Molecularly imprinted polymers selective for L-aspartic acid (LAA) have been prepared using the carboxy-betaine polymer bearing zwitterionic centres along the backbone. LAA is well known to promote good me-tabolism, t...Molecularly imprinted polymers selective for L-aspartic acid (LAA) have been prepared using the carboxy-betaine polymer bearing zwitterionic centres along the backbone. LAA is well known to promote good me-tabolism, treat fatigue and depression along with its significance in accurate age estimation in the field of forensic science and is an important constituent of ‘aspartame’, the low calorie sweetener. In order to study the intermolecular interactions in the prepolymerization mixture between the monomer and the template (LAA)/non-template (DAA), a computational approach was developed. It was based on the binding energy of the complex between the template and functional monomer. The results demonstrate that electrostatic in-teractions primarily guide the imprinting protocol. The MIP was able to selectively and specifically take up LAA from aqueous solution, human blood serum and certain pharmaceutical samples quantitatively. Hence, a facile, specific and selective technique to detect the amino acid, LAA in the presence of various interfer-rants, in different kinds of matrices is presented.展开更多
Biodegradable poly(alc-alt-Asp) was synthesized by ring-opening polymerization of the monomer 3-(S)-[(benzyloxycarbonyl)methyl] -morpholine-2, 5-dione and subsequent catalytic hydrogenation. Copolymers of the monomer ...Biodegradable poly(alc-alt-Asp) was synthesized by ring-opening polymerization of the monomer 3-(S)-[(benzyloxycarbonyl)methyl] -morpholine-2, 5-dione and subsequent catalytic hydrogenation. Copolymers of the monomer with glycolide, D,L-lactide and L-lactide were also prepared.展开更多
Five novel ternary complexes of rare earth ions with L-Aspartic acid (Asp) and o-phenanthroline (Phen) were synthesized in ethanol aqueous solution. Their compositions were characterized by elemental analysis, molar c...Five novel ternary complexes of rare earth ions with L-Aspartic acid (Asp) and o-phenanthroline (Phen) were synthesized in ethanol aqueous solution. Their compositions were characterized by elemental analysis, molar conductance, FT-IR, Raman, UV-VIS and TG-DTA. The compositions of the complexes were confirmed to be: RE( Asp)3PhenCl3·3H2O (RE: Ce3+ , Pr3+ , Nd3+ , Sm3+ , Er3+ ). The antibacterial activity test shows that all these complexes exhibit excellent antibacterial ability against Escherichia coli, Staphylococcus aureus and Candida albicans. The antimicrobial spectrum of the complexes are broad.展开更多
The electrocatalytic oxidation of dopamine(DA)was studied by electrochemical approaches at a carbon ionic liquid electrode(CILE)modified with the composite film of nafion and L-aspartic acid(NL-CILE).The CILE was fabr...The electrocatalytic oxidation of dopamine(DA)was studied by electrochemical approaches at a carbon ionic liquid electrode(CILE)modified with the composite film of nafion and L-aspartic acid(NL-CILE).The CILE was fabricated by replacing non-conductive organic binders with a room-temperature hydrophobic ionic liquid,1-butyl-3-methyl-imidazolium hexafluorophosphate.The composite film of NL was used as matrix to adsorb DA and catalyze the oxidation of DA in phosphate buffer solution(PBS).The electrochemical response of DA was investigated at the NL-CILE,the traditional carbon paste electrode(TCPE),CILE and the nafion modified CILE(N-CILE)in 0.1M PBS(pH 7.4),respectively.The results showed the superiority of NL-CILE to N-CILE,CILE and TCPE in terms of provision of higher sensitivity,faster electron transfer and better reversibility.Under optimum condition,the oxidation peak current was rectilinear with DA concentration range from 0.1μM to 0.1mM,with a detection limit of 0.03μM(S/N=3)by differential pulse voltammetry.The proposed method was applied to determine DA in samples successfully.展开更多
L-aspartic acid (Asp) pillared hydrotalcites were prepared by direct reaction of the L-Asp anion with layered double hydroxides (LDHs). The obtained samples were characterized by X-ray diffractometry (XRD), Four...L-aspartic acid (Asp) pillared hydrotalcites were prepared by direct reaction of the L-Asp anion with layered double hydroxides (LDHs). The obtained samples were characterized by X-ray diffractometry (XRD), Fourier transform infrared (FTIR), and thermogravimetric and differential thermal analysis (TG/DTA). The results show that the initial interlayer carbonate ions can be completely replaced by the L-Asp anion under the controlled conditions. The pillared hydrotalcites have a crystallized supramolecular structure and thermal stability. The L-Asp pillared LDHs were used in the enantiosorption of enantiopure phenylalanine (Pile), the results suggest that L-Asp pillared LDHs exhibit an excellent enantiosorption capability for D-Phe, and the adsorption isotherm fits Freundlich equation.展开更多
A new ternary complex of nickel(II) with L-aspartate (L-Asp) and 1, 10-phenan- throline(Phen), [Ni3(L-Asp)(Phen)5(H2O)3](ClO4)4?4.75H2O, has been synthesized in a mixed sol- vent of H2OC2H5OH at the pH value of 3. I...A new ternary complex of nickel(II) with L-aspartate (L-Asp) and 1, 10-phenan- throline(Phen), [Ni3(L-Asp)(Phen)5(H2O)3](ClO4)4?4.75H2O, has been synthesized in a mixed sol- vent of H2OC2H5OH at the pH value of 3. It crystallizes in triclinic, space group P1 with a = 11.861(2), b = 18.384(4), c = 19.746(3) ?, α = 107.68(1), β = 105.94(1), γ = 103.41(2)°, V = 3703.6(11) ?3, Mr = 1745.66, Z = 2, Dc =1.565 g/cm3, μ = 0.989 mm-1, F(000) = 1791, R = 0.0643 and wR = 0.1611. The complex contains two cations, binuclear [Ni2(L-Asp)(Phen)3(H2O)]2+ and mononu- clear [Ni(Phen)2(H2O)2]2+. All the nickel ions in the complex are six-coordinated with a distorted octahedral geometry, but the coordination environments for them are different. There exist hydrogen bonds and π-π stacking interactions in the complex.展开更多
