bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular Ordering of Vacuum‐Deposited 4,4′,4″‐tris(N‐(1‐naphthyl)‐N‐phenylamino) triphenylamine Thin Films
Authors: Oh Sung , Cho Young‐Rae , Choe Youngson , Park Dae‐Won 
Published: March 2007

AbstractA thin film of vacuum deposited 1‐TNATA(4,4′,4″‐tris(N‐(1‐naphthyl)‐ N‐phenylamino)triphenylamine) is placed between indium tin oxide (ITO) electrode and a hole transporting layer (HTL) in OLEDs. The molecular ordering of 1‐TNATA thin film is obtained by thermal annealing and electromagnetic field. As‐deposited 1‐TNATA thin films were not molecularly ordered according to Raman spectra results. Thermal annealing after deposition lead to closer stacking of 1‐TNATA molecules and made the 1‐TNATA film well‐ordered. While thermal annealing at 110 °C, the average surface roughness decreased from 10.2 to 7.2 nm.
Synthesis and Optical Nonlinearity of Thermally Stable Polyimides Incorporated with Electro‐Optic Chromophore as Side Chain
Authors: Ju Hyun Kyung , Lim Jong Sun , Yoon Sung Cheol , Lee Changjin , Choi Dong Hoon , Park Seung Ku , Kim Dong Wook 
Published: March 2007

AbstractWe prepared thermally durable nonlinear optical (NLO) polymers, based on a polyimide attached with a NLO chromophore as a side‐chain. The polyimide with two aromatic hydroxyls in the repeat unit was prepared by condensation polymerization between 2,2‐bis(3‐amino‐4‐hydroxyphenyl) hexafluoropropane and oxydiphthalic anhydride in DMAc, followed by imidization reaction. Mitsunobu coupling was carried out to incorporate the NLO chromophore into the polyimide backbone, to yield the side‐chain polymer with a loading level of the chromophore up to 65 wt%. The thermal characterization of the polymer showed that the NLO polyimide had Tg at 168 °C and was thermally stable up to 370 °C. The polymer solution was spin coated on the ITO glass to produce an optical quality film. The electro‐optic coefficient of the film was obtained using 1.55 µm laser source, giving 31 pm/V with an electrical poling field of 1 MV/cm. The temporal stability of the polymer was confirmed over 330 h at 85 °C under nitrogen condition.
Different Flocculation Behaviors Between Ternary‐Amine Polystyrene Latex and Poly(styrenesulfonate): Probe Charge Effect
Authors: Lee Yun‐Ha , Choi Young‐Wook , Park Jaejung , Park Myeong‐Sam , Go Seung‐Yong , Kang Hak‐Hee , Paik Ungyu , Sohn Daewon 
Published: March 2007

AbstractThe flocculation of strong polyelectrolyte, poly(styrene sulfonate), (PSS) with ternary amine‐functionalized polystyrene particles was investigated by dynamic light scattering (DLS). Ternary amine particles that show stable dispersion in pH 10 undergo different flocculation in a low pH conditions. In pH 3 condition, particles present fast aggregation and irreversible process (coagulation) but in pH 7 solution particles show slow aggregation and reversible process (depletion‐induced flocculation). By adding strong polyelectrolyte, aggregation rapidly removed in pH 7 but retained some concentration (about 5 mg/L) in pH 3. The homogeneity exponent λ to characterize the different flocculation behaviors presents not only difference as a function of pH but also distinction as a function of concentration in pH 3.
Supramolecular Nanodevice Based on Helical Encapsulation of Photo/Electroactive Oligomers
Authors: Je Jongtae , Kim Oh‐Kil 
Published: March 2007

AbstractOligophenylenevinylene (OPV)‐based A‐D‐A chain chromophores were synthesized by symmetrically linking electron‐ or energy‐acceptor units through an alkyl spacer. Phto‐induced thru‐space electron/energy‐transfer (eT/ET) was investigated in the presence and absence of amylose encapsulation with respect to the spacer length (D‐A distance) and acceptor strength. Fluorescence quenching of the D‐A chromophores suggests that with the helical encapsulation, eT/ET have a discrete D‐A distance dependence while the free chromophores have mixed contributions, some from eT but largely from self‐quenching due to aggregation and/or solvent deactivation.
The Structure and Performance of Ionic Polymer‐Metal Composite Actuators Prepared via Electroless Plating Process Using Various Alcohols
Authors: Lee Jang‐Woo , Yoo Young‐Tai 
Published: March 2007

