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Three types of fullerene (C60)-end-capped poly(4-diphenylaminostyrene) (C60–PDAS) and poly(4-diphenylaminostyrene) (PDAS) blends were prepared to investigate their potential as bipolar polymer semiconductors. The concentration of C60 in the C60–PDAS/PDAS blends strongly affected the hole and electron drift mobility values; the hole drift mobility decreased with an increase in the C60 concentration. However, the electron drift mobility increased with an increase in the C60 concentration. The hole and electron drift mobility values were almost the same for the 1/2 C60–PDAS/PDAS blend; therefore, this polymer blend was thought to be a bipolar polymer semiconductor. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Semiconducting polymers, poly(1,4-phenylene) (PPP) and poly(4-diphenylaminostyrene) (PDAS), which are soluble to organic solvents, were synthesized and were deposited by means of electrospray deposition (ESD). The ESD generated spherical shells of diameters ranging from a few to several tens of microns. The shells consisted of coagulation of nanometric particles of the semiconducting polymers. Formation of the shells was largely influenced by the concentration of spray solution. It was also found that the formation of shells can be achieved with various types of soluble polymers.

Block copolymerization of plural types of monomers offers a new opportunity for the preparation of a variety of multifunctional polymers. Poly(4-diphenylaminostyrene) (PDAS)-poly(9-vinylanthracene) (PVAN) binary block copolymer (PDAS-PVAN) was synthesized by (living) anionic polymerization using the benzyllithium/N,N,N′,N′-tetramethylethylenediamine system. The photoluminescence emission of PDAS-PVAN was enhanced by the fluorescence resonance energy transfer from PDAS block to PVAN block in PDAS-PVAN. The hole drift mobility of the copolymer was controllable by the amount of triphenylamino groups in the polymer chain. The optical and electrical properties of PDAS-PVAN were adjustable through the polymer chain structure. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Physical vapor deposition polymerization was achieved by evaporating vinyl monomers followed by heat treatment. This technique was utilized for preparing a hole-transport layer (HTL) and emissive layers (EMLs) of organic light emitting diodes (OLEDs). Adivinyl derivative of tetraphenyldiaminobiphenyl, DvTPD, was used both for the HTL and for the host material of red phosphorescent EML. A vinyl derivative of bis(N-carbazolyl)benzene, vmCP, was used for the host material of blue phosphorescent EML. The ELMs were doped with red or blue-emitting phosphorescent iridium complexes modified with styril units. After characterizing the devices that have single EML of red or blue emission, an OLED having multilayered ELM was prepared by stacking these layers to achieve quasi-white emission. It was found that the deposition polymerization was effective to improve the emission efficiency. The improvement appeared to be related to the proper carrier balance in the EML.

Hole transport copolymers consisting of 3,4-ethylenedioxythiophene (EDOT) and N-4-butylphenyl-N,Ndiphenylamine (BTPA) were synthesized by oxidative coupling reaction using FeCl3 as an oxidant. These copolymers showed good solubility and their thin films showed sufficient morphological stability. The copolymers showed an absorption maximum around 320 nm. Copolymers had an oxidation peak at approximately 1.03∼1.14 V versus the Ag/AgCl electrode. The hole mobility increased with increasing portion of the EDOT unit. The hole mobility of the copolymer containing 57% of the EDOT unit showed the highest mobility of 3×10-5 cm2/V·s.

Soluble poly(para-phenylene) having a long polymer chain (more than six repeat units) was synthesized with a tert-butyl end-group (t-PPP) and was found to have improved solubility and excellent optical properties. Poly(1,3-cyclohexadiene) (PCHD) consisting of only 1,4-cyclohexadiene (1,4-CHD) units was synthesized with a tert-butyl end-group (t-PCHD), and completely dehydrogenated to obtain t-PPP. This end-group effectively prevented the crystallization of t-PPP, and polymers containing up to 16 repeat units were soluble in tetrahydrofuran. Soluble t-PPP obtained had an ability to form a tough thin film prepared by spin-coating method. Optical analyses of t-PPP provided strong evidence for a linear polymer chain structure. A block copolymer of t-PPP and a soluble polyphenylene (PPH) was then synthesized, and the excellent optical properties were retained by this block copolymer along with its solubility.

