Table of Content

10 September 2005, Volume 26 Issue 9

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Articles

Synthesis and Characterization of a New Type of Mesoporous SAPO

XU Ling, ZHU Guang-Shan, CHU Bin, SHI Chun-Feng, GAN Mei-Na, XIE Ya-Ru, SHEN Qi-Hui, WANG Run-Wei, QIU Shi-Lun

2005, 26(9):  1585-1588. 

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A new type of mesoporous silicoaluminophosphate(SAPO-1) with worm-like structure was synthesized by hydrothermal method with embryonic silicate zeolite as the Si source. The slicoaluminophosphate molecular sieve was characterized by XRD, IR, TEM, SEM, TG and N₂ adsorption/desorption techniques. The results showed that SAPO-1 had a stronger acidity than the empirical SAPO prepared from TEOS. The catalytic reaction results showed that SAPO-1 was more active than conventional SAPO₂.

Synthesis, Characterization and Morphology Variety of Carbon Micro-coils

LI Wen-Jun, GUO Yan-Chuan, CHEN Li-Juan

2005, 26(9):  1589-1593. 

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Regular carbon micro-coils were obtained by a catalytic pyrolysis method with acetylene as a carbon resource and Ni as a catalyst and thiophene as a promotor. The morphology variety of carbon micro-coils which were obtained in different regions of the deposited furnace were examined in detail. Then, different reaction tubes were used to make the control experiments. The results of SEM, TEM, SAED and XRD show that the direction of gas current and the physical or chemical changes of catalyst grain cause the morphology variety of carbon micro-coils. Moreover, the structure, growth mechanism of carbon micro-coils and the effect of thiophene were discussed.

Preparation of Single Crystal CaSO₄ Nanotubes: A Nanotube Growing Route for Compound with Non-layered Structure

GAO Yuan-Hao, LIU Jin, NIU He-Lin

2005, 26(9):  1594-1597. 

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Single-crystal CaSO₄ nanotubes were prepared via a solvothermal process by using lamellar {Ti-O-Ti} polymer coupling oleic acid as the frame developing agent .The nanotubes were characterized by X-ray diffraction(XRD), energy dispersive X-ray analysis(EDX), transmission electron microscopy(TEM) and convergent beam electron diffraction(CBED). Lattice parameters of CaSO₄ single-crystal nanotubes are consistent with the standard values in JCPDS card of CaSO₄, which belongs to a hexagonal system, space group P3m1(164). The morphology of CaSO₄ nanotubes is mainly straight with inner hollow. The outer and inner diameters of the nanotubes are about 30 nm and 10 nm, respectively, and lengths reach up to 3.0 μm. The formation mechanism for CaSO₄ nanotubes was also discussed .This paper presents a promising solvothermal method for the preparation of nanotubes of self-nonlayered ionic crystals in terms of rolling of layer-by-layer grown from frame developing agent of lamellar Ti-O-Ti polymer coupling oleic acid.

Synthesis, Crystal Structure and Properties of Trisodium 5,3',5'-Trisulfonate-2,3,4,4'-tetrahydroxy-deoxybenzoin

YAN Xi, WU Fu-Li, LIU Yun, LI Jia-Mian, ZHENG Ze-Bao, YAN Hui-Qing, SI Shu-Feng

2005, 26(9):  1598-1602. 

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A new water soluble compound trisodium 5,3',5'-trisulfonate-2,3,4,4'-tetrahydroxy-deoxybenzoin(TTDB) was synthesized and characterized by IR, UV, ¹H NMR, and elemental analysis. Single crystals of(TTDB) was determined by X-ray single crystal diffraction. The scavenging effect of compounds on hydroxy radicals was detected by fluorescent spectrophotometry. The electrochemistry behavior of the compounds in non-aqueous solution DMF was carried out by means of cyclic voltammetry. The experimental result shows that the crystal [C₁4H₁7Na₃O₁8S₃] belongs to monoclinic space group C2/c with unit cell constants a={1.422 3(4) nm,} b=2.432 7(8) nm, c=1.359 6(4) nm, β=113.044(5)°, Z=8, V=4.329(2) nm³, D_c =1.925 Mg/m³, F(000)=2 568, M-r=638.43, R₁=0.095 0, wR₂=0.264 8. The half effective concentration EC₅0 of scanvenging hydroxy radicals of compounds THDB and TTDB are 53.1 and 47.3 μmol/L, respectively. The electrochemistry redox processes of THDB and TTDB are different.

Fast Synthesis of Ultra-fine Zeolite 4A at Low Temperature by Ultrasonic Method

ZHONG Sheng-Liang, ZHANG Mai-Sheng, SU Qiang

2005, 26(9):  1603-1606. 

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Zeolite 4A was quickly synthesized by ultrasonic method at low temperature. The products were characterized by XRD, IR, SEM and DSC, respectively. The results show that the crystallization rate of the product synthesized by using ultrasonic method is 24 times faster than that of conventional method. The whiteness of the products is 95%, the calcium ions exchange capacity is 335 mg CaCO-3/g zeolite 4A and the average particle size is 280 nm. Compared with the product synthesized by using conventional method, the thermal stability of the products prepared by ultrasonic method is decreased.

Hydrothermal Synthesis and Characterization of a Vanadium(Ⅳ) Phosphate Phosphite with Two-dimensional Layered Structures:[V₂O₂(OH)(HPO₃)(HPO₃)_0.7(PO₃OH)_0.3](C₆N₂H₁₆)_0.5

FU Wen-Sheng, LI Guang-Hua, WANG Li, LIANG Guo-Ming, SUN Yu-Yang, FENG Shou-Hua

2005, 26(9):  1607-1609. 

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An organically templated vanadium phosphate phosphite, [V₂O₂(OH)(HPO₃)(HPO₃)₀.75(PO₃OH)₀.3](C₆N₂H₁6)₀.5 (1), was hydrothermally synthesized and characterized by single crystal X-ray diffraction. Compound 1 crystallizes in monoclinic system, space group C2/c with cell parameters a=1.305 58(18) nm, b=1.020 69(10) nm, c=1.909 8(2) nm, V=2544.9(5) nm³ and Z=8. It possesses a layered architecture and organic template molecules located between the inorganic layers forming hydrogen bonds. The inorganic layers are constructed of V(Ⅳ)O₅ square pyramid, [PO₃OH²-] pyramid and [HPO²-₃] pseudo pyramid by sharing vertices.

Preparation of Ni/γ-Fe₂O₃ Composite Nanowires

CHEN Yan, YAN Hong, ZHANG Xiang-Yi

2005, 26(9):  1610-1612. 