AbstractNafion™‐based ionic polymer‐metal composite (IPMC) actuators were fabricated using an electroless plating method. This study aims to improve the formation of Pt electrode in IPMCs employing various alcohols as media in the 1st deposition step instead of water. It was found that ethanol formed a thicker and well‐dispersed Pt electrode layer, whereas methanol and n‐propanol produced thinner Pt electrodes than water. Especially, IPMCs constructed in ethanol demonstrated a bending displacement comparable to conventional IPMCs processed in water without significant back relaxation attributable to a thicker and well‐dispersed Pt electrode and its high capacitance. It is also interesting to note that the IPMCs prepared in n‐propanol exhibited the fastest actuation response of all.
Surface Modification via Plasma Polymerization of Allylamine for Antibody Immobilization
Authors: Basarir Fevzihan , Cuong Nguyen , Song Woo‐Keun , Yoon Tae‐Ho 
Published: March 2007

AbstractContinuous wave and pulsed plasma polymerization coatings of allylamine were investigated for antibody immobilization as a function of plasma power, monomer pressure and treatment time, and duty cycle. Conditions were optimized by evaluating the surface amine density of plasma polymer coated samples before and after aging in dry ethanol for 3 hrs. In addition, plasma polymer coatings were characterized by contact angle analyzer, α‐step, and FT‐IR/ATR. The continuous wave plasma polymerization provided amine density of 4.8 molecules/nm2 at the optimum condition of 20 W, 1 min, and 60 mTorr, while the pulsed plasma polymerization coating resulted in further increased amine density to 5.2 molecules/nm2 at the duty cycle of 60/100.
Novel Biodegradable Molecularly Imprinted Polymers Based on Poly(3‐hydroxybutyrate)
Authors: Oh Won‐Gyun , Kim Beom Soo 
Published: March 2007

AbstractNovel biodegradable molecularly imprinted polymers (MIP) based on poly(3‐hydroxybutyrate) (PHB) were prepared and characterized. Low molecular weight PHB diol was prepared from bacterial PHB, and was used to synthesize acrylate end‐capped PHB macromer. The synthesis of hydroxyl‐telechelic PHB and acrylate end‐capped macromer was confirmed using FT‐IR and 1H NMR. PHB macromer was used to prepare biodegradable crosslinked networks by photopolymerization with functional monomer (methacrylic acid) and a model template (theophylline). The theophylline‐imprinted polymer showed higher binding capacity for theophylline than non‐imprinted polymer (NIP). The data of theopylline binding into the theopylline‐imprinted polymer correlated well with the Scatchard plot. The equilibrium binding constant (KE) and the total number of bound sites of MIP ([PS]total) were 7.1 × 103 M−1 and 18.5 µmol/g, respectively, which were estimated from the negative slope and intercept in the Scatchard plot.
Synthesis and Helicity Induction of Poly(phenylacetylene)s Bearing Crown Ether Pendants. Reversible On‐Off Switching of the Induced Helical Chirality Tunable with Temperature
Authors: Sakai Ryosuke , Kakuchi Toyoji 
Published: March 2007

AbstractCis‐transoidal poly(phenylacetylene)s bearing 15‐crown‐5 (2a) and 18‐crown‐6 (2b) were prepared by stereoselective polymerization using Rh(nbd)BPh4. In the circular dichroism (CD) spectrum of 2a in the presence of the perchloric acid salt of L‐phenylglycine (L‐Pgly· HClO4), a characteristic induced CD (ICD) was observed in the absorption range corresponding to the polymer backbone. On the contrary, the 2b/L‐Pgly · HClO4 system did not show such an ICD spectrum. The ICD intensity of the 2a/L‐Pgly · HClO4 system drastically depended on temperature, i.e., the ICD disappeared at 30 °C or higher. Thus, the on‐off switching of the ICD of 2a was controllable by either the temperature modulation or the doping/undoping process of the chiral guest.
Effects of Biodegradable Triblock Copolymers on the Microencapsulation of Ascorbic Acid‐2‐Glucoside in W1/O/W2 Multi‐Emulsions
Authors: Cho Heui Kyoung , Cho Jin Hun , Cheong In Woo 
Published: March 2007

