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Novel luminous aliphatic polyamides were obtained from a condensation reaction of ethylene diamines and malonyl dichloride in the presence of triethylamine. These polymers appeared in blackish red and reddish orange solids and unusually exhibited a visible light-emission. Their fluorescence properties were significantly dependent on the excitation wavelength, media polarity, and acidity. These polymers emitted fairly strong visible lights in a wide range from blue to near yellow when excited at wavelengths longer than 305 nm. The emission bands significantly shifted to longer wavelengths during the increase in the polarity of the solvent used. Their fluorescence intensities significantly increased under acidic conditions.

Two types of polymers were synthesized such as poly[N-(2-ethylhexyl)carbazole-alt-N-(4-aminophenyl)carbazole] (PECAC) and poly[N-(2-ethylhexyloxy-phenyl) carbazole-alt-N-(4-aminophenyl)carbazole] (PEPCAC). These polymers are designed to have carbazole groups with wide band gap and a triarylamine moiety with a hole transporting property. Green and red phosphorescent polymer light emitting diodes (PhPLEDs) were fabricated with an emitting layer consisting of either PECAC or PEPCAC as a host matrix with suitable iridium complexed, Ir(ppy)3 as a green or IR-PIQCH as a red dopant, respectively. Red PhPLEDs doped with IR-PIQCH exhibited maximum EL emission peaks at 620 nm with higher luminescence and lower driving voltage, due to effective energy transfer from host polymers to IR-PIQCH red dopant. Based on HOMO and LUMO levels of the polymers and Ir(ppy)3, however, the synthesized polymers could not be served as suitable host polymers for Ir(ppy)3 green dopant. Ir(ppy)3 doped PhPLEDs exhibited red shift and wid...

Novel negative-type photocurable imide UV monomers were synthesized and characterized for an application to interdielectric layer in TFT-LCD array. Two different imide-type UV monomers were synthesized through 2 step reaction. In addition, alkali developable polymer matrix was also prepared by free radical random copolymerization of benzylmethacrylate and methacrylic acid in THF at 65°C. It was found from photolithographic process that via-hole with good resolution were obtained using optimum formulations, suitable for spin coating process, of negative-type imide UV monomers, photoinitiator, UV oligomer, and alkali developable polymer matrix.

We developed a mercury free Flat Fluorescent Lamp (FFL) with a high luminance by using the same discharge mode as PDP. Our FFL has the simple structure where the glass substrates are used as the dielectric layer. The panel has a striped line shape of 7-inch diagonal size. The Xe-Ne-He mixture gas was used to generate the plasma, and the gas discharge characteristics under both total gas pressure and partial gas pressure were investigated. The panel showed a maximum high luminance 7,270 cd/m2 under biasing 20 kHz pulse of 3 kV.

A dopant, 4,4′-bis(dimethyl[4-(2-phenyl-buta-1,3-dienyl)phenyl]amine) biphenyl (BPAB), was synthesized, and single layered polymer light emitting diode (PLED)s, ITO/Host:Dopant/Al, were fabricated with blends of poly(vinyl carbazole) (PVK) as host and BPAB as dopant. The electroluminescence (EL) was observed in doped PLEDs. From the EL and photoluminescence (PL) spectra, the existence of energy transfer from host to dopant was verified. With increasing content of dopant (BPAB), blue emission originated from PVK reduced, but didn't completely disappear, suggesting inefficient energy transfer from PVK to BPAB. When the content of BPAB was 15 wt%, yellow green emission from PLED was observed due to partial energy transfer from PVK to BPAB.

Poly(1,1′-biphenyl-4,4′-ylene vinylene-alt-2,5-bis(2-ethylhexyl)-1,4-phenylene vinylene] [poly(BPV-alt-BEHPV)] as a polymeric dopant, was synthesized by Honer-Emmons condensation from corresponding dialdehyde and diphosphonate monomers. Synthesized alternating polymer was used to fabricate single layer (ITO/Host:Dopant/Al) PLEDs with poly(vinyl carbazole) (PVK) as a host. Conjugated poly(BPV-alt-BEHPV) showed green emission from single layer ITO/poly(BPV-alt-BEHPV)/Al device. Emission colors from doped PLEDs were changed by energy transfer from blue originated from PVK to green with increasing the content of poly(BPV-alt-BEHPV).

We introduce indium zinc oxide (IZO) thin films grown at room temperature by using a low-frequency (LF) 60 Hz magnetron sputtering system. The flexible substrates are PES, PET and PC. The optical, electrical and structural properties of IZO films on flexible substrates were investigated. The alloy target was In2O3:ZnO (90:10 wt%) with a diameter of 3 inch and thickness of 5 mm. The vacuum chamber was evacuated down to pressure 5 × 10−6 torr prior to deposition. The flow rates of argon gas (99.999 %) were kept at a constant value of 30 sccm by a mass flow controller(MFC). The discharges were performed by power of 300 V, 310 V, 320 V. They have low sheet resistance of about 30 Ω/sq., high transmittance of over 85 % in the range of 400–700 nm. Also they showed good band gap of about 3.43 eV on polyethersulfone (PES) substrates, 3.50 eV on polyethylene terephthalate (PET) and 3.30 eV on polycarbonate (PC). The experimental results imply that the films with good qualities in surface morphology, transmittance a...