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With the silanized porous anodic alumina(PAA) as a templates, an array of concentric composite nanostructures of Ni nanotubes/γ-Fe₂O₃ nanowires were prepared by electrodeposition and chemical precipitation. The microstructure of the nanowires and nanotubes was studied by employing the transmission electron mircoscope(TEM) and X-ray diffraction(XRD) techniques respectively. The results show that the diameter of composite nanowires is about 50 nm, the shell of the composite nanowires is the amorphous Ni nanotuble with a thickness from 4-15 nm by varying electrodeposition parameters and it coats a polycrystalline γ-Fe₂O₃ core.

Analysis of D-Aspartic Acid and D-Glutamic Acid in Single Cells by Capillary Electrophoresis

ZHAO Shu-Lin, SHEN Jiang-Shan

2005, 26(9):  1612-1612,1731. 

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An analytical method was established to detect D-aspartic acid(D-Asp) and D-glutamic acid(D-Glu) in single cells. Cellular samples were derivatized with a fluorescence tagging reagent, naphthalene-2,2-dicarboxaldehyde in a mini-volume(3 μL) prior to the separation. Sixteen pair of amino acid enantiomers resolution was achieved by using a dual chiral selector system consisting of β-cyclodextrin(β-CD) and chiral micelles formed by sodium deoxycholate(SDC). The separation was coupled with laser induced fluorescence detection. Single neurons isolated from the ganglia of Aplysia were analyzed to determine the D/(D+L) molar ratios of Asp to Glu. D-Asp and D-Glu were found at high levels and its cellular distribution was highly heterogeneous.

Interaction Between CdS Nanoparticles and Cysteine

LIU Hui, LI Wen-You, YIN Hong-Zong, HE Xi-Wen, MEI Fang, CHEN Lang-Xing

2005, 26(9):  1613-1617. 

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CdS nanoparticles were synthesized and their spectra properties were studied. At the same time, the interaction mechanisms between CdS nanoparticles and cysteine and cysteine were investigated under different experimental conditions such as pH values, concentrations of cysteine and molar ratios of CdCl₂, CH₃CSNH₂. After cysteine being added to the CdS nanoparticles, the fluorescence intensity of CdS nanoparticles was stronger and their emission peak did not change at pH before isoelectric point, while the fluorescence intensity became stronger at the beginning and then quenched and the emission peak was red-shifted at pH values after isoelectric point. It’s proved that coordination interaction and electrostatic interaction were the two interaction forms between CdS and cysteine, which influenced the variations of fluorescence intensity, emission peak and bandgap of CdS nanoparticles at different pH balues before and after isoelectric point.

Determination of Aromatic Amine Compounds in Lipstick by Microwave-assisted Extraction High Performance Liquid Chromatography

WANG Zi-Ming, ZHOU Xin, ZHENG Jian, ZHANG Han-Qi, LIU Li, LI Ying, LIU Zhi-Hong, WANG Hong-Ju, ZENG Hong, HE Hui

2005, 26(9):  1618-1622. 

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A new method, microwave-assisted extraction(MAE) high-performance liquid chromatography(HPLC), for quantitative determination of aromatic amine compounds in lipstick was developed. The lipstick sample was coated on glass slide, then the glass was put in the extraction vessel and aromatic amine compounds in the sample were extracted by microwave radiation. The obtained extract was analyzed by HPLC. Three commercial lipsticks were analyzed and the satisfactory results were obtained. Compared with the other extraction methods, the MAE takes shorter time and the extraction yields of the aromatic amine compounds obtained by using MAE are higher.

Microwave-assisted Extraction of Aloin from Fresh Aloe Leaves

YANG Yi, HOU Xiang-Yan, GUO Zhen-Ku

2005, 26(9):  1623-1626. 

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A detail procedure for extracting aloin from fresh aloe leaves was developed by using an obturated microwave-assisted extraction (MAE) device with a pressure controlling unit. The mechanism of the microwave-assisted extraction was studied by transmission electronic micrography. The effects of the solvent sort, solvent, concentration, radiation time and microwave power were discussed in orthogonal experiments. The results show that the optimized extraction parameters were ethanol-water(volume ratio is 70∶30), radiation time 4 min, microwave power 340 W. Compared with Soxhlet extraction and ultrosonic extraction, microwave extraction is a rapid method with a higher yield and less solvent consumption.

A L-Cysteine Derivative as Ligand-exchange Chiral Stationary Phase for Liquid Chromatography

WANG Sheng-Qing, MENG Qing-Hua, GUO Ying, MA Yan-Shun, LONG Yuan-De, HUANG Tian-Bao

2005, 26(9):  1627-1630. 

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A novel chiral stationary phase(CysCSP) for ligand exchange chromatography was prepared by firstly synthesizing N,S-di(2-hydroxyl-3-octoxyl)propyl-L-cysteine as chiral selector via reaction of L-cysteine with glycidyl octyl ether and then coating it on YWG-C-{18} bonded stationary phase. The enantiomeric resolutions of some D,L-α-amino acids were achieved on CysCSP by using cupric acetate aqueous solution as the mobile phase, under the conditions of column temperature 20 ℃ and detection at UV 254 nm. The enantioselectivities α of D,L-α-amino acids separated were found to be in the range from 1.11 to 1.38 with the resolution R-s ranging from 1.1 to 2.8 and the column efficiency being from 5 000 to 9 000 n/m. The elution order of D-isomer before L-isomer was obersaved for all D,L-amino acids used.

Surface Molecularly Imprinted Polymer Nanowires Used for Protein Recognition

LI Yong, YANG Huang-Hao, ZHUANG Zhi-Xia, WANG Xiao-Ru

2005, 26(9):  1631-1633. 

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Molecularly imprinted polymers(MIPs) are artificial, template-made receptors with the ability to recognize and to specially bind the target molecule. The advantage of stability of the polymer, ease of the preparation and low cost of these MIPs have led to their assessment as substitutes for antibodies or enzymes in chemical sensors, catalysis and separations. Although creating a MIPs against small molecules is straightforward now, imprinting of large structures, such as proteins and other biomacromolecules, is still a challenge. The major problem associated with the imprinting of such large structures lies on the restricted mobility of them within highly cross-linked polymer networks and the poor efficiency in rebinding. In this paper, we present a technique for the preparation of polymer nanowires with the protein molecule imprinted and binding sites on surface. These surface imprinting nanowires exhibit highly selective recognition for a variety of template proteins, including albumin, hemoglobin and cytochrome c. Since the protein imprinted sites are located on, or close to, the surface, these imprinted nanowires have a good site accessibility towards the target protein molecules. Furthermore, the large surface area of the nanowires results in larger protein molecules binding capacity of the imprinted nanowires compared to previously report surface imprinting MIPs.

