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The sequence effects on the conformations and intra-molecular hydrogen bonds (NH···OC: H-bond) of collagen-like co-peptides (single chains) were analyzed using co-glycine (G)/L-proline (P) oligopeptides (6- and 9-mer, G/P = 1/2 mol), by QCC [B3LYP/6-31G(d,p)], with homo-oligopeptides. Each sequence was specified using three kinds of basic triplets of GPP, PGP, and PPG. The conformations (dihedral angles: φn/ψn) varied depending on the sequences. The conformation types of each unit were classified in the following three groups: φ/ψ of g−/g + (shorter polyproline II helical structure: P-like) with H-bond, g−/t + (polyproline II helical structure: PPII) with no H-bond, and φ/ψ of t−/g + with no H-bond. All H-bonds that have seven-membered ring were formed between units separated by one peptide. The positions and number (Nh) of H-bonds varied depending on the sequences. The H-bonds between CO of proline and NH of glycine unit were newly formed. The co-peptides that have no GPP triplet in N-end side (CH3CO-GPP) were found to be more stable than the corresponding blend models due to the formations of newly formed H-bonds. From the comparison with the structures observed for triple helix of collagen in other works and the findings (the existence of the CO group that have no H-bond), it was inferred that collagen may be formed by conformational rearrangement from P-like (single chain) to PPII (triple helix) and may be stabilized by inter-molecular hydrogen bonding between the residual CO groups and water molecules.

The structures and energies of anhydrate and hydrate (hydrate rate: h of 1) states of l-alanine (LA), glycine (G), l-proline (LP), and N-methyl glycine (MG) pentamers were calculated by quantum chemical calculation using B3LYP/6-31G(d,p), for four kinds of conformers (β-extended: φ/ψ = t−/t+, PPII: g−/t+, PPII-like: g−/g+, and α-helix: g−/g−). In LA and G, which have imino proton (NH), three conformation types of β-extended, PPII-like, and α-helix were obtained, and water molecules were mainly inserted between intra-molecular hydrogen bond of CO···HN in PPII-like and α-helix and attached to CO group in β-extended. In LA and G, PPII-like conformers were the most stable in the anhydrate and hydrate states, and the result for LA was different from some experimental and theoretical results reported by other works reporting that the main stable conformation of alanine oligopeptide was PPII. On the other hand, in LP and MG, which have no imino proton, two conformers (PPII and PPII-like) and three conformers (PPII, PPII-like, and α-helix) were obtained, respectively. PPII conformers were the most stable in the anhydrate and hydrate states, and the result for LP supported the reported experimental results that the main conformation of proline oligomer was PPII. It was found that the formation pattern and stability of conformation of oligopeptide were strongly dominated by the presence/absence of intra-molecular hydrogen bonding of CO···HN or the presence/absence of NH2 group in the starting amino acid.

The structure and association energy of hydrated l-alanine pentamers at the hydration rate (h) of 0–1 were calculated by quantum chemical calculation (QCC) using the density functional theory [B3LYP/6-31G(d, p)] method for three kinds of stable conformers (β-extended: t−/t+, PPII-like: g−/g+, α-helix: g−/g−) converged by convergent calculations from l-alanine pentamers in gas phase. Water molecules are mainly inserted between intramolecular hydrogen bond of CO–HN in PPII-like and α-helix conformers and attached to the CO group in β-extended conformer. α-Helix conformer turns to PPII-like conformer at higher hydration rate. The association energy decreased with the increase of the hydration rate, indicating that the conformers were stabilized by the hydration. It was found that PPII-like conformer, which was the most stable in the anhydrate state, was also the most stable in the hydrate state. This structure corresponds to a middle structure of PPII (g−/t+) and β-extended (t−/t+) structures. These results obtained by energy calculation using QCC support the experimental results by Eker et al. and Graf et al., who reported that alanine oligomer exhibited a mixture of PPII and β-extended structure in aqueous solution.

The conformational convergent calculations of alanine oligomer (2- to 7-mer) were performed by QCC in the order starting from 2-mer (4 × 164 kinds). The ϕ/ψ of 4- to 7-mer was converged to three types; α-helix (g+/g+ or g−/g−), PPII-like (g+/g− or g−/g+) and β-extended (t+/t− or t−/t+), in lower energy order. PPII-like was different from the PPII (g−/t+) reported, and considered to be 2.27 ribbon . The energy differences in left- and right-handed ‘methyl type’ of end group were found.

