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2013 Volume 30 Issue 2
2013, 30(2): 123-133
doi: DOI:10.3724/SP.J.1095.2013.20306
Abstract:
In recent years,rapid developments in the synthesis,catalytic properties and application of N-Heterocyclic carbene(NHC) have been achieved.Especially,in selective catalytic organic reactions,NHCs have shown high efficiency,good selectivity and excellent catalytic properties,and therefore have attracted great attention.This review briefly introduced the recent progress on the selective organic reactions catalysed by NHC from the perspectives of regioselectivity,diastereoselectivity and enantioselectivity.The prospects were described.
In recent years,rapid developments in the synthesis,catalytic properties and application of N-Heterocyclic carbene(NHC) have been achieved.Especially,in selective catalytic organic reactions,NHCs have shown high efficiency,good selectivity and excellent catalytic properties,and therefore have attracted great attention.This review briefly introduced the recent progress on the selective organic reactions catalysed by NHC from the perspectives of regioselectivity,diastereoselectivity and enantioselectivity.The prospects were described.
2013, 30(2): 134-137
doi: DOI:10.3724/SP.J.1095.2013.20104
Abstract:
Shape memory poly(vinylidene fluoride)/acrylic(PVDF/ACM) blends,in which tiny crystals of PVDF serve as the net points,were fabricated.Furthermore,carbon nanotubes(CNTs) were introduced to enhance the shape recovery properties.Fabrication,structure and performance of nanocomposites were investigated systemically.Our results show that PVDF and ACM are miscible,and the CNTs are all well dispersed.The resultant storage modulus of the shape memory materials is improved remarkably from 2000 MPa to 3130 MPa at 25℃,while the shape memory performance of them remains stable.
Shape memory poly(vinylidene fluoride)/acrylic(PVDF/ACM) blends,in which tiny crystals of PVDF serve as the net points,were fabricated.Furthermore,carbon nanotubes(CNTs) were introduced to enhance the shape recovery properties.Fabrication,structure and performance of nanocomposites were investigated systemically.Our results show that PVDF and ACM are miscible,and the CNTs are all well dispersed.The resultant storage modulus of the shape memory materials is improved remarkably from 2000 MPa to 3130 MPa at 25℃,while the shape memory performance of them remains stable.
2013, 30(2): 138-142
doi: DOI:10.3724/SP.J.1095.2013.20120
Abstract:
Poly(1-trimethylsilyl-1-propyne)(PTMSP) membranes were prepared by a solution-casting method in thickness ranging from 50 μm to 202 μm to study the effect of aging on their gas permeabilities.These membranes stored at room temperature display substantial decreases in gas permeability with time because of physical aging.The gas permeability decreased rapidly at first,and a slower,more gradual decrease and then almost leveled off was observed.PTMSP membrane stored in air exhibited slightly larger permeability decrement than that stored in N2.The decrease rate of gas permeability increased with the decrease of membrane thickness,and it decreased much more when the PTMSP membrane aged at high temperature of 100℃ in air,which is due to both physical aging and chemical aging.IR spectrum of the membrane indicates that storage of PTMSP at high temperature in air results in oxidation of the polymer with formation of CO groups.The gas permeability coefficient(P) of the membrane was inspected in more detail by determining the gas diffusion coefficient(D) and gas solubility coefficient(S).The S value hardly changed during storage,whereas the D value decreased with aging,which is responsible for the decrease of gas permeability.The decrease of D can be explained by the elimination of fractional free volume due to the volume relaxation and/or densification and the formation of polar groups in the polymer.
Poly(1-trimethylsilyl-1-propyne)(PTMSP) membranes were prepared by a solution-casting method in thickness ranging from 50 μm to 202 μm to study the effect of aging on their gas permeabilities.These membranes stored at room temperature display substantial decreases in gas permeability with time because of physical aging.The gas permeability decreased rapidly at first,and a slower,more gradual decrease and then almost leveled off was observed.PTMSP membrane stored in air exhibited slightly larger permeability decrement than that stored in N2.The decrease rate of gas permeability increased with the decrease of membrane thickness,and it decreased much more when the PTMSP membrane aged at high temperature of 100℃ in air,which is due to both physical aging and chemical aging.IR spectrum of the membrane indicates that storage of PTMSP at high temperature in air results in oxidation of the polymer with formation of CO groups.The gas permeability coefficient(P) of the membrane was inspected in more detail by determining the gas diffusion coefficient(D) and gas solubility coefficient(S).The S value hardly changed during storage,whereas the D value decreased with aging,which is responsible for the decrease of gas permeability.The decrease of D can be explained by the elimination of fractional free volume due to the volume relaxation and/or densification and the formation of polar groups in the polymer.
