The in situ synthesis of mesoporous nanotubes from natural minerals remains a great challenge. Herein, we report the successful synthesis of mesoporous silica nanotubes （MNTs） with a varying inner-shell thickness an...The in situ synthesis of mesoporous nanotubes from natural minerals remains a great challenge. Herein, we report the successful synthesis of mesoporous silica nanotubes （MNTs） with a varying inner-shell thickness and a preserved clay outer shell from natural-halloysite nanotubes （HNTs）. After the enlargement of the lumen diameter of the tubular aluminosilicate clay by acid leaching, uniform mesopores were introduced by a modified pseudomorphic transformation approach, while the clay outer shell was well-preserved. Using density functional theory calculations, the atomic structure evolution and the energetics during A1 leaching and Si-OH condensation were studied in detail. After the leaching of A1 ions from the HNTs, local structural changes from Al（Oh） to A1（V） at a medium leaching level and to AI（Td） at a high leaching level were confirmed. The calculated hydroxylation energy of two kinds of silica components in the acid-leached HNTs （the distorted two-dimensional silica source in the inner shell and the intact aluminosilicate structure in the outer shell） was 0.5 eV lower or 1.0 eV higher than that of bulk silica, which clarifies the different behavior of the silica components in the hydrothermal process. The successful synthesis of reactive MNTs from HNTs introduces a new strategy for the synthesis of mesoporous nanocontainers with a special morphology using natural minerals. In particular, MNT samples with numerous reactive AI（V） species and a specific surface area up to 583 m^2/g （increased by a factor of 10） are promising drugloading nanocontainers and nanoreactors.展开更多
Double-walled carbon nanotubes （DWCNTs） with high graphitization have been synthesized by hydrogen arc discharge. The obtained DWCNTs have a narrow distribution of diameters of both the inner and outer tubes, and mo...Double-walled carbon nanotubes （DWCNTs） with high graphitization have been synthesized by hydrogen arc discharge. The obtained DWCNTs have a narrow distribution of diameters of both the inner and outer tubes, and more than half of the DWCNTs have inner diameters in the range 0.6-1.0 nm. Field electron emission from a DWCNT cathode to an anode has been measured, and the emission current density of DWCNTs reached 1 A/cm2 at an applied field of about 4.3 V/~tm. After high-temperature treatment of DWCNTs, long linear carbon chains （C-chains） can be grown inside the ultra-thin DWCNTs to form a novel C-chain@DWCNT nanostructure, showing that these ultra-thin DWCNTs are an appropriate nanocontainer for preparing truly one-dimensional nanostructures with one-atom-diameter.展开更多
Improving the performance of reverse osmosis membranes remains great challenge to ensure excellent NaCl rejection while maintaining high water permeability and chlorine resistance. Herein, temperature-responsive intel...Improving the performance of reverse osmosis membranes remains great challenge to ensure excellent NaCl rejection while maintaining high water permeability and chlorine resistance. Herein, temperature-responsive intelligent nanocontainers are designed and constructed to improve water permeability and chlorine resistance of polyamide membranes. The nanocontainer is synthesized by layer-by-layer self-assembly with silver nanoparticles as the core, sodium alginate and chitosan as the repair materials, and polyvinyl alcohol as the shell. When the polyamide layer is damaged by chlorine attack, the polyvinyl alcohol shell layer dissolves under temperature stimulation of 37 ℃, releasing inner sodium alginate and chitosan to repair broken amide bonds. The polyvinyl alcohol shell responds to temperature in line with actual operating environment, which can effectively synchronize the chlorination of membranes with temperature response and release inner materials to achieve self-healing properties. With adding temperature-responsive intelligent nanocontainers, the NaCl rejection of thin film composite membrane decreased by 15.64%, while that of thin film nanocomposite membrane decreased by only 8.35% after 9 chlorination cycles. Effective repair treatment and outstanding chlorine resistance as well as satisfactory stability suggest that temperature-responsive intelligent nanocontainer has great potential as membrane-doping material for the targeted repair of polyamide reverse osmosis membranes.展开更多