Organic light-emitting diodes were prepared by coevaporating 4,4'-N,N'-dicarbazolylbiphenyl (CBP) host material, tris(2-phenylpyridinate) iridium(III) [Ir(ppy)3] dopant material, and their vinyl derivatives for the emissive layer. It was found that the emission spectrum changes with time during device operation when both the host and the dopant molecules have vinyl groups. This spectral change corresponded to the transition of emission from vinyl-modified Ir(ppy)3 to nonmodified Ir(ppy)3. The spectral transition was more prominent when an acrylate derivative was used in place of a vinyl derivative of CBP. A similar change in luminescence spectrum was observed when the film was polymerized by thermal annealing or electron-assisted deposition. It is speculated that the spectral transition is caused by the copolymerization of host and dopant molecules during device operation. Such a current-induced polymerization can be a novel and convenient method of preparing polymeric thin films by the physical vapor deposition of functional monomers.

Organic light-emitting diodes (OLEDs) were prepared by a deposition polymerization method, in which vinyl monomers were evaporated and then annealed after deposition. N,N'-diphenyl-N,N'-bis(4-vinylphenyl)benzidine (DvTPD) was used both for a hole transport layer (HTL) and for the host material of an emissive layer (EML). bis(1-phenylisoquinoline)acetylacetonate iridium(III) [Ir(piq)2acac] and its styryl derivative bis(1-phenylisoquinolinate)-6-(4-vinylphenyl)acetylacetonate iridium(III) [Ir(piq)2acac-vb] were used as dopants. Ir(piq)2acac and Ir(piq)2acac-vb showed comparable emission characteristics. The device lifetime was improved by the thermal polymerization of DvTPD, and it was further improved by polymerizing both the host and dopant molecules to form a copolymer instead of a molecularly dispersed EML. In addition, the device with a codeposition-polymerized EML showed a small tendency of luminescence efficiency to decrease with increasing luminance. Deposition polymerization, achieved by evaporating vinyl monomers followed by thermal annealing, can be a promising method for constructing OLED structures.

Photoconductive poly(4-butyltriphenylamine) particles were prepared by a chemical oxidative dispersion polymerization. The utilization of statistical copolymer of methyl methacrylate with 2-hydroxyethyl methacrylate (30:70) as a dispersant afforded particles with the narrowest distribution when the other experimental conditions such as the rate of monomer feed, and the dispersant concentration were appropriately selected. Porous particles were obtained at 40 °C using poly(vinyl pyrrolidone) as a dispersant.

A new electroluminescent polymer was prepared by oxidative coupling copolymerization of N -(4- n -butylphenyl)phenoxazine (PPX) and 9,9-di- n -butylfluorene (DBF) using iron(III) chloride. The obtained polymers were soluble in common organic solvents and had number-average molecular weight as high as 10,000. The UV–vis absorption maximum and photoluminescence peak shifted to longer wavelengths with the increase of PPX content. The increase of PPX content also caused increase of hole mobility and decrease of electron mobility. A simple single-layer light-emitting-diode device having a structure of indium tin oxide/polymer/Ca/Al was fabricated. The polymer containing 30% of PPX unit showed highest electroluminescent properties with a maximum luminance of 1084 cd/m 2 at 15.5 V operating voltage.

Polystyrene (PSt)/poly (4-butyltriphenylamine; PBTPA) composite particles was prepared by a chemical oxidative seeded dispersion polymerization of (4-butyltriphenylamine) with PSt seed particles that were prepared by nonaqueous dispersion polymerization of styrene. Monodisperse composite particles were obtained when the ratio of monomer to seed, the rate of monomer feed, and poly(N-vinyl pyrrolidone; PVP) concentration was appropriately selected. The introduction of PBTPA was confirmed by the presence of the characteristic absorption band attributed to PBTPA from a Fourier transform infrared spectra. The solvent extraction with ethyl acetate revealed that composite particles consisted of PSt core and PBTPA shell. Then two-dimensional arrays of composite particles were also fabricated.

We report fluorescence lifetime studies of a charge-transfer dye, dimethyl-amino-N-acetyl-3-aminobenzanthrone, embedded in a series of polymer matrices. In all polymers studied, the fluorescence lifetime has two components, indicating the existence of two classes of molecular environments. Microscopic studies on sub-ensembles of the dye molecules carried out in PMMA and PVAc matrices reveal that the polymer films are spatially heterogeneous with respect to their physical properties on scales of more than few hundreds of nm. The heterogeneity further increases on molecular scale, as observed by fluorescence lifetime distribution of the dye in the PMMA matrix.