2013, 30(2): 143-147
doi: DOI:10.3724/SP.J.1095.2013.20105
Abstract:
A prepolymer was prepared by reacting the obtained sulfonated polyester polyol with isophorone diisocyanate(IPDI) and trimethylolpropane(TMP).The seed emulsion containing viny and silicone was prepared by end-capping with bifunctional monomer β-hydroxyethyl methacrylate(HEMA) and modification by silane coupling agent γ-aminopropyl triethoxysilane(KH550).The silicone modified sulfonated polyurethane/acrylic composite emulsion was obtained by mixing methyl methacrylate(MMA) and butyl acrylate(BA) monomers.The silicone modified sulfonated polyurethane/acrylic composite emulsion was characterized by infrared spectroscopy.The core-shell structure of the composite emulsion was confirmed by the transmission electron microscopy.Thermogravimetric analysis showed that an increase of 20℃ of the largest thermal mass loss temperature could be observed for the organic silicon and acrylic modified films.Meanwhile,the crystallinity was decreased as revealed by X-ray diffraction result,which could help to improve the toughness of the film.In addition,when the organic silicon content is 1.9%,the tensile strength of the film is up to 25.03 MPa,its elongation at break is 328%,and has the lowest water absorption.
A prepolymer was prepared by reacting the obtained sulfonated polyester polyol with isophorone diisocyanate(IPDI) and trimethylolpropane(TMP).The seed emulsion containing viny and silicone was prepared by end-capping with bifunctional monomer β-hydroxyethyl methacrylate(HEMA) and modification by silane coupling agent γ-aminopropyl triethoxysilane(KH550).The silicone modified sulfonated polyurethane/acrylic composite emulsion was obtained by mixing methyl methacrylate(MMA) and butyl acrylate(BA) monomers.The silicone modified sulfonated polyurethane/acrylic composite emulsion was characterized by infrared spectroscopy.The core-shell structure of the composite emulsion was confirmed by the transmission electron microscopy.Thermogravimetric analysis showed that an increase of 20℃ of the largest thermal mass loss temperature could be observed for the organic silicon and acrylic modified films.Meanwhile,the crystallinity was decreased as revealed by X-ray diffraction result,which could help to improve the toughness of the film.In addition,when the organic silicon content is 1.9%,the tensile strength of the film is up to 25.03 MPa,its elongation at break is 328%,and has the lowest water absorption.
2013, 30(2): 148-152
doi: DOI:10.3724/SP.J.1095.2013.20099
Abstract:
A series of(E)-β-(alkoxy)arylethylenes was synthesized by the one-pot three-component reaction of substituted benzyl alcohol,dimethyl sulfoxide and alkyl alcohols under mild conditions.This method has the advantages of high yields(68%~82%) and simple workup.The structures of the products were identified by 1H NMR,13C NMR spectra and elemental analysis.In addition,the probable mechanism for the reaction was proposed.
A series of(E)-β-(alkoxy)arylethylenes was synthesized by the one-pot three-component reaction of substituted benzyl alcohol,dimethyl sulfoxide and alkyl alcohols under mild conditions.This method has the advantages of high yields(68%~82%) and simple workup.The structures of the products were identified by 1H NMR,13C NMR spectra and elemental analysis.In addition,the probable mechanism for the reaction was proposed.
2013, 30(2): 153-158
doi: DOI:10.3724/SP.J.1095.2013.20129
Abstract:
A series of 4-hydroxy-3-(2-imino ethyl)-2H-chromen-2-ones was first synthesized by the reaction of 4-hydroxy-3-acetyl coumarin and amines in alcohol with 4-methylbenzenesulfonic acid as catalyst under ultrasonic irradiation.The yields were in the range of 62%~94%.The structures of the products were confirmed by IR,1H NMR and HRMS.The structure of compound 3c was determined by X-ray single-crystal diffractions.The advantages of this method are high yield,shorter reaction time,mild condition and simple work-up procedures.