The preparation of pH-responsive nanocontainers by typical silane modification of the mesoporous silica nanoparticle(MSN)surface is usually high-cost,complex,and time-consuming,which remains a great challenge for effe...The preparation of pH-responsive nanocontainers by typical silane modification of the mesoporous silica nanoparticle(MSN)surface is usually high-cost,complex,and time-consuming,which remains a great challenge for effective corrosion protection of magnesium alloy.Here,a new strategy to construct pH-responsive nanocontainers(MSN-MBT@LDH)is demonstrated.The nanocontainers consist of corrosion inhibitor(2-mercaptobenzothiazole,MBT)loaded MSN core and layered double hydroxide(LDH)nanosheet shell serving as gatekeepers.The successful loading of MBT and encapsulation by LDH nanosheets were confirmed by a series of characterization such as scanning transmission electron microscopy coupled with energy dispersive X-ray spectroscopy(STEM-EDS)and N2 adsorption/desorption isotherms.The pH-responsive feature of the nanocontainers was demonstrated by determination of the MBT concentration in buffer solutions with different pH values.A smart corrosion protection system on Mg alloy is obtained by incorporating the synthesized nanocontainers into a self-assembled nanophase particle(SNAP)coating.The electrochemical tests and visual observations show that the hybrid coating has the best barrier properties and robustness in corrosion protection in NaCl corrosive solutions in comparison with the control coatings.The present method simplifies the synthesis processes of nanocontainers and eliminates the potential detrimental effect of excess gatekeepers on the coating.The findings provide new insights into the preparation of scalable nanocontainers.The self-healing coatings are expected to have widespread applications for corrosion protection of Mg alloy and other metals.展开更多
In-situ incorporation of layered double hydroxides(LDH)nanocontainers into plasma electrolytic oxidation(PEO)coatings on AZ91 Mg alloy has been achieved in the present study.Fumarate was selected as Mg corrosion inhib...In-situ incorporation of layered double hydroxides(LDH)nanocontainers into plasma electrolytic oxidation(PEO)coatings on AZ91 Mg alloy has been achieved in the present study.Fumarate was selected as Mg corrosion inhibitor for exchange and intercalation into the nanocontainers,which were subsequently incorporated into the coating.It was found that the thickness and compactness of the coatings were increased in the presence of LDH nanocontainers.The corrosion protection performance of the blank PEO,LDH containing PEO and inhibitor loaded coatings was evaluated by means of polarization test and electrochemical impedance spectroscopy(EIS).The degradation process and corrosion resistance of PEO coating were found to be greatly affected by the loaded inhibitor and nanocontainers by means of ion-exchange when corrosion occurs,leading to enhanced and stable corrosion resistance of the substrate.展开更多
A TiO_(2)@o-vanillin@TEOS-APTES nanocontainer was prepared by an experimental process in which,firstly,2-hydroxy-3-methoxybenzaldehyde(o-vanillin)was loaded in a TiO_(2) container to obtain TiO_(2)@o-vanillin.Then,TiO...A TiO_(2)@o-vanillin@TEOS-APTES nanocontainer was prepared by an experimental process in which,firstly,2-hydroxy-3-methoxybenzaldehyde(o-vanillin)was loaded in a TiO_(2) container to obtain TiO_(2)@o-vanillin.Then,TiO_(2)@o-vanillin was encapsulated by tetraethyl orthosilicate(TEOS).Finally,3-aminopropyl triethoxysilane(APTES)was used to modify the obtained sample.The morphology,structural phase and thermal stability of the TiO_(2)@o-vanillin@TEOS-APTES nanocontainer were analyzed using scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),Fourier transform infrared spectroscopy(FTIR),X-ray diffractometry(XRD)and thermal gravimetric analysis(TG).The release rate of o-vanillin was investigated using an ultraviolet-visible(UV-vis)spectrometer.The anti-corrosion performances of the epoxy,epoxy@o-vanillin and epoxy@TiO_(2)@o-vanillin@TEOS-APTES coatings on steel sheets were evaluated using an electrochemical method and scarification experiments.The results showed that the impedance value of the epoxy@TiO_(2)@o-vanillin@TEOS-APTES coating was two orders of magnitude higher than that of the blank epoxy coating,and one order of magnitude higher than that of the epoxy@o-vanillin coating.The maximum inhibition rate of the epoxy@TiO_(2)@o-vanillin@TEOS-APTES coating on the steel can reach 97.3%.The scarification experiments confirmed that the epoxy@TiO_(2)@o-vanillin@TEOS-APTES coating had the best anti-corrosion performance.展开更多