The interaction of L-Aspartic acid (Asp) with Vctoria Green S (VGS) in pH 6.0 Britton-Robinson buffer solution has been investigated by UV/Vis spectropbotometry and resonance light scattering (RLS) technique. Th...The interaction of L-Aspartic acid (Asp) with Vctoria Green S (VGS) in pH 6.0 Britton-Robinson buffer solution has been investigated by UV/Vis spectropbotometry and resonance light scattering (RLS) technique. The non-covalent interactions such as hydrogen bond, salt linkage and hydrophobic bond were proposed to explain the interaction between VGS and Asp. It indicated that Asp could link each other to form a long chain by salt linkages and hydrogen bonds in aqueous medium. Then the long chain surrounded the hydrophobic groups of VGS via hydrophobic interaction and reacted with VGS by salt linkages and hydrogen bonds to form a macromolecular aggregation. The aggregation was much bigger than VGS itself. So the color became deeper and the system's absorption and RLS intensity increased. The increase in the absorbance at 617nm was proportional to the concentration of Asp, providing a basis for the quantitative determination of Asp. This method was simple and efficient than the ordinary methods and had been applied to the direct determination of Asp with satisfactory results.展开更多
Poly(ethylene oxide)(PEO)-based polymer electrolytes show the prospect in all-solid-state lithium metal batteries;however,they present limitations of low room-temperature ionic conductivity,and interfacial incompatibi...Poly(ethylene oxide)(PEO)-based polymer electrolytes show the prospect in all-solid-state lithium metal batteries;however,they present limitations of low room-temperature ionic conductivity,and interfacial incompatibility with high voltage cathodes.Therefore,a salt engineering of 1,1,2,2,3,3-hexafluoropropane-1,3-disulfonimide lithium salt(LiHFDF)/LiTFSI system was developed in PEO-based electrolyte,demonstrating to effectively regulate Li ion transport and improve the interfacial stability under high voltage.We show,by manipulating the interaction between PEO matrix and TFSI^(-)-HFDF^(-),the optimized solid-state polymer electrolyte achieves maximum Li+conduction of 1.24×10^(-4)S cm^(-1)at 40℃,which is almost 3 times of the baseline.Also,the optimized polymer electrolyte demonstrates outstanding stable cycling in the LiFePO_(4)/Li and LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)/Li(3.0-4.4 V,200 cycles)based all-solid-state lithium batteries at 40℃.展开更多
With the rapid development of 5G information technology,thermal conductivity/dissipation problems of highly integrated electronic devices and electrical equipment are becoming prominent.In this work,“high-temperature...With the rapid development of 5G information technology,thermal conductivity/dissipation problems of highly integrated electronic devices and electrical equipment are becoming prominent.In this work,“high-temperature solid-phase&diazonium salt decomposition”method is carried out to prepare benzidine-functionalized boron nitride(m-BN).Subsequently,m-BN/poly(pphenylene benzobisoxazole)nanofiber(PNF)nanocomposite paper with nacremimetic layered structures is prepared via sol–gel film transformation approach.The obtained m-BN/PNF nanocomposite paper with 50 wt%m-BN presents excellent thermal conductivity,incredible electrical insulation,outstanding mechanical properties and thermal stability,due to the construction of extensive hydrogen bonds andπ–πinteractions between m-BN and PNF,and stable nacre-mimetic layered structures.Itsλ∥andλ_(⊥)are 9.68 and 0.84 W m^(-1)K^(-1),and the volume resistivity and breakdown strength are as high as 2.3×10^(15)Ωcm and 324.2 kV mm^(-1),respectively.Besides,it also presents extremely high tensile strength of 193.6 MPa and thermal decomposition temperature of 640°C,showing a broad application prospect in high-end thermal management fields such as electronic devices and electrical equipment.展开更多
Meeting the demands of complex and advanced applications requires the development of high-performance hybrid materials with unique properties.However,the integration of polymeric frameworks with MgO/WO_(3) composite l...Meeting the demands of complex and advanced applications requires the development of high-performance hybrid materials with unique properties.However,the integration of polymeric frameworks with MgO/WO_(3) composite layers faces challenges due to the lack of understanding of the formation mechanism and the challenge of determining the impact of self-assembled architecture on anticorrosive properties.In this study,we aimed to enhance the corrosion resistance of the MgO layer produced by plasma electrolysis(PE)of AZ31 Mg alloy by incorporating WO_(3) with partially phosphorated poly(vinyl alcohol)(PPVA).Two types of porous MgO layers were produced using the PE process with an alkaline-phosphate electrolyte,one with and one without WO_(3) nanoparticles,which were subsequently immersed in an aqueous solution of PPVA.Incorporating PPVA into the WO_(3)-MgO layer resulted in hybrids being deposited in a fragmented manner,creating a“laminar reef-like structure”that sealed most of the structural defects in the layer.The PPVA-sealed WO_(3)-based coating exhibited superior corrosion resistance compared to the other samples.Computational analyses were employed to explore the mechanism underlying the formation of PPVA/WO_(3) hybrids on the MgO layer.These findings suggest that PPVA-WO_(3)-MgO hybrid coatings can potentially improve corrosion resistance in various fields.展开更多