A series of 4-hydroxy-3-(2-imino ethyl)-2H-chromen-2-ones was first synthesized by the reaction of 4-hydroxy-3-acetyl coumarin and amines in alcohol with 4-methylbenzenesulfonic acid as catalyst under ultrasonic irradiation.The yields were in the range of 62%~94%.The structures of the products were confirmed by IR,1H NMR and HRMS.The structure of compound 3c was determined by X-ray single-crystal diffractions.The advantages of this method are high yield,shorter reaction time,mild condition and simple work-up procedures.
2013, 30(2): 159-164
doi: DOI:10.3724/SP.J.1095.2013.20142
Abstract:
2,7-Bis(benzylamine carbonyl ethoxy) naphthaedi(L) and its rare earth picorate complexes [RE(pic)3]L2(RE=Y,La,Eu,Tb) were synthesized and characterized by 1H NMR,IR spectra,elemental analysis and molar conductivity.The complexation with ct-DNA was studied by spectrometry,cyclic voltammetry and,viscosity measurements in Tris-HCl buffer solution(pH=7.20),and the interaction strength was La(Ⅲ) > Tb(Ⅲ) > Y(Ⅲ) > Eu(Ⅲ).
2,7-Bis(benzylamine carbonyl ethoxy) naphthaedi(L) and its rare earth picorate complexes [RE(pic)3]L2(RE=Y,La,Eu,Tb) were synthesized and characterized by 1H NMR,IR spectra,elemental analysis and molar conductivity.The complexation with ct-DNA was studied by spectrometry,cyclic voltammetry and,viscosity measurements in Tris-HCl buffer solution(pH=7.20),and the interaction strength was La(Ⅲ) > Tb(Ⅲ) > Y(Ⅲ) > Eu(Ⅲ).
2013, 30(2): 165-170
doi: DOI:10.3724/SP.J.1095.2013.20160
Abstract:
Three kinds vanadate-replaced polyoxometalates,α-1,2,3-K6H[SiW9V3O40],α-1,2-K6[SiW10V2O40] and α-K5[SiW11VO40](abbreviated as α-SiW9V3,α-SiW10V2,α-SiW11V) were synthesized and evaluated as tyrosinase inhibitors using the enzymological kinetic method.The results demonstrate that α-SiW9V3 can inhibit tyrosinase strongly,as demonstrated by the inhibition of the steady-state activity of the enzyme and the lengthening of the lag time.The IC50 of α-SiW9V3 was estimated to be 0.6841 mmol/L for the inhibition of mushroom tyrosinase.It resulted in the lag time of the monophenolase extension from 235 s to 650 s with 0.7 mmol/L of α-SiW9V3.The inhibition of α-SiW9V3 on monophenolase of mushroom tyrosinase proceeds as reversible process,and the inhibition of α-SiW9V3 is a competitive-uncompetitive mixed-Ⅱ type due to the oxidation of L-tyrosine.The inhibition constants(KI and KIS) are determined to be 4.22 mmol/L and 2.39 mmol/L,respectively.As for the α-SiW10V2,however,it is unsoluble in DMSO buffer,and its effect on the mushroom tyrosinase cannot be studied.While the inhibition ability of α-SiW11V on tyrosinase activity is rather weak.
Three kinds vanadate-replaced polyoxometalates,α-1,2,3-K6H[SiW9V3O40],α-1,2-K6[SiW10V2O40] and α-K5[SiW11VO40](abbreviated as α-SiW9V3,α-SiW10V2,α-SiW11V) were synthesized and evaluated as tyrosinase inhibitors using the enzymological kinetic method.The results demonstrate that α-SiW9V3 can inhibit tyrosinase strongly,as demonstrated by the inhibition of the steady-state activity of the enzyme and the lengthening of the lag time.The IC50 of α-SiW9V3 was estimated to be 0.6841 mmol/L for the inhibition of mushroom tyrosinase.It resulted in the lag time of the monophenolase extension from 235 s to 650 s with 0.7 mmol/L of α-SiW9V3.The inhibition of α-SiW9V3 on monophenolase of mushroom tyrosinase proceeds as reversible process,and the inhibition of α-SiW9V3 is a competitive-uncompetitive mixed-Ⅱ type due to the oxidation of L-tyrosine.The inhibition constants(KI and KIS) are determined to be 4.22 mmol/L and 2.39 mmol/L,respectively.As for the α-SiW10V2,however,it is unsoluble in DMSO buffer,and its effect on the mushroom tyrosinase cannot be studied.While the inhibition ability of α-SiW11V on tyrosinase activity is rather weak.