Anodic Stripping Voltammetric Immunoassay Based on Silver Enhanced Gold Label for Determination of Complement Ⅲ

CHU Xia, FU Xin, SHEN Guo-Li, YU Ru-Qin

2005, 26(9):  1634-1636. 

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A novel, sensitive anodic stripping volammetric immunoassay was developed based on silver-enhanced immuno-gold label. The immunoreaction was performed in a polystyrene microwell by using the sandwich format. Primary antibodies specific for C₃(complement Ⅲ) were adsorbed passively on the walls of a polystyrene microwell. The C₃ analyte was first captured by the primary antibody and then sandwiched by a secondary colloidal gold-labeled antibody. The addition of the silver enhancement solution results in the precipitation of a large amount of silver on colloidal gold labels due to the catalytic reduction which, after silver metal dissolution in an acidic solution, was determined by anodic stripping voltammetry(ASV) at a glassy-carbon electrode. The influence of some immunoassay conditions upon the anodic stripping peak current was examined and optimized. The anodic stripping peak current depended linearly on the logarithm of C₃ mass concentration over the range of 7.2 ng/mL to 7.33 μg/mL and a detection limit as low as 7ng/mL is achieved. The anodic stripping volammetric immunoassay was applied to the determination of C₃ concentration in human serum with satisfactory results.

Selective Reduction, Characterization and Biological Activity of 3-Aryl-1-ferrocynyl-2-(¹H-1,2,4-triazol-1-yl)-2-propen-1-one Derivatives

JIN Zhong, LIU Wei, HUO Ai-Hong, LIU Jian-Bing, FANG Jian-Xin

2005, 26(9):  1637-1639. 

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3-Aryl-1-ferrocenyl-2-(1H-1,2,4-triazole)-1-yl-2-propen-1-one derivatives were prepared from ferrocene and reduced to related saturated and unsaturated alcohol derivatives under the selective conditions, respectively. In addition, selective reduction of α,β-unsaturated ferrocenyl ketone was also discussed. The structures of the title compounds were characterized by elemental analysis,¹H NMR and X-ray diffraction analysis. It was shown that ferrocene, as an organometallic compound, was introduced into bioactive triazole compounds in search of potent bioactive substances. Bioassay displayed that some of the title compounds possess fungicidal activity against C. ara and the unsaturated alcohol derivatives showed higher plant-growth regulatory activity than saturated ones.

Comparative Proteome Analysis of Human Squamous Lung Carcinomas and Small Cell Lung Carcinomas

LUO Guo-An, DENG Bin, YE Neng-Sheng, WANG Yi-Ming

2005, 26(9):  1640-1644. 

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We employed 2-DE with matrix-assisted laser desorption/ionization mass spectrometry(MALDI-TOF-MS) analysis after in-gel digestion protocol to identify the expressing proteins of human squamous lung carcinomas(SQCLC) and small cell lung carcinomas(SCLC) from surgical resection of 16 lung tumor patients. From a total of 59 spots excised from the 2-DE gel, 53 proteins had matches returned from the database search leading to the identification of these proteins. Among them only about 10 proteins have a significant difference(7 for SQCLC and 3 for SCLC, respectively) between SQCLC and SCLC. Meanwhile, 34 proteins, which highly existed in both carcinomas with different expression levels, as well as 6 proteins with almost the same expression levels, were found as the common proteins for both carcinomas. Among these identified proteins, 24 proteins had been previously proposed as the associated proteins with lung carcinomas, and 4 proteins had been linked to the other human carcinomas but not proposed in lung carcinomas.

Synthesis and Characterization of 4-(2-Benzyloxy-ethoxycarbonyl)-2-oxetanone

WANG Liang, JIA Xiao-Hua, YUAN Zhi

2005, 26(9):  1645-1649. 

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4-(2-Benzyloxyethoxycarbonyl)-2-oxetanone, an β-substituted-β-lactones with latent pendent hydroxyl groups,was synthesized from L-aspartic acid. Firstly, bromosuccinic acid was synthesized from L-aspartic acid and it was dehydrated to bromosuccinic anhydride by TFFA. Then the anhydride was alcoholysized to the monoester mixture by 2-benzyloxy ethanol. Finally, the novel monomer was got through a intromolecular cyclization of the mixture ester, and then it was further purified by silicon gel chromatogram. The product and the intermediates were characterized by ¹H NMR}, ¹³C NMR and elemental analysis. In addition, 2-benzyloxy ethanol was synthesized with a simplyified procedure and high yield by using Williamson method.

Primary Investigation of Blue-green Algae and Their Toxins from Water Blooms in Guanting Reservoir of Beijing

SHI Hong-Xing, QU Jiu-Hui, WANG Ai-Min, LI Guo-Ting, LEI Peng-Ju, LIU Hui-Juan

2005, 26(9):  1650-1652. 

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This is the first report of the algal toxins of water bloom in Guanting Reservoir of Beijing. The algal compositions and one family of their toxins-microcystins were investigated. The dominant species in the blooms found in September of 2003 were Microcystis, whose ratio to the number of total algal cells reach 97.2%. The specific species of the microcystis in the bloom included microcystis aeruginosa(52.7%), microcystis wesenbergii(36.2%) and Microcystis pseudofilamentasa(8.3%). The qualitative analysis by HPLC shows that at least five microcystins were contained in the scum of the blooms. The major microcystins were microcystin-RR and microcystin-LR. The quantitative analysis by HPLC indicates that the blooms contained microcystin-RR 1.69 mg/g and microcystin-LR 1.44 mg/g dried sample. The other three microcystins would be studied later.

Structure Investigation of Water Soluble Polysaccharide CTP Isolated from the Carthamus tinctorius L.

HUO Xian, LIANG Zhong-Yan, ZHANG Ya-Jun, FEI Rui, ZHAO Wei, ZHANG Li-Xia

2005, 26(9):  1653-1655. 

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Carthamus tinctorius L. is a kind of Chinese traditional and herbal drugs. Polysaccharides as effective ingredients have extensive pharmaceutic values especially as the immune regulators. CTP is the water soluble polysaccharide isolated from the Carthamus tinctorius L.. By means of HPLC, partial hydrolysis with acid, periodate oxidation, Smith degradation, GC, methylation and GC-MS analysis, ¹³C NMR spectroscopy, the structure of CTP was identified. CTP is a kind of small molecular weight polysaccharide with many branches. The main chain of CTP is made up of(1→4)-linked-Glc with five side chains. They are(1→3,6), (1→6), (1→)-linked-Gal, (1→2)-linked-Glc, (1→6), (1→)-linked-Glc, and two(1→6)-linked-Glc respectively.

