided further details into the nature of the self-assembly of these systems. In the bulk state, these complexes self-assemble into well-ordered lamellar structures; the changing d-spacing distance (ranging from 4.98 to 2.32 nm) at different A-C16 loadings reveals that the molecular structures of the PVBT/A-C16 complexes are readily tailored. (C) 2008 Wiley Periodicals, Inc.
Bioinspired assembly of functional block-copolymer nanotemplates
(2013)
Lin, I. -Hong
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Cheng, Chih-Chia
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Chuang, Wei-Tsung
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Chen, Jem-Kun
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Jeng, U. -Ser
A new concept on bioinspired assembly of functional diblock copolymers, capable of forming different microstructures through nucleobase-induced supramolecular interactions, has been explored. In this paper, a new series of uracil-functionalized poly(epsilon-caprolactone)-b-(4-vinylbenzyl uracil)s (PCL-b-PVBU) have been prepared which exhibit a high self-complementary ability in solution and solid states owing to the formation of uracil-uracil pairs by induced hierarchical self-assembly. The ordered morphologies of PCL-b-PVBU diblock copolymers changed from a lamellar, hexagonally packed cylinder to a sphere with respect to the content of the hydrogen bond segment. Moreover, we further show that the PCL segment could be easily extracted by enzymatic degradation, leading to a cylinder porous structure of long-range order, which gives a facile method for the fabrication of uracil-functionalized nanotemplates. In addition, bio-complementary PCL-b-PVBU/9-hexadecyladenine (AC16) hierarchical supramolecular complexes formed through strong cooperative hydrogen bonding between the uracil group of PVBU and the adenine group of A-C16. When the mixing ratios of PCL-b-PVBU/AC16 differ from the stoichiometric ratio, these complexes self-assemble into well-ordered lamellar and hexagonal structures; the changing morphology at different AC16 loadings reveals that the molecular structures of the PCL-b-PVBU/AC16 complexes are readily tailored.
Characterization of patterned poly(methyl methacrylate) brushes under various structures upon solvent immersion
(2009-10-15)
Chen, Jem-Kun
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Hsieh, Chih-Yi
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Huang, Chih-Feng
;
Li, Po-min
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應用化學系
In this paper we describe a graft polymerization/solvent immersion method for generating various patterns of polymer brushes. We used a very-large-scale integration (VLSI) process and oxygen plasma system to generate well-defined patterns of polymerized methyl methacrylate (MMA) on patterned Si(1 0 0) surfaces through atom transfer radical polymerization (ATRP). After immersion of wafers presenting lines of these PMMA brushes in water and tetrahydrofuran, we observed mushroom-and brush-like regimes through grafting densities and surface coverages, respectively, for the PMMA brushes with various pattern resolutions. In the mushroom-like regime, the distance between lines of PMMA brushes was smaller than that of the lines patterned lithographically on the wafer; in the brush-like regime, this distance was approximately the same. This new strategy allows polymer brushes to be prepared through graft polymerization and then have their patterns varied through solvent immersion. (C) 2009 Elsevier Inc. All rights reserved.
Effect of an organically modified nanoclay on low-surface-energy materials of polybenzoxazine
(2008-07-16)
Fu, Huei-Kuan
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Huang, Chih-Feng
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Kuo, Shiao-Wei
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Lin, Han-Ching
;
Yei, Ding-Ru
Novel low surface free energy materials of polybenzoxazine/organically modified silicate nanocomposites have been prepared and characterized. The CPC (cetylpyridinium chloride)/ claylo%/poly(3-phenyl-3,4-dihydro-2H-1,3-benzoxazine) (PP-a) material possesses an extremely low surface free energy (12.7 Mj. M-2) after 4 h curing at 200'C, which is even lower than that of poly(tetrafluoroethylene) (22.0 Mj. M-2) calculated on the basis of the threeliquid geometric method. X-Ray photoelectron spectroscopy (XPS) shows a higher silicon content on the surface of the nanocomposites than for an average composition, which implies that the clay is more preferentially enriched on the outermost layer. In addition, the glass transition temperature (Tg) of the polybenzoxazine (PP-a) in the nanocomposite is 22.6'C higher and its thermal decomposition temperature is also 31.5'C higher than the pure PP-a. This finding provides a simple way to prepare low surface energy and high thermal stability materials.
