Table of Content

10 October 2008, Volume 29 Issue 10

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高等学校化学学报2008年第29卷第10期目次

2008, 29(10):  0.  doi:

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下期目次预览

2008, 29(10):  0.  doi:

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研究论文

Synthesis and Luminescence Properties of CdS Nanoparticles


PENG Ze-Ping^1,2, DENG Rui-Ping¹, LI Zhe-Feng^1,2, ZHANG Hong-Jie^1*

2008, 29(10):  1917-1920.  doi:

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CdS nanoparticles were successfully prepared by polyol method with PVP-K30 as a surfactant. The microstructure, size and morphology of the products were investigated in detail by XRD, TEM and SEM. The results indicate that uniform CdS nanospheres were achieved. Photoluminescence properties of the resulted nanoparticles(S1 and S3) were investigated, and the results indicate that the CdS nanoparticles could be used as a potential blue light emitting material.

Luminescence Properties of Ti³⁺ Doped Methyltriethoxysilane Modified SiO₂ Composite Coating

LAN Fang¹, CAO Cong-Rui¹, XIAO Bo¹, JIANG Xiao-Dong², YUAN Xiao-Dong², JIANG Bo^1*

2008, 29(10):  1921-1925.  doi:

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Titanium trichloride doped silica coating modified by methyltriethoxysilane(MTES) was prepared by sol-gel method using two steps hydrolytic condensation with tetraethoxysilane(TEOS) and MTES as the precursors and hydrochloric acid as the catalyst. The properties of the coating were characterized with IR spectroscopy, X-ray diffractometer, spectroscopic ellipsometry and luminescence spectroscopy. The result showed that Ti³⁺ doped SiO₂ coatings gave an excitation spectrum with two maxima, one at the wavelength of 250 nm, the other at the wavelength of 294 nm. Strong emission of Ti³⁺ doped SiO₂ coatings was observed with a maximum at 393 nm. The Si—OH peak of MTES modified SiO₂ composite coating is appreciably weaker and the Si—O—Si absoption peak is stronger than the normal Ti³⁺/SiO₂ coating, which indicates that the silicon-oxygen network is improved by addition of MTES. Calculation results show that the porous ratio of the MTES modified Ti³⁺/SiO₂ composite coating was reduced from 13.64% to 6.66%, indicating that the composite coating is much more compact. When the samples were aged in air at 25 ℃ for 30 d, the fluorescence disappeared completely for normal Ti³⁺/SiO₂ coating, while the fluorescence intensity of the MTES modified Ti³⁺/SiO₂ composite coating was only reduced by 18%. When aged in N₂ atmosphere at 25 ℃ for 30 d, the fluorescence intensities of both coatings were reduced by only 10%, Showing that the primary reason of fluorescence quenching is oxidization of Ti³⁺. Addition of MTES in the sol can effectively improve the surface structure of SiO₂ coating, which prevents Ti³⁺ from oxidization leading to a coating with stable fluorescence properties.

Synthesis, Characterization and Catalytic Activities of Mesoporous Titanosilicate Material with MFI Framework

ZOU Yong-Cun^*, WEI Shi-Gang, QU Xue-Jian

2008, 29(10):  1926-1929.  doi:

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Mesoporous titanosilicates with MFI structure were prepared by assembling from TS-1 nanocluster with mesoporous carbon as the hard-templates. The characterization results show that the sample is of 2D hexagonal ordered mesostructure with MFI micro-structure in the framework. Additionally, SEM images confirm the existence of macropores. Such titanosilicate shows a high catalytic activity in epoxidation of cyclohexene. This mesoporous TS-1 sample would have widely potential applications in industry because of the combining advantages of microporous TS-1(high catalytic activities) and mesoporous materials(mesoporous channels).

Synthesis, Characterization and Properties of Iron(Ⅲ) meso-Tetrakis(4-alkoxyphenyl)porphyrin Chloride

XU Yong-Jun¹, GU Zheng^2,3, ZHAO Hong-Bin^1,2*, WANG Li-Shen¹, NING Man-Xia¹, QIU Shi-Jun²

2008, 29(10):  1930-1936.  doi:

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A series of iron(Ⅲ) meso-tetrakis(4-alkoxyphenyl)porphyrin chloride were synthesized, seven of which were new compounds. Molecular structures of all synthesized compounds were confirmed by IR, UV, ¹H NMR, MS spectra and elemental analysis. Differential scanning calorimetry and polarizing microscope(PM) were used to probe the liquid crystal properties of the serial compounds. Eight compounds were found to exhibit liquid crystal(LC) properties, which behaved the single-change liquid crystals or the enantiotropic liquid crystals. Under PM, the LC texture was observed and filamentary optical one was displayed. The effects of alkoxy chains, metal ions of complexes and molecular space structure on liquid crystal properties were investigated. Verifying the (μ-oxy)bis[meso-tetrakis(4-alkoxyphenyl)porphyrin iron(Ⅲ)] and iron(Ⅲ) meso-tetrakis(4-alkoxyphenyl) porphyrin chloride could convert mutually in the adverse reaction by fluorescence spectrum.

Synthesis and Crystal Structure of a New 3D Supramolecular Polyoxometalate (4,4’-bipy){[Ag(4,4’-bipy)]₃[PMo₁₂^ⅥO₄₀]}·H₂O

WANG Xiao-Lan^1,2, WANG En-Bo^1*, XU Xin-Xin¹, LI Yang-Guang¹

2008, 29(10):  1937-1940.  doi:

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A new 3D supramolecular compound,(4,4’-bipy)[Ag(4,4’-bipy)]₃[PMo₁₂^ⅥO₄₀]·H₂O(1) was synthesized under mild hydrothermal condition, and the structure was characterized by elemental analysis, single crystal X-ray diffraction, IR and TGA. Compound 1 exhibits a photoluminescence property at room temperature. The structure of this compound consists of [PMo₁₂O₄₀]^3- anion, which is further connected by [Ag(4,4’-bipy)]₃⁺ unit to form a three-dimesional supramolecular network. Compound 1 crystallized in the triclinic system, space group P1, a=1.1275(2) nm, b=1.1910(2) nm, c=1.2898(3) nm, α=112.63(3)°, β=94.63(3)°, γ=99.53(3)°, V=1.5567(5) nm³, Z =1.