Smart coating for corrosion protection of metal materials(steel,magnesium,aluminum and their alloys)has drawn great attention because of their capacity to prevent crack propagation in the protective coating by releasi...Smart coating for corrosion protection of metal materials(steel,magnesium,aluminum and their alloys)has drawn great attention because of their capacity to prevent crack propagation in the protective coating by releasing functional molecules(healing agents or corrosion inhibitors)on demand from delivery vehicle,that is,micro/nanocontainer made up of a shell and core material or a coating layer,in a controllable manner.Herein,we summarize the recent achievements during the last 10 years in the field of the micro/nanocontainer with different types of stimuli-responsive properties,i.e.,pH,electrochemical potential,redox,aggressive corrosive ions,heat,light,magnetic field,and mechanical impact,for smart anticorrosion coating.The state-of-the-art design and fabrication of micro/nanocontainer are emphasized with detailed examples.展开更多
基金This work was supported by the National Natural Science Foundation of China （Nos. 41572036 and 51225403）, the Hunan Provincial Science and Technology Project （Nos. 2016RS2004 and 2015TP1006） and the National ＂Ten Thousand Talents Program＂ in China. Computing resources were provided by High Performance Computing Centre of Central South University and the National Supercomputing Center of China in Shenzhen. We acknowledge Yalin Xia, Huilin Lun and Binbin Guo for their kind help in sample preparation, characterization and drug loading experiment.
文摘The in situ synthesis of mesoporous nanotubes from natural minerals remains a great challenge. Herein, we report the successful synthesis of mesoporous silica nanotubes （MNTs） with a varying inner-shell thickness and a preserved clay outer shell from natural-halloysite nanotubes （HNTs）. After the enlargement of the lumen diameter of the tubular aluminosilicate clay by acid leaching, uniform mesopores were introduced by a modified pseudomorphic transformation approach, while the clay outer shell was well-preserved. Using density functional theory calculations, the atomic structure evolution and the energetics during A1 leaching and Si-OH condensation were studied in detail. After the leaching of A1 ions from the HNTs, local structural changes from Al（Oh） to A1（V） at a medium leaching level and to AI（Td） at a high leaching level were confirmed. The calculated hydroxylation energy of two kinds of silica components in the acid-leached HNTs （the distorted two-dimensional silica source in the inner shell and the intact aluminosilicate structure in the outer shell） was 0.5 eV lower or 1.0 eV higher than that of bulk silica, which clarifies the different behavior of the silica components in the hydrothermal process. The successful synthesis of reactive MNTs from HNTs introduces a new strategy for the synthesis of mesoporous nanocontainers with a special morphology using natural minerals. In particular, MNT samples with numerous reactive AI（V） species and a specific surface area up to 583 m^2/g （increased by a factor of 10） are promising drugloading nanocontainers and nanoreactors.
基金This work was supported by the National Natural Science Foundation of China （Grant No. 10974131）, the Nanotechnology Program of Shanghai Science and Technology Committee （No. 0952nm07100）, the Scienceand Technology Innovation Fund of the Shanghai Education Committee （No. 09ZZ85） and Shanghai Pujiang Talent Plan （No. 08PJ1405100）. We thank Professor Shoushan Fan of Tsinghua-Foxconn Nanotechnology Research Center for the HRTEM measurements, and Professor Pingheng Tan of the Institute of Semiconductors for some of the Raman measurements.