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

ポリエチレンイミン(PEI)の 5 量体水和モデルを用いた量子化学計算により，水和過程における配座の会合エネルギー(Ec)に及ぼす配座効果(torsion facter: ft の影響)の見積もりを行った．非水モデルとして構造最適化された 4 種の配座モデル [(ttt)5, (ttg+)5, (g+g+g+)5 および(tg+t)5, ft=1.00～1.35] を準備し，水和モデルは水和率(h)を 0～1 とし水分子をイミノ基に対し非連続または連続的に配置した．Ec は ft の増加とともに水の配置形式の影響を強く受けた．(tgt)5 配座では，水和率の増加(h>0.5)とともにキンク(trans→gauche)を伴う大きい構造ゆらぎが認められ Ec は増加傾向を示した．Ec の計算結果は PEI 結晶の水和過程での構造転移(tgt→ttt)に関する観測結果にほぼ対応し，構造転移の推進力の一つとしてらせん構造の構造ゆらぎが関係することが推察された．

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

The effect of polymer chain structure on the optical and electrical properties are reported for poly(4-diphenylaminostyrene) (PDAS), which was prepared by the living anionic polymerization of 4-diphenylaminostyrene (DAS) with the benzyllithium (BzLi)/ N , N , N ′, N ′-tetramethylethylenediamine (TMEDA) system. The optical properties of PDAS are strongly affected by the stereoregularity of the PDAS polymer chain; intramolecular excimer-forming fluorescence was observed from PDAS with a syndiotactic-rich configuration. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of PDAS were approximately −5.4 and −2.0 eV, respectively, regardless of the polymer chain structure. The hole and electron drift mobilities for PDAS were in the order of 10 −4 to 10 −5 (cm 2 /V s) and 10 −5 (cm 2 /V s), respectively, with negative slopes. The distance of each triphenylamino (TPA) group in the polymer chain was a major factor influencing the drift mobility of PDAS. The current–voltage ( I – V ) characteristics of PDAS were controllable according to the polymer chain structure of PDAS.

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.

Hydrate effects on the conformations of ethylene oxide oligomers (EO-x, x = 1–8 mers) were examined using quantum chemical calculations (QCC). Conformational analyses were carried out by RHF/6-31G. The models were constructed by locating a water molecule to each ether–oxygen in the structures optimized for non-hydrate oligomers. Hydrate ratio, h (h = H2Omol/Omol in oligomer), was set from 0 to 1.0. The six type conformations with repeated units of O–C, C–C and C–O bonds were examined. Conformational energy, E c (HF), was calculated as difference between the energy of oligomer with water molecules and that of non-hydrogen and/or hydrogen bonding water molecules. Hydrate energies for each conformer, ∆μ h (kcal/m.u., based on E c in non-hydrate state), were negative and linearly decreased with the increase of h values, and such effects with the increase of h values were weaken with increasing x values. These results were consistent with our previous results calculated using the permittivity, e (e = 0–80.1), by QCC. In non-hydrate (h = 0), the (ttt) x conformers were the most stable independent of x. However, in hydrate states (h = 0.44–0.67), the (tg+t) x conformers were the most stable independent of x values, and in h = 1, the (tg+t)8 conformer (8-mer) was most stable [∆E c(g) = −1.3 kcal/m.u., ∆E c(g): energy difference between a given oligomer and the (ttt) x oligomer]. These results supported the experimental those based on NMR analyses using dimethoxyethane and triglyme solutions. Molecular lengths (l) of (tg+t) x , (tg+g−) x and (g+g+g+) x conformers having higher x values significantly decreased with increasing h values. Such contraction with hydration, however, was independent of ΔE c(g) values of each conformer.