Proparation and Characterization of Stereoselective L-Histidine Imprinted Microspheres

ZHANG Zhao-Hui^1,2*, ZHANG Hua-Bin¹, WU Yu-Fang¹, LIU Li¹, LI Hui^1,2, YAO Shou-Zhuo²

2008, 29(10):  1941-1946.  doi:

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Stereoselective L-histidine imprinted microspheres(MIMs) were synthesized with precipitation polymerization using L-His as the template, methacrylic acid(MAA) as the functional monomer, ethylene glycol di-methacrylate(EGDMA) as the cross-linker, 2,2’-azobis-isobutyronitrile(AIBN) as the initiator, and water- acetonitrile microemulsion as dispersant. Equilibrium binding experiment and HPLC experiment were conducted to discuss the binding performance and the results show that two kinds binding sites is observed for the imprinted microspheres binding to the template with the maximum apparent binding constant 33.04 and 24.16 μmol/g, respectively. These imprinted microspheres exhibit an excellent stereoselectivity for L-histidine with the selective factor 2.14. The properties of polymers were characterized by IR spectra, thermalgravities analysis, and XRD, and the results indicate that the MIMs exhibit an excellent stability.

New Strategy Based on Dielectric Barrier Discharge Under Atmospheric Pressure to Inhibit Elemental Fractionation Effect in LA-ICP-MS

ZHANG Lu-Yuan^1,2, HU Sheng-Hong^1,2*, HU Zhao-Chu², HU Ming-Yue³, GUO Wei^1,2, LIU Yong-Sheng²

2008, 29(10):  1947-1952.  doi:

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A new strategy based on a house-made dielectric barrier discharge(DBD) device to inhibit elemental fractionation effect was developed. The DBD device was connected in between laser ablation cell and ICP torch. The aerosols induced by laser ablation were preionized in the DBD and the particle sizes of aerosol were decreased. The results indicate that elemental time-resolved signals are less fluctuant in DBD mode than normal mode during the laser ablation processes. In the ArF excimer 193 nm LA-ICP-MS, the average precision of signal intensities(RSD, n=3) with DBD mode and normal mode was 1.46% and 4.01%, respectively, and the signal intensities were reduced within 15%. While the average precision and signal intensities were found no significant change in presence and in absence of the DBD device for the 213 nm LA-ICP-MS. No obvious change was obtained for the elemental fractionation index in the 193 nm laser ablation system with the DBD device. The elemental fractionation index was closer to 1 with the DBD for 213 nm LA-ICP-MS. The results demonstrate the elemental fractionation effect was inhibited availably with the DBD device.

Rapid Spectrophotometric Detection of Hydrogen Peroxide Using (Au)_core(Ag)_shell Nanoparticle

JIANG Zhi-Liang^1,2*, LI Ji-Shun², ZHANG Nan-Nan², LIANG Ai-Hui², LIU Qing-Ye¹, HUANG Zhi¹

2008, 29(10):  1953-1958.  doi:

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Using 10 nm nanogold as seeds, the (Au)_core(Ag)_shell nanoparticles were prepared in the presence of AgNO₃ and trisodium citrate dehydrate, and they were purified by high-speed centrifugation to remove the excess trisodium citrate. The absorption peak of the purified (Au)_core(Ag)_shell nanoparticles is at 393 nm. In pH=4.4 HAc-NaAc buffer solution, hydroxyl radical produced from Fenton reaction oxidized the outer silver layer of the nanoparticles to form Ag⁺, and resulted in decreasing of the absorbance value at 393 nm. The concentration of H₂O₂ in the range of 6.58—421.1 μmol/L was linear to the decreased absorbance at 393 nm(ΔA_{393 nm}). Its regression equation was ΔA_{393 nm}=0.00111c+0.0210, and the correlation coefficient was 0.9908, with a detection limit of 1.73 μmol/L. This method was applied to the detection of H₂O₂ in wastewater, with satisfactory results.

Influence of Ionic ¹²⁵I Bound to Plasma Protein on Measurement of Labeled Drug Concentration in Blood

WU Ya-Qing, QIAN Jun, ZHU Jian-Hua

2008, 29(10):  1959-1962.  doi:

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The aim of this study was to investigate the influence of ionic ¹²⁵I on the results of pharmacokinetics study for biologic products. The ionic ¹²⁵I bound to plasma protein was studied through measuring precipitation rates of plasma protein bound ionic ¹²⁵I after TCA precipitation in vitro and in vivo, with which precipitation rates of ¹²⁵I-RGD-Sak in plasma of SD rats at different time were compared. The results of the experiment show that ionic ¹²⁵I could be bound to plasma protein and be deposited by TCA[in vitro: (1.26±0.14)%; in vivo: (1.38±0.33)%]. The precipitation rates were independent of the reaction time(10 to 1440 min) and ionic ¹²⁵I activity(14500 to 120000 count/min). Also, ionic ¹²⁵I attached to the surface of precipitate contributed a lot to the precipitation rate, which could be eliminated after 2 to 3 times TCA precipitation. The influence of the ionic 125I should be calibrated in ¹²⁵I tracing method applied to pharmacokinetics study for biological products.

Determination of Some Local Anesthetics by Resonance Rayleigh Scattering Method Coupled with Flow Injection Analysis

HU Xiao-Li¹, XU Dong-Po^1,2, LIU Zhong-Fang¹, LIU Shao-Pu^1*, HE You-Qiu¹, QIN Ming-You¹

2008, 29(10):  1963-1968.  doi:

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In hydrochloric acid medium, 12-tungstophosphoric acid(TP) reacts with some local anesthetics such as tetracaine(TC), procaine(PC) and lidocaine(LC) to form ion-associate complexes, resulting in a significant enhancement of resonance Rayleigh scattering(RRS) and appearance of new RRS spectra. Their maximum scattering peaks were at 345 nm(TP-TC), 368 nm(TP-PC), 379 nm(TP-LC), and the RRS intensities are proportional to the concentrations of the three local anesthetics in a certain range. Therefore, a novel method for the determination of TC, PC and LC by RRS coupled with flow injection analysis(FIA) was deve-loped, and the detection limits(3σ) were 0.5—9.5 ng/mL for different local anesthetics. Taking the TC-TP system with the highest sensitivity as an example, the effects of coexisting substances and analytical application were studied. The results show that the method has good selectivity and reproducibility. The recovery of the present method applied to the determination of TC in urine sample was 98.8%—103.2%. And the relative standard derivation for 9 successive determinations of 2.0 μg/mL TC was 1.7% with sampling frequency of 60 h^-1. In addition, the charge distribution of three anesthetics was calculated by quantum chemistry AM1 method, and the reaction mechanism was discussed from the difference of the anesthetics structure.