文摘Double-walled carbon nanotubes （DWCNTs） with high graphitization have been synthesized by hydrogen arc discharge. The obtained DWCNTs have a narrow distribution of diameters of both the inner and outer tubes, and more than half of the DWCNTs have inner diameters in the range 0.6-1.0 nm. Field electron emission from a DWCNT cathode to an anode has been measured, and the emission current density of DWCNTs reached 1 A/cm2 at an applied field of about 4.3 V/~tm. After high-temperature treatment of DWCNTs, long linear carbon chains （C-chains） can be grown inside the ultra-thin DWCNTs to form a novel C-chain@DWCNT nanostructure, showing that these ultra-thin DWCNTs are an appropriate nanocontainer for preparing truly one-dimensional nanostructures with one-atom-diameter.
基金This work was partially supported by the National Natural Science Foundation of China(Grant Nos.21776147,21606140,61604086,21905153 and 51472174)the Postdoc Applied Research Project Funding of Qingdao(Grant No.04000669)+3 种基金the International Science&Technology Cooperation Program of China(Grant No.2014DFA60150)the Department of Science and Technology of Shandong Province(Grant Nos.ZR2018BB066 and 2016GGX104010)the Qingdao Municipal Science and Technology Bureau(Grant No.19-6-1-91-nsh)the Department of Education of Shandong Province(Grant Nos.J16LA14 and J17KA013).Also,Dong Lifeng thanks financial support from the Malmstrom Endowed Fund at Hamline University.
文摘Improving the performance of reverse osmosis membranes remains great challenge to ensure excellent NaCl rejection while maintaining high water permeability and chlorine resistance. Herein, temperature-responsive intelligent nanocontainers are designed and constructed to improve water permeability and chlorine resistance of polyamide membranes. The nanocontainer is synthesized by layer-by-layer self-assembly with silver nanoparticles as the core, sodium alginate and chitosan as the repair materials, and polyvinyl alcohol as the shell. When the polyamide layer is damaged by chlorine attack, the polyvinyl alcohol shell layer dissolves under temperature stimulation of 37 ℃, releasing inner sodium alginate and chitosan to repair broken amide bonds. The polyvinyl alcohol shell responds to temperature in line with actual operating environment, which can effectively synchronize the chlorination of membranes with temperature response and release inner materials to achieve self-healing properties. With adding temperature-responsive intelligent nanocontainers, the NaCl rejection of thin film composite membrane decreased by 15.64%, while that of thin film nanocomposite membrane decreased by only 8.35% after 9 chlorination cycles. Effective repair treatment and outstanding chlorine resistance as well as satisfactory stability suggest that temperature-responsive intelligent nanocontainer has great potential as membrane-doping material for the targeted repair of polyamide reverse osmosis membranes.
基金Sichuan Science and Technology Program(2018JY0483)Young Elite Scientists Sponsorship Program by China Association for Science and Technology(YESS,2018QNRC001)+4 种基金Natural Science Foundation of Hunan Province(2020JJ4073)Open Project of Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province(CSPC202004)Foundation of Huaihua University Double First-rate Applied Characteristic Discipline Construction Projects of Materials Science and Engineering(19CKA002)the Fundamental Research Funds of China West Normal University(CXTD2020-1)the support from the National Science Foundation(CHE 1566283)。
文摘The preparation of pH-responsive nanocontainers by typical silane modification of the mesoporous silica nanoparticle(MSN)surface is usually high-cost,complex,and time-consuming,which remains a great challenge for effective corrosion protection of magnesium alloy.Here,a new strategy to construct pH-responsive nanocontainers(MSN-MBT@LDH)is demonstrated.The nanocontainers consist of corrosion inhibitor(2-mercaptobenzothiazole,MBT)loaded MSN core and layered double hydroxide(LDH)nanosheet shell serving as gatekeepers.The successful loading of MBT and encapsulation by LDH nanosheets were confirmed by a series of characterization such as scanning transmission electron microscopy coupled with energy dispersive X-ray spectroscopy(STEM-EDS)and N2 adsorption/desorption isotherms.The pH-responsive feature of the nanocontainers was demonstrated by determination of the MBT concentration in buffer solutions with different pH values.A smart corrosion protection system on Mg alloy is obtained by incorporating the synthesized nanocontainers into a self-assembled nanophase particle(SNAP)coating.The electrochemical tests and visual observations show that the hybrid coating has the best barrier properties and robustness in corrosion protection in NaCl corrosive solutions in comparison with the control coatings.The present method simplifies the synthesis processes of nanocontainers and eliminates the potential detrimental effect of excess gatekeepers on the coating.The findings provide new insights into the preparation of scalable nanocontainers.The self-healing coatings are expected to have widespread applications for corrosion protection of Mg alloy and other metals.