A New Monoterpenoid Glyciside from Schisandra chinensis

DAI Hao-Fu, TAN Ning-Hua, ZHOU Jun

2005, 26(9):  1656-1658. 

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The fruits of Schisandra chinensis(Turcz.) Baill. is a traditional Chinese medicine for treatment of cough, dyspnea, insomnia and chronic hepatitis. During our investigation of Schisandra chinensis collected in Liaoning province, the water soluble extract of Schisandra chinensis(Turcz.) Baill was found to possess a strong activity on cardiovascular system. Some water soluble chemical constitutents from this species were reported in our earlier paper. In continuation of our studies on the seeds of Schisandra chinensis, a new monoterpenoid glycoside, named Schisanchinin A(1), was isolated from the water soluble extract through column chromatography. The spectroscopic and chemical evidences revealed its structure to be p-menthane-1,8,9-triol 9-O-β-D-glucopyranoside(1).

Studies on Tryptophan Residue Modification and Fluorescence Spectrum of Hyaluronidase

TENG Li-Rong, CHU Yu-Zhuo, ZHANG Xiao-Ping, WANG Jing, HAN Song, YU Xiao-Kun, LIU Lan-Ying

2005, 26(9):  1659-1661. 

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Tryptophan residues in Hyaluronidase(HAase) were modified by N-bromosuccinimide(NBS). The results indicated that there were eleven tryptophan residues in HAase and one of them was exposed, which was proved to be essential for the activity of the enzyme. The study on fluorescence quenching of HAase showed that KI could not quench all of the fluorescence from Trp residues in HAase . Acrylamide(Acr), a polarized quencher without electronic charge, could quench almost all of the fluorescence from Trp residues in HAase . The collisional quenching constants(K-D) of HAase at different concentrations of Acr were calculated in terms of Stern-Volmer equation. The results implied that some of Trp residues were buried in the interior of HAase, and the Trp residue on the surface of HAase was not located in the hydrophobic pocket.

Raman Spectrum of SWNTs at Different Excitation Wavelengths

CHEN Lin-Tao, ZHANG Zhen-Long, BAI Ying, WANG Yu-Fang, MO Yu-Jun

2005, 26(9):  1662-1664. 

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The single-walled carbon nanotubes(SWNTs) was synthesized by electric arc discharge method, and the normal Raman and resonant Raman scattering spectra of SWNTs were measured at 457.5 and 632.8 nm laser excitation wavelengths. By theoretical analysis, the diameter distributions of SWNTs were obtained, the style and configuration parameter were speculated further. By a Lorentzian line-shape analysis of the spectral feature for G mode, the component of the tangential stretch mode of SWTNs was assigned. The variational curve of the value of I-G/I-D for its changing with the variation of the laser power was obtained under 632.8 nm excitation. Disfigurement structure of SWNTs have a variety when laser power is 2.5 mW. In the Raman scattering spectra of SWNTs under 457.5 nm excitation, the new Raman peak under 1 421 cm^-1 is discovered for the first time.

Degradation of Microcystins by Electro-Fenton Reaction Using an Activated Carbon Fiber Cathode

WANG Ai-Min, QU Jiu-Hui, SHI Hong-Xing, RU Jia, LIU Hui-Juan, LEI Peng-Ju

2005, 26(9):  1665-1668. 

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The degradation of Microcystins(MC-RR, MC-LR) via electro-Fenton reaction using the activated carbon fiber(ACF) felt cathode with a large surface area was experimentally investigated. The effect of applied current, initial pH values of solution and Fe²⁺ ion concentration were discussed in detail. The results show that 75% of MC-RR and 94% MC-LR were eliminated after 60 min electrolysis under the operation conditions of 6.6 mA/cm² current density, 1.0 mmol/L Fe²⁺ at pH=3. The results indicate that H₂O₂ could be effectively electrogenerated from O₂ reduction on the ACF felt cathode and microcystins could be rapidly eliminated.

Preparation and Properties of Mg_0.9Ti_0.1Ni_0.9X_0.1(X=Mn, Zn, Co, Fe) Quaternary Alloys

WANG Mei-Han, ZHANG Lian-Zhong, SUN Li-Xian, TAN Zhi-Cheng, XU Fen, YUAN Hua-Tang, ZHANG Tao

2005, 26(9):  1669-1672. 

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The effects of partial substitution of Mg, Ni in Mg-based alloy on its electrochemical and hydrogen storage properties were investigated. Mg_0.9Ti_0.1Ni_0.9X_0.1(X=Mn, Zn, Co, Fe) quaternary alloys were synthesized by mechanical alloying(MA) on the basis of the ternary Mg_0.9Ti_0.1Ni alloy. The X-ray diffraction showed that the X partial substitution of Ni promoted the amorphous process of Mg_0.9Ti_0.1Ni alloy. It was found that the Co-substituted and Fe-substituted alloys showed enhanced discharge capacities. The cycle life of the alloys was improved with the addition of Mn and Zn, especially Mg_0.9Ti_0.1Ni_0.9Zn_0.1 alloy remained to keep a higher discharge capacity after the 10 cycles of charge and discharge. The hydrogen content in Mg_0.9Ti_0.1Ni_0.9Co_0.1 alloy is higher than that in Mg_0.9Ti_0.1Ni} alloy, which is in agreement with the result measured by the electrochemistry.

Light Induced Interfacial Charge Transfer in Phenylcapped Aniline Tetramer/TiO₂/ITO Film Electrode

CAO Ya-An, MENG Qing-Ju, SONG Qing, SHU Yong-Chun, ZHAO Jun-Yan, YAO Jiang-Hong, BAI Yu-Bai, XU Jing-Jun

2005, 26(9):  1673-1676. 

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The band gap and energy level of surface states of TiO₂ casting film and the energy level of ground state, energy level gap(HOMO-LUMO) and energy level of dual polarons of phenylcapped aniline tetramer(PAT) were investigated by means of surface photovoltage spectroscopy(SPS), cyclic voltammograms with irradiation(CAGI) and the photocurrent action spectra(PAS). Based on the experimental results the energy band structures of PAT/TiO₂/ITO thin film electrode are determined and the photo-to-electric conversion of PAT/TiO₂/ITO thin film electrode and the possible mechanism for interfacial electron transfer in PAT/TiO₂/ITO thin film electrode are discussed.

Theoretical Study on the CF₃CH₃+^·OH Reaction

WANG Huan-Jie, REN Hao, FENG Da-Cheng, GU Yue-Shu

2005, 26(9):  1677-1681. 