Dimethyl carbonate(DMC)is a crucial chemical raw material widely used in organic synthesis,lithiumion battery electrolytes,and various other fields.The current primary industrial process employs a conventional sodium ...Dimethyl carbonate(DMC)is a crucial chemical raw material widely used in organic synthesis,lithiumion battery electrolytes,and various other fields.The current primary industrial process employs a conventional sodium methoxide basic catalyst to produce DMC through the transesterification reaction between vinyl carbonate and methanol.However,the utilization of this catalyst presents several challenges during the process,including equipment corrosion,the generation of solid waste,susceptibility to deactivation,and complexities in separation and recovery.To address these limitations,a series of alkaline poly(ionic liquid)s,i.e.[DVBPIL][PHO],[DVCPIL][PHO],and[TBVPIL][PHO],with different crosslinking degrees and structures,were synthesized through the construction of cross-linked polymeric monomers and functionalization.These poly(ionic liquid)s exhibit cross-linked structures and controllable cationic and anionic characteristics.Research was conducted to investigate the effect of the cross-linking degree and structure on the catalytic performance of transesterification in synthesizing DMC.It was discovered that the appropriate cross-linking degree and structure of the[DVCPIL][PHO]catalyst resulted in a DMC yield of up to 80.6%.Furthermore,this catalyst material exhibited good stability,maintaining its catalytic activity after repeated use five times without significant changes.The results of this study demonstrate the potential for using alkaline poly(ionic liquid)s as a highly efficient and sustainable alternative to traditional catalysts for the transesterification synthesis of DMC.展开更多
The stable operation of solid-state lithium metal batteries at low temperatures is plagued by severe restrictions from inferior electrolyte-electrode interface compatibility and increased energy barrier for Li^(+)migr...The stable operation of solid-state lithium metal batteries at low temperatures is plagued by severe restrictions from inferior electrolyte-electrode interface compatibility and increased energy barrier for Li^(+)migration.Herein,we prepare a dual-salt poly(tetrahydrofuran)-based electrolyte consisting of lithium hexafluorophosphate and lithium difluoro(oxalato)borate(LiDFOB).The Li-salt anions(DFOB−)not only accelerate the ring-opening polymerization of tetrahydrofuran,but also promote the formation of highly ion-conductive and sustainable interphases on Li metal anodes without sacrificing the Li^(+)conductivity of electrolytes,which is favorable for Li^(+)transport kinetics at low temperatures.Applications of this polymer electrolyte in Li||LiFePO_(4)cells show 82.3%capacity retention over 1000 cycles at 30℃and endow stable discharge capacity at−30℃.Remarkably,the Li||LiFePO4 cells retain 52%of their room-temperature capacity at−20℃and 0.1 C.This rational design of dual-salt polymer-based electrolytes may provide a new perspective for the stable operation of quasi-solid-state batteries at low temperatures.展开更多
In the last decade,numerous physical modification methods have been introduced to enhance triboelectric nanogenerator(TENG)performance although they generally require complex and multiple fabrication processes.This st...In the last decade,numerous physical modification methods have been introduced to enhance triboelectric nanogenerator(TENG)performance although they generally require complex and multiple fabrication processes.This study proposes a facile fabrication process for Poly(vinylidene fluoride)(PVDF)nanofiber(NF)mats incorporating additive and nonadditive physical modifications.Patterned PVDF NF mats are prepared by electrospinning using a metal mesh as the NF collector.As a negative triboelectric material,the TENG with the patterned PVDF NF mat exhibits superior performance owing to the engineered morphology of the contact layer.PVDF is crucial in TENGs owing to its superior ferroelectric properties and surface charge density when combined with specific electroceramics.Hence,the synergy of the physical modification methods is achieved by incorporating BaTiO3(BTO)nanoparticles(NPs)into the PVDF.By functionalizing BTO NPs with polydopamine,the TENG performance is further improved owing to the enhanced dispersion of NPs and improved crystallinity of the PVDF chains.Utilizing large NPs produces a nanopatterning effect on the NF surface,thereby resulting in the hierarchical structure of the NF mats.The source of the voltage signals from the TENG is analyzed using fast Fourier transform.展开更多
The conversion of waste polylactic acid(PLA)plastics into high-value-added chemicals through electrochemical methods is a promising and sustainable approach.However,developing efficient and highly selective catalysts ...The conversion of waste polylactic acid(PLA)plastics into high-value-added chemicals through electrochemical methods is a promising and sustainable approach.However,developing efficient and highly selective catalysts for lactic acid oxidation reaction(LAOR)and understanding the reaction process are challenging.Here,we report the electrooxidation of waste PLA to acetate at a high current density of 100 mA cm-2 with high Faraday efficiency(~95%)and excellent stability(>100 h)over a nickel selenide nanosheet catalyst.In addition,a total Faraday efficiency of up to 190%was achieved for carboxylic acids,including acetic acid and formic acid,by coupling with the cathodic CO_(2) reduction reaction.In situ experimental results and theoretical simulations revealed that the catalytic activity center of LAOR was dynamically formed NiOOH species,and the surface-adsorbed SeO_(x) species accelerated the formation of Ni~(3+)species,thus promoting catalytic activity.The mechanism of lactic acid electrooxidation was further elucidated.Lactic acid was dehydrogenated to produce pyruvate first and then formed CH_3CO due to preferential C-C bond cleavage,resulting in the presence of acetate.This work demonstrated a sustainable method for recycling waste PLA and CO_(2) into high-value-added products.展开更多