Rapid Preparation of Methacrylate Capillary Monolithic Columns by Photopolymerization

CHEN Na¹, ZHANG Yu-Ping^2*, ZHANG Yi-Jun², YE Xiong-Wen¹, QU Ling-Bo¹, YUAN Zhuo-Bin^3,1

2008, 29(10):  1969-1972.  doi:

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An organic-based monolithic column was quickly prepared inside the fused-silica capillary, and in situ photopolymerization was carried out in 150 s, using butyl-methacrylate(BMA) as a functional monomer, ethylene glycol dimethacrylate(EDMA) as a cross-linking agent, 1-propanol, 1,4-butanediol and water as porogenic solvents and Irgacure 1800 as an initiator. The electrophoretic and chromatographic behavior was comparatively evaluated using pressure-assisted CEC(p-CEC), CEC and low pressure-assisted liquid chromatography modes(LPLC). Baseline separation of the model analytes was respectively achieved including thiourea, toluene, naphthalene and biphenyl with the lowest theoretical height up to 8.0 μm for thiourea in the mode of p-CEC. A scanning electron micrograph of a cross-section of the capillary column shows that the monolithic columms were formed in the center of the capillary and adhered to the column inner wall.

Rayleigh Scattering Spectral Determination of Ultratrace Horseradish Peroxidase Based on o-Phenylenediamine Particles and Its Application

JIANG Zhi-Liang^*, LI Jian-Fu, LIANG Ai-Hui, LI Ji-Shun, TANG Ya-Fang, WANG Su-Mei, ZHANG Nan-Nan

2008, 29(10):  1973-1976.  doi:

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In pH 4.8 acetate buffer solution, o-phenylenediamine aggregated itself to particles in size of 380 nm, that exhibited five Rayleigh scattering peaks at 392, 420, 445, 484 and 507 nm. Horseradish peroxidase(HRP) has a strong catalytic effect on the H₂O₂ oxidation of o-phenylenediamine to 2,3-diaminophenazine, that caused significantly decreasing of the Rayleigh scattering intensity at 420, 445 and 484 nm. Under the optimal condition, the concentration of HRP in the range of 8.3×10^-12—4.17×10^-10 g/mL was all proportional to the decreased Rayleigh scattering intensity at 445 and 484 nm. Its regression equation, correlation coefficient and the detection limit were ΔI_{445 nm}=2.23c+11, ΔI_{484 nm}=1.47c+4.8; 0.9982, 0.9919; 3.6×10^-12 g/mL and 5.4×10^-12 g/mL HRP, respectively. A new enzyme catalytic-Rayleigh scattering spectral method was developed for assay of HRP, with a high sensitivity and selectivity, simplicity and rapidity. This assay was applied to the determination of HRP with satisfactory results.

Edman Degradation on Microfluidic Chip Operated with a Sequential Injection System

MU Jin-Xia, YIN Xue-Feng^*, CHEN Wen-Zhang

2008, 29(10):  1977-1981.  doi:

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Edman degradation reaction was carried out on microfluidic chip packed with C₁₈ beads as reaction cartridge, which was automatically manipulated by a sequential injection system. The program for sequential injection system, the column material for adsorption of protein or peptide and the temperature for Edman degradation reaction were optimized. The experiment results show that the N-terminal residue of protein or peptide can be obtained by Edman degradation on microfluidic chip with the advantages of faster reaction rate, less consumption of protein or peptide. The reported automatic method would be useful for increasing the confidence level of protein identification.

Influences of SMS Overexpression on Cellular and Medium SM Levels

SHI Yuan-Yuan^*, WANG Yu-Lan, LI Zhi-Qiang

2008, 29(10):  1982-1985.  doi:

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In order to study the relationship between sphingomyelin synthase(SMS) activity and sphingomyelin(SM) metabolism, we transfected HEK293 cells with SMS1 or SMS2, two isoforms and SMS, expression vector. The expression levels of SMS were monitored by SMS activity assay, and cellular and medium SM levels were determined by an established method. The results show that SMS1 overexpression significantly increased SMS activity(65%), cellular and medium SM levels(58% and 46%, p<0.01, respectively) in comparison with control cells. Whereas, SMS2 overexpression also significantly increased SMS activity(13%) and SM levels in the cells(33%, p<0.05) or in the medium(29%, p<0.05) in comparison with controls. The results show that SM levels can be regulated by SMS1 or SMS2, suggesting that the monitoring SMS activity could be an alternative approach to treat atherosclerosis.

Synthesis of Novel Fullerene α-Amino Acids and Preparation of Their Aqueous Nanoparticle Suspensions

ZHANG Jing, WANG Yan-Xia, KANG Feng, PENG Qi-Yun, YANG Xin-Lin^*

2008, 29(10):  1986-1989.  doi:

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Fullerene has been chemically functionalized by covalent attachment of different adducts onto the parent cage, to improve its solubility in polar organic solvents or to prepare aqueous solutions. This would be helpful for studying the biological activities of fullerene derivatives and their potential application in the biomedical field. N-Substituted 3,4-fullero pyrrolidine was synthesized via 1,3-dipolar cycloaddition of the azomethine ylide. Aspartic acid and glutamic acid with protected α-amino and α-carboxyl groups were reacted with the activated hydroxyl group of N-substituted 3,4-fullero pyrrolidine, respectively. The products were then deprotected, affording two novel fullerene α-amino acids, fullerene aspartic acid and fullerene glutamic acid. Their chemical structures were characterized via MALDI-TOF-MS, UV-Vis, FTIR and ¹H NMR. Furthermore, the aqueous nanoparticle suspensions of these fullerene amino acids were obtained by the method of organic solvent exchange, characterized by electron microscopy and zeta-potential analysis. The nanoparticle sizes of both fullerene amino acids were around 100 nm, with zeta-potentials of about 27 mV. The results indicate that these aqueous suspensions were rather stable with considerably homogeneous shape and size of nanoparticles, and thus were worthy of further investigating their potential application in the biomedical field.