2013, 30(2): 171-177
doi: DOI:10.3724/SP.J.1095.2013.20148
Abstract:
A novel hydrogen peroxide biosensor based on three-dimensionally ordered macroporous graphene-doped titanium dioxide modified ITO electrode(3DOM GR-Au-TiO2/ITO) was prepared by a sol-gel procedure using polystyrene colloidal crystals as template.Catalase has been successfully immobilized on the modified electrode.The cyclic voltammetry(CV),electrochemical impedance spectra(EIS) and chronoamperometric characterizations reveal that the modified electrode exhibits an excellent electrocatalytic activity,a wide linear range for H2O2 concentration from 3.0×10-6 mol/L to 3.6×10-3 mol/L with a detection limit of 4.2×10-7 mol/L(S/N=3),fast response,high sensitivity,good reproducibility and stability.
A novel hydrogen peroxide biosensor based on three-dimensionally ordered macroporous graphene-doped titanium dioxide modified ITO electrode(3DOM GR-Au-TiO2/ITO) was prepared by a sol-gel procedure using polystyrene colloidal crystals as template.Catalase has been successfully immobilized on the modified electrode.The cyclic voltammetry(CV),electrochemical impedance spectra(EIS) and chronoamperometric characterizations reveal that the modified electrode exhibits an excellent electrocatalytic activity,a wide linear range for H2O2 concentration from 3.0×10-6 mol/L to 3.6×10-3 mol/L with a detection limit of 4.2×10-7 mol/L(S/N=3),fast response,high sensitivity,good reproducibility and stability.
2013, 30(2): 178-184
doi: DOI:10.3724/SP.J.1095.2013.20163
Abstract:
Urea was used as a precursor of carbon to prepare carbon doped TiO2 nanotubes.The products obtained were characterized with Brunauer-Emmett-Teller surface area measurement(BET),X-ray diffraction(XRD),transmission electron microscopy(TEM),energy dispersive X-ray fluoresence spectroscopy(EDX),X-ray photoelectron spectroscopy(XPS),solid diffuse reflection UV-Vis spectroscopy(DRS) and fluorescence spectroscopy.The results showed that the visible light photocatalytic activity of the TiO2 nanotubes was improved obviously after doping C.In addition,the influences of doping amount of C,calcination temperature,dosage of catalyst and pH on the photocatalytic degradation activity of the TiO2 nanotubes were investigated.The degradation efficiency of rodamine B could reach 91% under 3 h visible light irradiation when the amount of doping C was 5.3%,calcination temperature was 400℃,dosage of catalyst was 1.5 g/L,pH of solution was 5.
Urea was used as a precursor of carbon to prepare carbon doped TiO2 nanotubes.The products obtained were characterized with Brunauer-Emmett-Teller surface area measurement(BET),X-ray diffraction(XRD),transmission electron microscopy(TEM),energy dispersive X-ray fluoresence spectroscopy(EDX),X-ray photoelectron spectroscopy(XPS),solid diffuse reflection UV-Vis spectroscopy(DRS) and fluorescence spectroscopy.The results showed that the visible light photocatalytic activity of the TiO2 nanotubes was improved obviously after doping C.In addition,the influences of doping amount of C,calcination temperature,dosage of catalyst and pH on the photocatalytic degradation activity of the TiO2 nanotubes were investigated.The degradation efficiency of rodamine B could reach 91% under 3 h visible light irradiation when the amount of doping C was 5.3%,calcination temperature was 400℃,dosage of catalyst was 1.5 g/L,pH of solution was 5.
2013, 30(2): 185-190
doi: DOI:10.3724/SP.J.1095.2013.20103
Abstract:
A CdSe/foam nickel thin film electrode was prepared by depositing the CdSe thin film on the foam nickel surface with potentiostatic method.The morphology and composition of CdSe/foam nickel thin film electrode were characterized by SEM,UV-Vis diffusive reflectance spectra(DRS) and energy dispersive spectra(EDS).The chemical oxygen demand(COD) removal efficiency was investigated during the process of photoelectrocatalytic degradation of crystal violet.The results show that the COD removal efficiency of 0.001 g/L crystal violet can reach to 84.3% when using the CdSe/foam nickle thin film electrode as working electrode and catalyst(deposition time is 30 min) under the following conditions:0.01 mol/L supporting electrolyte of NaCl,anodic bias potential of 0.4 V(vs.SCE),irradiation for 120 min with two incandescent lamps(100 W).