The repairing effect of poly(N-vinylpyrrolidone-co-methacrylic acid)on permed or bleached damaged hair was studied.The combing and tensile strength of permed and bleached hair before and after treatment with the copol...The repairing effect of poly(N-vinylpyrrolidone-co-methacrylic acid)on permed or bleached damaged hair was studied.The combing and tensile strength of permed and bleached hair before and after treatment with the copolymer solution were tested,and the effects of the mass fraction of copolymer solution and immerseing time on the combing and tensile strength for permed or bleached damaged hair were investigated.The repair mechanism of permed or bleached damaged hair was also explored.The results show that when the immersing time is 3 hours,the tensile strength of the permed hair increases with the mass fraction of the copolymer solution Tensile strength within 0%-0.3%,but no obvious change is observed when250 Yield strength the mass fraction is over 0.3%.Therefore,the optimal mass 200 fraction of the copolymer solution for repairing the permed hair(cN/dtex)is 0.3%.Similarly,the optimal mass fraction of the copolymer 150strength/solution for repairing the bleached hair is 0.5%.Furthermore,the effects of immersing time on the tensile strength of the100Tensile damaged hair fibers were compared between the permed and90 bleached hair before and after treatment with the copolymer500.40.30.500.10.2 solution.Coincidentally,the optimal immersion time for permedw(P(NVP-co-MAA))/%or bleached damaged hair is both 2 hours.The tensile strength of the permed and bleached hair soaked in 0.3%and 0.5%copolymer solutions for 2 hours increases by 15.55%and 18.12%,respectively,compared to untreated hair.Through infrared spectroscopy analysis,it is found that the amide II band in hair fibers shifted to the blue after repair,with the wave number shift of 11.12 and 11.09 cm^(-1),which confirm the formation of hydrogen bonds in the hair samples.Additionally,the urea hydrogen bond disruption experiment demonstrates that urea does not disrupt the hydrogen bonds in untreated hair fibers,but prevents the formation of new hydrogen bonds in damaged hair fibers.It further validates that the improvement of the tensile strength of the copolymer treated damaged hair fibers is mainly due to the formation of hydrogen bonds.After treatment with the copolymer,the dry and wet combing friction decrease by 30.73%and 28.55%for the permed hair,and decrease by 28.55%and 24.83%for the bleached hairs,respectively.The scanning electron microscope shows that the copolymer can flatten the cuticle and fill the space between the raised cuticles.展开更多
Gel-based polymer electrolytes are limited by the polarity of the residual solvent,which restricts the coupling-breaking behaviour during Li^(+)conduction,resulting in the Li^(+)transport kinetics being greatly affect...Gel-based polymer electrolytes are limited by the polarity of the residual solvent,which restricts the coupling-breaking behaviour during Li^(+)conduction,resulting in the Li^(+)transport kinetics being greatly affected.Here,we designed anion competitive gel polymer electrolyte(ACPE)by introducing lithium difluoro(oxalato)borate(LiDFOB)anion into the 1,3-dioxolane(DOL)in situ polymerisation system.ACPE enhances the ionic dipole interaction between Li^(+)and the solvent molecules and synergizes with Li^(+)across the solvation site of the polymer ethylene oxide(EO)unit,combination that greatly improves the Li^(+)transport efficiency.As a result,ACPE exhibits 1.12 mS cm^(−1)ionic conductivity and 0.75 Li^(+)transfer number at room temperature.Additionally,this intra-polymer solvation sheath allows preferential desolvation of DFOB−,which contributes to the formation of kinetically stable anion-derived interphase and effectively mitigates side reactions.Our results demonstrate that the assembled Li||NCM622 solid-state battery exhibits lifespan of over 300 cycles with average Coulombic efficiency of 98.8%and capacity retention of 80.3%.This study introduces a novel approach for ion migration and interface design,paving the way for high-safety and high-energy-density batteries.展开更多
The interfacial instability of the poly(ethylene oxide)(PEO)-based electrolytes impedes the long-term cycling and further application of all-solid-state lithium metal batter-ies.In this work,we have shown an effective...The interfacial instability of the poly(ethylene oxide)(PEO)-based electrolytes impedes the long-term cycling and further application of all-solid-state lithium metal batter-ies.In this work,we have shown an effective additive 1-adaman-tanecarbonitrile,which con-tributes to the excellent per-formance of the poly(ethylene oxide)-based electrolytes.Owing to the strong interaction of the 1-Adamantanecarboni-trile to the polymer matrix and anions,the coordination of the Li^(+)-EO is weakened,and the binding effect of anions is strengthened,thereby improving the Li^(+)conductivity and the electrochemical stability.The diamond building block on the surface of the lithium anode can sup-press the growth of lithium dendrites.Importantly,the 1-Adamantanecarbonitrile also regulates the formation of LiF in the solid electrolyte interface and cathode electrolyte interface,which contributes to the interfacial stability(especially at high voltages)and protects the electrodes,enabling all-solid-state batteries to cycle at high voltages for long periods of time.Therefore,the Li/Li symmetric cell undergoes long-term lithium plating/stripping for more than 2000 h.1-Adamantanecarbonitrile-poly(ethylene oxide)-based LFP/Li and 4.3 V Ni_(0.8)Mn_(0.1)Co_(0.1)O_(2)/Li all-solid-state batteries achieved stable cycles for 1000 times,with capacity retention rates reaching 85%and 80%,respectively.展开更多
文摘Molecularly imprinted polymers selective for L-aspartic acid (LAA) have been prepared using the carboxy-betaine polymer bearing zwitterionic centres along the backbone. LAA is well known to promote good me-tabolism, treat fatigue and depression along with its significance in accurate age estimation in the field of forensic science and is an important constituent of ‘aspartame’, the low calorie sweetener. In order to study the intermolecular interactions in the prepolymerization mixture between the monomer and the template (LAA)/non-template (DAA), a computational approach was developed. It was based on the binding energy of the complex between the template and functional monomer. The results demonstrate that electrostatic in-teractions primarily guide the imprinting protocol. The MIP was able to selectively and specifically take up LAA from aqueous solution, human blood serum and certain pharmaceutical samples quantitatively. Hence, a facile, specific and selective technique to detect the amino acid, LAA in the presence of various interfer-rants, in different kinds of matrices is presented.