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The elementary reaction of CF₃CH₃+^·OH was studied by using density functional theory(DFT) B3LYP method with the 6-31G(d,p) basis set. There are six pathways of the reaction of CF₃CH₃ with ^·OH radical: direct hydrogen abstraction, direct fluorine abstraction, CF₃ substitution, CH₃ substitution, fluorine substitution and hydrogen substitution. Four substitution reactions are S_N2 reaction. We affirmed that the main reaction pathway of the reaction CF₃CH₃+^.OH is a direct hydrogen abstraction.

DFT Study of Molecular Structure and Vibrational Spectrum of Strychnine

GUO Yong, XUE Ying, XIE Dai-Qian, YAN Guo-Sen

2005, 26(9):  1682-1685. 

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Density functional theory(DFT) method at B3LYP/6-31G^* level was used to optimize the geometric structure of strychnine contained in natural drug Strychos rux-vomica L.. The equilibrious geometry parameters of strychnine was obtained and compared with its experimental ones. The harmonic force field and fundamental frequencies of the title molecule were calculated at B3LYP/6-31G^* level of the theory. A set of scaling factor was constituted according to the different normal modes and used to scale the calculated frequencies for strychnine. The mean difference between the theoretical and experimental frequencies was found to be 19.0 cm^-1. According to the normal modes and IR intensities in DFT calculation, we gave a consummate and reasonable assignment and interpretation to the observed vibrational spectrum of strychnine.

Theoretical Investigation of Structure and Electronic Spectrum of Benzil

DUAN Xiao-Hui, HE Rong-Xing, LI Xiang-Yuan, LUO Chun-Yan

2005, 26(9):  1686-1689. 

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In this work, the two isomers of benzil, cis-skewed(c-S) and trans-planar(t-P) configurations, were optimized both in gas phase and in solution. Based on the corresponding optimal structures, the absorption and emission spectra are discussed at the level of TD-B3LYP/6-31+G^*. The polarizable continuum model is applied in the calculations in solution. The calculated results indicate that the cis-skewed configuration is slightly favored when the polarity of the solvent increases. T₁ and S₁ states of the two isomers as well as S₂ state of the cis-skewed configuration all arise from the local excitation of n→π^*

Catalysis and Substituent Effects of Monomanganese-porphyrins and Monoiron-porphyrins for α-Pinene Oxidation with Air

YANG Wei-Jun, GUO Can-Cheng, MAO Yan-Li, LI Guo-Cheng

2005, 26(9):  1690-1694. 

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Catalysis and substituent effects of monomanganese-porphyrins and monoiron-porphyrins with different substituents on the phenyl rings for α-pinene oxidation with air were studied. The results showed that the product mixture was composed of components resulting from the oxidation of C=Cbond and allylic secondary and primary C-H bonds in α-pinene. No oxidation products of allylic tertiary C-H bond were detected. the main component of the product mixture was α-pinene oxide. The yields of various oxidation products increased linearly with the increase of the reaction time when α-pinene oxidation was catalyzed by the experimental mentallo-porphyrins. With increasing the electron-donating abilities of the substituents on the meso sites of phenyl rings of monomanganese-porphyrins and monoiron-porphyrins, their catalytic activities was weakened and the conversions of α-pinene decreased. There were linear relationships between the reaction kinetic constant k and the substituent constant σ of the two kinds of metallo-porphyrins, and the Hammett equations: lnk=1.2168σ-7.9968 for monomanganese-porphyrins and lnk=0.6251σ-8.2426 for monoiron-porphyrins. The linear coefficients were 0.950 7 and 0.971 5, respectively.

Synthesis of Nanocrystalline Titania and Photocatalytic Degradation of Phthalate Esters

CHU Ren-He, YAN Fu-Cheng, YAN Ji-Chang, WANG Yue-Hong, WANG Ying, ZHAO Kai, SHI Jin-E, LI Xiao-Kun, CUI Xiao-Ying, ZHAI Yu-Juan

2005, 26(9):  1695-1698. 

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Rutile titania with different shapes(shuttle-like, sphere with needles, uniform particles) was prepared by manipulative hydrolysis of TiCl₄ in aqueous solution with a high acidity in the absence or presence of PEG-1000. The products were characterized by means of XRD, TEM and UV-Vis. As a result, shuttle-like nanocrystalline appeared and the aggregation was improved with the increase of the amount of acid and the decrease of the concentration of TiCl₄ in the absence of PEG-1000. Uniform nanoparticles were obtained in the presence of PEG-1000, and the diameter of the particles decreased with increasing the amount of PEG-1000. The photocatalyzed degradation of phthalate esters in aqueous suspensions of titanium dioxide shows that the synthesized titania has a high photocatalytic activity. The degradation products were analyzed by GC-MS technique and probable pathways for the degradation of PEs were proposed.

Effect of Ce_0.67Zr_0.33O₂ on Catalytic Properties of Fe₂O₃/Al₂O₃ Catalyst for Methane Combustion

CHEN Qing-Quan, ZHANG Li-Juan, CHEN Yao-Qiang, WANG Min, GONG Mao-Chu

2005, 26(9):  1699-1703. 

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In order to find a kind of low-cost and high-capability catalyst for methane combustion, a series of CeO₂-ZrO₂-Al₂O₃ solid solution, in which the content of Ce₀.67Zr₀.33O₂ and Al₂O₃ were different, were prepared by co-precipitation method. Fe₂O₃-based catalysts supported on the solids were prepared by impregnation. Their characterizations and catalytic activity were tested by BET, TPR, XRD methods after being calcined at 600 ℃ or aging in water gas at 1 000 ℃. It is indicated that addition of Stoichiometric Ce₀.67Zr₀.33O₂ into the Al₂O₃ support improved the catalytic capability of the Fe₂O₃/CeO₂-ZrO₂-Al₂O₃ catalyst, increased the catalyst's specific surface areas, promoted its redox ability, and stabilized its crystal structure. In particular, when m(Ce₀.67Zr₀.33O₂)∶m(Al₂O₃) was 1∶2, the Fe₂O₃/CeO₂-ZrO₂-Al₂O₃ catalyst possessed the best catalytic capability and the best resistance to aging at high temperature.

Electrochemical Oxidation-degradation of Phenol on Ti/PbO₂ and Ti/Ru-Ti-Sn Oxide Coating Electrodes

LIN Hai-Bo, LIU Xiao-Bo, SUN Zhi-Quan, ZHANG Heng-Bin

2005, 26(9):  1704-1708. 