A CdSe/foam nickel thin film electrode was prepared by depositing the CdSe thin film on the foam nickel surface with potentiostatic method.The morphology and composition of CdSe/foam nickel thin film electrode were characterized by SEM,UV-Vis diffusive reflectance spectra(DRS) and energy dispersive spectra(EDS).The chemical oxygen demand(COD) removal efficiency was investigated during the process of photoelectrocatalytic degradation of crystal violet.The results show that the COD removal efficiency of 0.001 g/L crystal violet can reach to 84.3% when using the CdSe/foam nickle thin film electrode as working electrode and catalyst(deposition time is 30 min) under the following conditions:0.01 mol/L supporting electrolyte of NaCl,anodic bias potential of 0.4 V(vs.SCE),irradiation for 120 min with two incandescent lamps(100 W).
2013, 30(2): 191-195
doi: DOI:10.3724/SP.J.1095.2013.20082
Abstract:
The poor electrocatalytic stability of the carbon-supported palladium(Pd/C) catalyst for formic acid oxidation and the catalytic performance of the Pd/C catalyst for the decomposition of formic acid are the two problems of the direct formic acid fuel cell(DFAFC).It was found from the investigation that after the Pd/C catalyst is dipped in NaVO3 solution,VO3- can be adsorbed on the Pd/C catalyst.After the Pd/C catalyst is adsorbed with VO3-,the catalytic performance of the Pd/C catalyst for the decomposition of formic acid would be significantly inhibited,and the amount of CO produced from the decomposition of formic acid would be reduced,with the poison probability of the Pd/C catalyst by CO significantly reduced.Consequently,the peak current density at the Pd/C catalyst after dipping in NaVO3 solution for formic acid oxidation is 13% higher than that at the Pd/C catalyst without dipping in NaVO3 solution.The measurements of chronoamperometric curves indicate that the peak current density for formic acid oxidation at Pd/C catalyst after dipping in NaVO3 solution for 6000 s is 42% higher than that at the Pd/C catalyst without dipping in NaVO3 solution.The results demonstrate that dipping in NaVO3 solution can improve the electrocatalytic ability of Pd/C toward oxidation of formic acid,especially the electrocatalytic stability.
The poor electrocatalytic stability of the carbon-supported palladium(Pd/C) catalyst for formic acid oxidation and the catalytic performance of the Pd/C catalyst for the decomposition of formic acid are the two problems of the direct formic acid fuel cell(DFAFC).It was found from the investigation that after the Pd/C catalyst is dipped in NaVO3 solution,VO3- can be adsorbed on the Pd/C catalyst.After the Pd/C catalyst is adsorbed with VO3-,the catalytic performance of the Pd/C catalyst for the decomposition of formic acid would be significantly inhibited,and the amount of CO produced from the decomposition of formic acid would be reduced,with the poison probability of the Pd/C catalyst by CO significantly reduced.Consequently,the peak current density at the Pd/C catalyst after dipping in NaVO3 solution for formic acid oxidation is 13% higher than that at the Pd/C catalyst without dipping in NaVO3 solution.The measurements of chronoamperometric curves indicate that the peak current density for formic acid oxidation at Pd/C catalyst after dipping in NaVO3 solution for 6000 s is 42% higher than that at the Pd/C catalyst without dipping in NaVO3 solution.The results demonstrate that dipping in NaVO3 solution can improve the electrocatalytic ability of Pd/C toward oxidation of formic acid,especially the electrocatalytic stability.
2013, 30(2): 196-202
doi: DOI:10.3724/SP.J.1095.2013.20065
Abstract:
The lead dioxide-tungsten carbide(PbO2-WC) electrodes were prepared on stainless steel substrate by composite electrodeposition.The influences of temperature,current density and WC granule concentration on electrode performance were studied.Analyses of oxygen evolution curves,Tafel curves,scanning electron microscope,X-ray diffraction were used to investigate the performance changes after modified by WC granule.The optimal conditions were obtained as follows,temperature:70℃,current density:0.015~0.025 A/cm2,WC granule concentration in plating solution:40 g/L.In the process of codeposition,the results showed that the growth of PbO2 is preferred,with the PbO2 grain refined by WC granule,and the coating became denser.In comparison to the PbO2 electrode,the PbO2-WC composite electrode exhibits a stronger corrosion resistance and a lower oxygen evolution potential.