Effect of intermolecular hydrogen bonding on low-surface-energy material of poly(vinylphenol)
(2007-04-07)
Lin, Han-Ching
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Wang, Chih-Feng
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Kuo, Shiao-Wei
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Tung, Pao-Hsiang
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Huang, Chih-Feng
We discovered that poly(vinylphenol) (PVPh) possesses an extremely low surface energy (15.7 mJ/m(2)) after a simple thermal treatment procedure, even lower than that of poly(tetrafluoroethylene) ( 2.0 mJ/m(2)) calculated on the basis of the two-liquid geometric method. Infrared analyses indicate that the intermolecular hydrogen bonding of PVPh decreases by converting the hydroxyl group into a free hydroxyl and increasing intramolecular hydrogen bonding after thermal treatment. PVPh results in a lower surface energy because of the decrease of intermolecular hydrogen bonding between hydroxyl groups. In addition, we also compared surface energies of PVPh-co-PS (polystyrene) copolymers (random and block) and their corresponding blends. Again, these random copolymers possess a lower fraction of intermolecular hydrogen bonding and surface energy than the corresponding block copolymers or blends after similar thermal treatment. This finding provides a unique and easy method to prepare a low-surface-energy material through a simple thermal treatment procedure without using fluoro polymers or silicones.
Formation of honeycomb structures and superhydrophobic surfaces by casting a block copolymer from selective solvent mixtures
(2007-02-02)
Tung, Pao-Hsiang
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Kuo, Shiao-Wei
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Jeong, Kwang-Un
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Cheng, Stephen Z. D.
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Huang, Chih-Feng
Poly(vinyl phE!nol)-block-polystyrene (PVPh-b-PS) diblock copolymers are synthesized by sequential anionic polymerization with sec-butyl lithium as the initiator. The Pvph-b-PS diblock copolymer is cast (on a substrate) from several solvent mixtures that contain tetrahydrofuran/toluene ratios of 1:0.1, 1:1, and 1:2. After solvent evaporation the resulting films are characterized by SEM, TEM, and contact angle measurements. A honeycomb structure is fabricated from the vesicle structure at relatively low toluene contents. On the contrary, at relatively higIier toluene contents, a micelle structure with porous microspheres is formed, which possesses higher surface roughness and results in film surface superhydrophobicity. The simple method described here that uses common/selective mixed solvents may be easily extended to prepare honeycomb structures and superhydrophobic surfaces simultaneously from a wide variety of block copolymers by carefully controlling the weight composition of the block copolymer and the selective solvent con-tent.
Glass transition temperature enhancement of PMMA through copolymerization with PMAAM and PTCM mediated by hydrogen bonding
(2010-02-15)
Lin, Chien-Ting
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Kuo, Shiao-Wei
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Huang, Chih-Feng
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Chang, Feng-Chih
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應用化學系
A series of poly(methyl methacrylate-co-methacrylamide-co-tricyclodecyl methacrylate) (PMMA-co-PMAAM-co-PTCM) copolymers possessing high glass transition temperatures and high transparency are prepared. By incorporating the aliphatic tricyclodecyl methacrylate moiety into the PMMA-co-PMAA main chain results in high glass transition temperature and high transparency of PMMA-based polymeric material. The TCM content affects the fraction of hydrogen bonding in these terpolymers, small content of TCM does not sacrifice the fraction of hydrogen-bonded association in and does not cause T(g) decrease. The extent of free amide group plays the major role in dictating moisture absorption of terpolymers. The incorporation of TCM significantly reduces the moisture absorption of terpolymers due to its hydrophobic and bulky tricyclodecyl group. In addition, the TCM plays the role of inert diluent to convert portion of the strong self-associated hydrogen bonded amide groups into inter-associated hydrogen bonding between carbonyl groups of ester units and MAAM. (C) 2010 Elsevier Ltd. All rights reserved.
