The living cationic polymerization of 4-[2-(tert-butyldimethylsiloxy)ethyl]styrene (TBDMES) was studied in methylcyclohexane (MeChx)/methylchloride (MeCl) (50/50 V/V) solvent mixture at -80 degrees C. The initiator 1,...The living cationic polymerization of 4-[2-(tert-butyldimethylsiloxy)ethyl]styrene (TBDMES) was studied in methylcyclohexane (MeChx)/methylchloride (MeCl) (50/50 V/V) solvent mixture at -80 degrees C. The initiator 1,1-diphenylethylene (DPE) capped 2-chloro-2,4,4-trimethylpentane (TMPCl) was formed in situ in conjunction with titanium tetrachloride (TiCl(4)). The Lewis acidity of TiCl(4) was decreased by the addition of titanium(IV) isopropoxide (Ti(OiPr)(4)) to accomplish living polymerization of TBDMES. Hydrolysis of poly(TBDMES) in the presence of tetra-butylammonium fluoride yielded poly[4-(2-hydroxyethyl)styrene] (poly(HOES)). FT-IR, NMR and DSC demonstrated the hydrolysis was complete.展开更多
Pheniramine maleate (PA), an antihistamine, was determined by Differential Pulse Stripping voltammetry using nano polypyrrole (Ppy) and nano poly(3,4-ethylenedioxythiophene) (PEDOT) modified glassy carbon electrodes. ...Pheniramine maleate (PA), an antihistamine, was determined by Differential Pulse Stripping voltammetry using nano polypyrrole (Ppy) and nano poly(3,4-ethylenedioxythiophene) (PEDOT) modified glassy carbon electrodes. The cyclic voltammetric behavior of pheniramine was studied in aqueous acidic, neutral and alkaline conditions. One well-defined oxidation peak was observed in the cyclic voltammograms at all pHs. The influence of pH, scan rate and concentration revealed irreversible electron transfer and the oxidation was diffusion controlled adsorption. The SEM analysis confirmed good accumulation of PA on the electrode surface. A systematic study of influence of various experimental parameters that affect the stripping voltammetric response was carried out and the maximum peak current conditions were arrived at. Calibration was made under maximum peak current conditions. The range of study was 0.05 to 0.4 μg/mL on Ppy/GCE and 0.025 to 0.4μg/mL on PEDOT/GCE and the lower limit of determination were 0.035μg/mL on Ppy/GCE and 0.016μg/mL on PEDOT/GCE. The suitability of the method for the determination of PA in pharmaceutical preparations and urine samples was also ascertained.展开更多
Composites of Maghnite-H, a Montmorillonite sheet silicate clay, exchanged with protons, and Poly(3,4-ethylenedioxythiophene) (PEDOT) were prepared by in situ chemical polymerization of the 3,4-ethylenedioxythiophene,...Composites of Maghnite-H, a Montmorillonite sheet silicate clay, exchanged with protons, and Poly(3,4-ethylenedioxythiophene) (PEDOT) were prepared by in situ chemical polymerization of the 3,4-ethylenedioxythiophene, without the use of solvent or oxidant. The effect of changing monomer/clay ratio was studied and the resultant composite structures were characterized by Inferred spectroscopy, 27Al and 13CSolid-State NMR spectroscopy, scanning electron microscopy and powder X-ray diffraction. All analyses are consistent with a structure were the polymer is (partially) intercalated into the clay structure, which in favourable cases lead to exfoliation. The presence of the clay in the polymer leads to a desired increase in thermal stability as witnessed by thermogravimetry.展开更多
Poly(styrene-co-4-vinylpyridine)-neodymium complexes(NdCl_3·PS4VPY)with variouscontents of the functional group and neodymium have been prepared and characterized.Theinfrared and X-ray photoelectron spectra indic...Poly(styrene-co-4-vinylpyridine)-neodymium complexes(NdCl_3·PS4VPY)with variouscontents of the functional group and neodymium have been prepared and characterized.Theinfrared and X-ray photoelectron spectra indicate that uncoordinated 4-vinylpyridine(4VPY)unitsremain in the NdCl_3·PS4VPY complexes.The catalytic behaviour of NdCl_3·PS4VPY was described briefly.展开更多
A novel tetrafunctional initiator, C [CH_2O (CH_2)_3 OOCCH(Br)CH_3]_4 (1), was synthesized through the reaction oftetraol with α-bromopropionyl chloride, and then was used as initiator of atom transfer radical polyme...A novel tetrafunctional initiator, C [CH_2O (CH_2)_3 OOCCH(Br)CH_3]_4 (1), was synthesized through the reaction oftetraol with α-bromopropionyl chloride, and then was used as initiator of atom transfer radical polymerization (ATRP) in thepreparation of 4-armed polystyrene (PSt) with narrow polydispersity. The structure, molecular weight and molecular weightdistribution (MWD) of each arm were studied by ~1H-NMR and GPC data of hydrolyzed products of the 4-armed PSt. TheATRP of St using 1/CuBr/bpy as initiator system is of 'living' character based on the following evidence: narrow MWD,constant concentration of chain radical during the polymerization, control of molecular weight by the molar ratio of monomerconsumed to 1. The 4-armed poly(St-b-p-nitrophenyl methacrylate) [poly(St-b-NPMA)] was prepared by the ATRP ofNPMA using 4-armed PSt with terminal bromine as the initiator, and characterized by FT-IR, ~1H-NMR spectra and GPCcurves. The micelles with PSt as core, and PNPMA as shell were formed by dropping DMSO into a solution of 4-armedpoly(St-b-NPMA) in DMF, as proved by laser light scatter (LLS) method.展开更多