The optical and electrical characteristics of soluble polyphenylene (PPH) homopolymers obtained by the complete dehydrogenation of poly(1,3-cyclohexadiene) (PCHD) are reported for the first time. The optical properties were strongly affected by the molar ratios of 1,2-/1,4-phenylene (Ph) units. The HOMO and LUMO energy levels were approximately −5.2 and −2.0 eV, and the microstructure did not influence those energy levels or the band gap energies. The generation of carriers (both electron and hole) in the polymer films was observed, and the drift mobility of electrons and holes was affected by the molar ratios of 1,2-/1,4-Ph units in the polymer chain. The drift mobility of electrons in PPH homopolymers with a high content of 1,4-Ph units was in the order of 10 −4 to 10 −5 (cm 2 /Vs). The I – V characteristics of soluble PPH homopolymers were controllable by the microstructure of PPH. The 1,2-Ph unit imparted appropriate solubility and toughness to the PPH homopolymers.

Photorefractive active block copolymers were successfully synthesized via an atom transfer radical polymerization of acrylate containing liquid crystalline moiety and hole transporting carbazole moiety. Resulting copolymers were characterized by gel permeation chromatography, NMR, and DSC. Copolymers afforded the transparent films showing birefringent nature. Photorefractive characteristics of copolymers with 2 wt% of trinitro- fluorenone as a photosensitizer were investigated by four wave mixing and two-beam coupling methods with a He-Ne laser. For the block copolymer, higher diffraction efficiency and larger coupling gain were observed compared with the corresponding statistical random copolymer.

We report the preparation of a new electroluminescent polymer by the oxidative coupling copolymerization of N-(4-n-butylphenyl)phenoxazine and 9,9-di-n-butylfluorene with ferric(III) chloride. The reaction yields soluble polymers with a weight-average molecular weight as high as 9000. The reactivity has been studied with respect to the reaction time, temperature, and feed ratio of the comonomers. Under optimum conditions, a copolymer with a 50% comonomer incorporation ratio can be obtained in a 75% yield. The polymers have been characterized with differential scanning calorimetry, cyclic voltammetry, and optical spectroscopy. A simple single-layer light-emitting-diode device of an indium tin oxide/polymer/Mg-Ag structure shows a luminance of 200 cd/m 2 at an 18-V operating voltage.

We report a concept of organic molecular charge dopant in organic-inorganic composites and study its effect on the composite conductivity. Thin film composites are prepared from a 1:1 dispersion of TiO2 or other metal oxide particles in a polymer binder. Introduction of a small percentage of triphenylamine (TPA) derivative dopants increases the dark conductivity by up to five orders of magnitude. This phenomenon is explained in terms of electron donation by the dopant to a continuous network of aggregated metal oxide particles.

Sulfonation is one of the most commonly used methods for the surface modification of polymers. In this study, the sulfonation of poly(propylene) (PP) films with fuming sulfuric acid has been investigated with the focus onthe surface reaction. Analysis of the sulfonated PP films by X-ray photoelectron spectroscopy (XPS), attenuated total reflectance (ATR) infrared spectroscopy, and chemical modification demonstrated the formation of C=C double bonds and sulfate groups in the sulfonation process. These results and a comparison with low-density polyethylene (LDPE) films led us to propose a new sulfonation mechanism involving hydride abstraction and the formation of β-sultones.

Novel light-emitting copolymers containing 4-n-butyltriphenylamine and either anthracene, diphenylanthracene or perylene units were synthesized by polycondensation of two types of dibromides in the presence of bis(1,5-cyclooctadiene)nickel(0). The structure and incorporation ratio of the copolymers were determined by 1 H NMR analysis. From the results of yield and molecular weight measured by gel permeation chromatography, the reactivity of arene units with the 4-n-butyltriphenylamine unit shows decreasing tendency in the order diphenylanthracene>anthracene>perylene. The results of ionization potential measurement reveal that the copolymers have not only hole transporting ability but also electron transporting ability. Single-layer electroluminescent devices were fabricated using these copolymers as a charge transporting and light emitting layer.

