A novel soft polymer template containing a double-layer structure,which includes a thin layer of polymethylmethacrylate(PMMA)used as a pattern layer and a thicker layer of polydimethylsiloxane(PDMS)used as a back laye...A novel soft polymer template containing a double-layer structure,which includes a thin layer of polymethylmethacrylate(PMMA)used as a pattern layer and a thicker layer of polydimethylsiloxane(PDMS)used as a back layer,was fabricated from a replica molding process.Anodic aluminum oxide(AAO)template was used as the replica mold to be replicated to the polymethylmethacrylate layer by a thermal infiltration process under a vacuum condition.Results indicate that PMMA/PDMS soft templates with different sizes could be easily fabricated from the as-prepared AAO replica mold.The PMMA/PDMS soft templates were then employed to imprint a TiO_2 gel for achieving TiO_2 nano-pore arrays.After the imprinting process,the PDMS layer was firstly peeled off and the PMMA layer was then removed into acetonitrile,which can avoid any demolding problems like damages or distortions.The TiO_2 nano-pore arrays with the crystalline of anatase could be obtained at a heat treatment temperature of 450°C.展开更多
Thermodynamic stability, microvoid distribution and phases transformation of natural pozzolana opal shale(POS) were studied systematically in this work. XRD analysis showed that opal-CT, including microcrystal cristob...Thermodynamic stability, microvoid distribution and phases transformation of natural pozzolana opal shale(POS) were studied systematically in this work. XRD analysis showed that opal-CT, including microcrystal cristobalite and tridymite, is a major component of POS. DTA and FT-IR indicated that there were many hydroxyl groups and acid sites on the surface of amorphous SiO_2 materials. FE-SEM analysis exhibited amorphous SiO_2 particles(opal-A) covering over stacking sequences microcrystal cristobalite and tridymite. Meanwhile, MIP analysis demonstrated that porosity and pore size distribution of POS remained uniform below 600 ℃. Because stable porous microstructure is a key factor in improving photocatalyst activity, POS is suited to preparing highly active supported.展开更多
For shale of Lower Silurian Longmaxi Formation in Chongqing,southeast Sichuan Basin,characteristics of micro-nano pores in marine shale reservoirs were well studies by means of Field-Emission Scanning Electron Microsc...For shale of Lower Silurian Longmaxi Formation in Chongqing,southeast Sichuan Basin,characteristics of micro-nano pores in marine shale reservoirs were well studies by means of Field-Emission Scanning Electron Microscope and Low-temperature Low-pressure Adsorption Experiment of CO_(2)and N_(2).Results showed that six types of pore were developed in the shale of Longmaxi Formation,i.e.,organic pores,intergranular pores,intragranular pores,intercrystalline pores,dissolution pores and microfractures,among which the organic pores and intragranular pores in interlayers of clay minerals were most developed,and a plenty of dissolution pores were also well developed because of high thermal evolution degree.BET specific surface area of the shale in Longmaxi Formation ranged from 3.5 to 18.1 m^(2)/g,BJH total pore volume was from 0.00234 to 0.01338 cm^(3)/g,DA specific surface area of micropores vaired from 1.3 to 7.3 m^(2)/g,and DA pore volume ranged from 0.00052 to 0.00273 cm^(3)/g.The specific surface area of micropores in the shale accounted for 23.1%-80.2%of total specific surface area with an average of 50.3%,and the pore volume of micropores accounted for 12.1%-48.5%of total pore volume with an average of 32.3%.Micropore was the main storage space in shale reservoir for methane adsorption,that because capacities of specific surface area provided by micropores were considerably greater than those provided by mesopores and macropores.Pore size distribution of the shale was complex,and multiple different peaks occurred in the pore size curves,showing two or three peaks in the range from 0 to 100 nm and four peaks occasionally.TOC had a good linear relationship with pore structure parameters of micropores,mesopores t macropores and total pores in the shale,indicating that TOC was the most important control factor for micron-to nano-pore structure in the shale.After normalization of pore structure parameters to TOC,the pore structure parameters of total pores and mesopores t macropores,had positive linear relationships with content of clay minerals but negative linear relationships with content of brittle minerals,indicating that clay minerals and brittle minerals mainly controlled development of mesopores and macropores in the shale.展开更多