Tetra(4-diazoniumbenzene)porphyrin(TDBP) was synthesized via diazo-reaction of tetra-(4-aminobenzene)porphyrin(TABP). From the analysis results of MALDI-TOF mass spectroscopy and FTIR,it was confirmed that the synthes...Tetra(4-diazoniumbenzene)porphyrin(TDBP) was synthesized via diazo-reaction of tetra-(4-aminobenzene)porphyrin(TABP). From the analysis results of MALDI-TOF mass spectroscopy and FTIR,it was confirmed that the synthesized porphyrin derivative mainly consists of tetra(4-diazoniumbenzene) porphyrin with trace tri- and di-substituted compounds. The self-assembly of TDBP with poly(styrene sulfonate)(PSS) was carried out and a novel TDBP/PSS multilayer ultrathin film on silicon substrate was obtained. The self-assembled film is very sensitive to heat and light,after heating or irradiation of UV light,the thin film becomes very stable towards polar solvents such as DMF. The coupling reaction of TDBP with phenol and the thermal stability of TDBP were also investigated preliminary. [WT5HZ]展开更多
The self-assembly between poly(4-diazonium styrene) (PDS) and poly(sodiumsulfonate styrene)(PSS) was investigated.The mutilayer ult ra thin films were fabricated layer-by-layer successfully from PDS and PSS.Af ter hea...The self-assembly between poly(4-diazonium styrene) (PDS) and poly(sodiumsulfonate styrene)(PSS) was investigated.The mutilayer ult ra thin films were fabricated layer-by-layer successfully from PDS and PSS.Af ter heating for 10 min at 70℃ the multilayer film became very stable towards po lar solvents.No considerable changes were observed for the heated film soaked i n DMF (20℃) for 48 h,while the unheated film almost destroyed at same conditio n.The dramatic improvement in stability of the film towards polar solvents shou ld be attributed to the conversion of bonds between the layers of the film from ionic bond to covalent bond under heating.Y(4 DIAZONIUMSTYRENE)ANDPOLY(SODIUMSULFONATESTYRENE)YANGZhaohui,JIANGWei,CAOWeixiao(CollegeofChemistryandMolecularEngineering ,PekingUniversity ,Beijing 10 0 871)Abstract Theself assemblybetweenpoly( 4 diazoniumstyrene) (PDS)andpoly(sodiumsulfonatestyrene) (PSS)wasinvestigated .Themutilayerultrathinfilmswerefabricatedlayer by layersuccessfullyfromPDSandPSS .Afterheatingfor 1 0minat 70℃themultilayerfilmbecameverystabletowardspolarsolvents.NoconsiderablechangeswereobservedfortheheatedfilmsoakedinDMF ( 2 0℃ )for48h ,whiletheunheatedfilmalmostdestroyedatsamecondition.Thedramaticimprovementinstabilityofthefilmtowardspolarsolventsshouldbeattributedtotheconversionofbondsbetweenthelayersofthefilmfromionicbondtocovalentbondunderheating .Keywords Poly( 4 diazoniumstyrene) 。展开更多
Platinum （Pt） implants coated with poly （3, 4-ethylenedioxythiophene）/carbon nanotube （PEDOT/CNT） composite films were implanted into the brain of rats, and the brain response was evaluated 6 weeks after the imp...Platinum （Pt） implants coated with poly （3, 4-ethylenedioxythiophene）/carbon nanotube （PEDOT/CNT） composite films were implanted into the brain of rats, and the brain response was evaluated 6 weeks after the implantation. The surface morphology of Pt implants with and without the PEDOT/CNT coating was studied using scanning electron microscopy （SEM）. After 6 weeks post-implantation, the expression of laminin （vascular endothelial marker） and neuronal nuclei （NeuN, neuronal marker） were evaluated by immnohistochemistry. It is revealed that the obvious improvements of the surface density of blood vessels and neurons aound the Pt implants with the coating, which were evidenced by laminin and NeuN staining in the zone within the distance of 150 μm to the implant interface. These results suggest the PEDOT/CNT composite films can improve the biocompatibility of the Pt electrodes while it is implanted in brain.展开更多
A new polymer-supported reagent--poly{[4-hydroxy(tosyloxy)iodo]styrene} has good reactivity in the formation of 2-amino-4-arylthiazoles, and the procedure of regeneration and cycle are also described.