Synthesis, Crystal Structure and Biological Activity of Novel Anthranilic Diamides Containing 1,2,3-Thiadiazole

DONG Wei-Li¹, XU Jun-Ying¹, LIU Xing-Hai¹, LI Zheng-Ming^1*, LI Bao-Ju^2*, SHI Yan-Xia²

2008, 29(10):  1990-1994.  doi:

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Since the public introduction of phthalic acid diamides and anthranilic diamides by Nihon Nohyaku, Bayer CropScience and DuPont, respectively, diamides have been the focus of synthesis in the field of agrochemical industry.Especially anthranilic diamides as insecticides, furthermore which also displayed good herbicidal and fungicidal activities, have recently attracted considerable attention. In the investigation of new agrochemicals, 1,2,3-thiadiazole derivatives often display good biological activities, and some diamides containing 1,2,3-thiadiazole possess good insecticide and fungicidal activities. In order to search for novel diamides which have high activities, a series of novel anthranilic diamides containing 1,2,3-thiadiazole were designed and synthesized, their structures were identified by means of elemental analysis, ¹H NMR, and the structure of compound 7g was determined by X-ray single crystal diffraction method. The preliminary results of biological activity experiment show that some of the title compounds exhibited a favourable fungicidal activity.

Synthesis of Human Growth Hormone Gene by the Combination of Chemical and Enzymatic Method

ZHAO Xiang-Yang, GAO Chao-Hui, JIN Lu, WANG Xi, MENG Qing-Fan, TENG Li-Rong^*

2008, 29(10):  1995-1998.  doi:

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According to the amino acid sequence and codon preference of E. coli, the human growth hormone(hGH) gene was optimized to avoid rare codons. The total length of the synthesized gene was 1040 bp because a promoter and a signal peptide sequence were added into it. Thirty oligonucleotides were designed and synthesized. The whole DNA sequence was synthesized by the improved two-step method. The sequencing result show that two complete correct gene were synthesised. The error rate of synthesized gene treated by T7 endonuclease I reduced 93.93% in comparison with the standard two-step synthesis method.

Stability Improvement of the Cry1Ac Protein by Site-directed Mutagenesis of W544F

WANG Fa-Xiang¹, XIA Li-Qiu^1,2*, DING Xue-Zhi¹, ZHAO Xin-Min¹, SHAN Shi-Ping¹, MO Xiang-Tao¹, ZHANG You-Ming¹, YU Zi-Niu²

2008, 29(10):  1999-2002.  doi:

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One major problem in the field applications of Bacillus thuringiensis Cry toxins is that their exposure to sunlight can bring about reduced bioactivity, mainly because of the most vulnerable indole ring of tryptophan(W) residue. W544 is the unique tryptophan in the domain Ⅲ of Cry1Ac toxin, which forms part of a buried hydrophobic cluster involving the conserved F578 and F604, and are organized in a “propeller-like” pattern, playing a clear structural role in protein stability. In this study, W544 was conservatively substituted with phenylalanine(F) to determine whether its stability was affected in the resulting mutant. Comparative analysis results by SDS-PAGE show that the protoxin of W544F was more stable than the wild-type Cry1Ac, when treated with ultraviolet irradiation, trypsin and preserved at room temperature. The distance between two vertex of crystals of W544F were 0.6 μm longer and unsmooth when compared with that of the wild-type Cry1Ac under an atomic force microscope. Addionally the mutation W544F had similar insecticidal activity to wild-type Cry1Ac, but when treated with ultraviolet irradiation for 9 h, it still maintained more than 4 times higher toxicity against Helicoverpa armigera than the wild-type Cry1Ac. In conclusion, the W544F mutation can enhance the stability of the Cry1Ac protein and may contribute to solving the major problem of the field applications of Cry1Ac toxin.

Design, Synthesis and Characterization of Novel Fluorescein-based Calcium Fluorescent Probe Fluo-Cl

HAN Jie, LI Jian-Li, HE Huai-Zhen, WU Xiang-Long, SHI Zhen^*

2008, 29(10):  2003-2006.  doi:

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The role of intracellular calcium ions is of high interest in the fields of cellular biology. Calcium plays a critical role in regulating numerous physiological cellular phenomena. There is a close relation between the change in the consent ration of free calcium and the function of the cell, signal transmission and the cell injury or death. So it is very important to determine the consentration and the distribution of the intracellular free calcium. Fluorescent indicators have been widely used for imaging calcium. They are highly sensitive and offer imaging by fluorescent microscopy in an easier and less cell damaging way than other methods. In this paper we describe the design, synthesis, characterization and spectral characteristic of novel fluorescein-derived calcium fluorescent probes. The fluorescent spectrum and the calcium titration curve of the novel compound Fluo-Cl were reported for the first time. The synthesis of fluorescein-based calcium fluorescent probe Fluo-Cl was researched. The calcium titration curve of Fluo-Cl shows that after chelating with calcium the fluorescent relative intensity has been enhanced greatly.

Acetalization of Aromaldehyde and Ethyleneglycol in Novel PEG Thermoregulated Ionic Liquids

ZHI Hui-Zhen, LUO Jun, MA Wei, LÜ Chun-Xu^*

2008, 29(10):  2007-2010.  doi:

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Novel PEG ionic liquids(IL200, IL400, IL1000) were prepared and used as the solvent for the acetalization of aromaldehyde and ethylene glycol catalyzed by p-toluenesulfonic acid. The ionic liquids and toluene have the advantages of both homogeneous and heterogeneous phases at different temperatures with the ease of product as well as catalyst separation. The catalyst(p-toluenesulfonic acid) was soluble in ionic liquids and insoluble in toluene. The optimum conditions: ILs 3 mL, toluene 5 mL, p-toluenesulfonic acid 6 mmol, benzaldehyde 5 mmol, ethylene glycol 15 mmol, the yield was 92% in 4 h at 80 ℃. The yields of the acatalization of aromaldehyde and ethylene glycol catalyzed by the system was 54.6%—97.8%. The ionic liquids played the role of solvent and the catalyst system were recycled up to 5 times without any significant loss of activity.