Three-component blend system based on polyfluorene derivative ( SK32 ®), substituted polyacetlyene ( PTMSDPA ) and iridium complex ( red dopant ) were fabricated as a single emitting layer for white OLED. The two polymers and iridium complex were well mixed to provide transparent films. Its electro-optical properties were investigated in terms of emission color, brightness, and luminescence efficiency. The optimal weight ratio for white emission was 100 ( SK32 ®): 5 ( PTMSDPA ): 0.5 ( red dopant ). The color coordination at this ratio was (x = 0.33, y = 0.33), completely matching to white color. The luminance was 831 cd/m2 at 17 V, its current efficiency was estimated to 1.15 cd/A at 9 V and the maximum power efficiency reached 0.44 lm/W at 7 V.

New poly(diphenylacetylene)s with alkoxy and fluoroalkyl groups as electron-donating and electron-withdrawing groups, respectively, were synthesized by using a WCl 6 -n-Ph 4 Sn catalyst. The polymer solutions emitted strong, bluish-green lights when photo-excited. The polymers that contained the electron-donating alkoxy groups showed longer fluorescence-maximum peaks when compared to the polymers that contained the electron-withdrawing fluoroalkyl groups. However, such an effect of the substituent on the absorption property was not clearly seen. The emission bands of the solid films did not show any significant red shift, relative to that of the dilute solution.

We developed a Flat Fluorescent Lamp(FFL) with a high luminance by using the same discharge mode as PDP. Our FFL has a simple and unique structure where the glass substrates are used as dielectric layers. The panel has a striped line shape of 10 inch diagonal size. The Xe-Ne and Xe-He, Xe-Ne-He mixture gases were used to generate the plasma. The panel showed a maximum luminance 8,610cd/m2 under bias of 20kHz pulse of 2.9kV.

X-ray lithography is one of the most powerful processes in the fabrication of nano/micro structures with a high aspect ratio. This process enables the fabrication of closed-cell type ultra-slim barrier ribs for PDP. In this paper, ultra-slim barrier ribs of 12 μm upper width before sintering were fabricated by x-ray lithography.

The monomer methacryloyloxyethyl abietate (2) was synthesized by a simple two-step reaction starting from abietic acid. The homopolymerization of 2 and its copolymerization with MMA using AIBN as an initiator provided high-molecular-weight polymers 3−6 (10 × 103 300 °C. These results indicate that these polymers are thermally stable and glassy at room temperature. The absorption bands due to the conjugated carbon−carbon double bonds within the abietate group significantly decreased with an increase in the exposure doses. Normalized absorbance as a function of UV exposure doses nonlinearly changed because of the occurrence of a certain threshold at 1.0 J/cm2 in all polymers. Solvent extraction experiment re...

Ag electrodes with line width uniformity for large-sized plasma display panels were successfully fabricated through a photolithographic process using photosensitive Ag pastes with optimized photosensitive properties. The photosensitivity of the Ag electrode pastes in the photolithographic process was investigated as a function of the types and contents of photoinitiators, the molecular weights and acid values of acrylic binders with carboxylic acid groups, and the process variables, such as the UV-light intensity and dose, with a step tablet. This study revealed that the photoinitiator was a major parameter for the photosensitivity of the Ag electrode pastes. With the photosensitivity of the photosensitive Ag electrode pastes optimized by the study of the photoinitiator contents, Ag electrodes with line width uniformity were achieved with an HSP-188 photoinitiator content of 15 wt % on the basis of the reactive monomers, regardless of the variation of the light dose from 250 to 350 mJ/cm2 and intensity from 15 to 25 mW/cm2. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

Core-shell silver (Ag)–polyaniline (PAni) nanocomposites have been synthesized by the in-situ gamma radiation-induced chemical polymerization method. Aqueous solution of aniline, a free-radical oxidant, and/or silver metal salt were irradiated by γ-rays. Reduction of the silver salt in aqueous aniline leads to the formation of silver nanoparticles which in turn catalyze oxidation of aniline to polyaniline. The resultant Ag-PAni nanocomposites were characterized by using different spectroscopy analyses like X-ray photoelectron, UV–visible, and infrared spectroscopy. The optical absorption bands revealed that the bands at about 400 nm are due to the presence of nanosilver and the blue-shifted peak at ∼ 555 nm is due to the presence of metallic silver within the PAni matrix. X-ray diffraction pattern clearly indicates the broad amorphous polymer and the sharp metal peaks. Scanning electron microscopy and transmission electron microscopy of the nanocomposite showed a uniform size distribution with spherical and granular morphology. Thermogravimetric analysis revealed that the composites have a higher degradation temperature than polyaniline alone. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5741–5747, 2007

A blend of side-chain liquid crystal polymer (SCLCP) and low molecular weight liquid crystal (LMWLC) was used to investigate a phase separation behavior induced by temperature. Phase separation at room temperature was observed only for the compositions higher than 60 wt% LMWLC because of good miscibility between two components. An interesting phenomenon was observed when the film transmittance for a phase-separated sample as a function of temperature was measured under cross-polarizer. That is, transmittance below TNI of LMWLC was observed lower than that below TSI of SCLCP, which was not expected initially. The fact was considered as a micro-phase separation induced by an interfacial effect between SCLCP and LMWLC phase.