The lead dioxide-tungsten carbide(PbO2-WC) electrodes were prepared on stainless steel substrate by composite electrodeposition.The influences of temperature,current density and WC granule concentration on electrode performance were studied.Analyses of oxygen evolution curves,Tafel curves,scanning electron microscope,X-ray diffraction were used to investigate the performance changes after modified by WC granule.The optimal conditions were obtained as follows,temperature:70℃,current density:0.015~0.025 A/cm2,WC granule concentration in plating solution:40 g/L.In the process of codeposition,the results showed that the growth of PbO2 is preferred,with the PbO2 grain refined by WC granule,and the coating became denser.In comparison to the PbO2 electrode,the PbO2-WC composite electrode exhibits a stronger corrosion resistance and a lower oxygen evolution potential.
2013, 30(2): 203-207
doi: DOI:10.3724/SP.J.1095.2013.20067
Abstract:
Composite conductive polymers consisting of polypyrrole(PPy) and polyaniline(Pani) were synthesized successfully using cyclic voltammetry technique with 0.3 mol/L oxalic acid in the corresponding monomer solutions.The properties of the anticorrosion assembled with conducting polymers were investigated by IR,polarization curve,SEM,electrochemical impedence spectroscopy and free corrosion potentials.The result has shown that in 1 mol/L H2SO4,composite conductive polymers have the redox reaction with the stainless steel substrate,deactivating the stainless steel surface.When the molar ratio of aniline and pyrrole is 1:3,the prepared composite conductive polymers protect stainless steel with the minimum corrosion current,the highest corrosion potential,and the longest protected time.Electrochemistry impedance measurements indicate that the polypyrrole and polyaniline have the redox reaction with the stainless steel substrate,promoting the stainless steel surface passivation;however,the deactivated membrane may be destroyed and cause the stainless steel to be corroded when Cl- diffuses to the stainless steel surface.
Composite conductive polymers consisting of polypyrrole(PPy) and polyaniline(Pani) were synthesized successfully using cyclic voltammetry technique with 0.3 mol/L oxalic acid in the corresponding monomer solutions.The properties of the anticorrosion assembled with conducting polymers were investigated by IR,polarization curve,SEM,electrochemical impedence spectroscopy and free corrosion potentials.The result has shown that in 1 mol/L H2SO4,composite conductive polymers have the redox reaction with the stainless steel substrate,deactivating the stainless steel surface.When the molar ratio of aniline and pyrrole is 1:3,the prepared composite conductive polymers protect stainless steel with the minimum corrosion current,the highest corrosion potential,and the longest protected time.Electrochemistry impedance measurements indicate that the polypyrrole and polyaniline have the redox reaction with the stainless steel substrate,promoting the stainless steel surface passivation;however,the deactivated membrane may be destroyed and cause the stainless steel to be corroded when Cl- diffuses to the stainless steel surface.
2013, 30(2): 208-213
doi: DOI:10.3724/SP.J.1095.2013.20102
Abstract:
An oxidation technology,glow-discharge electrolysis plasma,has been successfully used to graft stearic acid onto iron-substrate for the fabrication of superhydrophobic iron-surface.To optimize the fabrication conditions,several important parameters such as the discharge voltage,the discharge time,the concentrations of supporting electrolyte and stearic acid ethanol solution were examined systematically.The wettability,structure and resultant composition of iron substrate were characterized by contact goniometer,X-ray photoelectron spectroscopy(XPS),Fourier transform infrared spectroscopy(FTIR) and SEM.Under the optimized conditions,the contact angle(CA) for the modified iron-substrate surfaces is up to 154° and the sliding angle(SA) is less than 5°.
An oxidation technology,glow-discharge electrolysis plasma,has been successfully used to graft stearic acid onto iron-substrate for the fabrication of superhydrophobic iron-surface.To optimize the fabrication conditions,several important parameters such as the discharge voltage,the discharge time,the concentrations of supporting electrolyte and stearic acid ethanol solution were examined systematically.The wettability,structure and resultant composition of iron substrate were characterized by contact goniometer,X-ray photoelectron spectroscopy(XPS),Fourier transform infrared spectroscopy(FTIR) and SEM.Under the optimized conditions,the contact angle(CA) for the modified iron-substrate surfaces is up to 154° and the sliding angle(SA) is less than 5°.