Properties of Poly[L-(aspartic acid)-co-L-lysine] Grafted with Cholesterol Conjugated Low Molecular Weight Poly(ethylenimine) for Gene Delivery

WANG Yan-Ming, ZHANG Zhen-Fang, YU Qi, WANG Lian-Yong, KONG De-Ling^*, YU Yao-Ting

2008, 29(10):  2011-2014.  doi:

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A new type of tumor-targeted non-viral gene vector, PSL-PEI600-Chol, was synthesized by ring-opening of poly[succinimide-co-lysine](PSL) with low-molecular weight poly(ethylenimine)(PEI600) and its cholesterol derivatives, respectively. The important parameters for preparation of PSL-PEI600-Chol/DNA complexes and characterization of physico-chemical properties of this delivery system were also investigated. It is indicated that PSL-PEI600-Chol could form compact complexes with DNA at a mass ratio higher than 5. The transfection efficiencies of PSL-PEI600-Chol were evaluated in different cell lines and the results showed that cholesterol modification could enhance the delivery of pEGFP-C1 into tumor cells HepG2 and Hela. These results suggest that with a lower cytotoxicity, higher gene delivery capacity and versatility for chemical conjugation, PSL-PEI600-Chol could warrant further investigation for a promising nonviral gene vector.

Application of Chiral [2,2]Paracyclophane Monophosphines in Catalytic Asymmetric Hydrogenation of Dehydroamino Acid Derivatives

ZHANG Tang-Zhi, CHEN Di, HOU Xue-Long*, DAI Li-Xin

2008, 29(10):  2015-2019.  doi:

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Two chiral paracyclophane mono phosphites were synthesized and used with some other paracyclophane monophosphines as ligands in catalytic asymmetric hydrogenation of dehydroamino acid derivatives, giving products in moderate enantioselectivity. The role of planar chirality was demonstrated in the reactions.

Preparation of Metallic Iron Nanoparticles with Liquid Phase Chemical Reduction Method

ZHU Yan-Chao¹, ZHAO Jing-Zhe², ZHOU Bing¹, ZHAO Xu^1*, WANG Zi-Chen¹

2008, 29(10):  2020-2024.  doi:

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The preparation of nanomaterials is a great challenge in the fields of synthetic chemistry and materials science, because materials with nanoscale and micro-scale structure have unique properities. Nanostructures with controlled size and shape are important from both fundamental application and technological viewpoints. In fact, it is well-known that the size and shape are two primary variables determining physical (such as magnetic, optical, etc.) as well as chemical(reactivity, catalysis, etc.) properties of nanoparticles. Here a simple method for the synthesis of iron nanoparticles under a relative mild condition by developing effective synthetic technique is reported. Using this method, iron nanoparticles with particle sizes about 15—50 nm were prepared by the reduction of ferrous chloride with hydration hydrazine in aqueous solution at room temperature, with citric acid’s appearance. The resulting metallic powders were characterized by XRD, EDX and FESEM. The magnetic performance of the obtained Fe nanoparticles were also discussed.

Microwave Synthesis and Electrochemical Property of One Dimensional Nanostructured MnO₂

ZHANG Wei-Xin^*, WANG Qiang, REN Xiang-Bin, YANG Ze-Heng, WANG Hua

2008, 29(10):  2025-2028.  doi:

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Based on the hydrothermally-synthesized nanostructured γ-MnOOH precursor and with K₂S₂O₈ as an oxidant, nanostructured α/β-MnO₂ samples were prepared by a singel-mode microwave-heating method. The samples were characterized by X-ray diffraction and Transmission Electron Microscopy. The results show that α-MnO₂ nanofibers were prepared when the γ-MnOOH nanofibers synthesized at 100 ℃ were used as the precursors, while β-MnO₂ nanorods were obtained with the γ-MnOOH nanorods synthesized at 150 ℃ as the precursors. The electrochemical performance of α/β-MnO₂ was also investigated by galvanostatic discharge test. When the as-prepared α-MnO₂ nanofiber and β-MnO₂ nanorod samples are used for Li/MnO₂ battery, the discharge capacities are 270.23 and 186.66 mA·h/g, respectively.

Studies on Mechanism of Vesicle Structure Transform Induced with Quaternary Ammonium Gemini Surfactants

HUANG Bei-Bei, XU Xiao-Ming, LI Dong-Hua, LAN Qin, HAN Guo-Bin^*

2008, 29(10):  2029-2034.  doi:

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A combination of dynamic light-scattering and fluorescence probe techniques was used to study the structure transform of lecithin vesicle with surfactants with different spacer chain lengths. The mechanism of structure transform of vesicle is explored by model and effective packing parameter theory. The results show that the main reason which leads to the structure transform is the change of superficial electric charge and the asymmetric distribution of the surfactant molecular. Furthermore, the structure of surfactant is also one of the reasons. Surfactants with different spacer chain lengths have different effects on the changs of the structure of the vesicle, which turn out to have some rules.

Theoretical Study of Hydrazine Decomposition Mechanism on Metal Surfaces

ZHANG Jun, XIE LI, XIA Wen-Sheng^*, WAN Hui-Lin^*

2008, 29(10):  2035-2039.  doi:

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The mechanism of N₂H₄ decomposition on Fe, Ru, Pt and Cu surfaces was analyzed by UBI-QEP(Unity Bond Index-Quadratic Exponential Potential) method. The results show that N—N bond cleavage in N₂H₄ is dominant decomposition route with the order of metal activity: Ru~Fe>Pt>Cu, but the product selectivity is significantly varied with metal surfaces. The main products on Fe and Ru are predicted to be H₂ and N₂ which is little formed via species N₂H_x, and the activity on Ru is higher than that on Fe, in contrast, on Pt and Cu the products are NH₃, N₂ and H₂, and the formed species N₂H during decomposition could be transformed into N₂ and H₂, and the activity on Pt is more than that on Cu.

Effects of HCl Gas on Gas Sensitivity of PEDOT Prepared via Modified LB Film Method

ZHENG Hua-Jing^*, JIANG Ya-Dong, XU Jian-Hua, YANG Ya-Jie

2008, 29(10):  2040-2043.  doi:

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An arachidic acid(AA)/poly(3,4-ethylenedioxythiophene)(PEDOT) multilayer LB film was prepared via a modified LB film method. The theories were utilized to explain the effects of HCl gas on the gas sensitivity of PEDOT LB film. The gas sensitivity mechanism of PEDOT multilayer film can be explained by the charge transfer between π system of PEDOT and oxidization HCl system. The gas sensitivity of PEDOT LB film deposited interdigital electrode to HCl was tested. The results show that film thickness, treating temperature, deposition speed have different influences on the film gas sensitivity. The AA/PEDOT film deposited device exhibited nonlinear behavior to HCl gas at a lower volume fraction(20—60 μL/L) and linear response behavior at a higher gas concentration was observed. The time of the compound LB film of the AA/PEDOT responding to the 30 μL/L HCl gas is about 20 s, it is far quicker than that of the PEDOT-PRESS film(is about 80 s). When the film press attains the 45 mN/m, the sensitivity of the AA/PEDOT film descends on the contrary.