AbstractA skin‐active functional material, AA2G (ascorbic acid‐2‐glucoside, W1 phase), was encapsulated via a stepwise emulsification method using PEO‐PLGA‐PEO and PEO‐PCL‐PEO biodegradable triblock copolymers as wall materials. The emulsion stability of the W1/O/W2 multi‐emulsions was observed using a ferroxyl test method and on‐line turbidity analysis for a short period of time. The morphology of the multi‐emulsions was observed using the laser confocal and optical microscopes. The use of copolymers in W1 phase was found to be more effective. The copolymers decreased the size of the multi‐emulsions and enhanced emulsion stability.
Preparation of Polymer/Drug Nano‐ and Micro‐Particles by Electrospraying
Authors: Park Chul Ho , Kim Min Young , Yoo Ji Youn , Kim Ki‐Hyun , Lee Jong‐Chan , Lee Jonghwi 
Published: March 2007

AbstractThe surface energy control capability of electrohydrodynamic force provides electrospraying with various potential advantages such as simple particle size control, mono‐dispersity, high recovery, and mild processing conditions. Herein, particle fabrication of biodegradable polymers using electrospraying was developed. The major processing parameters such as the conductivity of spraying liquids, flow rate, etc., were examined to obtain the successful apparatus configuration of electrospraying. The choice of a consolidation medium was critical in obtaining well‐dispersed nanoparticles. When triphenylphosphate aqueous solution was employed as a consolidation medium, its concentration was not an effective parameter to control the aggregation of primary particles. When organic solvents were employed, the processing windows of electrospraying were relatively narrow than water‐based systems.
Heparin Immobilized Small Intestinal Submucosa for Cardiovascular Applications
Authors: Jee Kyoung Soo , Bae Jin Woo , Shin Jae Seung , Han Dong Keun , Park Ki Dong 
Published: March 2007

AbstractA novel chemical modification of biological tissue was developed by the immobilization of heparin to small intestinal submucosa (SIS) using glutaraldehyde (GA). Heparinized SIS tissue was characterized by measuring in vitro plasma protein adsorption, platelet adhesion, in vitro fibroblast attachment, and in vivo calcification. Lower protein adsorption and platelet adhesion were observed on heparinized SIS than non‐modified SIS. The attachment of human dermal fibroblast on the heparinized SIS was significantly increased, and the amount of calcium deposited on the modified SIS was much less than fresh SIS. These results demonstrated that heparin immobilized SIS can be applied as a novel bioprosthesis for a variety of cardiovascular applications.
The Effects of Co‐Immobilization of Epidermal Growth Factor and Adhesion Factor on the Proliferation of Ligament Cell
Authors: Park Yong‐Soon , Seo Young‐Kwon , Lee Hwa‐Sung , Kwon Soon‐Yong , Park Jung‐Keug 
Published: March 2007

AbstractThe epidermal growth factor and cell adhesion factor were co‐immobilized on a tissue culture plate to allow the proliferation of human ligament cells. The co‐immobilized surfaces were prepared by irradiating a photo‐reactive polypeptide containing azidophenyl‐derivatized side‐chains with UV. The immobilized cell adhesion factor induced initial cell adhesion on the surfaces, and the immobilized cell growth factor appeared to induce cell proliferation. The ligament cells proliferated on the EGF‐immobilized plate until 10 days post‐culture. The co‐immobilization of the epidermal growth factor appears to be an effective method for healing an anterior cruciate ligament through the rapid proliferation of ligament cells.
Radial Flow Type Bioreactor for Bioartificial Liver Assist System Using PTFE Non‐Woven Fabric Coated with Poly‐amino Acid Urethane Copolymer
Authors: Miskon Azizi , Sasaki Noriko , Yamaoka Tetsuji , Uyama Hiroshi , Kodama Makoto 
Published: March 2007

