ATRP-template dispersion polymerization of methacrylic acid (MAA) on the template of polyvinyl pyrrolidone (PVP K-30) was carried out in the aqueous solution by using methyl 2-bromopropionate (MBP)/CuC1/2,2'-bi...ATRP-template dispersion polymerization of methacrylic acid (MAA) on the template of polyvinyl pyrrolidone (PVP K-30) was carried out in the aqueous solution by using methyl 2-bromopropionate (MBP)/CuC1/2,2'-bipyridine (bpy) as the initiation system. The scanning electron microscopy (SEM), dynamic light scattering (DLS) and gel permeation chromatography (GPC) were employed for evaluating the results of polymerization. As a result, the minimonomer droplets formed due to the H-bond interaction of PVP-MAA. The stability of droplets was dependent on pH and the concentrations of both PVP and MAA. When pH 〈 2, the coagulum of PVP-MAA formed, whereas when pH 〉 4.5, the droplets were not observable by DLS. In order to prepare the stable latex, the concentration of PVP should be lower than 9 wt%, whilst the concentration of MAA should be lower than 5.5 wt%. The optimum condition was pH 2.4, PVP 4.76 wt% and MAA 5 wt%, by which the stable latex of ca. 50 nm nanoparticles of PMAA/PVP was prepared by ATRP polymerization and simultaneously the molar mass of PVP was duplicated by PMAA according to GPC diagrams. In contrast, by using AIBN, KPS and KPS-Na2SO3 redox initiation system, the coagulum accompanying with the larger molar mass of PMAA was obtained, irrespective of pH and concentrations of PVP and MAA.展开更多
In order to investigate the partition of initiators for quasi-static precipitation polymerization of acrylamide (AAm) and methacrylic acid (MAc) in ethanol, azo-initiators were employed with various functional gro...In order to investigate the partition of initiators for quasi-static precipitation polymerization of acrylamide (AAm) and methacrylic acid (MAc) in ethanol, azo-initiators were employed with various functional groups such as --COOCH3 (V- 601, dimethyl 2,2'-azobis(isobutyrate)), --CN (V-65, 2,2'-Azobis(2,4-diemthylvaleronitrile)), --COOH (V-501, 4,4'-azobis(4-cyanovaleric acid)) and --NH-(VA-061, 2,2'-azobis[2-(2-imidazolin-2-yl)propane]), respectively. Particle size, induction time and kinetics of polymerization were investigated by the scanning electron microscopy (SEM) and gravimetry. It was observed that the polymerization parameters, such as the particle size, induction time and polymerization rate, were considerably affected by the functional groups of initiators. Besides, the monomer concentration also played important roles in the particle formation. By using V-601, the polymerization rate was strongly correlated with the total surface area of particles and the concentration of initiators. However, by using V-50 l, the polymerization rate was strongly related to WoQo, where W0 is the initial concentration of monomers and Ci,0, the initial concentration of initiators. The results indicated that the different functional groups determined the different partition types of initiators between the minimonomer droplets and the continuous phase due to the molecular interactions of initiator and monomers. V-601 was all partitioned in the continuous phase, but a part of V-65 was partitioned in the minimonomer droplets. Besides the V-501 dissolved in the continuous phase, a part of V-501 was adsorbed on the surface of minimonomer droplets. VA-061 destroyed the stability of minimonomer droplets by the formation of zwitterions with MAA.展开更多