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The electrochemical oxidation-degradation of phenol in aqueous solution were studied on Ti/PbO₂ and Ti/Ru-Ti-Sn oxide coating electrodes. The effects of different electrodes on the electrochemical oxidation reactions and reaction intermediates of phenol were investigated by using UV-Vis spectroscopy. The electrogeneration of hydroquinone and pyrocatechol were detected by the method of high performance liquid chromatography(HPLC). The results show that the oxidation-degradation of phenol in aqueous solution are attributed to a further oxidation of hydroxylated products(hydroquinone and pyrocatechol).

Ab initio Study on Crystal Orbital of One-dimensional Phthalocyaninato Polymers

YANG Bao-Hua, AI Ya-Fan, HUANG Yuan-He

2005, 26(9):  1709-1711. 

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The band structures and electronic properties of several phthalocyaninato polymers and their derivatives are calculated by using the ab initio self-consistent-field crystal orbital method based on density functional theory. The calculated results show that these polymers are semiconductors. The differences in polymeric manner and degree of conjugation not only affect the energy gaps but also the band structures. The substituents almost have no influence on the band patterns of the corresponding polymers, but its electronic characteristics influences the band levels.

Effects of Variation of Elemental Compositions of Cesium Salts of Keggin Type Heteropolyacids on Selectively Catalytic Oxidation Performance of Propane

LI Xiu-Kai, LEI Yu, ZHAO Jing, JI Wei-Jie, ZHANG Zhi-Bing, CHEN Yi

2005, 26(9):  1712-1715. 

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The selective catalytic oxidation behavior of propane over the cesium salts of heteropoly acids with different elemental compositions were systematically studied. Special attentions were paid to the series of H₃+n-xCs_xPMo_12-nV_nO₄0 catalysts(n=0₄, x=0₃) as well as the H_0.5Cs_2.5PW₁2O₄0, H₁.5Cs_2.5PW₁1VO₄0 and H_1.5Cs_2.5SiMo₁2O₄0 catalysts. The catalysts were characterized by means of BET, UV-Vis diffuse reflectance spectroscopy, FTIR, XRD, TPR and SEM to understand their physico-chemical properties. The substitution of Mo⁶⁺ with V⁵⁺ increased the acidity and oxidation ability of the HPAs of H₃+nPMo₁2-nV_nO₄0(n=0₄) samples. Substitution of proton with Cs⁺ not only modified the surface acidity, but also affected the redox property as well as the structural stability of the samples, therefore, had a substantial impact on the catalytic performance for the series of H_3+n-xCs_xPMo₁2-nV_nO₄0(n=0₄, x=0₃) catalysts. It was found that the structural stability of HPCs increased steadily with increasing the number of cesium cation up to 3. The optimal number of cesium substitution varied along with the number of vanadium atoms existing in the primary structure of heteropoly anions. The appropriate elemental composition of heteropoly anions was found to be the key factor determining the overall catalytic behavior of the Keggin type heteropoly compounds, and the best results was achieved over the H_1.5Cs_2.5PMo₁₁VO₄0 catalyst. The reaction data collected on various HPCs in this study suggest that the composition of structural atoms of heteropoly anions and the number of balanced cations are closely related to acidity, redox property and catalytic performance of HPCs, and these data also accord well with the theoretical predictions.

Photoconductivity of CdS Nanorods/TiOPc Composite Photoconductors

SUN Jing-Zhi, CAO Jian, LI Han-Ying, HONG Jian, WANG Mang

2005, 26(9):  1716-1721. 

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The photoconductive properties of composite photoreceptors based on titanophthalocyanine(TiOPc) and CdS nanorods were sytematically investigated with photoinduced discharge technique. Upon excitation via 570 nm light, the composite photoreceptors showed evident enhancement in photosensitivity(S). A 32% increase in S was observed for a composite in a mass fraction of 5% CdS nanorods with respect to TiOPc component. The electronic structure data of CdS and TiOPc, together with the analysis of the surface photovoltage spectroscopic curves indicated that there existed a process of charge transfer from CdS to TiOPc, which is the mechanism for the sensitization of TiOPc by CdS nanorods, thereby bringing the high photoconductivity of TiOPc component into play. This study provided an example of promising method to improve the performance of opto-electronic devices by inorganic semiconductor materials in nanostructure.

Dehydrogenation of Propane to Propene in the Presenceof CO₂ over Gallium Oxide

ZHENG Bo, HUA Wei-Ming, YUE Ying-Hong, GAO Zi

2005, 26(9):  1722-1725. 

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Dehydrogenation of propane to propene in the presence or absence of CO₂ over gallium oxide was investigated. Ga₂O₃ exhibited the high dehydrogenation activity, which was even more active than chromium oxide catalyst. The dehydrogenation reaction was suggested to proceed through a heterolytic dissociation reaction pathway instead of a redox mechanism, and it was enhanced by CO₂ due to the existence of the reverse water gas shift reaction and the Boudouard reaction. This promotion effect of CO₂ was more evident at above 823 K. The high catalytic activity of Ga₂O₃ was probably associated with an abundance of surface medium-strong acid sites related to the coordinatively unsatured Ga³⁺ cations and the conjugated effect of proton and oxide. The deactivation of the catalyst was due to the coke deposition as well as the loss of the active oxygen species on the surface which could not be recovered during the regeneration.

Electrochemical Synthesis and Analysis of SERS Activity of Gold Nanoparticles Films

SHEN Li-Ming, YANG Zhi-Lin, REN Bin, WU De-Yin, GU Ren-Ao, TIAN Zhong-Qun

2005, 26(9):  1726-1731. 

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Surface-enhanced Raman scattering(SERS)-active gold nanoparticles(AuNPs) films were prepared with a one-step electrochemical method. The orthogonal design was used to investigate the experimental conditions influencing the morphologies and the SERS activity of the AuNPs. A condition was found to obtain the optimal SERS activity. The SEM study reveals that the AuNPs films were composed of closely packed AuNPs. The Finite Difference Time Domain(FDTD) simulation result indicates that the coupling between particles plays an important role in the enhancement SERS of AuNPs.

Characterization and Properties of Poly(vinyl alcohol)/Hydroxylapatite Hydrogels Prepared by Compound in situ with Sol-gel Method

ZHENG Yu-Dong, WANG Ying-Jun, CHEN Xiao-Feng, LIU Qing, WU Gang

2005, 26(9):  1732-1734. 

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A new kind of bioactive polyvinyl alcohol (PVA)/ hydroxylapatite (HA) blend hydrogels were prepared by compound in situ with sol-gel synthesis of HA. The structures and properties of the blend hydrogels with different HA contents were investigated. The crystal structure and dispersed statement of HA in hydrogels were characterized by XRD, FTIR and SEM. PVA/HA hydrogels were also prepared by physical mixing as a comparison. Ultrafine granular-crystalline HA powder was formed in blend hydrogels with sol-gel synthesis of HA in situ when compounding with PVA solution. Whereas HA was dispersed hon-uniformly and formed agglomeration of HA powder in blend hydrogels when compoumding with PVA by physical mixing. As a additional crystal core, HA accelerated the crystallization of PVA hydrogels, and increased the mechanical strength of the blend hydrogels.