基金supported by the Beijing Municipal Project for Developing Advanced Human Resources for Higher Education(Elastomers and Biomaterials).
文摘The living cationic polymerization of 4-[2-(tert-butyldimethylsiloxy)ethyl]styrene (TBDMES) was studied in methylcyclohexane (MeChx)/methylchloride (MeCl) (50/50 V/V) solvent mixture at -80 degrees C. The initiator 1,1-diphenylethylene (DPE) capped 2-chloro-2,4,4-trimethylpentane (TMPCl) was formed in situ in conjunction with titanium tetrachloride (TiCl(4)). The Lewis acidity of TiCl(4) was decreased by the addition of titanium(IV) isopropoxide (Ti(OiPr)(4)) to accomplish living polymerization of TBDMES. Hydrolysis of poly(TBDMES) in the presence of tetra-butylammonium fluoride yielded poly[4-(2-hydroxyethyl)styrene] (poly(HOES)). FT-IR, NMR and DSC demonstrated the hydrolysis was complete.
文摘Pheniramine maleate (PA), an antihistamine, was determined by Differential Pulse Stripping voltammetry using nano polypyrrole (Ppy) and nano poly(3,4-ethylenedioxythiophene) (PEDOT) modified glassy carbon electrodes. The cyclic voltammetric behavior of pheniramine was studied in aqueous acidic, neutral and alkaline conditions. One well-defined oxidation peak was observed in the cyclic voltammograms at all pHs. The influence of pH, scan rate and concentration revealed irreversible electron transfer and the oxidation was diffusion controlled adsorption. The SEM analysis confirmed good accumulation of PA on the electrode surface. A systematic study of influence of various experimental parameters that affect the stripping voltammetric response was carried out and the maximum peak current conditions were arrived at. Calibration was made under maximum peak current conditions. The range of study was 0.05 to 0.4 μg/mL on Ppy/GCE and 0.025 to 0.4μg/mL on PEDOT/GCE and the lower limit of determination were 0.035μg/mL on Ppy/GCE and 0.016μg/mL on PEDOT/GCE. The suitability of the method for the determination of PA in pharmaceutical preparations and urine samples was also ascertained.
文摘Composites of Maghnite-H, a Montmorillonite sheet silicate clay, exchanged with protons, and Poly(3,4-ethylenedioxythiophene) (PEDOT) were prepared by in situ chemical polymerization of the 3,4-ethylenedioxythiophene, without the use of solvent or oxidant. The effect of changing monomer/clay ratio was studied and the resultant composite structures were characterized by Inferred spectroscopy, 27Al and 13CSolid-State NMR spectroscopy, scanning electron microscopy and powder X-ray diffraction. All analyses are consistent with a structure were the polymer is (partially) intercalated into the clay structure, which in favourable cases lead to exfoliation. The presence of the clay in the polymer leads to a desired increase in thermal stability as witnessed by thermogravimetry.
基金The project was supported by the National Natural Science Foundation of China
文摘Poly(styrene-co-4-vinylpyridine)-neodymium complexes(NdCl_3·PS4VPY)with variouscontents of the functional group and neodymium have been prepared and characterized.Theinfrared and X-ray photoelectron spectra indicate that uncoordinated 4-vinylpyridine(4VPY)unitsremain in the NdCl_3·PS4VPY complexes.The catalytic behaviour of NdCl_3·PS4VPY was described briefly.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 29774027).