Stability of Colloidal Gas Aphrons Prepared Solely by Nonionic Surfactant

YAN Yong-Li^1*, HE Fei¹, ZHANG Jia-Ming², QU Cheng-Tun¹, ZHANG Ning-Sheng¹

2008, 29(10):  2044-2048.  doi:

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Stable colloidal gas aphrons(CGA) were prepared solely by polyoxyethylene-type nonionic surfactant(C₁₂EO_n). Four different EO chain lengths namely C₁₂EO₃, C₁₂EO₅, C₁₂EO₇ and C₁₂EO₉ were considered. The microstructure and rheological properties on these colloidal systems were studied via optical microscopy and viscosimeter in attempt to explore the stability mechanisms. The experimental results suggest that CGA stabilized solely by C₁₂EO₃ and C₁₂EO₅ respectively exhibit the presence of lamellar liquid crystal adsorbed at the air/liquid interface, and could maintain more than 20 h without occurrence of collapse. In the case of CGA generated from C₁₂EO₇ and C₁₂EO₉, respectively, there is not any optical fine structure between two air bubbles and thus have a poor stability only for several minutes. It is concluded that the stability of CGA stabilized solely by C₁₂EO_n surfactants is attributed to the presence of lamellar liquid crystalline phases located at the gas/liquid interface. The role of liquid crystal in stabilizing CGA could be explained in several mechanisms including hydrodynamic drainage, the mechanical strength of the liquid film and the diffusion rate of entrapped gas.

Non-equilibrium Behavior of Salt-forming in Boiling Evaporation Process for the System of MgSO₄-K₂SO₄-H₂O at 75 ℃

ZHOU Huan^*, CUI Shi-Guang, SHA Zuo-Liang, YUAN Jian-Jun, ZHONG Jian-Jiang, HU Bing

2008, 29(10):  2049-2054.  doi:

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The behavior of salt-forming under a non-equilibrium status was experimentally determined for the system of MgSO₄-K₂SO₄-H₂O during boiling evaporation. The experiments of solution evaporation were carried out at a constant boiling temperature of 75 ℃ by a heating agent with a fixed temperature of 105 ℃. The evaporation intensity used was about 240—260 g/(h·L). The compositions of liquid and solid phase were analyzed at the time when primary nucleation occurs and several points of further evaporation. According to the experimental results the concepts of primary, extend and conditional salt-forming regions were proposed. The experimental results show that: (1) the primary salt forming regions of K2SO4, Leonite, Langbenite and MgSO₄·H₂O were observably different from those in Equilibria Phase Diagram. The width of primary forming region of K₂SO₄ and Langbenite are reduced, and the width of primary forming regions of Leonite and MgSO₄·H₂O are extended in different degrees. (2) Under the condition of having crystal seed, the width of salt-forming region is larger than that of primary salt-forming region in different degrees for different salts. (3) The extend salt forming regions of each salt caused an overlap. In the overlay region, what kind of the salt is formed depending on the seed of crystal. This overlay region is defined as conditional salt forming region, which is a special character in the non-equilibrium state phase diagram, and does not exist in the Equilibria Phase Diagram and Metastable Phase Diagram.

Raman Spectral Analysis of the Anti-freezing Mechanism of Dimethyl Sulfoxide

OUYANG Shun-Li, ZHOU Mi, CAO Biao, LU Guo-Hui, Gao Shu-Qin, LI Zuo-Wei^*

2008, 29(10):  2055-2058.  doi:

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A series of mixures of dimethyl sulfoxide(DMSO) and water with various volume ratios were measured by Raman spectrum. we also used computer software to seek Raman peak area ratio via peak separation method of spectral band of water. Based on the experimental results and analysis with mixture model, it was known that after mixing antifreezer dimethyl sulfoxide and water, its SO groups and O—H groups of water molecule can form the hydrogen bond to prevent the formation of tetrahedral structure ice. Simultaneously, it was also proved that the effect of antifreezer dimethyl sulfoxide is the best, as volume ratio of dimethyl sulfoxide to water is 1∶1.

Electrochemical Reduction Characteristics of 2-Chloronitrobenzene in Ionic Liquid BMIMBF₄-H₂O

LIU Ying-Zi, XIAO Li-Ping, ZHANG Kai, ZHAO Shu-Feng, ZHANG Jing-Bo, LU Jia-Xing^*

2008, 29(10):  2059-2064.  doi:

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The electrochemical reduction of 2-chloronitrobenzene was investigated in the room temperature ionic liquid 1-n-butyl-3-methylimidazolium tetrafluorobrate(BMIMBF₄) on a Cu disc microelectrode by using cyclic voltammetry and AC(Alternating Current) impedance method, with some water as the resource of hydrogen. The results show that the electroreduction of 2-chloronitrobenzene is a reaction controlled by diffusion. The AC impedance plots at different potentials show that the reaction is controlled by both electrochemical polarization and diffusion processes, which appears at higher and lower frequencies, respectively. With the increase of applied potentials, the semi-circles appeared at higher frequencies and became smaller and smaller, and it illustrates that the reaction is carried out easier. The influence of electrolysis potential, the concentration of 2-chloronitrobenzene and the passed charge were studied to optimize the electrolytic conditions, with the maximal yield to be 86.2%.

Ordered Adsorption of Polyethylene on Hydroxylated β-Cristobalite(100) Surface

MU Dan^1,2, LÜ Zhong-Yuan¹, HUANG Xu-Ri^1*, SUN Chia-Chung¹

2008, 29(10):  2065-2069.  doi:

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The adsorption of polyethylene(PE) chain on the hydroxylated β-cristobalite(100) surface was studied by molecular dynamics simulations. The regular pattern of the surface acts as a template to guide the PE chain folding on the surface along [110] direction. There are two different kinds of configurations for PE chain adsorbed onto such a patterned surface depending on whether the environment is in vacuum or in solution, respectively. However, they both possess two-dimensional adsorption configurations. The adsorption of poly(ethylene oxide)(PEO) on the same surface is also simulated for comparison. The results of this polar polymer being adsorbed onto the polar surface are different from the former results.