文摘Biodegradable poly(alc-alt-Asp) was synthesized by ring-opening polymerization of the monomer 3-(S)-[(benzyloxycarbonyl)methyl] -morpholine-2, 5-dione and subsequent catalytic hydrogenation. Copolymers of the monomer with glycolide, D,L-lactide and L-lactide were also prepared.
基金Project supported by Shanghai Technology Committee Research Fund (0552nm036)Shanghai Leading Academic Discipline Project (T0402)+1 种基金Shanghai-Unilever Research and Development Fund (200406)Shanghai Education Committee Research Fund (05DZ19)
文摘Five novel ternary complexes of rare earth ions with L-Aspartic acid (Asp) and o-phenanthroline (Phen) were synthesized in ethanol aqueous solution. Their compositions were characterized by elemental analysis, molar conductance, FT-IR, Raman, UV-VIS and TG-DTA. The compositions of the complexes were confirmed to be: RE( Asp)3PhenCl3·3H2O (RE: Ce3+ , Pr3+ , Nd3+ , Sm3+ , Er3+ ). The antibacterial activity test shows that all these complexes exhibit excellent antibacterial ability against Escherichia coli, Staphylococcus aureus and Candida albicans. The antimicrobial spectrum of the complexes are broad.
基金supported by the National Natural Science Foundation of China(No.20875076)the Scientific Initializing Foundation of Northwest University(No.PR09036)+1 种基金the Science Foundation of Northwest University(No.09NW02)the NWU Doctorate Dissertation of Excellence Funds(No.08YYB06).
文摘The electrocatalytic oxidation of dopamine(DA)was studied by electrochemical approaches at a carbon ionic liquid electrode(CILE)modified with the composite film of nafion and L-aspartic acid(NL-CILE).The CILE was fabricated by replacing non-conductive organic binders with a room-temperature hydrophobic ionic liquid,1-butyl-3-methyl-imidazolium hexafluorophosphate.The composite film of NL was used as matrix to adsorb DA and catalyze the oxidation of DA in phosphate buffer solution(PBS).The electrochemical response of DA was investigated at the NL-CILE,the traditional carbon paste electrode(TCPE),CILE and the nafion modified CILE(N-CILE)in 0.1M PBS(pH 7.4),respectively.The results showed the superiority of NL-CILE to N-CILE,CILE and TCPE in terms of provision of higher sensitivity,faster electron transfer and better reversibility.Under optimum condition,the oxidation peak current was rectilinear with DA concentration range from 0.1μM to 0.1mM,with a detection limit of 0.03μM(S/N=3)by differential pulse voltammetry.The proposed method was applied to determine DA in samples successfully.
基金Project(20376085) supported by the National Natural Science Foundation of ChinaProject(05C053) supported by Education Department of Hunan Province, China
文摘L-aspartic acid (Asp) pillared hydrotalcites were prepared by direct reaction of the L-Asp anion with layered double hydroxides (LDHs). The obtained samples were characterized by X-ray diffractometry (XRD), Fourier transform infrared (FTIR), and thermogravimetric and differential thermal analysis (TG/DTA). The results show that the initial interlayer carbonate ions can be completely replaced by the L-Asp anion under the controlled conditions. The pillared hydrotalcites have a crystallized supramolecular structure and thermal stability. The L-Asp pillared LDHs were used in the enantiosorption of enantiopure phenylalanine (Pile), the results suggest that L-Asp pillared LDHs exhibit an excellent enantiosorption capability for D-Phe, and the adsorption isotherm fits Freundlich equation.
基金This work was supported by the Natural Science Foundation of Guangxi Province (No. 9912044)
文摘A new ternary complex of nickel(II) with L-aspartate (L-Asp) and 1, 10-phenan- throline(Phen), [Ni3(L-Asp)(Phen)5(H2O)3](ClO4)4?4.75H2O, has been synthesized in a mixed sol- vent of H2OC2H5OH at the pH value of 3. It crystallizes in triclinic, space group P1 with a = 11.861(2), b = 18.384(4), c = 19.746(3) ?, α = 107.68(1), β = 105.94(1), γ = 103.41(2)°, V = 3703.6(11) ?3, Mr = 1745.66, Z = 2, Dc =1.565 g/cm3, μ = 0.989 mm-1, F(000) = 1791, R = 0.0643 and wR = 0.1611. The complex contains two cations, binuclear [Ni2(L-Asp)(Phen)3(H2O)]2+ and mononu- clear [Ni(Phen)2(H2O)2]2+. All the nickel ions in the complex are six-coordinated with a distorted octahedral geometry, but the coordination environments for them are different. There exist hydrogen bonds and π-π stacking interactions in the complex.
