A SBA-16-type mesoporous silica material was synthesized under a moderately acidic condition of 0.5 mol·L -1 HCl solution.These mesoporous materials were characterized with X-ray diffraction(XRD)pattern,scanning ...A SBA-16-type mesoporous silica material was synthesized under a moderately acidic condition of 0.5 mol·L -1 HCl solution.These mesoporous materials were characterized with X-ray diffraction(XRD)pattern,scanning electron microscopy(SEM),transmission electron microscopy(TEM),and nitrogen adsorption-desorption measurements.The three-dimensional microporosity of the prepared mesoporous silica having ordered hexagonal mesoporous structure was evidenced by the well-defined XRD patterns combined with TEM photographs.SEM observation showed a highly ordered cubic crystal structure for the prepared mesoporous silica.The size of these crystallites was maintained within the range of 4—6 μm,which is fairly important for the application to the stationary phase for separation.The nitrogen adsorption-desorption analysis revealed that the prepared mesoporous silica possessed a small pore diameter of 3.68 nm,a total surface area of 363.65 m2·g -1 ,a total pore volume of 0.38 cm3·g -1 ,and a pore-wall thickness of 6.63 nm.These features may lead to higher thermal and hydrothermal stability,excellent microporosity,and good connectivity.The mesoporous silica prepared in this study exhibited potential applications to catalysis,sensoring,and separation.展开更多
Conjugated block copolymers have gained increasing interests in recent years. Development of a novel method for facile synthesis of conjugated block copolymers with desired structures and functions is greatly desired....Conjugated block copolymers have gained increasing interests in recent years. Development of a novel method for facile synthesis of conjugated block copolymers with desired structures and functions is greatly desired. In this mini review, we summarized the recent advances in one-pot synthesis of conjugated block copolymers containing π-conjugated polythiophene and helical polyisocyanide segments by using a nickel（Ⅱ） complex as single catalyst. The sequential living polymerization of the two monomers proceeded in a controlled manner, affording expected block copolymers in high yields with controlled molecular weights（Mns） and narrow molecular weight distributions（Mw/Mns）. By using this method, a family of block copolymers with expected structure and tunable compositions can be facilely prepared. Introducing functional groups onto the pendant, these block copolymers can exhibit interesting self-assembly property, tunable light emission and multi-responsiveness.展开更多
Phase change materials(PCMs)are promising thermal energy storage materials due to their high specific latent heat.Conventional PCMs typically exploit the solid–liquid(s–l)transition.However,leakage and leaching are ...Phase change materials(PCMs)are promising thermal energy storage materials due to their high specific latent heat.Conventional PCMs typically exploit the solid–liquid(s–l)transition.However,leakage and leaching are common issues for solid–liquid PCMs,which have to be addressed before usage in practical applications.In contrast,solid–solid(s–s)PCMs would naturally overcome these issues due to their inherent form stability and homogeneity.In this study,we report a new type of s–s PCM based on chemically linked polyethylene glycol(PEG,the PCM portion)with polylactic acid(PLA,the support portion)in the form of a block co‐polymer.Solid‐solid latent heat of up to 56 J/g could be achieved,with melting points of between 44°C and 55°C.For comparison,PEG was physically mixed into a PLA matrix to form a PEG:PLA composite.However,the composite material saw leakage of up to 9%upon heating,with a corresponding loss in thermal storage capacity.In contrast,the mPEG/PLA block co‐polymers were found to be completely homogeneous and thermally stable even when heated above its phase transition temperature,with no observable leakage,demonstrating the superiority of chemical linking strategies in ensuring form stability.展开更多
文摘A SBA-16-type mesoporous silica material was synthesized under a moderately acidic condition of 0.5 mol·L -1 HCl solution.These mesoporous materials were characterized with X-ray diffraction(XRD)pattern,scanning electron microscopy(SEM),transmission electron microscopy(TEM),and nitrogen adsorption-desorption measurements.The three-dimensional microporosity of the prepared mesoporous silica having ordered hexagonal mesoporous structure was evidenced by the well-defined XRD patterns combined with TEM photographs.SEM observation showed a highly ordered cubic crystal structure for the prepared mesoporous silica.The size of these crystallites was maintained within the range of 4—6 μm,which is fairly important for the application to the stationary phase for separation.The nitrogen adsorption-desorption analysis revealed that the prepared mesoporous silica possessed a small pore diameter of 3.68 nm,a total surface area of 363.65 m2·g -1 ,a total pore volume of 0.38 cm3·g -1 ,and a pore-wall thickness of 6.63 nm.These features may lead to higher thermal and hydrothermal stability,excellent microporosity,and good connectivity.The mesoporous silica prepared in this study exhibited potential applications to catalysis,sensoring,and separation.
基金financially supported by the National Natural Science Foundation of China(Nos.21622402,51673057 and 21574036)1000 plan Program for Young Talents of China
文摘Conjugated block copolymers have gained increasing interests in recent years. Development of a novel method for facile synthesis of conjugated block copolymers with desired structures and functions is greatly desired. In this mini review, we summarized the recent advances in one-pot synthesis of conjugated block copolymers containing π-conjugated polythiophene and helical polyisocyanide segments by using a nickel（Ⅱ） complex as single catalyst. The sequential living polymerization of the two monomers proceeded in a controlled manner, affording expected block copolymers in high yields with controlled molecular weights（Mns） and narrow molecular weight distributions（Mw/Mns）. By using this method, a family of block copolymers with expected structure and tunable compositions can be facilely prepared. Introducing functional groups onto the pendant, these block copolymers can exhibit interesting self-assembly property, tunable light emission and multi-responsiveness.
基金Science and Engineering Research Council,Grant/Award Number:GAP/2019/00314。
文摘Phase change materials(PCMs)are promising thermal energy storage materials due to their high specific latent heat.Conventional PCMs typically exploit the solid–liquid(s–l)transition.However,leakage and leaching are common issues for solid–liquid PCMs,which have to be addressed before usage in practical applications.In contrast,solid–solid(s–s)PCMs would naturally overcome these issues due to their inherent form stability and homogeneity.In this study,we report a new type of s–s PCM based on chemically linked polyethylene glycol(PEG,the PCM portion)with polylactic acid(PLA,the support portion)in the form of a block co‐polymer.Solid‐solid latent heat of up to 56 J/g could be achieved,with melting points of between 44°C and 55°C.For comparison,PEG was physically mixed into a PLA matrix to form a PEG:PLA composite.However,the composite material saw leakage of up to 9%upon heating,with a corresponding loss in thermal storage capacity.In contrast,the mPEG/PLA block co‐polymers were found to be completely homogeneous and thermally stable even when heated above its phase transition temperature,with no observable leakage,demonstrating the superiority of chemical linking strategies in ensuring form stability.