A hyperbranched polymer (HBP) was prepared by the condensation polymerization of 4-hydroxymethylphenyldiphenylamine (TPA–CH2OH) and was compared with the corresponding linear polymer (LP) prepared by condensation polymerization of 4-methyltriphenylamine (MTPA) and formaldehyde (FA). It was found that the HBP had higher molecular weight with same molecular volume by using gel permeation chromatography (GPC) equipped with low angle laser light scattering (LALLS) and refractive index (RI) detectors. Electronic and optical properties of the two types of polymers were also examined. The two types of polymers showed almost same absorption in the UV–visible region, while HBP showed stronger emission than LP and a new excimer band at 470 nm. The cyclic voltammography showed that HBP had a redox peak around 1.22 V versus Ag/AgCl electrode, indicating that it has hole transporting ability. HBP is soluble in common organic solvents and forms good quality thin films. Their excellent morphological and thermal stability renders them advantageous for electroluminescence applications.

A new concept of inorganic nanoparticle dopant into organic hole transporting materials (HTM) is proposed for the design of semiconducting composites. Composites consisting of HTM and TiO2 nanoparticles were prepared using a polymer as a matrix. TiO2 nanoparticles were prepared by sol–gel method starting from titanium tetraisopropoxide. The particle size of TiO2 ranged from 2 to 5 nm. It was found that electrons were transferred from HTM to TiO2, leaving holes in HTM. The composites showed semiconducting characteristics with the conductivity on the order of 10−8 S/cm. A device consisting of ITO/composite/Al showed rectifying ability. The number of the holes was approximately one per 7×105 molecules of N,N,N′,N′-tetraphenylbenzidine (TPD) for the composite consisting of polycarbonate, TPD and TiO2 with the weight ratio of 100:100:3.

Semiconducting nanocomposite was prepared from tetraphenylbenzidine (TPD) and titanium oxide using polycarbonate as a binder. Titanium oxide was prepared by sol–gel process in the presence of binder and TPD. The conductance of the composite reached ca. 3×10 −8 S/cm with the titanium oxide content of 3% of TPD. The film containing only TPD or titanium oxide had conductivity lower than 10 −13 S/cm.

Multifunctional succinates have been prepared as monolithic molecular photorefractive materials which contain an electron-transporting fluorene moiety and an electrooptically active (EO) chromophore. The synthesized succinates form amorphous glass at room temperature with the aid of a flexible diester spacer and butoxycarbonyl group attached to the fluorene unit. Long-wavelength absorption bands were observed in addition to the peaks from fluorene and the EO chromophore, which are due to the charge transfer interaction between electron-accepting fluorene and electron-donating aniline units. Compounds showed photorefractivity without the addition of a photosensitizer, a polymeric binder or a plasticizer, indicating that they are completely monolithic photorefractive materials. Succinate with a 4-dicyanovinylaniline chromophore showed excellent properties, i.e., 32% diffraction efficiency at 55 V/µm and 125 cm-1 coupling gain at 65 V/µm. The electron-transporting nature of space-charge field buildup was confirmed from the coupling direction.

A novel synthetic method for the preparation of high-molecular-weight conjugated polymers in presented. It consists of the oxidation copolymerization of different arenes with triphenylamine. The structure of the copolymers was characterized by 1 H and 13 C NMR spectra. The copolymers have good solubility in common organic solvents and are thermally stable. Photoluminescence (PL) spectra (see Figure) showed that the color of emission depends on the type of arene units in the copolymer chain. Cyclic voltammetry (CV) measurements revealed electrochemical activity of the copolymers.

Hole transporting polymers were prepared by condensation polymerization of triphenylamine and N,N,N',N'-tetraphenylbenzidine (TPD) having alkyl group with aldehydes in the presence of p-toluenesulfonic acid. The obtained polymers had molecular weight higher than 10,000 and good film formation ability. It was found that the aromatic amine monomers were connected with aldehyde monomer at the p-position of the phenyl group. TPD-aldehyde polymers had almost the same UV absorption and redox potentials as those of TPD monomer indicating that the electronic structure of amine unit did not change by the polymerization. The hole transporting mobility was in the range of 10 -3 -10 -6 cm 2 /Vs. The electroluminescent device consisting of ITO/TPD polymer/Alq/Mg-Ag had a maximum luminance of 9000 cd/m 2 .