Preparation conditions of nano-size cationically charged particles (TiO2) were studied for application to electrophoretic display. It was found that highly charged TiO2 particles could be prepared by milling 1.0 g of TiO2 particles, 0.5 g of silane additive as a charge controlling agent and 0.5 g of dispersant in 100 mL of cyclohexanone as a suspension fluid for 8–10 h using pot mill, followed by treatment with 0.4 g of acetic acid. The zeta potential and mobility of white (TiO2) charged particles were measured to be 63.76 mV and 3.11 × 10−5 cm2/V s, respectively. The e-paper display panel fabricated with charged TiO2 particles exhibited low threshold voltage (10 V) and 5.32/1 contrast ratio at 30 V.

Polyazomethine-type conjugated polymers were synthesized by Schiff-base reaction. One was poly(PZ-PBI) with alternating phenothiazine (PZ) and azomethine units (-C = N-) , and the other was poly(CZ-PBI) comprising alternating carbazole (CZ) and azomethine groups. Conjugated polymers exhibited improved solubility in common organic solvents due to alkyl side chains on phenothiazine and carbazole rings as well as polar azomethine groups in main chains. Single- and double-layer PLEDs were fabricated. Their electroluminescent properties were studied from the viewpoint of polymer structure vs. emission color and efficiency.

Two types of blue electroluminescent conjugated polymers, poly(BP-alt-BCV) and poly(BFMP12-BPV), were prepared by Horner-Emmons polycondensation and used as host polymers for the phosphorescent dopant, (bsn)2Ir(acac). Poly(N-vinylcarbazole) (PVK), known as a blue emitting material, was also used for comparison with these polymers. Electrophosphorescence of PLEDs with these dopant/host systems was investigated in terms of luminescence, efficiency, emission color, and energy transfer. The poly(BP-alt-BCV) showed blue emission of high color purity (x = 0.18, y = 0.19), however, poly(BP-alt-BCV) host/phosphorescent (bsn)2Ir(acac) dopant showed red emission (x = 0.60, y = 0.37) due to an efficient energy transfer from poly(BP-alt-BCV) host polymer to phosphorescent (bsn)2Ir(acac) dopant.

Studies on the formulation of photosensitive paste for transparent soft mold press (TSMP) method have been performed. With the optimum formulation of the photosensitive paste the box-type barrier rib with good flexibility and high solvent resistance was fabricated, suitable for the panel material of the electrophoretic display. Cationically-charged white particles were prepared by using TiO2 nanoparticles, silane coupling agent with amino groups, dispersant and acetic acid. The cationically charged TiO2 particles exhibited 74.09 mV of zeta potential and 3.11 × 10-5 cm2/Vs of mobility. Electrophoretic display fabricated with the charged TiO2 particles exhibited 10 V of low driving voltage and maximum contrast ratio (5.3/1) at 30 V.

A new blue electroluminescent conjugated polymer, poly(BP-alt-BCV), was prepared by Hornor–Emmons polycondensation of [5-carbazol-9-yl-3-(diethoxy-phosphorylmethyl)-2-(2-ethyl-hexyloxy)-benzyl]-phosphonic acid diethyl ester (PHBP) and 4,4′-biphenyldicarboxaldehyde (BPCA) in the presence of tert-BuOK in THF. UV-visible absorption maximum (λmax,UV, π-π* transition) of poly(BP-alt-BCV) was measured at 340 nm. PL maximum (λmax,PL) values of poly(BP-alt-BCV) were obtained at 406 and 430 nm, when excited at its own λmax,UV. It was found that double layer [ITO/poly(BP-alt-BCV)/Alq3 (50 Å)/Al] PLED exhibited maximum EL peak at 440 nm and blue emission (x = 0.1794, y = 0.1878), similar to the NTSC standard blue (x = 0.14, y = 0.08).

A series of poly(N-vinyl carbazole)-based random copolymers containing photosensitive cinnamoyl moieties capable of generating negative type patterned images were synthesized and characterized. First, poly(N-vinyl carbazole-ran-hydroxyethyl methacrylate) copolymers, P(VK-ran-HEMA), were prepared by free radical polymerization of VK and HEMA monomers using AIBN as an initiator in THF. In second step, cinnamoyl groups were introduced by post reaction. Photoluminescent properties of synthesized photosensitive copolymers were measured and, upon UV exposure, negative patterned images with high resolution were produced by standard photolithographic process.