基金Acknowledgements: This work was supported by the Natural Science Foundation of Anhui Province (No. 2006K J128B) and the Young Teacher Natural Science Foundation of Anhui Province Commission (No. 2006jp 1139).
文摘The interaction of L-Aspartic acid (Asp) with Vctoria Green S (VGS) in pH 6.0 Britton-Robinson buffer solution has been investigated by UV/Vis spectropbotometry and resonance light scattering (RLS) technique. The non-covalent interactions such as hydrogen bond, salt linkage and hydrophobic bond were proposed to explain the interaction between VGS and Asp. It indicated that Asp could link each other to form a long chain by salt linkages and hydrogen bonds in aqueous medium. Then the long chain surrounded the hydrophobic groups of VGS via hydrophobic interaction and reacted with VGS by salt linkages and hydrogen bonds to form a macromolecular aggregation. The aggregation was much bigger than VGS itself. So the color became deeper and the system's absorption and RLS intensity increased. The increase in the absorbance at 617nm was proportional to the concentration of Asp, providing a basis for the quantitative determination of Asp. This method was simple and efficient than the ordinary methods and had been applied to the direct determination of Asp with satisfactory results.
基金supported by National Natural Science Foundation of China(Grant No.U1930113),ChinaNational Natural Science Foundation of China(52072036)
文摘Poly(ethylene oxide)(PEO)-based polymer electrolytes show the prospect in all-solid-state lithium metal batteries;however,they present limitations of low room-temperature ionic conductivity,and interfacial incompatibility with high voltage cathodes.Therefore,a salt engineering of 1,1,2,2,3,3-hexafluoropropane-1,3-disulfonimide lithium salt(LiHFDF)/LiTFSI system was developed in PEO-based electrolyte,demonstrating to effectively regulate Li ion transport and improve the interfacial stability under high voltage.We show,by manipulating the interaction between PEO matrix and TFSI^(-)-HFDF^(-),the optimized solid-state polymer electrolyte achieves maximum Li+conduction of 1.24×10^(-4)S cm^(-1)at 40℃,which is almost 3 times of the baseline.Also,the optimized polymer electrolyte demonstrates outstanding stable cycling in the LiFePO_(4)/Li and LiNi_(0.8)Mn_(0.1)Co_(0.1)O_(2)/Li(3.0-4.4 V,200 cycles)based all-solid-state lithium batteries at 40℃.
基金The authors are grateful for the support and funding from the Foundation of National Natural Science Foundation of China(52373089 and 51973173)Startup Foundation of Chongqing Normal University(23XLB011),Science and Technology Research Program of Chongqing Municipal Education Commission(KJQN202300561)Fundamental Research Funds for the Central Universities。
文摘With the rapid development of 5G information technology,thermal conductivity/dissipation problems of highly integrated electronic devices and electrical equipment are becoming prominent.In this work,“high-temperature solid-phase&diazonium salt decomposition”method is carried out to prepare benzidine-functionalized boron nitride(m-BN).Subsequently,m-BN/poly(pphenylene benzobisoxazole)nanofiber(PNF)nanocomposite paper with nacremimetic layered structures is prepared via sol–gel film transformation approach.The obtained m-BN/PNF nanocomposite paper with 50 wt%m-BN presents excellent thermal conductivity,incredible electrical insulation,outstanding mechanical properties and thermal stability,due to the construction of extensive hydrogen bonds andπ–πinteractions between m-BN and PNF,and stable nacre-mimetic layered structures.Itsλ∥andλ_(⊥)are 9.68 and 0.84 W m^(-1)K^(-1),and the volume resistivity and breakdown strength are as high as 2.3×10^(15)Ωcm and 324.2 kV mm^(-1),respectively.Besides,it also presents extremely high tensile strength of 193.6 MPa and thermal decomposition temperature of 640°C,showing a broad application prospect in high-end thermal management fields such as electronic devices and electrical equipment.
基金supported by the National Research Foundation of Korea(NRF)funded by the Korean government(MSIT)(no.2022R1A2C1006743)。
文摘Meeting the demands of complex and advanced applications requires the development of high-performance hybrid materials with unique properties.However,the integration of polymeric frameworks with MgO/WO_(3) composite layers faces challenges due to the lack of understanding of the formation mechanism and the challenge of determining the impact of self-assembled architecture on anticorrosive properties.In this study,we aimed to enhance the corrosion resistance of the MgO layer produced by plasma electrolysis(PE)of AZ31 Mg alloy by incorporating WO_(3) with partially phosphorated poly(vinyl alcohol)(PPVA).Two types of porous MgO layers were produced using the PE process with an alkaline-phosphate electrolyte,one with and one without WO_(3) nanoparticles,which were subsequently immersed in an aqueous solution of PPVA.Incorporating PPVA into the WO_(3)-MgO layer resulted in hybrids being deposited in a fragmented manner,creating a“laminar reef-like structure”that sealed most of the structural defects in the layer.The PPVA-sealed WO_(3)-based coating exhibited superior corrosion resistance compared to the other samples.Computational analyses were employed to explore the mechanism underlying the formation of PPVA/WO_(3) hybrids on the MgO layer.These findings suggest that PPVA-WO_(3)-MgO hybrid coatings can potentially improve corrosion resistance in various fields.