Hydrate effects on the conformations of ethylene oxide oligomers (EO-x, x = 1–8 mers) were examined using quantum chemical calculations (QCC). Conformational analyses were carried out by RHF/6-31G. The models were constructed by locating a water molecule to each ether–oxygen in the structures optimized for non-hydrate oligomers. Hydrate ratio, h (h = H2Omol/Omol in oligomer), was set from 0 to 1.0. The six type conformations with repeated units of O–C, C–C and C–O bonds were examined. Conformational energy, Ec (HF), was calculated as difference between the energy of oligomer with water molecules and that of non-hydrogen and/or hydrogen bonding water molecules. Hydrate energies for each conformer, ∆μh (kcal/m.u., based on Ec in non-hydrate state), were negative and linearly decreased with the increase of h values, and such effects with the increase of h values were weaken with increasing x values. These results were consistent with our previous results calculated using the permittivity, e (e = 0–80.1), by QCC. In non-hydrate (h = 0), the (ttt)x conformers were the most stable independent of x. However, in hydrate states (h = 0.44–0.67), the (tg+t)x conformers were the most stable independent of x values, and in h = 1, the (tg+t)8 conformer (8-mer) was most stable [∆Ec(g) = −1.3 kcal/m.u., ∆Ec(g): energy difference between a given oligomer and the (ttt)x oligomer]. These results supported the experimental those based on NMR analyses using dimethoxyethane and triglyme solutions. Molecular lengths (l) of (tg+t)x, (tg+g−)x and (g+g+g+)x conformers having higher x values significantly decreased with increasing h values. Such contraction with hydration, however, was independent of ΔEc(g) values of each conformer.

The grafting reaction of poly( N -vinylcarbazolyl)lithium (PNVCLi) with tert -butyllithium onto fullerene-C 60 (C 60 ) was examined to explore the possibility of preparing new materials for effective photovoltaic cells. When the molar ratio of C 60 /Li was over four, the grafting reaction products obtained were completely soluble in tetrahydrofuran. The number-average molecular weight of the grafting reaction products obtained was greater than that of the respective parent PNVCs, indicating the formation of PNVC with a C 60 end-group. Gel permeation chromatography and 13 C NMR analyses showed that the product of the grafting reaction was C 60 bonded to PNVC and t -butyl groups. UV/vis and PL spectra suggested that this PNVC may be useful for preparing effective photovoltaic cells.

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.

Conformational analyses using quantum chemical calculations were carried out for 1- to 4-mers of ethylene oxide (EO) and ethylene imine (EI) oligomer models (EO-x and EI-x, x = 1 - 4) in the liquid phase using four solvents (permittivity: e = 2.0 ~80.1). The results were compared against those obtained in the gaseous phase. The calculations involved either RHF/6-31+G(d,p) or B3LYP/6-31G(d) // SCRF/IPCM, based on the observed and calculated results for the energy difference between trans- and cis-dichloroethane. The conformations repeated for a unit of X-C, C-C and C-X bonds (X: O or N) were examined. For both oligomers, the energies of every conformer decreased with increasing e values, and were linear against the Kirkwood function (Kf = (e-1)/(2e+1)). For the EO oligomers, the (ttt)x conformer was most stable in the gaseous phase. In liquid phases, however, the preference for the gauche-conformation (gauche preference) of the C-C bonds increased with higher values of e. In the case of EO-3, the (tg+t)x conformer was most stable above an e value of 8.9, which were in good agreement with those observed for triglyme solutions using NMR analysis. For the EI oligomers, the (tg+t)x conformer was most stable in either gaseous or liquid phase, and the gauche preference of the C-C bonds in both phases were comparable. These results were in good agreement with those observed for di-MEDA solutions using NMR analysis. It was estimated that such small solvent effects on gauche preferences of the EI oligomers result in weakening for hydrogen bonds (NH-N) of neighboring imino groups by solvents.

A well-controlled anionic polymerization of 4-diphenylaminostyrene (DAS) with alkyllithium (RLi) has been achieved for the first time. The nucleophilicity and solubility of RLi, 4-diphenylaminostyryllithium (DASLi), and poly(4-diphenylaminostyryl)lithium (PDASLi) were very important controlling factors. An initiator system of tert-butyllithium (t-BuLi)/N,N,N′,N′-tetramethylethylenediamine (TMEDA) in toluene was found to be very effective. In this system, the t-BuLi/TMEDA complex reacts with toluene to form the benzyllithium (BzLi)/TMEDA complex, and this complex initiates the anionic polymerization of DAS. The DASLi/TMEDA and PDASLi/TMEDA complexes have sufficient nucleophilicity and stability as propagating species, without the metalation of toluene, and as a result, living anionic polymerization was achieved. The high molecular weight poly(4-diphenylaminostyrene) (PDAS), synthesized using the RLi/TMEDA system, had a syndiotactic-rich configuration, independent of the polymerization solvent.