Novel red phosphorescent iridium complex with two phenyl-isoquinoline ligands and one 2-acetyl-cyclopentanone ligand (IR-PIQCP) was designed and synthesized. The electroluminescent (EL) characteristics of IR-PIQCP were evaluated in the EL device. The three kinds of EL devices were fabricated by the vacuum deposition method, and the layer-structures of the devices were ITO/NPD/IR-PIQCP (5%), IR-PIQCP (10%) or IR-BTPAC (10%) in CBP/Balq/Alq/LiF/Al. Emission characteristics of the IR-PIQCP (5%) and IR-PIQCP (10%) devices were about 570 cd/m2 and 550 cd/m2 at 11 mA/cm2 at the same current density respectively. The EL spectra of the IR-PIQCP (5%) and IR-PIQCP (10%) devices were detected at about 627 nm and 629 nm as the maximum peak with red phosphorescence.

Two types of photoinitiators were synthesized: (1) a α,ω-telechelic oligomeric photoinitiator, by the reaction of poly(propylene glycol) diglycidylether (PPGDGE) and 2-hydroxy-2-methyl-1-phenyl-propan-1-one (Darocur 1173), and (2) a polymeric photoinitiator, by copolymerization of a monomer that had a liquid crystalline property, 4-[ω-(2-methylpropenoyloxy)decanoxy]-4′-cyanobiphenyl, with a vinyl monomer that had a photosensitive group. For comparison, low-molecular-weight (low-MW) photoinitiator (Darocur 1173) also was used. Attention was directed to the structural effect of the photoinitiators on the electro-optical properties of polymer-dispersed liquid crystal (PDLC) film in which the LC phase occupied a major volume (80 wt % of the composite film). For the preparation of PDLC films by the polymerization-induced phase separation method, the optimum UV-curing temperature was observed at 50°C, a temperature slightly higher than the cloud temperature (Tcloud) of the low-MW LC/matrix-forming material mixture. It was found that the electro-optical performance of the PDLC cell fabricated with the oligomeric or polymeric photoinitiator was better than that of the PDLC cell made with a low-MW photoinitiator (Darocur 1173), exhibiting lower driving voltage (V90) and higher contrast ratio under identical formulation conditions. Oligomeric photoinitiators allowed premature phase separation between the LC and matrix phases, resulting in relatively pure LC-rich phases. For the polymeric photoinitiator, incorporation of mesogenic moieties into the photoinitiator resulted in not only a well-defined LC/matrix morphology but also in low driving voltage (V90) because of reduced friction at the LC/matrix interfaces. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 162–169, 2006

A novel ink-jet printing method with the precision nozzle(φ = 0.2 mm and L = 1.0 mm)for fine pattening of phosphor layer in PDP was investigated. In order to optimize the rheological properties of the phosphor paste for the precision nozzle, the composition of the paste was developed by proper combinations of binder polymer, solvnet, dispersant, phosphor powder and additives. It was found that combination of hydroxypropylcellulose and poly(methylmethacrylate-co-methacrylic acid)as binder polymer and 50 wt%of phosphor powder in the paste resulted in suitable processability to the ink-jet printing with the precision nozzle and produced phosphor layers with 29 μm of thickness after sintering process.

A new method of fabricating electrophoretic display sheet was developed utilizing a photolithographic process. In this method, stripe-type barrier ribs with height of 50–80 μm and gap between ribs of 100–150 μm were patterned on the transparent electrode substrate by photolithographic process using a negative-type photoresist. Microspheres dispersed in UV curable monomer system were closely packed into the spaces between the barrier ribs. After laminating the upper ITO film, the resulting sheet was UV-irradiated to give an electrophoretic display panel with uniform packing of microspheres.

Vinylbenzyl abietate (VBA) was synthesized by the reaction of 4-vinylbenzyl chloride with sodium abietate. VBA homopolymer and copolymers of VBA with methyl methacrylate (MMA) were prepared in benzene using azobisisobutyronitrile as an initiator. The compositions of the copolymers were measured with 1 H NMR. The monomer reactivity ratios were determined by Kelen-Tudos plot. The reactivity of VBA for the copolymerization was much larger than that of MMA. The glass transition temperature and the initial decomposition temperature of the homopolymer were higher than those of the copolymers. The polymers with the abietic acid moiety were crosslinked with UV irradiation. This result means that VBA can be a vinyl monomer for the preparation of photocrosslinkable polymers.

Linear, branched, and grafted polyamine flocculants were synthesized and applied for dye wastewater treatment. The effect of polyamines on color removal was investigated by comparing two treatments: (i) alum alone and (ii) alum/polyamine in combination. Compared to alum alone treatment, the use of polyamine flocculants in combination with alum was highly efficient in color and turbidity removal. Addition of a small amount of polyamine (40 mg/L) reduced alum dosage by 50% while improving color removal efficiency by 20%. Branched polyamines were more efficient than grafted polyamines presumably because branched polyamine has higher charge density than grafted polyamine. Our results indicate that the use of alum/polyamine system is beneficial in dye wastewater treatment. The effects of polyamine flocculants on total organic carbon removal and zeta potential were also discussed.