Solid State NMR Study of Starch-sodium Acrylate Grafted Copolymer

KONG Xu-Xin, XU Kun, WANG Pi-Xin, CHEN Qun

2005, 26(9):  1735-1738. 

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The domain-structure of a series of starch/poly(sodium acrylate) grafted samples, in comparison with starch, poly(sodium acrylate) and starch/poly(sodium acrylate) blend, was studied by high-resolution solid-state ¹³C NMR spectroscopy at room temperature. The crystallinity of starch was found to decrease greatly in the grafted and blended samples. The obtained values of ¹H spin-lattice relaxation time in rotating frame T_1ρ and ¹H spin-lattice relaxation time T₁ showed that the starch and poly(sodium acrylate) components in both grafted and blended samples have the compatibility on nanometer scale. In the ¹³C CP/MAS spectra, the chemical shift of the carbonyl group of poly(sodium acrylate) is found to be dependent on the composition of the grafted samples. This result indicates further that the starch and the poly(sodium acrylate) components of the grafted samples exhibita compatibility at the molecular level, which is better than that of the blend sample.

Synthesis and Properties of Styrene/Maleimide Copolymer with Active Side-group

PU Hong-Ting, JIANG Wei-Chun, LIU Ling

2005, 26(9):  1739-1742. 

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Styrene/N-(4-hydroxyphenyl) maleimide copolymer(SHMI), which has an active side-group and can be reacted with other organic molecules with special optical and electrical properties, were synthesized. SHMI can be used as backbone for functional and special polymers. The structures of SHMI products were studied by FTIR, NMR and GPC. DSC and TGA were employed to study the thermal transition and thermal degradation of SHMI. It is shown that SHMI is an alternating copolymer with high glass transition temperature(T_g =526 K), good solubility and film-forming properties. The thermal degradation kinetics of SHMI can be fitted by Arrhenius equation. The initial thermal degradation temperature(T_d1) of SHMI is 661 K.

Synthesis and Properties of Chiral Conjugated Polymer Incorporating (R)- and (S)-1,1'-Binaphthyl and Oxadiazole Units

CHEN Ling-Wu, CHENG Yi-Xiang, SONG Jin-Feng, ZOU Xiao-Wei

2005, 26(9):  1743-1746. 

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Chiral conjugated polymers P-1 and P-2 were obtained by the polymerization of (S)-6,6'-dibromo-2,2'-bisbutoxy-1,1'-binaphthyl and (R)-6,6'-dibromo-2,2'-bisbutoxy-1,1'-binaphthyl with 2,5-bis(tri-n-butyltinphenyl)-1,3,4-oxadiazole(M-2) respectively via Stille coupling reaction catalyzed by Pd(PPh₃)₄. Both monomers and polymers were characterized by NMR, MS, FTIR, UV, DSC-TG, fluorescent spectroscopy, GPC and CD spectra. The butoxy substitutents on binaphthyl rings as a side chain of the polymers can improve the solubility in organic solvents and facile electro-optical sensors. 1,3,4-Oxadiazole unit is a better chromophore, and has good hole-transporting and stability for oxygen and heat. The polymers can emit very strong blue fluorescence. They are expected to have the potential application in the materials of interesting electro-optical molecular sensors.

Surface Properties of Hydroxy-terminated Polystyrenes

WANG Xin-Ping, CHEN Zhi-Fang, NI Hua-Gang, SHEN Zhi-Quan

2005, 26(9):  1747-1751. 

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The surface properties of hydroxy-terminated polystyrenes were investigated by Wilhelmy plate technique and sessile drop method. The results show that the static contact angles for water on the air-side surface and the advancing contact angles of the films were almost the same as the unfunctionalized polymer. However, the contact angles on the glass-side surface and the receding contact angles were found to decrease greatly. At the same time, it was found that the molecular weight distribution(PDI) of the polymer was an important factor to affect the surface dynamic behavior of hydroxy-terminated polystyrene. The advancing contact angles of the film with broad PDI decrease with increasing of temperature, and reach a minimum at 40 ℃, whereas that of narrow PDI polymer have not been affected by temperature. The similar result was obtained by heating the film against water. DMA results show that the loss modulus, storage modulus and tanδ of PS-OH-1 began to change sharply at 40 ℃ at which the minimum of contact angle appeared. The reason may be attributed to the polymer molecules with lower molecular weight segregating to surface, which result in molecules in surface layer having a higher activity. We speculate that the observed results about the minimum contact angle at 40 ℃ are associated with the enhanced molecular freedom on surface and changes in bulk structure such as crystallinity.

Measurement of the Apparent Chain Propagation Rate Constantsfor Graft Copolymerization by Reactive Extrusion

SHI Qiang, ZHU Lian-Chao, CAI Chuan-Lun, YIN Jing-Hua

2005, 26(9):  1752-1756. 

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In this work, the macromolecular peroxide-induced grafting of MAA onto LLDPE by reactive extrusion was chosen as model system to study the apparent chain propagation rate coefficients for both graft reaction(k_p,g) and homopolymerization of grafting monomers(k_p,h). The time-evolution rates of graft copolymerization and homopolymerization both exhibited two stages, linear and flat stage, which were controlled by monomer solubility and diffusion. By measuring the concentration of free-radicals and initial polymerization rate, which were determined with electron spin resonance spectroscopy(ESR) and Fourier transform infrared spectroscopy(FTIR), k_p,g and k_p,h were obtained. It was found that k_p,g increased with increasing temperature, while k_p,h decreased when the temperature was over 200 ℃, this has been attributed to the effect of ceiling temperature. That the value of k_p,h was always larger than k_p,g was also observed, indicating that graft copolymerization was not dominant reaction in this grafting process. The measured data were in agreement with theoretical calculations, which showed that this technique reliably and directly provides individually apparent chain propagation rate coefficients.

Dynamic Rheological Behavior of Particles-filled HDPE Composite Systems

DONG Qi-Qiong, ZHENG Qiang, DU Miao

2005, 26(9):  1757-1560. 