基金support from National Natural Science Foundation of China(No.52071067 and U1737102)Mobility Programme of the Sino-German Center(M-0056)+1 种基金the Fundamental Research Funds for the Central Universities(N2002009)FUNCOAT project(H2020-MSCA-RISE-2018,Grant Agreement N 823942).
文摘In-situ incorporation of layered double hydroxides(LDH)nanocontainers into plasma electrolytic oxidation(PEO)coatings on AZ91 Mg alloy has been achieved in the present study.Fumarate was selected as Mg corrosion inhibitor for exchange and intercalation into the nanocontainers,which were subsequently incorporated into the coating.It was found that the thickness and compactness of the coatings were increased in the presence of LDH nanocontainers.The corrosion protection performance of the blank PEO,LDH containing PEO and inhibitor loaded coatings was evaluated by means of polarization test and electrochemical impedance spectroscopy(EIS).The degradation process and corrosion resistance of PEO coating were found to be greatly affected by the loaded inhibitor and nanocontainers by means of ion-exchange when corrosion occurs,leading to enhanced and stable corrosion resistance of the substrate.
基金supported by the National Natural Science Foundation of China(21878024)the Innovation Team Project of Colleges and Universities in Liaoning Province(2018479-14,LT2015001).
文摘A TiO_(2)@o-vanillin@TEOS-APTES nanocontainer was prepared by an experimental process in which,firstly,2-hydroxy-3-methoxybenzaldehyde(o-vanillin)was loaded in a TiO_(2) container to obtain TiO_(2)@o-vanillin.Then,TiO_(2)@o-vanillin was encapsulated by tetraethyl orthosilicate(TEOS).Finally,3-aminopropyl triethoxysilane(APTES)was used to modify the obtained sample.The morphology,structural phase and thermal stability of the TiO_(2)@o-vanillin@TEOS-APTES nanocontainer were analyzed using scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS),Fourier transform infrared spectroscopy(FTIR),X-ray diffractometry(XRD)and thermal gravimetric analysis(TG).The release rate of o-vanillin was investigated using an ultraviolet-visible(UV-vis)spectrometer.The anti-corrosion performances of the epoxy,epoxy@o-vanillin and epoxy@TiO_(2)@o-vanillin@TEOS-APTES coatings on steel sheets were evaluated using an electrochemical method and scarification experiments.The results showed that the impedance value of the epoxy@TiO_(2)@o-vanillin@TEOS-APTES coating was two orders of magnitude higher than that of the blank epoxy coating,and one order of magnitude higher than that of the epoxy@o-vanillin coating.The maximum inhibition rate of the epoxy@TiO_(2)@o-vanillin@TEOS-APTES coating on the steel can reach 97.3%.The scarification experiments confirmed that the epoxy@TiO_(2)@o-vanillin@TEOS-APTES coating had the best anti-corrosion performance.
基金the National Natural Science Foundation of China (Nos.41576079,41922040)the Qingdao National Laboratory for Marine Science and Technology (No.QNLM20160RP0413)the AoShan Talent Program Supported by Qingdao National Laboratory for Marine Science and Technology (No.2017ASTCP-ES02)
文摘Smart coating for corrosion protection of metal materials(steel,magnesium,aluminum and their alloys)has drawn great attention because of their capacity to prevent crack propagation in the protective coating by releasing functional molecules(healing agents or corrosion inhibitors)on demand from delivery vehicle,that is,micro/nanocontainer made up of a shell and core material or a coating layer,in a controllable manner.Herein,we summarize the recent achievements during the last 10 years in the field of the micro/nanocontainer with different types of stimuli-responsive properties,i.e.,pH,electrochemical potential,redox,aggressive corrosive ions,heat,light,magnetic field,and mechanical impact,for smart anticorrosion coating.The state-of-the-art design and fabrication of micro/nanocontainer are emphasized with detailed examples.