Homopolymerization and Block Copolymerization of N-Vinylpyrrolidone by ATRP and RAFT with Haloxanthate Inifers
(2009-11-10)
Huang, Chih-Feng
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Nicolay, Renaud
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Kwak, Yungwan
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Chang, Feng-Chih
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Matyjaszewski, Krzysztof
Difunctional haloxanthate inifers were used for successive reversible addition-fragmentation transfer (RAFT) polymerization of N-vinylprrolidone (NVP) and atom transfer radical polymerization (ATRP) of styrene (St), methyl actylate (MA), and methyl methacrylate (MMA). Since a quantitative dimerization of NVP in the presence of bromoxanthate inifer occurred, two chloroxanthate mifers, S-[1-methyl-4-(6-chloropropionate)ethyl acetate] O-ethyl dithrocarbonate (CPX) and S-[1-methyl-4-(6-chloroisobutyrate)ethyl accetate] O-ethyl dithiocarbonate (CiBX), were synthesized. These two difunctional chloroxanthate imfers were used to prepare PNVP-b-PSi, PNVP-b-PMMA, AND PNVP-b-PMA block copolymers, where each block was synthesized by different polymerization procedures (either RAFT or ATRP). In the RAFT-first approach, well-controlled polymerization of NVP was observed. Well-defined PNVP-b-PSt (M(n, GPC) = 15,000 G/MOL AND M(w)/M(n) < 1.4 and PNVP-b-PMMA (M(n, GPC) = 50,600 g/mol and M(w)/M(n) < 1.3) were successfully synthesized through a subsequent chain extension by ATRP. A reshuffling reaction between propagating acrylate radicals in poor control of the MA chain extenstion. In the ATRP-first approach a well-controlled polymerization was observed only for the ATRP of MMA with the CiBX initrator (M(n) = 13,000 and M(w)/M(n) < 1.3). Significant reshuffling reactions between the xanthate moiety and styryl/acrylate propagating radicals were observed with the CPX initrator. This resulted in poor control and broad molecular weight distribution for the subsequent RAFT chain extension of NVP. Thus, teh chloroxanthate inifers provide synthetic access to well-defined PNVP-b-PSt and PNVP-b-PMMA, but not to PNVP-b-PMA block copolymers.
Hydrogen-bonding interactions mediate the phase behavior of an A-B/C block copolymer/homopolymer blend comprising poly(methyl methacrylate-b-vinylpyrrolidone) and poly(vinylphenol)
(2006-08-08)
Lee, Hsin-Fang
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Kuo, Shiao-Wei
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Huang, Chih-Feng
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Lu, Jiann-Shing
;
Chan, Shih-Chi
We have investigated a new type of A-B/C blend, formed between poly(methyl methacrylate-b-vinylpyrrolidone) and poly(vinylphenol) (PMMA-b-PVP/PVPh), that displays unusual phase behavior. In this blend, the PMMA (A) and PVP (B) blocks within the PMMA-b-PVP (A-B) copolymer are miscible; although PVPh (C) experiences attractive interactions (xi <= 0) through hydrogen bonding, with both the PVP and PMMA blocks, its interaction with the former block is significantly stronger than that with the latter (xi(BC) >> xi(AC)). We investigated the miscibility and phase behavior of this novel A-B/C blend through the use of FTIR spectroscopy, DSC, C-13 CP/MAS solid-state NMR spectroscopy, and TEM. The proton spin-lattice relaxation time in the rotating frame (T-1 rho(H)), which we determined using 13C NMR spectroscopy, indicates that phase separation occurs for blends containing ca. 20-60 wt % PVPh. TEM images indicated clearly that the morphology of phase separation consists of a matrix of homogeneous mixed PVP/PVPh and micellar domains of excluded PMMA. This special phase behavior and miscibility is due mainly to the diversity of interactions that exist between the PMMA/PVPh and PVP/PVPh units.