Preparation of Polymethyl Methacrylate(PMMA) Nanosphere and Technique of Coating Ag Layer

CHEN Zhi-Hua^1,2, WU Zheng¹, ZHANG Qi-Qing², BAO Jian-Jun^1,4, WANG Lian-Zhou^1,3, LU Gao-Qing^1,3, ZHU Xian-Fang^1,2,3*

2008, 29(10):  2070-2073.  doi:

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In this paper, we reported a two-step technique for fabrication of PMMA/Ag nano coreshell structure with well-established processing parameters and an ease control. Firstly, we fabricated the monodisperse PMMA nanospheres with a diameter of about 170 nm by emulsifier-free emulsion polymerization. Then, we modified the PMMA nanospheres surface with (3-methacryloxypropyl) trimethoxysilane(MATS) and (3-mercaptopropyl) trimethoxysilane(MPTMS), resulting in a uniform sulfhydryl (SH)-group modified outlayer and Ag nanoparticles further grew on the modified surface of PMMA nanospheres with an effective interaction between sulfhydryl(SH) groups and Ag⁺. In doing so, finally we synthesized PMMA/Ag core-shell composited nanoparticles. The structure of the synthesized sample was investigated by scanning electron microscopy(SEM), transmission electron microscopy(TEM) and UV-Vis extinction spectra. The results indicate that the well-dispersed PMMA/Ag core-shell nanoparticles with uniform particle size distribution were successfully fabricated using this improved technique.

Fabrication of Dual-layer Matrimid^®/PSf Hollow Fiber Membrane and Its Gas Separation Performance

DING Xiao-Li^1,2, CAO Yi-Ming^1*, ZHAO Hong-Yong^1,2, WANG Li-Na¹, YUAN Quan¹

2008, 29(10):  2074-2078.  doi:

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Dual-layer Matrimid^®/PSf hollow fiber membranes for gas separation were fabricated via co-extrusion technology. The hollow fiber membranes have an ultrathin dense-selective layer of 0.21 μm. The hollow fiber membranes have a CO₂ permeance of 46.29 GPU with a CO₂/CH₄ selectivity coefficient of 51.39 at 25 ℃and 0.5 MPa. And the hollow fiber membranes have an O₂ permeance rate of 6.38 GPU with an O₂/N₂ selectivity coefficient of 7.13 at 25 ℃and 0.5 MPa. The effects of the test temperature and the feed pressure on the gas separation performance were investigated. Finally, the aging phenomena were investigated.

Preparation of Monodisperse Silica/PMMA Core/Shell Nanoparticles with Controllable Shell Thickness by Soap-free Emulsion Polymerization

FANG Jian-Yong, LIU Xiao-Li, LU Zi-Yang, ZHAO Chun-Shan, GAO Ge, YANG Wen-Sheng, LIU Feng-Qi^*

2008, 29(10):  2079-2082.  doi:

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Monodisperse silica/PMMA core-shell nanoparticles were prepared by soap-free emulsion polymerization and the modified Stöber process. 3-Methacryloxy-propyltriethysilane(MPS) tailored surfaces of silica can be obtained from sol-gel preparation with Stöber process. The core-shell nanoparticles prepared from the soap-free emulsion polymerization were efficiently created with a uniform polymer shell. The shell thickness of PMMA was increased from 6.4 nm to 96.3 nm as judged by dynamic light scattering with increasing the amount of the MMA monomer. Thermogravimetric analysis result indicates the mean PMMA contents of 22.25%—93.41%. The results of SEM and TEM show a well-defined core-shell morphology for the inorganic/PMMA nanoparticles.

Preparation and Polarizing Orientation of PMMA Types of NLO Film

ZHANG Tao, WANG Shi-Wei, ZHAO Li-Sha, ZHAO Bing^*, CUI Zhan-Chen^*

2008, 29(10):  2083-2085.  doi:

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The poly[(DR₁A)-co-(MMA)-co-(MA)] nonlinear optical polymeric materials were prepared through sealed-tube reactive method in high yields. The material can be made into good films by spin coating, the chromophore in the films can be oriented by corona polarization. We study the chromophore oriented before and after polarization by polarized infrared spectrometry and polarized ultraviolet spectrometry.

Fabrication and Properties of Chitosan Hydrogel Filled Multilayer Microcapsules

FAN Guo-Qiang, TONG Wei-Jun, HU Xiao-Hong, GAO Chang-You^*

2008, 29(10):  2086-2090.  doi:

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In a solution containing water soluble chitosan(CML) derivative which was obtained by grafting lactic acid and methacrylic acid, CaCO₃ microparticles doped with the CML[CaCO₃(CML)] were fabricated. Layer-by-layer assembly of polystyrene sulfonate sodium salt(PSS) and poly(allylamine hydrochloride)(PAH) was then conducted on the CaCO₃(CML) microparticles to form core-shell particles. Core removed by disodium ethylenediaminetetraacetate dihydrate yielded the PSS/PAH multilayer microcapsules having the CML in their interiors. The CML hydrogel was formed in situ by a photoinduced crosslinking. The as-prepared microcapsules preserved the microscopic morphology of their template particles. Unlike the traditional multilayer microcapsules, these CML hydrogel filled microcapsules remained their spherical shape after drying, but their size was decreased from 6.8 μm to 4.6 μm. The capsule size and shape were recovered after hydration. These microcapsules showed a high loading efficiency of fluorescent dyes including negatively charged fluorescein and bovine serum albumin, positively charged rhodamine, and neutral Nile red in both water and organic solutions.

Research on Sphericization of Polyimide

JIANG Yuan-Yuan, QUE Zheng-Bo, WANG Xiao-Dong, HUANG Pei^*

2008, 29(10):  2091-2095.  doi:

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A new method for preparing PI microspheres was proposed. The properties of the solution and dispersion medium were modulated as PVP had been added. The effects of PVP and its content on the morphology, size of PI microspheres were investigated. The results show that the favorable spherical polymer particles were obtained with PVP in the solution. The average size of PI microspheres decreased with the increase of the PVP content and better size distribution was also measured. Meanwhile, the molecular weight of the polymer decreased lightly. The morphology of PI microspheres with water was better than that of with ethanol. The size of microspheres decreased with the increase of PVP concentration in water, and the uniformity of microspheres was also improved. PVP played roles of nucleation, balling and dispersion respectively in the whole process. The polyimide microspheres could be prepared in the micro-scale by this way.