Barrier ribs in color plasma display panels (PDPs) function to maintain the discharge space between two glass plates as well as to prevent optical crosstalk. Patterning of barrier ribs is one of the unique processes for making PDPs. In this work, photosensitive barrier rib pastes were prepared by incorporating binder polymer, solvent, functional monomers, photoinitiator, and barrier rib powder. Studies of the function of the materials for the barrier rib paste were undertaken. After optimization of the paste formulation and photolithographic process, the barrier rib could be obtained with good resolution up to 110–120 μm height and 80–90 μm width. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2092–2099, 2002

Aromatic polyimides were synthesized from aromatic carboxylic acid dianhydrides, 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA), 4,4′-(2,2,2-trifluoro-1-phenylethylidene)diphthalic anhydride (3FDA), and pyromellitic dianhydride (PMDA), with four typical aromatic diamines. These included polyimide (PI) from 2,2-bis(4-aminophenyl)hexafluoropropane (4BDAP) by two-step procedures; amidation to polyamic acid (PAA), followed by thermal imidization of PAA. The chemical and physical properties of the newly prepared polyimides were compared in terms of their chemical structures, inherent viscosity, thermal property, transmission, dielectric constant, UV cutoff, water absorption, and refractive index. PIs 3FDA/4BDAP and 6FDA/4BDAP were soluble in common organic solvents, whereas others were not. In particular, it was found that the solubility was dependent on the temperature of imidization. The chemical and physical properties of the newly prepared polyimides derived from 3FDA were similar to the polyimides derived from 6FDA. The solubility of polyimide containing an ether functional group in the dianhydride moiety was better than that of the ether functional group in the diamine moiety. The polymers with ether linkage in dianhydride moiety exhibited lower glass transition temperature than their functionality-reversed analogous polymers with ether linkage in diamine moiety. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 38–44, 2002

Eu3+-doped Y2O3 red phosphor `was prepared in order to study the relationship between variation of Eu3+ content and an excitation source such as low and high voltage energy and a vacuum ultraviolet (147 nm). The luminescence properties of pigment-coated Y2O3:Eu by various coating methods and different energy sources were also investigated. Excitation under a vacuum ultraviolet (VUV) for the red phosphor with different amounts of Eu3+ activator exhibited similar luminescence property with the case of being excited by electrons accelerated under low voltage conditions. The surface of Y2O3:Eu red phosphor was treated with α-Fe2O3 pigment by two different methods to improve color purity. One was the adsorption utilizing α-Fe2O3 submicron-particles on the phosphor and the other was a precipitation method utilizing Fe(NO3)3-urea or -hexamethylenetetramine (HMTA). The red phosphor treated with an increasing amount of α-Fe2O3 showed decreasing luminescent intensity, but the color purity improved. The luminescent properties of phosphor treated with α-Fe2O3 pigment by the adsorption method exhibited much less dependency on the applied energy source. Surface treatment by the precipitation method, however, resulted in much a faster decrease of luminescent intensity with a lowering of the applied voltage and VUV region because of a more homogeneous coating of α-Fe2O3 pigment on the phosphor.

Unsaturated polyester (UP) resin is one of the major thermosetting resins and is very useful as a matrix resin of composite material for its processibility. UP resin, however, has several shortcomings: it is weak in alkalis, volume shrinkage occurs during the crosslinking reaction of the oligomeric UP resin with a styrene monomer, and it is also brittle. The mechanical properties of UP resin can be enhanced by blending it with various materials. In this study, polyurethane (PU) was used as a modifier to improve the toughness of the UP resin. The effect of the polyol molecular weight as a PU soft segment and the PU contents on the toughness of PU-modified UP resins were studied. A UP/PU polymer network may occur through a reaction between an isocyanate group in the methyl diisocyanate (MDI) and a hydroxyl one in the UP molecules. The maximum toughness was observed at approximately 2 wt % of the PU content. These results can be rationalized by the incorporation of a rubbery PU segment into a brittle UP resin. © 2002 John Wiley & Sons, Inc. J Appl Polym Sci 84: 735–740, 2002; DOI 10.1002/app.10169

Agglomerating agents were synthesized in a latex form utilizing a seeded emulsion polymerization method to get high solid content NBR latex without exhibiting excessively high viscosity and unstability in the concentration process. An agglomerating agent synthesized with ethylacrylate in the core part and methacrylamide as the hydrophilic monomer in the shell effectively increased the average size of the NBR base latex when it was mixed with the NBR latex and settled for about 2 h. The NBR latex, treated with the proper amount of an agglomerating agent, could be concentrated up to 60.5 wt % solid, while an untreated NBR latex could only be concentrated to 45.0 wt % solid due to the viscosity buildup. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 276–282, 2002; DOI 10.1002/app.10325