AbstractRecently, various types of hybrid bioartificial liver using the porcine hepatocytes have been widely studied but their clinical usage is limited by various difficulties. One of the most efficient bioreactor is the radial flow system equipped with silicon oxygenator. Here, our bioreactor system provides the oxygenator and the radial flow of medium that supplies the nutrient efficiently. The adhesion and growth of the cultured hepatocytes are greatly improved by using polytetrafluoroethylene (PTFE) non‐woven fabrics coated with poly‐amino acid urethane copolymer (PAU). Its functional activities were established after being kept for one week at the high value in this bioreactor system. These results indicate that, PTFE non‐woven fabric and radial flow technique is proven to be the best bioreactor for a hybrid artificial liver support system (HALS).
Synthesis and Evaluation of PEG Derivatives for Crosslinking Cells
Authors: Ito Michiko , Tateishi Tetsuya , Taguchi Tetsushi 
Published: March 2007

AbstractThe objective of this study is synthesis, characterization, and evaluation of a novel crosslinker to form spheroids. Our approach was based on the crosslinking of cell membrane using a polymeric crosslinker via hydrophobic interaction. A crosslinker poly(ethylene glycol) derivative with oleyl groups as hydrophobic group at both ends was synthesized, and then characterized with gel permeation chromatography and Fourier‐transform infrared spectroscopy. Furthermore, cell culture experiments were performed to confirm spheroid formation. Spheroids were successfully obtained when the crosslinker was added to cell suspension. This polymeric crosslinker was useful in the formation of cell spheroid.
Electrochemical Properties of PVDF‐Based Nanocomposite Solid Polymer Electrolytes
Authors: Jeong Soo‐Kyeong , Lee Yu‐Jin , Jo Nam‐Ju 
Published: March 2007

AbstractPoly(vinylidene fluoride) (PVDF)‐based nanocomposite solid polymer electrolytes (NSPEs) were prepared and ion conduction property was investigated according to the filler content. The organically modified clay (Cloisite®15A, C15A) was used as a filler because it has had a good compatibility with PVDF. X‐ray diffraction measurement revealed the dispersion of C15A in PVDF and the states of exfoliation and intercalation of C15A were also observed by transmission electron microscopy. In order to confirm the ion conduction properties of NSPEs with LiCF3SO3, ac impedance analyzer and FT‐IR spectrometer were used. The highest ionic conductivity was appeared in NSPE containing 5wt% of C15A and the maximum conductivity was 1.04 × 10−3 S cm−1. And the improvement of electrochemical stability of NSPEs by adding C15A was confirmed.
Electrochemical Properties of PEO‐Based Polymer Electrolytes Blended with Different Room Temperature Ionic Liquids
Authors: Kim Yeon Hwa , Cheruvally Gouri , Choi Jae Won , Ahn Jou Hyeon , Kim Ki Won , Ahn Hyo Jun , Choi Doo Seong , Song Choong Eui 
Published: March 2007

AbstractPolymer electrolyte (PE) based on poly(ethylene oxide)‐lithium bis(trifluoromethane sulfonyl)imide (PEO‐LiTFSI) was blended with three room temperature ionic liquids (RTILs), namely 1‐butyl‐3‐methylimidazolium bis(trifluoromethane sulfonyl)imide (BMITFSI), 1‐butyl‐3‐methylimidazolium tetrafluoroborate (BMIBF4) and 1‐butyl‐3‐methylimidazolium trifluoromethanesulfonate (BMICF3SO3) with a view to enhance the room temperature ionic conductivity to acceptable levels for use in lithium batteries. The incorporation of 80 parts by weight (pbw) of the RTILs in 100 pbw of PEO‐LiTFSI resulted in enhanced ionic conductivity, the effect being more pronounced at lower temperatures. Evaluation of electrochemical properties showed that PEs with RTILs exhibit an electrochemical stability window between −1.0 V and 4.5 V vs Li/Li+ and good reversibility of redox reactions on cycling. The optimum results were obtained with the incorporation of BMITFSI in the PE, which exhibited a low and stable interfacial resistance on lithium metal.
Synchronous Crosslinking Imidized Polymer Electrolytes Having Fully Interpenetrating Polymer Networks (Full‐IPNs) Structure for Application in Membrane Fuel Cell
Authors: Kim Sang‐Gyun , Ahn Hae‐Ryun , Min Da‐Young , Nam Seung‐Eun , Lee Kew‐Ho 
Published: March 2007