Reusable palladium nanoparticles highly dispersed in porous and hydrophilic interpenetrating polymer networks(IPN),i.e.,Pd@IPN hybrid gels,are employed for catalysis of Suzuki and Heck coupling reactions.Good yields a...Reusable palladium nanoparticles highly dispersed in porous and hydrophilic interpenetrating polymer networks(IPN),i.e.,Pd@IPN hybrid gels,are employed for catalysis of Suzuki and Heck coupling reactions.Good yields are obtained with high turnover frequencies when the reactions are run with very low Pdloadings.The use of IPN gives better recyclability than that of crosslinked polyvinyl alcohol alone.The polymer networks allow the reactants to have easy access to the Pd metals.The catalysts combine high activity with the reusability offered by the heterogeneous system,without the need for strong coordination or chelating ligands.展开更多
Nanopore-based technologies for the detection of single molecules have shown great promise in many applications,such as DNA sequencing,ion recognition and detection,nucleic acids and proteins detections,and mimicing i...Nanopore-based technologies for the detection of single molecules have shown great promise in many applications,such as DNA sequencing,ion recognition and detection,nucleic acids and proteins detections,and mimicing ions transportation across biological membranes[1,2].The advantages of nanopore-based technologies mainly include high efficiency,versatility,and simple principles.The passage of analytes through a nanopore induces the change of ionic current,which is used for the detection and study of the ions,biomolecules and polymers,etc.[3].展开更多
Streaming potential is mainly related to electrokinetic energy conversion,which has been considered to show promising potential for advanced technologies,especially sensing.The inherent property of streaming potential...Streaming potential is mainly related to electrokinetic energy conversion,which has been considered to show promising potential for advanced technologies,especially sensing.The inherent property of streaming potential is that the energy conversion process is always a continuous state.However,practical applications include many cases of discontinuous states,such as nonlinear sensing.Here,we report a discontinuous streaming potential electrokinetic energy conversion fluid system.Experiments and theoretical calculations reveal that this system exhibits a discontinuous electrokinetic effect and provides a gating liquid slip in micropores,offering the advantages of gating liquid charge coupling and interfacial drag reduction.Moreover,the system is demonstrated in a wearable fall-down alert application.We expect this liquid gating energy conversion system to open up a platform for the design and application of autonomous health monitoring devices,seismic sea wave warning systems,and beyond.展开更多
基金financially supported by the National Natural Science Foundation of China(No.51073035)the International Corporation Project(No.201101088)with Science and Technology Bureau,Nanjing Municipal
文摘ATRP-template dispersion polymerization of methacrylic acid (MAA) on the template of polyvinyl pyrrolidone (PVP K-30) was carried out in the aqueous solution by using methyl 2-bromopropionate (MBP)/CuC1/2,2'-bipyridine (bpy) as the initiation system. The scanning electron microscopy (SEM), dynamic light scattering (DLS) and gel permeation chromatography (GPC) were employed for evaluating the results of polymerization. As a result, the minimonomer droplets formed due to the H-bond interaction of PVP-MAA. The stability of droplets was dependent on pH and the concentrations of both PVP and MAA. When pH 〈 2, the coagulum of PVP-MAA formed, whereas when pH 〉 4.5, the droplets were not observable by DLS. In order to prepare the stable latex, the concentration of PVP should be lower than 9 wt%, whilst the concentration of MAA should be lower than 5.5 wt%. The optimum condition was pH 2.4, PVP 4.76 wt% and MAA 5 wt%, by which the stable latex of ca. 50 nm nanoparticles of PMAA/PVP was prepared by ATRP polymerization and simultaneously the molar mass of PVP was duplicated by PMAA according to GPC diagrams. In contrast, by using AIBN, KPS and KPS-Na2SO3 redox initiation system, the coagulum accompanying with the larger molar mass of PMAA was obtained, irrespective of pH and concentrations of PVP and MAA.