2013, 30(2): 214-219
doi: DOI:10.3724/SP.J.1095.2013.20090
Abstract:
The underpotential deposition(UPD) of zinc from alkaline media on Au substrate has been studied by cyclic voltammetry and chronoampermetry.Experimental conditions such as the concentration of zinc precursor and scanning rate have been investigated.The analysis of the experimental data clearly showed the UPD process was initiated at-0.935 V(vs.SCE).In adaition,the concentration change of metal cation may affect the kinetics of the UPD process.The potentiostatic transients suggested an adatom-incorporation limited,two-dimensional(2D) instantaneous nucleation and growth mechanism.In addition,the adsorption of hydroxyl group could exert significant influence on the UPD of zinc on Au.
The underpotential deposition(UPD) of zinc from alkaline media on Au substrate has been studied by cyclic voltammetry and chronoampermetry.Experimental conditions such as the concentration of zinc precursor and scanning rate have been investigated.The analysis of the experimental data clearly showed the UPD process was initiated at-0.935 V(vs.SCE).In adaition,the concentration change of metal cation may affect the kinetics of the UPD process.The potentiostatic transients suggested an adatom-incorporation limited,two-dimensional(2D) instantaneous nucleation and growth mechanism.In addition,the adsorption of hydroxyl group could exert significant influence on the UPD of zinc on Au.
2013, 30(2): 220-224
doi: DOI:10.3724/SP.J.1095.2013.20118
Abstract:
Perfluorooctane sulfonate(PFOS) can quench the fluorescence of rhodamine B(RhB) in pH=1.81 Britton-Robinson(BR) buffer solution,and results in light scattering enhancement by electrostatic forces and hydrophobic interactions.In this work,a light scattering-fluorescence ratio method of PFOS was established with a common spectrofluorometer by measuring the light emission signals through one scanning,out of which a ratio of the intensity of light scattering at 340 nm to that of fluorescence at 596 nm could be obtained.The linear range is from 0.17 to 10.0 μmol/L,and the limit of detection(3σ) is 17 nmol/L.The method has been applied to the determination of PFOS in the environmental samples with RSD≤4.2%.
Perfluorooctane sulfonate(PFOS) can quench the fluorescence of rhodamine B(RhB) in pH=1.81 Britton-Robinson(BR) buffer solution,and results in light scattering enhancement by electrostatic forces and hydrophobic interactions.In this work,a light scattering-fluorescence ratio method of PFOS was established with a common spectrofluorometer by measuring the light emission signals through one scanning,out of which a ratio of the intensity of light scattering at 340 nm to that of fluorescence at 596 nm could be obtained.The linear range is from 0.17 to 10.0 μmol/L,and the limit of detection(3σ) is 17 nmol/L.The method has been applied to the determination of PFOS in the environmental samples with RSD≤4.2%.
2013, 30(2): 225-231
doi: DOI:10.3724/SP.J.1095.2013.20127
Abstract:
Blue luminescent gold(Au) quantum dots(QDs) were facilely prepared through a one-pot synthesis at room temperature.The as prepared Au QDs were well water-soluble and biocompatable.The mean size of Au QDs is about 3.0 nm.Gold QDs colloids showed a considerable blue fluorescence emission at 430 nm under excitation of 305 nm.Experimental results demonstrated that the addition of L-cysteine could significantly enhance the characteristic emission of Au QDs at 430 nm.Therein,a simple,rapid,sensitive detection of L-cysteine in aqueous solution was established.Under optimized conditions,the characteristic fluorescence intensity of Au QDs at 430 nm is linearly proportional to the concentration of L-cysteine in the range of 0.0 to 4.0×10-6 μmol/L and a detection limit as low as 5 nmol/L was obtained.The relative linear relationship coefficient is 0.9976.The relative standard deviation for 11 replicate detections of 2.0 μmol/L L-cysteine was 2.8%.In addition,this method also demonstrated a high selectivity to amino acids due to the strong affinity of L-cysteine to gold atoms.