Separation of styrene - methyl methacrylate - acrylonitrile terpolymers by chemical composition was studied using high-performance liquid chromatography (HPLC). Cross-linked polyacrylamide (PAA) gel or polyacrylonitrile (PAN) gel was used as a stationary phase for normal-phase HPLC and cross-linked polystyrene (PS) gel for reversed-phase HPLC. Each system was based on a solvent gradient, and the separation was governed by an adsorption mechanism. Terpolymers were successfully separated by the cross-fractionation, i.e., the combination of two types of HPLC systems with PAN and PAA columns or PAN and PS columns. The chemical composition distribution (CCD) of a high-conversion terpolymer was analyzed by this cross-fractionation technique with the combination of PAA and PAN columns. The CCD obtained experimentally was reasonably consistent with that of theoretical calculation.

A new acrylate bearing N,N′-diphenyl-N,N′-bis(4-methylphenyl)-[1,1′-biphenyl]-4,4′-diamine (TPD) was synthesized to apply for hole transport layer of an electroluminescent (EL) device. The thin film of this monomer was fabricated with physical vapor deposition. The obtained thin film was preliminarily irradiated with UV light and then heated up to 400 K in vacuum. The resulting polymer film, 60 nm thick, which had a polymer conversion of 96% had a smooth surface. This even surface could be maintained up to the heating of 420 K. These processes of deposition and polymerization were monitored with in situ reflection infrared spectroscopy. The EL device made of polymer thin film had three times higher efficiency than that from the monomer thin film.

A novel bifunctional chromophore was synthesized by using tolyldiphenylamine (TDPA) and N -(4-nitrophenyl)-piperidine (NPP) units as a hole transporting and a second-order nonlinear optical (NLO) materials, respectively. The chromophore was reacted with paraformaldehyde (FA) using p -toluenesulfonic acid as a catalyst to prepare a main-chain polymer for single component photorefractive (PR) materials. This polymer was mixed with C 60 (charge generating agents) and tricrecyl phosphate (plasticizer) to provide PR devices. The device showed a high photoconductive (PC) sensitivity of 10 −9 cm Ω −1 W −1 and the response time of 4 ms by a four-wave mixing (FWM) measurements at an applied electric field of 80 V/μm using writing intensity of 150 mW/cm 2 , which is the fastest value reported for the organic PR device to date. PR composites consisting of hole transporting polymer showed shorter response times than one consisting of the low molecular weight chromophore.

A thin film of triphenylaminemethylacrylate was fabricated by physical vapor deposition onto an indium–tin oxide substrate over a temperature range from 230 to 290 K. This thin film was subsequently polymerized by UV irradiation in vacuum with the aim of fabricating electroluminescent devices. Polymerization of the thin film in vacuum was investigated by in-situ FT–IR reflection absorption spectroscopy. UV irradiation achieved a polymer conversion of around 100%. Though the polymerization time increased at the lower temperature of the substrate, the surface flatness of the thin film was improved. The polymerization mechanism was elucidated as a simple radical polymerization on the basis of the order of monomer consumption rate. The number-average molecular weight increased with decreasing UV intensity.

We report a study on the differences in red-shifted excimer band in photoluminescence (PL) and electroluminescence (EL) spectra of thin films of a copolymer of dibutylfluorene and butylphenylphenoxazine. The relative intensity of the excimer band in PL spectra increases with temperature above the polymer glass transition, and with the intensity of the excitation light. In EL spectra, on the other hand, the relative excimer intensity is seen to decrease with increasing driving voltage. These opposite trends originate from the different nature of excitations in PL and EL spectra: photoexcitation directly creates singlet excitons while electric excitation proceeds via interaction of injected electrons and holes. In case of electric excitation, the observed results might be due to trap-assisted excimer formation.