Conformational analyses have been carried out for ethylene oxide (EO) and ethylene imine (EI) oligomer models (single chain) by quantum chemical calculations (RHF/6-31+G(d,p)). The conformations repeated for a unit of X-C, C-C and C-X bonds (X: O or N) were examined. For optimizations of the EI oligomers, some designation systems with trans values were used, taking account of pseudoasymmetry. For the EO oligomers (EO-x, x = 2- to 8-mers), (ttt)x and (tg+t)x conformers were first and second stable (ΔE = 1.17–1.26 kcal/m.u.), respectively. On the contrary, for the EI oligomers (EI-x, x = 2- to 11-mers), (tg+t)x and (ttt)x were first and second stable (ΔE = 1.32–1.42 kcal/m.u.), respectively. Therefore, the gauche preference of C-C bond in EI-x is stronger than that in EO-x. The calculated structures of (ttt)x and (tg+t)x in EO-x agreed with those observed by XRD analysis for PEO crystals in stretched (planar zigzag) and original (7/2 helix) states, respectively. The calculated structures of (tg+t)x and (ttt)x in EI-x also agreed with those observed for PEI crystals in dehydrate (7/2 helix) and hydrate (planar zigzag) states, respectively. However, the dihedral angles (EO-8) and the 5 mol length (EI-11) in both helices did not agree with each of the observed values for the polymers. Each difference between the oligomers (single chain) and polymers was estimated by the effect of intermolecular interactions in PEO or PEI. For (tg+t)x of EI-11, the existence of metastable skewed helical structures (reversed and/or kinked) were estimated in addition to the helix.

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.

Polymers having 2,5-diphenyl-1,3,4-oxadiazole (BCO) or anthracene (BCA) as an electron transport unit and N,N′-diphenyl-N,N′-bis(4-butylphenyl)-benzidine (BTPD) as a hole transport unit were prepared by condensation polymerization using Friedel–Crafts reaction. It was found that BCO was less reactive than BCA. The low reactivity of the BCO monomer can be explained by the oxygen atom in the oxadiazole unit, which acts as a Lewis base and reduces the activity of the catalyst. The redox behavior measured by cyclic voltammetry showed for both BTPD-BCO and BTPD-BCA almost the same oxidation potential. In addition, the BTPD-BCO also exhibited a reduction peak. Hole and electron drifts mobility of the polymers were measured by the time-of-flight method. The hole drift mobility of both BTPD-BCO and BTPD-BCA was 7.4 × 10−5 cm2 V−1 s−1. The electron drift mobilities of BTPD-BCO and BTPD-BCA were 6.5 × 10−5 cm2 V−1 s−1 and 5.2 × 10−6 cm2 V−1 s−1, respectively. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3083–3089, 2007

The reactivity of three types of quinones (3,4,5,6-tetrachloro-1,2-(o-)-benzoquinone (TOQ), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), and 2,3,5,6,-tetrachloro-1,4-(p-)-benzoquinone (TCQ)) was examined for the dehydrogenation of poly(1,3-cycohexadiene) (PCHD) composed of 1,2-cyclohexadiene and 1,4-cyclohexadiene units. The order of reactivity was TOQ > DDQ > TCQ. The steric hindrance of CO groups in the quinones appeared to be an important factor in determining their reactivity. DDQ was found to be an appropriate dehydrogenation reagent for PCHD. The reactivity of TCQ was considerably low for PCHD containing 1,2-cyclohexadiene units. The reactivity of TOQ was too high and side reactions occurred, causing the formation of structural defects. Copyright © 2007 Society of Chemical Industry