Investigation of NiSi fully-silicided gate on SiO2 and HfO2 for applications in metal-oxide-semiconductor field-effect transistors
(2006-07-01)
Huang, Chih-Feng
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Tsui, Bing-Yue
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電子工程學系及電子研究所
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Department of Electronics Engineering and Institute of Electronics
Effective work function modulation (phi(m,eff)) and the thermal/electrical stability of NiSi fully-silicided (FUSI) gates on SiO2 and HfO2 are investigated. A new method, implant-to-silicide, differing from the,pre-doped method, is used to realize Phi(m,eff) adjustments. The Phi(m,eff) of NiSi FUSI gates on SiO2 can be tuned by incorporating BF2+ or P+ dopants after silicidation. Nevertheless, the Fermi-pinning effect was observed in the NiSi/HfO2 gate which limits the Phi(m,eff) adjustment. A thin SiO2 interfacial layer can reduce the Fermi-pinning effect. A NiSi FUSI gate on SiO2 is thermally stable up to 600 degrees C. The thermal stress and impurity diffusion after a prolonged 600 degrees C annealing degraded the oxide integration. The temperature of the post-silicidation process should be as low as possible to lessen the thermal stress and impurity diffusion.
Low threshold voltage CMOSFETs with NiSi fully silicided gate and Modified Schottky barrier source/drain junction
(2007)
Lin, Chia-Pin
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Tsui, Bing-Yue
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Hsieh, Chih-Ming
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Huang, Chih-Feng
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電子工程學系及電子研究所
Low threshold voltage CMOSFETs with NiSi fully silicided gate and Modified Schottky barrier source/drain junction were fabricated. Symmetric threshold voltage was obtained by implant-to-silicide technique. Lateral growth rate and thermal stability of NiSi on SiO2 were investigated. Single silicide and low temperature process make the proposed process very promising in sub-45nm technology nodes.
Miscibility and hydrogen-bonding behavior in organic/inorganic polymer hybrids containing octaphenol polyhedral oligomeric silsesquioxane
(2008-09-04)
Yen, Ying-Chieh
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Kuo, Shiao-Wei
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Huang, Chih-Feng
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Chen, Jem-Kun
;
Chang, Feng-Chih
In this study, we Investigated the miscibility behavior and mechanism of interaction of poly(methyl mechacrylate) (PMMA), poly(vinyl pyrrolidone) PVP, and PMMA-co-PVP blends with octa(phenol)octasilsequioxane (OP-POSS). For the PMMA/OP-POSS binary blend, the value of the association constant (K(A) = 29) was smaller than that in the poly(vinyl phenol) (PVPh)/PMMA (K(A) = 37.4) and ethyl phenol (EPh)/PMMA (K(A) = 101) blend systems, implying that the phenol groups of the OP-POSS units in the PMMA/OP-POSS blends interacted to a lesser degree with the C=O groups of PMMA than they did in the other two systems. In addition, the ionic conductivity of a LiClO(4)/PMMA-co-PVP polymer electrolyte was increased after blending with OP-POSS.
Nucleobase-grafted polycaprolactones as reversible networks in a novel biocompatible material
(2013)
Lin, I. -Hong
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Cheng, Chih-Chia
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Huang, Cheng-Wei
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Liang, Mei-Chih
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Chen, Jem-Kun
A series of nucleobase-grafted polycaprolactones have been prepared which exhibits a high complementary ability in solution and solid states owing to the formation of uracil-adenine pairs by induced hierarchical self-assembly. In addition, they can self-organize into spherical structure and result in excellent biomaterial properties.
PMSE 226-Synthesis and characteristics of hydrogen-bonding supramolecules composed of octaphenol-functionalized polyhedral oligomeric silsesquioxane
(2008-04-06)
Lu, Chu-Hua, Jr.