Two-dimensional charge-transfer molecules based on N,N′-dialkyl-2,4-dinitro-1,5-diaminobenzene have been synthesized. 1H and 13C-NMR spectroscopy, elemental analysis and mass spectroscopy were used to elucidate their chemical structures. The physical and non-linear optical properties of this new family of dyes containing alkyl chain; C3H7, C6H13, C8H17, C10H21, C11H23 and C18H37 are discussed, taking into account the possible role of alkyl chain length. These two-dimensional molecules have a significantly large off-diagonal β component in contrast to one-dimensional molecules. These compounds showed no powder second-harmonic generation (SHG) at 1.064 μm being centrosymmetric, however, their poled guest-host systems with poly(methyl methacrylate) and co-crystals with p-nitroaniline were SHG active. Powder SHG as high as 37 times that of urea was observed from N,N′-dihexyl-2,4-dinitro-1,5-diaminobenzene with its mixture with p-nitroaniline. Second-harmonic generation of N,N′-dioctadecyl-2,4-dinitro-1,5-diaminobenzene (DIODD) was studied as Langmuir–Boldgett monolayers. The Langmiur–Blodgett monolayer of a 1: 1 mixture of DIODD and arachidic acid showed second-order non-linear optical coefficients d11 and d13 of 11 × 10−9 and 3.85 × 10−9 esu, respectively, at a tilt angle of 60°. For the first time, a relationship between the microscopic polarizabilities and the molecular orientation of two-dimensional charge-transfer molecules has been established. In the light of the present experimental and theoretical data analysis, the potential of two-dimensional charge-transfer molecules for second-order non-linear optics is discussed.

Acrylate type of monomer having tetraphenyldiaminobiphenyl (TPD) unit was prepared and was homo- and copolymerized with n-butyl acrylate using AIBN as an initiator. Electrochemical property of synthesized polymers was evaluated with cyclic voltammetry. All polymers exhibited the irreversible oxidation peak at 1.1 V in the initial cycle due to the oxidative coupling of TPD unit and two pairs of reversible oxidation and reduction peaks were observed in the subsequent cycles. Drift mobilities of synthesized polymers were in the range of 10-5 cm2/V s at applied field of 1.6 × 105 V/cm and were 100 times higher than that of PVK. Photorefractivity of polymers doped with 4-(N,N-diethylamino)-β-nitrostyrene (nonlinear chromophore) and fullerene (C60, charge generator) was investigated with two-beam coupling (2BC) technique. A 100-μm thick composite film showed gains of 9 and 40 cm-1 at an external electric fields of 50 and 70 V/μm, respectively. The phase shift between the index grating and interference pattern w...

Binary random copolymers of styrene with butadiene, methyl methacrylate, and t-butyl methacrylate, and styrene-methyl methacrylate-acrylonitrile random terpolymers were separated by adsorption chromatography. The HPLC conditions required for the sample to adsorb to the stationary phase are discussed. Sequence length as well as composition affected the elution volume of block and graft copolymers of styrene and butadiene. A mixture of terpolymers having different composition was separated to each component by cross-fractionation using two types of adsorption chromatography.

The electric field-induced dynamic phase-matching of second harmonic generation (SHG) waveguide was demonstrated by using a main chain polyarylamine. The linear and nonlinear optical properties of this polymer are presented. The optimum phase-matching thickness was controlled by applying an electric field to the polymer waveguide. The effective phase-matching thickness variation induced by poling is about 0.025 μm that is six times larger than full width at the half-maximum (FWHM) of phase-matching thickness in conventional slab waveguide. The efficient phase-matched SHG was observed from a taperless slab wave-guide. The optical loss of poled polymer on glass substrate at 632.8 nm was 2.7 dB/cm. © 1995 John Wiley & Sons, Inc.

Novel asymmetric succinate (TH-NVA) containing electron accepting thioxanthone and electron-donating 4-(2-nitrovinyl)aniline derivative was synthesized. TH-NVA was found to readily form an amorphous glass when the liquid sample was cooled in air at room temperature. Differential scanning calorimetry revealed that the melting point of the crystalline sample and the glass transition temperature of the glassy sample are 130 and 44°C, respectively. The absorption tail in the longer wavelength region was due to the charge transfer interaction between electron-accepting and-donating units. In two-beam coupling experiments, TH-NVA showed asymmetric energy transfer (coupling gain: 42 cm-1) without an external electric field.

A catheterization study and treatment of coronary arteriopathy are performed by investigating the coronary artery from different angles to find the region to be treated. In doing so, our system always started from the initial value of the loading factor, using this only for the first time, and the system started from the last loading factor the second time and later, at all angles. Therefore, depending on the angle, the loading factor at the start of fluoroscopy sometimes became unstable, and it took time to stabilize. This made the starting image too dark (undershoot x-ray condition) or fogged by halation (overshoot x-ray condition). With the system manufacturer, we developed a tube voltage and tube current setting method for the initial value of the loading factor. We installed software which preset the loading factor at the start of fluoroscopy depending on the angle, and an auto memory function of the last loading factor for each angle. This function allows the system to control the tube voltage and tube current for any angle. As a result, the system can acquire a more stabilized image from the start of fluoroscopy. This method of determining the initial loading factor is an effective way to stabilize the fluoroscopy image quickly.