文摘A novel tetrafunctional initiator, C [CH_2O (CH_2)_3 OOCCH(Br)CH_3]_4 (1), was synthesized through the reaction oftetraol with α-bromopropionyl chloride, and then was used as initiator of atom transfer radical polymerization (ATRP) in thepreparation of 4-armed polystyrene (PSt) with narrow polydispersity. The structure, molecular weight and molecular weightdistribution (MWD) of each arm were studied by ~1H-NMR and GPC data of hydrolyzed products of the 4-armed PSt. TheATRP of St using 1/CuBr/bpy as initiator system is of 'living' character based on the following evidence: narrow MWD,constant concentration of chain radical during the polymerization, control of molecular weight by the molar ratio of monomerconsumed to 1. The 4-armed poly(St-b-p-nitrophenyl methacrylate) [poly(St-b-NPMA)] was prepared by the ATRP ofNPMA using 4-armed PSt with terminal bromine as the initiator, and characterized by FT-IR, ~1H-NMR spectra and GPCcurves. The micelles with PSt as core, and PNPMA as shell were formed by dropping DMSO into a solution of 4-armedpoly(St-b-NPMA) in DMF, as proved by laser light scatter (LLS) method.
文摘Tetra(4-diazoniumbenzene)porphyrin(TDBP) was synthesized via diazo-reaction of tetra-(4-aminobenzene)porphyrin(TABP). From the analysis results of MALDI-TOF mass spectroscopy and FTIR,it was confirmed that the synthesized porphyrin derivative mainly consists of tetra(4-diazoniumbenzene) porphyrin with trace tri- and di-substituted compounds. The self-assembly of TDBP with poly(styrene sulfonate)(PSS) was carried out and a novel TDBP/PSS multilayer ultrathin film on silicon substrate was obtained. The self-assembled film is very sensitive to heat and light,after heating or irradiation of UV light,the thin film becomes very stable towards polar solvents such as DMF. The coupling reaction of TDBP with phenol and the thermal stability of TDBP were also investigated preliminary. [WT5HZ]
文摘The self-assembly between poly(4-diazonium styrene) (PDS) and poly(sodiumsulfonate styrene)(PSS) was investigated.The mutilayer ult ra thin films were fabricated layer-by-layer successfully from PDS and PSS.Af ter heating for 10 min at 70℃ the multilayer film became very stable towards po lar solvents.No considerable changes were observed for the heated film soaked i n DMF (20℃) for 48 h,while the unheated film almost destroyed at same conditio n.The dramatic improvement in stability of the film towards polar solvents shou ld be attributed to the conversion of bonds between the layers of the film from ionic bond to covalent bond under heating.Y(4 DIAZONIUMSTYRENE)ANDPOLY(SODIUMSULFONATESTYRENE)YANGZhaohui,JIANGWei,CAOWeixiao(CollegeofChemistryandMolecularEngineering ,PekingUniversity ,Beijing 10 0 871)Abstract Theself assemblybetweenpoly( 4 diazoniumstyrene) (PDS)andpoly(sodiumsulfonatestyrene) (PSS)wasinvestigated .Themutilayerultrathinfilmswerefabricatedlayer by layersuccessfullyfromPDSandPSS .Afterheatingfor 1 0minat 70℃themultilayerfilmbecameverystabletowardspolarsolvents.NoconsiderablechangeswereobservedfortheheatedfilmsoakedinDMF ( 2 0℃ )for48h ,whiletheunheatedfilmalmostdestroyedatsamecondition.Thedramaticimprovementinstabilityofthefilmtowardspolarsolventsshouldbeattributedtotheconversionofbondsbetweenthelayersofthefilmfromionicbondtocovalentbondunderheating .Keywords Poly( 4 diazoniumstyrene) 。
基金Funded by the High Tech Research and Development ("863") Program of China (2006AA02Z4E6)the National Natural Science Foundation of China (Nos. 21073136, 81271364)
文摘Platinum （Pt） implants coated with poly （3, 4-ethylenedioxythiophene）/carbon nanotube （PEDOT/CNT） composite films were implanted into the brain of rats, and the brain response was evaluated 6 weeks after the implantation. The surface morphology of Pt implants with and without the PEDOT/CNT coating was studied using scanning electron microscopy （SEM）. After 6 weeks post-implantation, the expression of laminin （vascular endothelial marker） and neuronal nuclei （NeuN, neuronal marker） were evaluated by immnohistochemistry. It is revealed that the obvious improvements of the surface density of blood vessels and neurons aound the Pt implants with the coating, which were evidenced by laminin and NeuN staining in the zone within the distance of 150 μm to the implant interface. These results suggest the PEDOT/CNT composite films can improve the biocompatibility of the Pt electrodes while it is implanted in brain.
文摘A new polymer-supported reagent--poly{[4-hydroxy(tosyloxy)iodo]styrene} has good reactivity in the formation of 2-amino-4-arylthiazoles, and the procedure of regeneration and cycle are also described.