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The dynamic rheological behavior of the high-density polyethylene(HDPE) filled with carbon black(CB), or graphite(GP), i.e. HDPE/CB and HDPE/GP composites, was studied. The pseudo-solidlike behavior appearing in high-loaded composites could be attributed to the formation of the filler percolated network structure. In the composites with the same matrix, the filler kind and the geometric parameters of filler(particle shape, particle size and particle size distribution) play an important role in the dynamic rheological properties at low frequencies, the percolation behavior of the rheological parameters and the percolation threshold(φ_c). Compared with the geometric parameters of the filler particles, the filler kind exerts a more striking influence on them. The composites filled with particles having a large surface activity and large specific surface area possess a lower value of φ_c.

Surface Patterning on the Electro-sensitive Polymer Film

SONG Wen-Long, SUN Tao-Lei, JIANG Lei, LIU Feng-Qi, BAI Yu-Bai

2005, 26(9):  1761-1764. 

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Surface patterning was aroused much interest because of its great importance in the applications to microfluidic devices, etc. In this paper, we report a novel method to realize surface patterning on an electro-sensitive polymerpoly(2-acrylamido-2-methylpropanesulfonic acid). Through imposing the external electrical field utilizing a copper mesh film used in SEM as electrode, the film exhibits different properties in the areas that contact or not contact with the metal part of the mesh, which resulting in a pattern being the same as the mesh. This effect can be well explained by the conformational change of the polymer chains in the electric field.

Synthesis and Characterization of a Novel Photoalignment Liquid Crystalline Polymer

WU Li-Ping, ZHU Jun, SHI Ke-Yu, ZHANG Peng, GUO Xian-Zhi, HE Shang-Jin, DU Zong-Jie, ZHANG Bao-Long

2005, 26(9):  1768-1770. 

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A kind of novel liquid crystalline oxetane monomers containing biphenyl, flexible spacer and cinnamoyl group was synthesized. The monomer was initiated to polymerize by boron trifluoride etherate and resulted in photoreactive polymer, which was highly sensitive to the LPL photochemically. The thermal properties and the mesophase structure of the polymer were investigated by DSC and thermal optical polarized microscope. Three exothermal peaks corresponding to an isotropic-nematic transition, nematic-smectic transition and smectic-crystal transition, respectively, were found on the DSC cooling curve of the polymer. Well-developed fan texture was observed by optical polarizing microscope. The polymer was spin-coated on a SiO₂ glass substrate from DMF solution, resulting in a thin film. Irradiation of a LP-UV light resulted in anisotropic cycloadditions of the cinnamon acyl groups, which caused the alignment of biphenyl groups in side chains at the same time. The differences of absorbance at different irradiation time were obtained which can be used to explain that the polymer can be applied in photoalignment layer.

Synthesis and Characterization of Electro-active and Biodegradable Block Copolymer of Aniline Pentamer with Polylactide

HUANG Li-Hong, HU Jun, ZHUANG Xiu-Li, MA Jia, CHEN Xue-Si, JING Xia-Bin, GUO Yi, LI Meng-Yan, Peter I. Lelkes, WEI Yen

2005, 26(9):  1771-1773. 

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Every slight movement of human body, such as beat of heart, contract of muscles, thinking of brain, is associated with bioelectricity. In search for a neural conducting tissue engineering material which can {ideally} conduct bioelectrical signals in vivo, the block copolymer of polylactide(PLA) and aniline pentamera material which is electro-active, remarkably biocompatible and biodegradable, was designed and synthesized. The aniline pentamer is similar with polyaniline in electrical chemical properties, but more soluble than the latter. The copolymer is prepared by condensation polymerization between carboxyl-capped aniline pentamer and {dihydroxyl}-capped PLA, with N,N'-dicyclohexylcarbodiimide(DCC) as a condensing agent. The co-polymerization of aniline pentamer and PLA can not only reduce the toxicity of aniline pentamer, but also make the {material} easily to degrade and excrete from the body. These properties of the copolymer provide a favorable prospect in biomedical application in vivo. The synthesized material is investigated by FTIR, ¹H NMR, UV, and cyclic voltammetric measurements.

Antibacterial Property and Mechanism of Cationic Polyacrylamide of Quaternary Pyridine Salt

WANG Rui-Xin, GAO Bao-Jiao, GUO Jian-Feng, HE San-Xiong

2005, 26(9):  1774-1776. 

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Two series of cationic polyacrylamide of quaternary pyridine salt-type were synthesized, which have different cationic degrees and molecular weights respectively. The antibacterial property of QPAV was investigated, the influence of various factors on the antibacterial property was examined by using E. Coli as the disease-leading bacterium and the method of plate counting live bacterium. The antibacterial mechanism of QPAV was studied by using the method of measuring the activity of β-D-galactosidase. The experiment results show that QPAV possesses an excellent antibacterial property. The higher the cationic degree of QPAV is, the stronger the antibacterial property is. In certain range of molecular weight, the higher molecular weight of QPAV is, the better the antibacterial effect is. The pH value also influences the antibacterial property of QPAV. The antibacterial effect of QPAV is based on sterilization action certainly and is not only a restraining action.

Annealing and Quasi-quenching Processes of Phase-Separated PMMA/SAN Thin Film Studied by in situ AFM with Hot Stage

LIAO Yong-Gui, YOU Ji-Chun, LI Xue, SUN Zhao-Yan, SHI Tong-Fei, AN Li-Jia

2005, 26(9):  1777-1779. 

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The morphology and phase shift of phase-separated PMMA/SAN thin film on silicon wafer were studied by in situ AFM with hot stage through the annealing and quasi-quenching. The results show that the phase shifts are different between high temperature and room temperature, and between ultrahigh vacuum and ambient and between in situ and ex situ although the morphologies are almost invariable. The reasons were discussed simply.

Anionic Polymerization of Methyl Methacrylate Initiated by Thiocyanate-Lithium Organocuprates

LIANG Jian-Guo, HAN Bing-Yong, YANG Wan-Tai

2005, 26(9):  1780-1782. 

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Polymerizations of methyl methacrylate(MMA) initiated by lithium homocuprate and lithium heterocuprate from cuprous thiocyanate in tetrahydrofuran solution were carried out. Polymerizations initiated by lithium homocuprate were sensitive to the mass ratio of monomer to initiator and reaction temperature. At 10 ℃, with the increase of the mass ratio of monomer to initiator, the molecular weight of PMMA increased and the color of the reaction system response got more and more darker. This was often the signal of the thermal instability of organocopper. This may hint that the living end had already been destroyed. Low reaction temperature made the initiator efficiency obviously dropping. In addition, with the decrease of reaction temperature, syndiotactic degree of PMMA increased. Polymerizations initiated by lithium heterocuprate showed that heterocuprate was more efficient initiators than homocuprate. Under the same reaction conditions, PMMA from polymerization initiated by heterocuprate had narrower MWD and higher syndiotactic degree.