It was found that poly[(4-azidophenyl)carbory)ethyl methacrylate] film irradiated by W light under an electric field showed larger second harmonic generation (SHG) than one without irradiation. This is the first photoactivatable nonlinear optical polymer. The increasee of SHG by irradiation was explained by the increase of the β value because a photoreaction changes the azido groups to amino and azo groups

The present review is mainly concerned with the macromolecular organic nonlinear optical materials for frequency doubling. Organic polymer materials are expected to apply the optical devices for the transparent, easy processability and so on. Recently some studies were carring out about the polymer, chromophore and device structures. These topics are introduced in this review. One of the major problems for poled polymer systems is the lack of thermal stability after aligningchromophore units. In order to prevent the decay, some ferroelectric or crosslinkable polymers carrying chromophore moiety were prepared. They showed large d coefficients and stability. Previously, the chromophores having shorter absorption wavelength band than the harmonic wavelength have been used. However, it has made possible to apply the longer absorption wavelength chromophores by using Cherenkov type phase matching. Besides, it has reported that the novel two-directional charge transfer molecules possessed large off-diagonal, β components has shown a small decay of d 33 even when the order parameter has relaxed. In optical waveguide structure, quasi phase matching accomplished by periodically poled or bleached waveguide structure was effective method to obtain harmonic light. As the practical and adroid method to achieve phase matching in waveguide, a attempt was made to adjust and suppress the phase matching condition by continuing to apply external dc voltage during frequency doubling. The guide-layer made of low Tg polymer was effective for quick response of chromophore alignment and change of refractive index against external electric field.

With the combination of acrylonitrile (polar) gel and nonpolar eluent or of styrene (nonpolar) gel and polar eluent, poly(styrene-co-methylmethacrylate) was separated by the adsorption mechanism. The former is designated as normal and the latter as reversed phase. With other combinations, the copolymer was separated mainly by fractional dissolution mechanism. The molecular weight effect on the reversed-phase HPLC was smaller than that on the normal phase. Poly(styrene-co-n-butyl methacrylate) also was separated on the basis of chemical composition by normal and reverse-phase HPLC. However, poly(styrene-co-t-butyl methacrylate) was separated only by reverse-phase HPLC

Two bifunctional succinates have been prepared as molecular photorefractive materials, which contain a hole-transporting triphenylamine moiety and an electro-optically active chromophore. The synthesized succinates formed stable amorphous glasses at room temperature. Succinate with 4-dicyanovinylaniline moiety as an electro-optic chromophore showed excellent photorefractive properties, i.e., 65% of diffraction efficiency, and 188 cm−1 of two-beam coupling gain at 60 V/μm, which are comparable to that observed in one of the most efficient photorefractive polymers.

ω-Anthracenyl-functionalized soluble polyphenylene (AN-SPP) with a well-controlled polymer chain was synthesized. The optical and electrical properties were strongly affected by the anthracenyl end-group. The UV absorption and photoluminescence emission were enhanced and shifted toward the longer wavelength region in comparison to that of soluble polyphenylene. The optical band gap energies of the main chain and the anthracenyl end-group were 3.15 and 3.89 eV, respectively. The highest occupied molecular orbital/lowest unoccupied molecular orbital energy levels of the main chain and the anthracenyl end-group of AN-SPP were −4.98/−1.81 eV and −7.25/−3.36 eV, respectively. The current–voltage characteristics of AN-SPP were controllable by the presence of the anthracenyl end-group. Copyright © 2008 John Wiley & Sons, Ltd.

In order to obtain some insight into the structure of an ultrahigh-molecular-weight polyethylene sample, 13C CP/MAS NMR experiments have been carried out at temperatures from 23 to −108°C. The peak for the crystalline component moves upfield with a decrease in temperature, which is contrary to what was reported previously for a melt-crystallized polyethylene sample. On the basis of x-ray diffraction results and quantum-chemical calculations, it is suggested that the methylene carbons are in the distorted orthorhombic form at low temperatures.