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Huang, Chih-Feng
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Chang, Feng-Chih
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應用化學系
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Department of Applied Chemistry
PMSE 229-Synthesis and characterization of stimuli-responsive ZnS/PNIPAM hollow spheres
(2008-08-17)
Fu, Huei-Kuan
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Huang, Chih-Feng
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Kuo, Shiao-Wei
;
Chang, Feng-Chih
;
應用化學系
POLY 368-Synthesis of photoisomerizable block copolymers by atom transfer radical polymerization
(2008-08-17)
Huang, Chih-Feng
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Matyjaszewski, Krzysztof
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Chang, Feng-Chih
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Russell, Thomas P.
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應用化學系
POLY 369-Controllably living polymerizations of poly(e-caprolactone)-block-poly(4-vinylpyridine) for two-phase extraction of metal ions
(2008-08-17)
Lu, Chu-Hua, Jr.
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Huang, Chih-Feng
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Chang, Feng-Chih
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應用化學系
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Department of Applied Chemistry
Polybenzoxazine as a mold-release agent for nanoimprint lithography
(2007-05-22)
Wang, Chih-Feng
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Chiou, Shih-Feng
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Ko, Fu-Hsiang
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Chen, Jem-Kun
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Chou, Cheng-Tung
One of the most important tasks remaining to be resolved in nanoimprint lithography is the elimination of the resist sticking to the mold during demolding. Previously, the main approach was to apply a thin layer of fluorinated alkyl silane mold-release agent on the surface on the mold; however, this involves complicated steps and high costs. The low surface free energy material polybenzoxazine provides an efficient mold-release agent for silicon molds that is easier to process, costs less, and has no side reactions.
Polyhedral oligomeric silsesquioxane containing copolymers for negative-type photoresists
(2006-09-22)
Lin, Ho-May
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Wu, Shi-Yin
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Huang, Pei-Yuan
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Huang, Chih-Feng
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Kuo, Shiao-Wei
A series of methacrylate copolymers containing polyhedral oligomeric silsesquioxane (POSS) was synthesized from the free radical copolymerization of methacrylic acid, methyl methacrylate, and isobutyl propylmethacryl polyhedral oligosilsesquioxanes, and then were modified with glycidyl methacrylate to serve as negative-type photoresists. The UV/Vis spectroscopy reveals that the incorporation of POSS moiety into the copolymer results in a slight decrease in transparency from 99 to 92.5% (at wavelength = 365 nm). The photosensitivity in terms of resist sensitivity (D-n(0.5)), contrast (gamma), and photopolymerization rate are significantly increased with increase in the POSS content. In addition, the induction time is reduced from 0.520 to 0.515 min after incorporating the POSS unit based on photo-DSC analyses. These observed results can be rationalized as due to hydrogen bonding interactions between siloxane and hydroxyl groups in copolymers which tend to attract the methacrylate double bonds surrounding POSS units to crosslink, thereby enhancing the photopolymerization rate and sensitivity. We further evaluate the lithographic property of a photoresist under a collimated exposure.
Preparation of the stimuli-responsive ZnS/PNIPAM hollow spheres
(2009-02-23)
Fu, Huei-Kuan
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Kuo, Shiao-Wei
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Huang, Chih-Feng
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Chang, Feng-Chih
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Lin, Han-Ching
Novel quantum dots ZnS/poly(N-isopropylacrylamide) (PNIPAM) hybrid hollow spheres were obtained by localizing free radical polymerization of NIPAM and crosslinker (MBA) at the peripheral of PCL nanoparticles, followed by biodegradation of PCL with an enzyme of the Lipase PS. The formation of ZnS/PNIPAM hollow spherical structures and the thermo-sensitive reversible properties was systematically investigated by transmission electron microscopy (TEM) and dynamic light scattering (DLS), respectively. The ZnS/PNIPAM hollow spheres possess the photoluminescence properties and a swelling and deswelling at about 32 degrees C, which agrees well with the slight red shift in photoluminescence spectra. (c) 2009 Elsevier Ltd. All rights reserved.