Blue luminescent gold(Au) quantum dots(QDs) were facilely prepared through a one-pot synthesis at room temperature.The as prepared Au QDs were well water-soluble and biocompatable.The mean size of Au QDs is about 3.0 nm.Gold QDs colloids showed a considerable blue fluorescence emission at 430 nm under excitation of 305 nm.Experimental results demonstrated that the addition of L-cysteine could significantly enhance the characteristic emission of Au QDs at 430 nm.Therein,a simple,rapid,sensitive detection of L-cysteine in aqueous solution was established.Under optimized conditions,the characteristic fluorescence intensity of Au QDs at 430 nm is linearly proportional to the concentration of L-cysteine in the range of 0.0 to 4.0×10-6 μmol/L and a detection limit as low as 5 nmol/L was obtained.The relative linear relationship coefficient is 0.9976.The relative standard deviation for 11 replicate detections of 2.0 μmol/L L-cysteine was 2.8%.In addition,this method also demonstrated a high selectivity to amino acids due to the strong affinity of L-cysteine to gold atoms.
2013, 30(2): 232-238
doi: DOI:10.3724/SP.J.1095.2013.20140
Abstract:
The interaction of Cyclen-Co(Ⅱ) with bovine serum albumin(BSA) was investigated by fluorescence method.The results show that the Cyclen-Co(Ⅱ) strongly quenches the fluorescence of BSA.It has been proved that the fluorescence quenching mechanism belongs to the static quenching by Stern-Volmer equation and Lineweaver-Burk equation.According to Lineweaver-Burk equation and thermodynamics equation,the binding constants,binding sites and thermodynamics parameters were obtained at different temperatures in the aqueous solution and in the solutions of Brij35,CTAB,SDS surfactants.The Van der Waals' forces play a main role in the binding of Cyclen-Co(Ⅱ) with BSA.
The interaction of Cyclen-Co(Ⅱ) with bovine serum albumin(BSA) was investigated by fluorescence method.The results show that the Cyclen-Co(Ⅱ) strongly quenches the fluorescence of BSA.It has been proved that the fluorescence quenching mechanism belongs to the static quenching by Stern-Volmer equation and Lineweaver-Burk equation.According to Lineweaver-Burk equation and thermodynamics equation,the binding constants,binding sites and thermodynamics parameters were obtained at different temperatures in the aqueous solution and in the solutions of Brij35,CTAB,SDS surfactants.The Van der Waals' forces play a main role in the binding of Cyclen-Co(Ⅱ) with BSA.
2013, 30(2): 239-241
doi: DOI:10.3724/SP.J.1095.2013.20151
Abstract:
A series of high-strength and processable polyimide(PI) moulding compounds with different content of diamine was prepared from 3,3',4,4'-biphenyl tetracarboxylic diandhydride(BPDA) and 4,4'-diaminodiphenyl ether(4,4'-ODA),3,4'-diaminodiphenyl ether(3,4'-ODA) through chemical imiidization.The rheological,mechanical and thermal resistance properties of the PI moulding compounds were investigated.With the increasing of 3,4'-ODA content,the impact strength of the PI could be maintained without dramatic change.The rheological properties of the PI were enhanced and the glass transition temperature can reach 275℃.The impact strength of the PI is about 141 kJ/m2.Processability of the PI is superior at 20 MPa.
A series of high-strength and processable polyimide(PI) moulding compounds with different content of diamine was prepared from 3,3',4,4'-biphenyl tetracarboxylic diandhydride(BPDA) and 4,4'-diaminodiphenyl ether(4,4'-ODA),3,4'-diaminodiphenyl ether(3,4'-ODA) through chemical imiidization.The rheological,mechanical and thermal resistance properties of the PI moulding compounds were investigated.With the increasing of 3,4'-ODA content,the impact strength of the PI could be maintained without dramatic change.The rheological properties of the PI were enhanced and the glass transition temperature can reach 275℃.The impact strength of the PI is about 141 kJ/m2.Processability of the PI is superior at 20 MPa.
2013, 30(2): 242-244
doi: DOI:10.3724/SP.J.1095.2013.20086
Abstract:
Acridinedione derivatives were synthesized by refluxing aromatic aldehyde,5,5-dimethyl-1,3-cyclohexanedione and aniline/4-methyl-aniline in aqueous solutions via a multi-component one-pot condensation process.The yields of the target compounds varied from 69% to 90%.The established protocol possesses the virtues of environmental benign and high efficiency toward the preparation of acridinedione derivatives.
Acridinedione derivatives were synthesized by refluxing aromatic aldehyde,5,5-dimethyl-1,3-cyclohexanedione and aniline/4-methyl-aniline in aqueous solutions via a multi-component one-pot condensation process.The yields of the target compounds varied from 69% to 90%.The established protocol possesses the virtues of environmental benign and high efficiency toward the preparation of acridinedione derivatives.