基金supported by the National Key Research and Development Program of China(2022YFB4101800)National Natural Science Foundation of China(22278077,22108040)+2 种基金Key Program of Qingyuan Innovation Laboratory(00221004)Research Program of Qingyuan Innovation Laboratory(00523006)Natural Science Foundation of Fujian Province(2022J02019)。
文摘Dimethyl carbonate(DMC)is a crucial chemical raw material widely used in organic synthesis,lithiumion battery electrolytes,and various other fields.The current primary industrial process employs a conventional sodium methoxide basic catalyst to produce DMC through the transesterification reaction between vinyl carbonate and methanol.However,the utilization of this catalyst presents several challenges during the process,including equipment corrosion,the generation of solid waste,susceptibility to deactivation,and complexities in separation and recovery.To address these limitations,a series of alkaline poly(ionic liquid)s,i.e.[DVBPIL][PHO],[DVCPIL][PHO],and[TBVPIL][PHO],with different crosslinking degrees and structures,were synthesized through the construction of cross-linked polymeric monomers and functionalization.These poly(ionic liquid)s exhibit cross-linked structures and controllable cationic and anionic characteristics.Research was conducted to investigate the effect of the cross-linking degree and structure on the catalytic performance of transesterification in synthesizing DMC.It was discovered that the appropriate cross-linking degree and structure of the[DVCPIL][PHO]catalyst resulted in a DMC yield of up to 80.6%.Furthermore,this catalyst material exhibited good stability,maintaining its catalytic activity after repeated use five times without significant changes.The results of this study demonstrate the potential for using alkaline poly(ionic liquid)s as a highly efficient and sustainable alternative to traditional catalysts for the transesterification synthesis of DMC.
基金funding from the Natural Science Foundation of Hubei Province,China(Grant No.2022CFA031)supported by the Natural Science Foundation of China(Grant No.22309056).
文摘The stable operation of solid-state lithium metal batteries at low temperatures is plagued by severe restrictions from inferior electrolyte-electrode interface compatibility and increased energy barrier for Li^(+)migration.Herein,we prepare a dual-salt poly(tetrahydrofuran)-based electrolyte consisting of lithium hexafluorophosphate and lithium difluoro(oxalato)borate(LiDFOB).The Li-salt anions(DFOB−)not only accelerate the ring-opening polymerization of tetrahydrofuran,but also promote the formation of highly ion-conductive and sustainable interphases on Li metal anodes without sacrificing the Li^(+)conductivity of electrolytes,which is favorable for Li^(+)transport kinetics at low temperatures.Applications of this polymer electrolyte in Li||LiFePO_(4)cells show 82.3%capacity retention over 1000 cycles at 30℃and endow stable discharge capacity at−30℃.Remarkably,the Li||LiFePO4 cells retain 52%of their room-temperature capacity at−20℃and 0.1 C.This rational design of dual-salt polymer-based electrolytes may provide a new perspective for the stable operation of quasi-solid-state batteries at low temperatures.
基金supported by the Research Program funded by the SeoulTech(Seoul National University of Science and Technology).
文摘In the last decade,numerous physical modification methods have been introduced to enhance triboelectric nanogenerator(TENG)performance although they generally require complex and multiple fabrication processes.This study proposes a facile fabrication process for Poly(vinylidene fluoride)(PVDF)nanofiber(NF)mats incorporating additive and nonadditive physical modifications.Patterned PVDF NF mats are prepared by electrospinning using a metal mesh as the NF collector.As a negative triboelectric material,the TENG with the patterned PVDF NF mat exhibits superior performance owing to the engineered morphology of the contact layer.PVDF is crucial in TENGs owing to its superior ferroelectric properties and surface charge density when combined with specific electroceramics.Hence,the synergy of the physical modification methods is achieved by incorporating BaTiO3(BTO)nanoparticles(NPs)into the PVDF.By functionalizing BTO NPs with polydopamine,the TENG performance is further improved owing to the enhanced dispersion of NPs and improved crystallinity of the PVDF chains.Utilizing large NPs produces a nanopatterning effect on the NF surface,thereby resulting in the hierarchical structure of the NF mats.The source of the voltage signals from the TENG is analyzed using fast Fourier transform.
基金financially supported by the National Key R&D Program of China (2021YFA1501700)the National Science Foundation of China (22272114)+4 种基金the Fundamental Research Funds from Sichuan University (2022SCUNL103)the Funding for Hundred Talent Program of Sichuan University (20822041E4079)the NSFC (22102018 and 52171201)the Huzhou Science and Technology Bureau (2022GZ45)the Hefei National Research Center for Physical Sciences at the Microscale (KF2021005)。
文摘The conversion of waste polylactic acid(PLA)plastics into high-value-added chemicals through electrochemical methods is a promising and sustainable approach.However,developing efficient and highly selective catalysts for lactic acid oxidation reaction(LAOR)and understanding the reaction process are challenging.Here,we report the electrooxidation of waste PLA to acetate at a high current density of 100 mA cm-2 with high Faraday efficiency(~95%)and excellent stability(>100 h)over a nickel selenide nanosheet catalyst.In addition,a total Faraday efficiency of up to 190%was achieved for carboxylic acids,including acetic acid and formic acid,by coupling with the cathodic CO_(2) reduction reaction.In situ experimental results and theoretical simulations revealed that the catalytic activity center of LAOR was dynamically formed NiOOH species,and the surface-adsorbed SeO_(x) species accelerated the formation of Ni~(3+)species,thus promoting catalytic activity.The mechanism of lactic acid electrooxidation was further elucidated.Lactic acid was dehydrogenated to produce pyruvate first and then formed CH_3CO due to preferential C-C bond cleavage,resulting in the presence of acetate.This work demonstrated a sustainable method for recycling waste PLA and CO_(2) into high-value-added products.