Improved electroluminescent efficiencies in polymer light-emitting diodes(LEDs) have been reported to be obtained either by constructing multi-layer devices or by using polymer blends in a light emitting layer. In this work, conjugated copolymers, poly((PZV-PV)-co-(CZV-PV)) containing (N-2-ethylhexyl)-3,6-phenothiazinylene vinylene(PZV) unit and (N-2-ethylhexyl)-3,6-carbazolylene vinylene(CZV) unit in different ratio were synthesized by Horner-Emmons reaction utilizing potassium t -butoxide. Homopolymers, poly(PZV-PV) and poly(CZV-PV) were also synthesized. Polymer LED's fabricated with poly(PZV-PV) and poly(CZV-PV) homopolymers as light emitting layers exhibited EL maximum at 570 nm amd 500 nm, respectively. LED's made with poly((PZV-PV)-co-(CZV-PV)) copolymers, however, showed EL maxima shifted to longer wavelengths.

Transparent conducting electrode film is highly desirable for application in touch screen panels (TSPs), flexible and wearable displays, sensors, and actuators. A sputtered film of indium tin oxide (ITO) shows high transmittance (90%) at low sheet resistance (50 Ω/cm2). However, ITO films lack mechanical flexibility, especially under bending stress, and have limitation in application to large-area TSPs (over 15 inches) due to the trade-off in high transmittance and low sheet resistance properties. One promising solution is to use metal mesh-type transparent conducting film, especially for touch panel application. In this work, we investigated such inter-related issues as UV imprinting process to make a trench layer pattern, the synthesis of core-shell-type Ag and Cu@Ag composite nanoparticles and their paste formulation, the filling of Ag and Cu@Ag mixture nanoparticle paste to the trench layer, and touch panel fabrication processes.

Highly flexible and efficient silver nanowire-based organic light-emitting diodes (OLEDs) have been successfully fabricated by employing a n-type hole injection layer (HIL). The silver nanowire-based OLEDs without light outcoupling structures exhibited excellent device characteristics such as extremely low turn-on voltage (3.6 V) and high current and power efficiencies (44.5 cd A(-1) and 35.8 lm W(-1)). In addition, flexible OLEDs with the silver nanowire transparent conducting electrode (TCE) and n-type HIL fabricated on plastic substrates showed remarkable mechanical flexibility as well as device performance.

Three types of conjugated polymers, poly(PZ‐Pi), poly(PZ‐BPI) and poly(PZ‐NPI) were synthesized by Schiff‐base reaction. These new conjugated polymers exhibited improved solubility in common organic solvents due to the presence of alkyl side chains as well as azomethine groups, Double layer LEDs made with the synthesized polymers as emitting layer and Alq3 as electron transporting layer exhibited enhanced EL emission and efficiency compared to those of single layer LEDs. Double layer LEDs exhibited gradual shift in the emission peak th the single layer LED, made of only Alq3 as the emitting layer as the thickness of Alq3 layer increased.

Polyamine flocculants were synthesized and applied for the removal of color, turbidity, and organic compounds from dye wastewater. The effect of polyamine on color removal was investigated by comparing 2 treatments: 1) alum alone and 2) alum/polyamine in combination. The effects of polyamine flocculant, concentration, types, and pH on the removal efficiency of colored materials were investigated. Polyamine flocculants were highly efficient in the removal of color and turbidity from dye wastewater. Compared with alum alone treatment, an addition of 25 mg/L of polyamine could reduce alum dosage by more than 50% and improve the color and turbidity removal efficiency. Highly efficient color removal was obtained by adding polyamine as a flocculant at widely different pH ranges. Results indicate that the use of polyamine flocculant is cost effective in dye wastewater treatment because it minimizes the amount of sludge produced as the dosage of inorganic coagulant is highly reduced. Effects of zeta potential and...

Aromatic dialdehyde based on phenothiazine and aromatic diamine were used to synthesize polyazomethine type conjugated polymer, poly(PZ-PI) which had good solubility in common organic solvents. The UV absorption maximum(λmax,UV) and edge(λedg,UV) of poly(PZ-PI) were observed at 415 and 510 nm, respectively. The threshold voltage of ITO/polymer/Mg and ITO/polymer/Alq3(100 A)/Mg device was at 10 V and 7 V, respectively. Besides double layer LED with Alq3 exhibited both enhanced emission intensity and efficiency compared to the single layer LED.

In this study, polyamine flocculants were synthesized and applied to Nak-dong river raw water in Korea to examine their efficiency in reducing turbidity, total organic carbon (TOC) and UV254. Synthesized polyamines were effective as flocculants for water treatment and the addition of organic polymer caused a reduction of 50-80% of the consumption of polyaluminium chloride (PAC). The effects of polyamine on the removal of turbidity, TOC and UV254 were investigated via both jar and pilot tests. The adsorption and separation mechanisms for the removal of turbidity and TOC by using the polymer flocculants were also observed.