Preparation and Characterization of Modified Nano Carbon Black/Polyurethane Composites

LIU Xin-Hai^1,3, ZHAO Ying^1*, LIU Zhi², WANG Du-Jin¹, WU Jin-Guang², XU Duan-Fu¹

2008, 29(10):  2096-2100.  doi:

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Surface modified nano carbon black particles(MCB) were used to prepare PU/MCB and PU/CB composites. FTIR, TEM, rheological methods and mechanical properties test were utilized to characterize the nano particles and their composites. FTIR results indicate that partial hydrogen-bonding structure in PU composites changed due to the interaction between nano particles and PU molecules. The tensile strength and elongation at break of the PU/MCB composites can be reinforced by adding optimal content (<5%) of MCB particles. The rheological results indicate that there are obvious interactions between PU molecules and carbon black particles in solution.

Synthesis and pH and Temperature Sensitive Properties of OSM₁-PCLA-PEG-PCLA-OSM₁ Block Copolymers

HAO Tang-Na, QIAO Ming-Xi, GU Jian-Chun, LI Zhen, HU Hai-Yang, ZHAO Xiu-Li, CHEN Da-Wei^*

2008, 29(10):  2101-2106.  doi:

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A new kind of biodegradable pH and temperature sensitive block copolymers were synthesized by ring-opening and conventional free radical polymerizations. The chemical structure of OSM₁-PCLA-PEG-PCLA-OSM₁ block copolymers was characterized via FTIR and ¹H NMR. Critical micelle concentration and particle size distribution were studied by fluorospectrophotometer and laser size detector to verify the copolymers micelle formation. The results of sol-gel transition show that the block copolymers solution possesses both pH and temperature sensitive properties. Different block copolymer solutions can form a stable gel obviously at certain temperature. OSM₁-PCLA-PEG-PCLA-OSM₁ block copolymers could be potential intelligent polymers materials for drug delivery system because of its pH and temperature sensitive properties.

Synthesis and Characterization of Amphiphilic Poly(epsilon-caprolactone)-b-hyperbranched Polyglycidol

LI Xiao-Hui, WANG Liang, YANG Jing, SONG Cun-Xian^*

2008, 29(10):  2107-2110.  doi:

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A novel diblock copolymer of poly(ε-caprolactone)-b-hyperbranched polyglycidol(PCL-b-HPG) was synthesized via a two-step reaction. Firstly, a hydroxyl-terminated PCL was prepared via the ring-opening polymerization using 1-dodecanol as the initiator. The obtained PCL was further treated with naphthalene potassium to get a PCL-based macro-initiator. Secondly, initiated by this macro-initiator glycidol segments were successfully linked to the PCL and the amphiphilic copolymer of PCL-b-HPG was obtained. The structure of PCL-b-HPG was characterized via ¹H NMR, GPC and IR spectra. The component ratio of the two blocks was calculated via the ¹H NMR spectra. IR results show that there are numerous hydroxyl end groups in these copolymers. Single peak was observed by GPC, which further confirmed that these polymers were true copolymers, not just blends. After the copolymerization of glycidol the viscosity decreased, which should increase generally as the molecular weight was increasing. This might be caused by the hyperbranched structure of polyglycidol block. These new materials may provide a promising opportunity to realize.

Preparation and Properties of the ETFE Humidity Sensing Filmsby Pre-irradiation Grafting Method

FU Qun, WANG De-Qing, JIAO Zheng, WU Ming-Hong^*

2008, 29(10):  2111-2114.  doi:

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Acrylic acid(AA) and sodium styrene sulfonate(SSS) were grafted onto poly(ethylene-co-tetrafluoroethylene)(ETFE) film by pre-irradiation technique using electronic beam from a 2 MeV accelerator at room temperature. A humidity sensing film with strong acid and weak acid groups was prepared. Infrared spectroscopy analysis of the grafted film confirmed the existence of sulfonate and carboxylic acid groups in the grafted film. Thermal and chemical properties of the grafted films were investigated. The crystallinity and static contact angle of the grafted films decrease, meanwhile the hydrophilicity of the grafted films increases with increasing grafting yield. A resistive-type humidity sensor was prepared using the grafted film, and its electrical response to humidity was examined. The resistive of the sensor changes linearly by 4 orders of magnitude over almost whole humidity range(5%—98%RH). Furthermore, the sensor exhibits a quick response(absorption: less than 1 min; desorption: less than 2 min) and small hysteresis(less than 2%RH).

研究快报

Synthesis of Cellulose Acetates with Low Degree of Substituent and Their Water Solubility

CAO Yan¹, LI Hui-Quan^1*, ZHANG Yi¹, ZHANG Jun^2*, HE Jia-Song²

2008, 29(10):  2115-2117.  doi:

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Cellulose acetates with low degree of substituent(DS) were homogeneously synthesized in an ionic liquid, 1-allyl-3-methyl-imidazolium chloride(AmimC1). Under mild reaction conditions, cellulose monoacetates(CMA) with the DS in a range from 0.34 to 1.60 were obtained. NMR analysis shows that the distribution of acetyl moieties among the three OH groups of anhydroglucose unit is C6C3>C2 for the synthesized CMA. The water solubility measurement shows that the CMA samples with the DS ranging from 0.65 to 1.06 are readily dissolved in water. The relationship between the structure and water solubility of CMA was briefly discussed.

Synthesis of Dendrimer-like Star Polymer by the Combination of ATRP and Click Chemistry

DUAN Ming^*, ZHANG Lie-Hui, LI Juan

2008, 29(10):  2118-2120.  doi:

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A new approach to the synthesis of dendrimer-like star polymer, [(PMMA)₂PSt]₄, was presented via the combination of atom transfer radical polymerization(ATRP) and ckick chemistry. Firstly four-arm bromine-terminated polystyrene(PSt-Br)₄ was obtained from ATRP of styrene using pentaerythritol tetra(2-bromoisobutyrate) as an initiator, and the (PSt-Br)₄ was efficiently converted to the azido-terminated polymers[(PSt-N₃)₄] through the bromine substitution reaction with sodium azide. Furthermore, the(PSt-N₃)₄ reacted with propargyl 2,2-bis[2-(bromomethyl)propionato]propionyrate via a click reaction, 1,3-dipolar cycloaddition reaction, and the polymer[(PSt-Br₂)₄] containing eight end-bromine was obtained. The (PSt-Br₂)₄ could further serve as a macroinitiator for the ATRP of methyl methacrylate(MMA). Accordingly, the dendrimer-like star polymer, [(PMMA)₂PSt]₄ was successfully prepared. The structure of [(PMMA)₂PSt]₄ was characterized via IR, ¹H NMR, GPC and DSC.