AbstractPolymer electrolyte films having fully interpenetrating polymer networks (Full‐IPNs), composed of styrene‐maleic anhydride alternating copolymer (PSMAn) and isobutylene‐maleic anhydride alternating copolymer(PisoMAn), have been prepared by using 2,2′‐benzidinedisulfonic acid(BDSA) as the imidizing crosslinker. The resulting films were characterized by using TGA, EA, IEC, water uptake, and proton conductivity. The purpose of this work deals with the synchronous crosslinking imidization reaction of between polymers as a synthetic method, in order to prepare novel heat‐resistant polymer electrolytes for application in membrane fuel cell.
Polymer Electrolyte Membranes Based on Room Temperature Ionic Liquid: 2,3‐Dimethyl‐1‐octyl imidazolium hexafluorophosphate (DMOImPF6)
Authors: Sekhon S. S. , Lalia B. S. , Kim C. S. , Lee W. Y. 
Published: March 2007

AbstractRoom temperature ionic liquid: 2,3‐dimethyl‐1‐octylimidazolium hexafluorophosphate (DMOImPF6) has been incorporated in polyvinylidenefluoride ‐co‐ hexafluoropropylene (PVdF‐HFP) to develop non‐aqueous polymer electrolyte membranes. The conductivity of polymer electrolyte membranes depends upon the composition of ionic liquid and maximum conductivity of 1.35 × 10−3 S/cm at 120 °C has been observed. The addition of plasticizers has been found to enhance the conductivity of polymer electrolytes by one order of magnitude which depends upon the dielectric constant of plasticizer.
Study on PEFC Membrane Based on Crosslinked FEP Using EB‐Grafting
Authors: Matsuura Akio , Kakigi Tomoyuki , Sato Yukiko , Fujii Kazuki , Mitani Naohiro , Li Jingye , Oshima Akihiro , Washio Masakazu 
Published: March 2007

AbstractPolymer electrolyte fuel cell (PEFC) membranes based on crosslinked tetrafluoroethylene‐co‐hexafluoropropylene (FEP) have been fabricated by pre‐irradiation grafting method. The chemical structures of crosslinked materials have been analyzed by Differential Scanning Calorimeter (DSC) and 19F solid‐state Nuclear Magnetic Resonance (NMR) spectroscopy. The radical yields of irradiated samples were measued by Electron Spin Resonance (ESR), and the mechanism of grafting reaction has been discussed. The styrene grafted materials were sulfonated by chlorosulfonic acid. The ion exchange capacity of the obtained sulfonated crosslinked FEP (S‐FEP‐X) showed 2.0 to 2.4 meq/g, which were 2.2 to 2.7 times higher than that of Nafion®112. Glass transition temperatures (Tg) of S‐FEP‐X were almost independent on crosslinking dose of FEP, and show about 96 °C, which are slightly higher than that of Nafion®. The electrochemical properties of the membranes have been measured, and cell performances of them have been evaluated. Ionic conductivities (ICs) of S‐FEP‐X are 1.2 to 1.6 times higher than that of Nafion®. The higher network densities gave the higher open circuit voltage (OCV). The power density of S‐FEP‐600kGy was about 10% higher than that of Nafion® at 500mA/cm2. Thus, the obtained sulfonated membranes can be expected to apply for high efficiency PEFC.
Electrochemical Polymerization of Aniline by Current Pulse Method in the Presence of m‐Aminobenzoic Acid in Chlorhydric Acid Solution
Authors: Binh Phan Thi 
Published: March 2007