BACKGROUND: Poly(1,3-cyclohexadiene) (PCHD) is of interest as a precursor for the synthesis of a new class of high-performance hydrocarbon polymers. ω-Functionalization of PCHD offers a new opportunity for the preparation of a variety of multifunctional PCHD derivatives. RESULTS: ω-Functionalized PCHD containing a fluorenyl (or anthracenyl) group at the polymer chain end was successfully synthesized by post-polymerization reaction of poly(1,3-cyclohexadienyl)lithium (PCHDLi) with alkyl halides containing a fluorescent functional group. The degree of nucleophilicity of PCHDLi and the control of side reactions were very important factors to achieve a high conversion for the post-polymerization reactions of PCHDLi. The ω-functionalized PCHDs obtained exhibited strong photoluminescence and the wavelength of the fluorescence was adjustable by changing the structure of the ω-functional group. CONCLUSION: ω-Functionalized PCHD is a preferable precursor that can be utilized to obtain a new class of multifunctional hydrocarbon polymers containing six-membered rings in the main chain. Copyright © 2007 Society of Chemical Industry

各種のアイソタクチックメタクリル酸メチルのオリゴマーの量子化学計算による立体配座解析(エネルギー比計算)を行い観測結果と比較した．計算は非らせん条件(トランス 2 面角入力値:180°)で行った．3, 7 量体での最安定構造はそれぞれの観測結果とほぼ一致した．末端主鎖の立体配座は末端基のかさ高さに影響を受け，tert-ブチル基ではトランスが，プロトン，メチルまたは n-プロピル基では側鎖の回転を伴いゴーシュが安定であった．7, 9 および 11 量体の最安定構造は，7 量体の観測結果と同様，トランス鎖の中間にゴーシュをもつキンク構造であり，オリゴマーの結晶がポリマー(全トランスの 10/1 らせん)と異なることが推定された．11 量体のみがらせんがキンクした構造であり，らせん条件(-160°入力)で計算した均一らせんとのエネルギー差はわずかであった．この結果はポリマーが 10 モノマー単位のらせんであることを支持している．

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.

Chemical composition and its distribution of styrene (St)-ethyl acrylate (EA) copolymers synthesized by emulsion copolymerization under different monomer ratios and polymerization conditions were examined by 1H-NMR and high-performance liquid chromatography (HPLC), respectively, and compared with those of bulk copolymers. It was newly found that the chemical composition of copolymer at early stage is affected by the concentration of emulsifier (SDS, sodium dodecyl sulfate) and monomer/water ratio, and is almost independent of the concentration of initiator or polymerization temperature. The EA fraction decreased with the increase of SDS concentration and converged to the value calculated using distribution factor (fd) when SDS concentration was extrapolated to zero. These results indicate that the EA fraction in micelle decreased compared to the expected value from fd due to the interaction of EA monomer with emulsifier. From HPLC, it was found that each copolymer showed a sharp single peak at an early stage of polymerization indicating that no homopolymer or copolymer with different composition was produced.

The photon energy of vacuum ultraviolet (VUV) light is higher than the binding energy of some chemical bonds in organic molecules, such as C–C, C–H, or C–O. Therefore, VUV light is able to cause the scission of various bonds in polymer molecules, which can lead to the decomposition of the polymeric molecules. Degradation of polymers by VUV has been studied with the purpose of investigating damage to polymeric materials by VUV, developing new photoresist materials, revealing the degradation mechanism, and modifying polymer surfaces, etc. The degradation mechanism of poly(methyl methacrylate) (PMMA) has been extensively studied for evaluation as a new photoresist material. It was found that the side chain ester group is decomposed by VUV irradiation, leading to a polymer containing carboncarbon double bonds. In addition, scission of the main chain also occurred. If an ester group is easily cleaved by VUV, it may be expected that aliphatic polyesters, which contain ester groups in the main chain, will be degraded to small volatile molecules and may function as good photoresist materials. Aliphatic polyesters are soluble in common organic solvents, which enables good thin films to be easily formed. It is well known that aliphatic polyesters are easily degraded by biological reactions, and although many studies have been performed regarding the biodegradation of aliphatic polyesters, only a few studies have investigated degradation by irradiation with UV or VUV light. In this report, the degradation of aliphatic polyesters by VUV was investigated and compared with that of PMMA. The study concentrated on the reaction mechanism, the effect of oxygen and application of an external electric field during irradiation. EXPERIMENTAL