Four types of conjugated polymers, poly(MEHPV‐PV), poly(MEHPV‐BPV), poly(MEHPV‐AV) and poly(PZV‐AV) were synthesized by Horner‐Emmons reaction using potassium tert‐butoxide. The Horner‐Emmons reaction gave electroluminescent(EL) copolymers in good yield. Of the EL copolymers synthesized, poly(PZV‐AV) containing phenothiazinylene vinylene and anthrylene vinylene as repeat unit exhibited red color in the light emitting diode(LED) which was very close to the NTSC standard red. Besides, double layer LED made with Alq3 electron transport layer exhibited both enhanced emission intensity and efficiency compared to the single layer LED.

Photocrosslinkable polyimide-type non-linear optical (NLO) polymers were obtained by multi-step reactions. Polyimide substrate polymer (P05) made from 3,3′-diamino-4,4′-dihydroxybiphenyl (HAB) and aromatic dianhydride (6FDA) had higher molecular weight than other polyimides due to the high nucleophilicity of the amine group in HAB compared to the one in 2,2′-bis(3-amino-4-hydroxyphenyl)hexafluoropropane(Bis-AP-AF) with the electron-withdrawing group. The introduction of DR-1 chromophore into the polyimide substrate polymers depended on the steric factor between the bulky DR-1 chromophore and the substrate polyimide in the polymer reaction via the Mitsunobu reaction. In the DR-i substituted NLO polyimides, Tg decreased with the increasing amount of DR-1 chromophore. Photocrosslinkable NLO polyimide (P05-DR-cin) was obtained by the introduction of the photoreactive cinnamoyl group into the DR-1 substituted polyimides. The electro-optic coefficient (r33) of the NLO polymer was determined with an exp...

Poly(ethylene terephthalate) (PET) texture was exposed to oxygen plasma glow discharge to produce peroxides on its surfaces. These peroxides were then used as catalysts for the polymerization of acrylic acid (AA) in order to prepare a PET introduced by a carboxylic acid group (PET-A). Chitosan and quaternized chitosan (QC) were then coupled with the carboxyl groups on the PET-A to obtain chitosan-grafted PET (PET-A-C) and QC-grafted PET (PET-A-QC), respectively. These surface-modified PETs were characterized by attenuated total reflection Fourier transform IR spectroscopy, electron spectroscopy for chemical analysis, and a contact angle goniometer. The amounts of AA, chitosan, and QC grafted on the PET surfaces as determined by the gravimetric method were about 6, 8, and 9 μg/cm2, respectively. The antibacterial activity of the surface-modified PET textures was investigated using a shake flask method. After 6 h of shaking, the growth of bacteria was markedly inhibited by PET with ionically (86% in PET-A−-C+) and covalently (75% in PET-A-C) grafted chitosan and with covalently grafted QC (83% in PET-A-QC). After the laundering the inhibition of the growth of the bacteria was maintained in the range of 48–58%, showing the fastness of the chitosan-grafted PET textures against laundering. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2769–2778, 2001

Prior to curing, we evaluated thermal stability of poly(butylene succinate) (PBS). Above 170°C, PBS was severely degraded and the degradation could not be successfully stabilized by an antioxidant. PBS was crosslinked effectively by DCP at 150°C, and the gel fraction was increased as DCP content increased. The major structure of crosslinked PBS is supposed to consist of an ester and an aliphatic group. The tensile strength and elongation of PBS were improved with increasing content of DCP, but tear strength was only slightly affected. The higher the crosslinking, the lower the heat of crystallization (ΔHc) and heat of fusion (ΔHf). However, the melt crystallization temperature (Tc) of crosslinked PBS was higher than that of PBS. The viscosity of crosslinked PBS increased and exhibited rubbery behavior as the content of curing agent increased. The biodegradability of crosslinked PBS did not seriously deteriorate. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1115–1124, 2001

Two types of conjugated polymer, poly(MEHPV-co-BPV)s and poly (MEHPV-alt-BPV), were synthesized by dehydrohalogenation and Honer-Emmons condensation, respectively. Single layer type light-emitting diodes were fabricated utilizing synthesized polymers and their electro-optical properties were examined. Emission spectrum of poly (MEHPV-co-BPV)s had two peaks in the blue and orange region which originated from BPV and MEHPV moiety, respectively. This may be due to the mixture of two homopolymers or the macroblock nature of the BPV and MEHPV unit in the poly(MEHPV-co-BPV)s. However, LED made from poly(MEHPV-alt-BPV) showed a relatively sharp single peak at the yellow-green region due to the alternating nature of the repeat units.