基金financially supported by the National Natural Science Foundation of China(No.51073035)
文摘In order to investigate the partition of initiators for quasi-static precipitation polymerization of acrylamide (AAm) and methacrylic acid (MAc) in ethanol, azo-initiators were employed with various functional groups such as --COOCH3 (V- 601, dimethyl 2,2'-azobis(isobutyrate)), --CN (V-65, 2,2'-Azobis(2,4-diemthylvaleronitrile)), --COOH (V-501, 4,4'-azobis(4-cyanovaleric acid)) and --NH-(VA-061, 2,2'-azobis[2-(2-imidazolin-2-yl)propane]), respectively. Particle size, induction time and kinetics of polymerization were investigated by the scanning electron microscopy (SEM) and gravimetry. It was observed that the polymerization parameters, such as the particle size, induction time and polymerization rate, were considerably affected by the functional groups of initiators. Besides, the monomer concentration also played important roles in the particle formation. By using V-601, the polymerization rate was strongly correlated with the total surface area of particles and the concentration of initiators. However, by using V-50 l, the polymerization rate was strongly related to WoQo, where W0 is the initial concentration of monomers and Ci,0, the initial concentration of initiators. The results indicated that the different functional groups determined the different partition types of initiators between the minimonomer droplets and the continuous phase due to the molecular interactions of initiator and monomers. V-601 was all partitioned in the continuous phase, but a part of V-65 was partitioned in the minimonomer droplets. Besides the V-501 dissolved in the continuous phase, a part of V-501 was adsorbed on the surface of minimonomer droplets. VA-061 destroyed the stability of minimonomer droplets by the formation of zwitterions with MAA.
基金supported by Natural Science Foundation of Fujian Province of China(No.2018J06003)Natural Science Foundation of Zhejiang Province(Nos.Y4090504 and LY12E03001)+1 种基金Department of Science and Technology of Zhejiang Province(No.2012C24003)the National Natural Science Foundation of China(Nos.21973061 and 21674063)。
文摘Reusable palladium nanoparticles highly dispersed in porous and hydrophilic interpenetrating polymer networks(IPN),i.e.,Pd@IPN hybrid gels,are employed for catalysis of Suzuki and Heck coupling reactions.Good yields are obtained with high turnover frequencies when the reactions are run with very low Pdloadings.The use of IPN gives better recyclability than that of crosslinked polyvinyl alcohol alone.The polymer networks allow the reactants to have easy access to the Pd metals.The catalysts combine high activity with the reusability offered by the heterogeneous system,without the need for strong coordination or chelating ligands.
基金supported by the National Natural Science Foundation of China(21804090)the National Key Research and Development Program of China(2021YFC2102902)+1 种基金the State Key Laboratory of Analytical Chemistry for Life Science(SKLACLS1910)the Science Research Fund of Shaoxing University(20185008)。
文摘Nanopore-based technologies for the detection of single molecules have shown great promise in many applications,such as DNA sequencing,ion recognition and detection,nucleic acids and proteins detections,and mimicing ions transportation across biological membranes[1,2].The advantages of nanopore-based technologies mainly include high efficiency,versatility,and simple principles.The passage of analytes through a nanopore induces the change of ionic current,which is used for the detection and study of the ions,biomolecules and polymers,etc.[3].
基金National Natural Science Foundation of China(52025132,21975209,21621091,12075191)National Key R&D Program of China(2018YFA0209500)+3 种基金National Science Foundation of Fujian Province(2022J02059)Fundamental Research Funds for the Central Universities in China(20720220085)111 Project(B17027,B16029)Science and Technology Projects of Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(grant no.RD2022070601).
文摘Streaming potential is mainly related to electrokinetic energy conversion,which has been considered to show promising potential for advanced technologies,especially sensing.The inherent property of streaming potential is that the energy conversion process is always a continuous state.However,practical applications include many cases of discontinuous states,such as nonlinear sensing.Here,we report a discontinuous streaming potential electrokinetic energy conversion fluid system.Experiments and theoretical calculations reveal that this system exhibits a discontinuous electrokinetic effect and provides a gating liquid slip in micropores,offering the advantages of gating liquid charge coupling and interfacial drag reduction.Moreover,the system is demonstrated in a wearable fall-down alert application.We expect this liquid gating energy conversion system to open up a platform for the design and application of autonomous health monitoring devices,seismic sea wave warning systems,and beyond.