Soluble polyphenylene (PPH) homopolymers with a controlled polymer chain structure were synthesized for the first time by the complete dehydrogenation of poly(1,3-cyclohexadiene) (PCHD) having a 1,2-addition (1,2-CHD unit) and 1,4-addition (1,4-CHD unit). The reactivity of PCHD for dehydrogenation strongly depends on the polymer chain structure. The rate of dehydrogenation is fast on a long sequence of 1,4-CHD units, while it is considerably impeded by the presence of 1,2-CHD units in the polymer chain. With a reaction temperature higher than 90 °C, complete dehydrogenation of PCHD proceeds successfully to yield soluble PPH homopolymers. The polymers obtained are soluble in polar solvents. Therefore, the soluble PPH homopolymers appear to be polar macromolecules, and the conversion of polarity occurs during the dehydrogenation process. UV and fluorescence spectra clearly indicate the nature of a conjugated PPH homopolymer.

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.

The dehydrogenation of poly(1,3-cyclohexadiene)–polystyrene binary block copolymers obtained by anionic copolymerization with alkyllithium/amine systems was investigated for the first time. The dehydrogenation of the poly(1,3-cyclohexadiene) block, which was composed of 1,2-cyclohexadiene (1,2-CHD) and 1,4-cyclohexadiene (1,4-CHD) units, was strongly affected by the polymer chain structure. The existence of 1,2-CHD units prevented the dehydrogenation of the poly(1,3-cyclohexadiene) block in the binary block copolymer. The rate of dehydrogenation was fast on a long sequence of 1,4-CHD units, whereas it was relatively slow for 1,2-CHD/1,4-CHD (≈1/1) unit sequences. The bonding of the polystyrene block to the polymer chain effectively improved not only the rate of dehydrogenation of a long sequence of 1,4-CHD units but also that of the polymer chain with a high content of 1,2-CHD units. The dehydrogenation of a poly(1,3-cyclohexadiene) block containing a small number of 1,2-CHD units progressed via step-by-step reactions. The dehydrogenation of a long sequence of 1,4-CHD units proceeded as the first step. Subsequently, in the second step, the 1,2-CHD/1,4-CHD (≈1/1) unit sequences remaining in the polymer chain were dehydrogenated. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3526–3537, 2006

The aggregation of poly(1,3-cyclohexadiene) (PCHD), obtained by anionic polymerization with alkyllithium/amine systems, was examined using size exclusion chromatography (SEC) and size exclusion chromatography coupled with a multiangle laser light scattering photometer (SEC-MALS). The PCHD polymer chain has a structure consisting of a main chain formed by 1,2-addition (the 1,2-CHD unit) and 1,4-addition (the 1,4-CHD unit). Mild stirring with relatively low temperature in the polymerization reaction forms an aggregation of PCHD. The molecular weight and molar ratio of 1,2-CHD/1,4-CHD units in the polymer chain strongly influence the aggregation of PCHD. In a high molecular weight PCHD, containing ∼50% 1,2-CHD units, an aggregation of the polymer was observed in tetrahydrofuran (THF) solution at room temperature. This aggregation of PCHD was soluble in 1,2,4-trichlorobenzene (TCBz) and could be separated into each polymer molecule. In contrast, a polymer chain with a high content of 1,4-CHD units having a relatively low cis-stereospecificity was easily soluble in THF and TCBz without aggregating. A long polymer chain structure with a high content of 1,2-CHD units is considered to be the reason for the generation of strong intermolecular forces contributing to the aggregation of PCHD with the solvophobic interactions. The degree of aggregation could be controlled by the conditions of the PCHD polymer solution. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1442–1452, 2006

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.

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.

The influence of the microstructure on the oxidation of poly(1,3-cyclohexadiene) (PCHD) homopolymer, obtained by anionic polymerization with alkyllithium/ amine systems, was investigated for the first time. PCHD has a structure consisting of a main chain formed by 1,2-addition (the 1,2-CHD unit) and 1,4-addition (the 1,4-CHD unit). The molar ratio of 1,2-CHD/1,4-CHD units in the polymer chain strongly influenced the extent of oxidation of PCHD. A polymer chain with a high content of 1,4-CHD units was easily oxidized by air and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). In contrast, the progress of oxidation was prevented in the case of PCHD containing 52% of 1,2-CHD units.