AbstractElectrical and structural properties of polyaniline powder doped by chloride and m‐aminobenzoic acid on graphit electrode through current pulse method have been investigated by conductivity measurement, infrared spectroscopy, thermal analysis and scanning electron microscopy. The infrared spectra for the both products showed the clear presence of benzoid and quinoid ring vibrations at 1567 cm−1 and 1489 cm−1, respectively. The microstructural observation by scanning electron microscopy showed a knitted morphology of polyaniline doped by m‐aminobenzoic acid the conductivity of which was found 0.635 S/cm, higher than that of polyaniline synthesized in chlorhydric acid solution (0.368 S/cm). The conductive materials were decomposited at about 380 degree.The detail results will be discussed below.
Synthesis and Characterization of Al(OH)3/Polystyrene Nanocomposite Latex Particles by Emulsion Polymerization
Authors: Park Eun Ju , Heo Hoon , Lim Kwon Taek 
Published: March 2007

AbstractThe inorganic/organic core‐shell type nanocomposite particles of Al(OH)3/PSt were synthesized through the emulsion polymerization of styrene (St, shell monomer) with ammonium persulfate (APS, initiator), polyoxyethylene (50) nonyl phenyl ether (NP‐1050, nonionic surfactant), and ammonium (POE) alkyl arylether sulfate (EU‐S133D, anionic surfactant) in the presence of the modified Al(OH)3 particles. The improved compatibility of Al(OH)3 surface with St achieved by the modification with 3‐(trimethoxysilyl) propyl methacrylate (γ‐MPS) enabled to form a polymer shell around the mineral particles. The structure of nanocomposites prepared from different feed ratio of Al(OH)3/St was investigated by scanning (SEM) and transmission (TEM) electron microscopies.
Functionalization of Multi‐Walled Carbon Nanotubes with Poly(2‐ethyl‐2‐oxazoline)
Authors: Tan Soon Huat , Goak Jeung Choon , Lee Naesung , Kim Jeong‐Yeol , Hong Sung Chul 
Published: March 2007

AbstractMulti‐walled carbon nanotubes (MWCNTs) were successfully functionalized with water‐soluble poly(2‐ethyl‐2‐oxazoline) (PEOX) through a polymer wrapping process. Pristine MWCNTs were first treated with nitric acid (HNO3) at 120 °C for 24 hours. The resulting carboxylated MWCNTs were then mixed with 10 wt.% PEOX in ethanol, followed by sonication using a horn‐type sonicator for 30 min and stirring at room temperature for 24 hours. Thereafter, unreacted free polymer was washed out repeatedly by centrifugation with an excess amount of ethanol. Scanning electron microscopy exhibited that the diameter of MWCNTs increased approximately by 10 nm after the functionalization of MWCNT with PEOX. Thermogravimetric analysis showed that approximately 15 wt.% polymer was incorporated in the functionalized MWCNTs. The functionalized MWCNTs gave excellent and stable dispersion in water as well as other organic solvents such as ethanol and DMF.
Fabrication of a Nano‐Porous Polyoxazoline‐Coated Tip for Scanning Probe Nanolithography
Authors: Lee Jae‐Hyuck , An Young‐Chul , Choi Dong‐Sik , Lee Myoung‐Jae , Kim Kyung‐Min , Lim Jung‐Hyurk 
Published: March 2007

AbstractA nano‐porous polyoxazoline‐coated silicon tip was developed by ring opening polymerization of 2‐methyl‐2‐oxazoline. The tip surface modified with the nano‐porous polyoxazoline has pore sizes from 30 nm to 100 nm, which can easily absorb large‐molecular‐weight biomolecules in their pores. In combination with dip‐pen nanolithograpy (DPN) technique, this can generate protein nanostructures 60 times faster than what one can obtain with the conventional silicon tip. We discuss the fabrication of the nano‐porous polymers on the surface and how to use this novel tip for scanning probe lithography‐based nanopatterning of biomolecules.