Both fully conjugated polymer poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene vinylene-alt-9,10-anthrylene vinylene] [poly(MEHPV-AV)] and conjugated/nonconjugated block copolymers poly(alkanedioxy-2-methoxy-1,4-phenylene-1,2-ethenylene-9,10-anthrylene-1,2-ehthenylene-3-methoxy-1,4-phenylene)[poly(BFMPx-AV), (x = 4, 8, and 12)] were synthesized by Horner–Emmons reaction utilizing potassium tert-butoxide. Of these synthesized polymers poly(BFMP4-AV) and poly(BFMP8-AV), which has four and six methylene groups as solubility spacer in the main chain exhibited liquid crystalline to isotropic transition in addition to the two first order transitions. Light-emitting diode (LED)s made from the organic solvent soluble poly(BFMP12-AV) as emitting layer showed blue shift in the emission spectrum compared to the one made from fully conjugated poly(MEHPV-AV). Although poly(BFMP12-AV) had higher barrier to the electron injection from cathode than poly(MEHPV-AV), the luminance efficiency of LED made from poly(BFMP12-AV) was about 25 times higher than the one made from poly(MEHPV-AV), which had fully conjugated structure. LEDs fabricated by both poly(BFMP12-AV) and poly(MEHPV-AV) exhibited Stoke's shift in the range of 155 to 168 nm from the absorption maximum due to the excimer formation between the ground and excited state anthracene groups. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 3173–3180, 2000

Thermally stable poly(α-methyl styrene-co-maleimide) (MSMI) and poly(α-methyl styrene-co-4-carboxyphenyl maleimide) (MSCM) substrate polymers were obtained readily by free radical polymerization of comonomers. Introduction of a DR1 chromophore to the maleimide units of MSMI substrate polymer by the Mitsunobu reaction was dependent on the reaction solvent. The degree of substitution of DR1 into the MSMI polymer was bound to be 91.1 mol % and 0.4 mol % by UV spectrometers in the THF and DMF solvent, respectively. DR1 chromophore was, however, substituted in the MSCM polymer at 33.0 mol % by Mitsunobu reaction in the THF solvent. Both substrate and NLO polymer exhibited high thermal stability due to the incorporation of maleimide units in the polymer chain. The glass transition temperature (T g ) and initial decomposition temperature (T i ) of the NLO polymer were in the range of T g = 185°C and T i = 310-345°C. The electro-optic coefficient (r 33 ) of NLO polymer was determined with an experimental setup capable of the real-time measurement while varying both the poling field and temperature. The NLO polymer MSMI-THF had a higher r 33 value than MSCM-DR due to an increased degree of substitution of DR1 chromophore. MSMI-THF had a maximum r 33 value of 16 pm/V at 135 MV/m poling field with a 632.8 nm light source.

Copolymerizations of p-dichlorobenzene (DCB)/4-bromophenyl ether (BPE), DCB/4,4'-dibromobiphenyl (DBB), and DBB/BPE pairs with sodium sulfide under high temperature (270-290°C) utilizing N-methyl-2-pyrrolidinone (NMP) as solvent were carried out to give C(DCB/BPE), C(DCB/DBB), and C(DBB/BPE) copolymers, respectively. The reactivity of dihaloaromatic monomers toward thiolate anion in the polycondensation reaction followed the order DBB > DCB > BPE. The reactivity gap between DBB and DCB toward thiolate anion seemed to be smaller than that between BPE and DCB, resulting in both high yield and high molecular weight in the C(DCB/DBB) copolymers compared to C(DCB/BPE) copolymers. The copolymerization of DBB/BPE pair with sodium sulfide, which has larger reactivity gap than the DCB/ DBB or DCB/BPE pair, gave mixtures of PBS and PPSE homopolymers especially in the range of 50-80 mol % BPE in the feed. The C(DCB/DBB) and C(DCB/BPE) copolymers, however, exhibited random copolymer character in all comonomer ratios in the feed as evidenced by copolymer composition and DSC data.

Photoinduced nematic (N)-to-isotropic (I) and thermal I–N phase transition behaviour of liquid crystals (LCs) with donor–acceptor azobenzenes was investigated. Photoirradiation of mixtures of the azobenzenes and host LC resulted in N–I phase transition due to trans–cis photoisomerisation of the azobenzenes, and the N phase recovered when the irradiated sample was kept in the dark because of thermal cis–trans back-isomerisation. Time-resolved measurements with a laser pulse (355 or 532 nm; 10 ns fwhm) revealed that the photoinduced N–I phase transition took place within 200–300 µs in all samples. The rate of the thermal I–N phase transition was affected strongly by the strength of the donor and the acceptor. The response time of the thermal I–N phase transition corresponded closely to the lifetime of the cis isomer of the azobenzenes, hence we can conclude that the rate-determining step of the thermal recovery of the N phase was the cis–trans isomerisation process. The time necessary for the thermal I–N phase transition decreased with increasing donor and acceptor strength, because the thermal cis–trans isomerisation of the azobenzene with a stronger donor–acceptor pair became faster. The N phase recovered within 500 ms in the mixture of the azobenzene (with tertiary amine as the donor and nitro group as the acceptor) and host LC at 37°C.