A series of different benzaldehydes-4-tolyldiphenylamine polymers has been oxidized by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and tetrachloro-1,4-benzoquinone (p-chloranil), and also doped by 10-camphorsulfonic acid in order to increase their conductivity. The doped polymers were characterized by 1H NMR spectroscopy, cyclic voltammetry, UV, and IR spectroscopy. It was found by 1H NMR spectroscopy that the oxidation yield increased with the increased amount of oxidation agent. It was shown that optical and electrochemical bandgaps of the polymers decreased after oxidation. Conductivity measurements revealed that the applied oxidation and doping procedure resulted in decreased electrical resistance of their initial polymers, down to the level of semiconducting materials. An increased thermal stability of the polymer after oxidation was confirmed by differential scanning calorimetry.

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.

Photosulfonation of low-density polyethylene (LDPE) films by UV irradiation in the presence of gaseous sulfur dioxide (SO 2 ) and oxygen (O 2 ) was studied by attenuated total reflectance (ATR) infrared spectroscopy and X-ray photoelectron spectroscopy (XPS). The ATR and XPS analysis and chemical modification of UV-irradiated LDPE films demonstrated the generation of C=C double bonds and sultones in the reaction. These results indicated the possibility that sulfur trioxide (SO 3 ) was produced during the photosulfonation. New pathways for the SO 3 reaction with LDPE films, resulting in the formation of sulfonic acid groups, were proposed.

Research Group on NMR, The Society of Polymer Science, Japan, has continued assessments of the reliability of NMR measurements of polymers. In the present study, 1H and 13C NMR data for isotactic poly(methyl methacrylate) (it-PMMA) having a t-butyl end group were collected on 27 NMR spectrometers by a round-robin method, to survey the accuracy of NMR spectroscopic determination of degree of polymerization (DP) of the polymer by the end group analysis as well as other basic NMR parameters such as chemical shift and spectral resolution. Five samples of it-PMMAs whose DP’s range from 53 to 5200 were prepared with t-BuMgBr in toluene. 1H and 13C NMR spectra were measured in nitrobenzene-d5 at 110 °C. The standard deviations (σ) for chemical shift measurements of 1H and 13C NMR signals were 0.001–0.004 ppm and 0.04–0.18 ppm, respectively. A singlet signal due to t-butyl group at initiating chain end of the it-PMMA is separately observed from the signals due to the monomeric units in 1H NMR spectra measured in nitrobenzene-d5. Thus DP of the polymer can be determined by the equation of DP = 3 × [OCH3]/[t-C4H9]. The value of σ for DP determination by 1H NMR increased as DP increased (6.4–23.4%). However, the averaged values of DP agreed well with those determined by SEC. 13C NMR analysis of DP was possible for the it-PMMA with DP up to ca. 250. The values agreed with those determined by 1H NMR spectroscopy. 1H NMR determination of DP by 5 runs using single spectrometers (100 and 500 MHz) gave much better reproducibility; σ 3.9–9.2% and 0.7–3.4% for the measurements with 100 and 500 MHz instruments, respectively.

Sulfonation of low-density polyethylene (LDPE) films with fuming sulfuric acid was studied by X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance (ATR) infrared spectroscopy. The ATR spectra showed the formation of CC double bonds and multiple sulfur atom containing groups for the sulfonation of LDPE films. This led us to propose that the abstraction reaction of hydride ion by sulfur trioxide (SO3) in fuming sulfuric acid might account for the formation of the CC double bonds. It was considered that after the abstraction reaction, these double bonds react with SO3, resulting in the production of alkene sulfonic acids and sultones, along with the formation of sulfate groups as a result of reaction of the double bonds with sulfuric acid. Experimental data by treatment of the sulfonated LDPE films with KOH and thiourea supported the proposed idea, estimating the approximate molar ratio of the products. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 2435–2442, 2004

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.