文摘The repairing effect of poly(N-vinylpyrrolidone-co-methacrylic acid)on permed or bleached damaged hair was studied.The combing and tensile strength of permed and bleached hair before and after treatment with the copolymer solution were tested,and the effects of the mass fraction of copolymer solution and immerseing time on the combing and tensile strength for permed or bleached damaged hair were investigated.The repair mechanism of permed or bleached damaged hair was also explored.The results show that when the immersing time is 3 hours,the tensile strength of the permed hair increases with the mass fraction of the copolymer solution Tensile strength within 0%-0.3%,but no obvious change is observed when250 Yield strength the mass fraction is over 0.3%.Therefore,the optimal mass 200 fraction of the copolymer solution for repairing the permed hair(cN/dtex)is 0.3%.Similarly,the optimal mass fraction of the copolymer 150strength/solution for repairing the bleached hair is 0.5%.Furthermore,the effects of immersing time on the tensile strength of the100Tensile damaged hair fibers were compared between the permed and90 bleached hair before and after treatment with the copolymer500.40.30.500.10.2 solution.Coincidentally,the optimal immersion time for permedw(P(NVP-co-MAA))/%or bleached damaged hair is both 2 hours.The tensile strength of the permed and bleached hair soaked in 0.3%and 0.5%copolymer solutions for 2 hours increases by 15.55%and 18.12%,respectively,compared to untreated hair.Through infrared spectroscopy analysis,it is found that the amide II band in hair fibers shifted to the blue after repair,with the wave number shift of 11.12 and 11.09 cm^(-1),which confirm the formation of hydrogen bonds in the hair samples.Additionally,the urea hydrogen bond disruption experiment demonstrates that urea does not disrupt the hydrogen bonds in untreated hair fibers,but prevents the formation of new hydrogen bonds in damaged hair fibers.It further validates that the improvement of the tensile strength of the copolymer treated damaged hair fibers is mainly due to the formation of hydrogen bonds.After treatment with the copolymer,the dry and wet combing friction decrease by 30.73%and 28.55%for the permed hair,and decrease by 28.55%and 24.83%for the bleached hairs,respectively.The scanning electron microscope shows that the copolymer can flatten the cuticle and fill the space between the raised cuticles.
基金supported by the National Natural Science Foundation of China(22008053,52002111)the Natural Science Foundation of Hebei Province(B2021208061,B2022208006,B2023208014)the Beijing Natural Science Foundation(Z200011).
文摘Gel-based polymer electrolytes are limited by the polarity of the residual solvent,which restricts the coupling-breaking behaviour during Li^(+)conduction,resulting in the Li^(+)transport kinetics being greatly affected.Here,we designed anion competitive gel polymer electrolyte(ACPE)by introducing lithium difluoro(oxalato)borate(LiDFOB)anion into the 1,3-dioxolane(DOL)in situ polymerisation system.ACPE enhances the ionic dipole interaction between Li^(+)and the solvent molecules and synergizes with Li^(+)across the solvation site of the polymer ethylene oxide(EO)unit,combination that greatly improves the Li^(+)transport efficiency.As a result,ACPE exhibits 1.12 mS cm^(−1)ionic conductivity and 0.75 Li^(+)transfer number at room temperature.Additionally,this intra-polymer solvation sheath allows preferential desolvation of DFOB−,which contributes to the formation of kinetically stable anion-derived interphase and effectively mitigates side reactions.Our results demonstrate that the assembled Li||NCM622 solid-state battery exhibits lifespan of over 300 cycles with average Coulombic efficiency of 98.8%and capacity retention of 80.3%.This study introduces a novel approach for ion migration and interface design,paving the way for high-safety and high-energy-density batteries.
基金supported by National Natural Science Foundation of China(Grant No.22209012).
文摘The interfacial instability of the poly(ethylene oxide)(PEO)-based electrolytes impedes the long-term cycling and further application of all-solid-state lithium metal batter-ies.In this work,we have shown an effective additive 1-adaman-tanecarbonitrile,which con-tributes to the excellent per-formance of the poly(ethylene oxide)-based electrolytes.Owing to the strong interaction of the 1-Adamantanecarboni-trile to the polymer matrix and anions,the coordination of the Li^(+)-EO is weakened,and the binding effect of anions is strengthened,thereby improving the Li^(+)conductivity and the electrochemical stability.The diamond building block on the surface of the lithium anode can sup-press the growth of lithium dendrites.Importantly,the 1-Adamantanecarbonitrile also regulates the formation of LiF in the solid electrolyte interface and cathode electrolyte interface,which contributes to the interfacial stability(especially at high voltages)and protects the electrodes,enabling all-solid-state batteries to cycle at high voltages for long periods of time.Therefore,the Li/Li symmetric cell undergoes long-term lithium plating/stripping for more than 2000 h.1-Adamantanecarbonitrile-poly(ethylene oxide)-based LFP/Li and 4.3 V Ni_(0.8)Mn_(0.1)Co_(0.1)O_(2)/Li all-solid-state batteries achieved stable cycles for 1000 times,with capacity retention rates reaching 85%and 80%,respectively.