Monomers containing N,N',N,N'-tetraphenylbenzidine (TPD) were prepared by introducing two alkyl or alkoxy substituents into the p-position of two of the four phenyl groups in the triphenylamine unit. The monomers were copolymerized with 1,4-divinylbenzene (DVB) in the presence of p-toluenesulfonic acid and Lewis acids, such as SnCl 4 and BF 3 . The polymerization conditions and the catalyst types showed a marked influence on yield, molecular weight and even polymer structure. 1 H NMR measurements revealed that, by using p-toluenesulfonic acid as a catalyst, the linkage between the TPD unit and DVB occurs at the p-position of the phenyl group and at the m-position of the tolyl group in the TPD unit, whereas, with SnCl 4 or BF 3 catalyst, substitution occurs exclusively at the p-position of TPD. All polymers are soluble in common organic solvents, which allows the preparation of thin films of good quality. The rigid structure of the polymeric backbone results in a high thermal stability up to 400 °C. The results of ionization potential measurements and the redox behavior showed that the introduction of the TPD unit into this kind of polymer backbone does not change its electronic structure. On the basis of high electroactivity, the polymers were successfully used as hole transport layers in two-layer electroluminescence devices.

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.

New triarylamine-based polymers have been synthesized by polyaddition of 4-tolyldiphenylamine (TDPA) with 1,4-divinylbenzene (DVB) or 1,3-diisopropenylbenzene (IPB) in the presence of p-toluenesulfonic acid. 1H NMR spectra revealed that DVB units were linked to TDPA units not only at p-position but also at m-position to aryl group in TDPA-DVB polymer. On the other hand, IPB was less reactive and TDPA-IPB polymer was achieved only in a p-linkage. The incorporation of DVB or IPB did not significantly affect the electronic structure of TDPA unit as confirmed by UV spectra and cyclic voltammetry. From differential scanning calorimetric (DSC) measurements, glass transition temperatures of TDPA-DVB and TDPA-IPB polymers were estimated to be 169°C and 132°C, respectively. The resulting polymers have good solubility in conventional organic solvents (e. g. chloroform, tetrahydrofuran and toluene).

New hole transport polymers have been synthesized by condensation polymerization of 4-tolyldiphenylamine (TDPA) with various types of aldehyde. The reaction conditions have been investigated to yield polymers with high molecular weight. It is found that the molecular weight and yield of the TDPA–aldehyde polymers strongly depend on the electron donor–acceptor nature of the substituent on the aromatic ring of the aldehyde monomer. Structural characterization by 1H NMR spectroscopy shows that the addition condensation reaction occurs exclusively at the para position of TDPA. The electrochemical and optical properties of polymers have been investigated by cyclic voltammetry and UV–vis spectroscopy. Cyclic voltammograms of all polymers show well-defined pairs of reduction and oxidation peaks, indicating that the polymers are electrochemically active. All polymers show low conductivities of magnitude 10−14 S cm−1. Differential scanning calori-metry measurements reveal that TDPA–aldehyde polymers exhibit glass transitions in the range 170–230 °C. These polymers possess good solubility and the films show sufficient morphological stability. © 2001 Society of Chemical Industry

4-Tolyldiphenylamine (TDPA) and N,N′-diphenyl-N,N′-bis(4-methylphenyl)-1,1′-biphenyl-4,4′-diamine (TPD), were reacted with benzaldehyde (BA) using p-toluenesulfonic acid as a catalyst to yield linear polymers. The polymers were reacted with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in tetrahydrofuran (THF) at room temperature. 1H-NMR showed that all the methine protons in the residue of BA were completely removed at the mole ratio of repeating unit : DDQ, 2 : 1. The resulting polymers showed good solubility in chloroform or THF. The reacted TDPA-BA and TPD-BA polymers gave new UV absorption peaks at 697.0 and 722.5 nm and showed reversible redox potentials about 0.994 and 1.021 V, respectively. Direct current (d.c.) conductivity of the reacted polymers was in the range of 10−11 S/cm, which is more than two orders higher than the unreacted polymers. The polymer showed pentad split electron spin resonance (ESR) signal, whose concentration was one in 670 or 230 repeating unit for TDPA-BA and TPD-BA polymers, respectively. Copyright © 2001 John Wiley & Sons, Ltd.

Synthesis of New Hole Transport Polymers Based on N,N ′-Diphenyl- N,N ′-bis(4-methylphenyl)-1,4-phenylenediamine

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 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.