Pre-polymerized vinyl trimethoxy silane(PVTMS)@MWCNT nano-aerogel system was constructed via radical polymerization,sol-gel transition and supercritical CO_(2)drying.The fabricated organic-inorganic hybrid PVTMS@MWCNT...Pre-polymerized vinyl trimethoxy silane(PVTMS)@MWCNT nano-aerogel system was constructed via radical polymerization,sol-gel transition and supercritical CO_(2)drying.The fabricated organic-inorganic hybrid PVTMS@MWCNT aerogel structure shows nano-pore size(30-40 nm),high specific surface area(559 m^(2)g^(−1)),high void fraction(91.7%)and enhanced mechanical property:(1)the nano-pore size is beneficial for efficiently blocking thermal conduction and thermal convection via Knudsen effect(beneficial for infrared(IR)stealth);(2)the heterogeneous interface was beneficial for IR reflection(beneficial for IR stealth)and MWCNT polarization loss(beneficial for electromagnetic wave(EMW)attenuation);(3)the high void fraction was beneficial for enhancing thermal insulation(beneficial for IR stealth)and EMW impedance match(beneficial for EMW attenuation).Guided by the above theoretical design strategy,PVTMS@MWCNT nano-aerogel shows superior EMW absorption property(cover all Ku-band)and thermal IR stealth property(ΔT reached 60.7℃).Followed by a facial combination of the above nano-aerogel with graphene film of high electrical conductivity,an extremely high electromagnetic interference shielding material(66.5 dB,2.06 mm thickness)with superior absorption performance of an average absorption-to-reflection(A/R)coefficient ratio of 25.4 and a low reflection bandwidth of 4.1 GHz(A/R ratio more than 10)was experimentally obtained in this work.展开更多
基金supported by the Ministry of Science and Technology of China through 863-project under grant 2009AA03Z218the Major Program of the National Natural Science Foundation of China under Grant No.90923012the Research Fund for the Doctoral Program of Higher Education of China under grant 200806980023
文摘A novel soft polymer template containing a double-layer structure,which includes a thin layer of polymethylmethacrylate(PMMA)used as a pattern layer and a thicker layer of polydimethylsiloxane(PDMS)used as a back layer,was fabricated from a replica molding process.Anodic aluminum oxide(AAO)template was used as the replica mold to be replicated to the polymethylmethacrylate layer by a thermal infiltration process under a vacuum condition.Results indicate that PMMA/PDMS soft templates with different sizes could be easily fabricated from the as-prepared AAO replica mold.The PMMA/PDMS soft templates were then employed to imprint a TiO_2 gel for achieving TiO_2 nano-pore arrays.After the imprinting process,the PDMS layer was firstly peeled off and the PMMA layer was then removed into acetonitrile,which can avoid any demolding problems like damages or distortions.The TiO_2 nano-pore arrays with the crystalline of anatase could be obtained at a heat treatment temperature of 450°C.
基金Funded by the National Natural Science Foundation of China(Nos.51278086,51578108)Special Fund for Scientific Research in the Public Interest by Ministry of Water Resource of the People’s Republic of China(No.201501003)
文摘Thermodynamic stability, microvoid distribution and phases transformation of natural pozzolana opal shale(POS) were studied systematically in this work. XRD analysis showed that opal-CT, including microcrystal cristobalite and tridymite, is a major component of POS. DTA and FT-IR indicated that there were many hydroxyl groups and acid sites on the surface of amorphous SiO_2 materials. FE-SEM analysis exhibited amorphous SiO_2 particles(opal-A) covering over stacking sequences microcrystal cristobalite and tridymite. Meanwhile, MIP analysis demonstrated that porosity and pore size distribution of POS remained uniform below 600 ℃. Because stable porous microstructure is a key factor in improving photocatalyst activity, POS is suited to preparing highly active supported.
基金This work was supported by National Natural Science Foundation of China(No.41690134)National Science and Technology Major Project of China(No.2017ZX05035002-006).
文摘For shale of Lower Silurian Longmaxi Formation in Chongqing,southeast Sichuan Basin,characteristics of micro-nano pores in marine shale reservoirs were well studies by means of Field-Emission Scanning Electron Microscope and Low-temperature Low-pressure Adsorption Experiment of CO_(2)and N_(2).Results showed that six types of pore were developed in the shale of Longmaxi Formation,i.e.,organic pores,intergranular pores,intragranular pores,intercrystalline pores,dissolution pores and microfractures,among which the organic pores and intragranular pores in interlayers of clay minerals were most developed,and a plenty of dissolution pores were also well developed because of high thermal evolution degree.BET specific surface area of the shale in Longmaxi Formation ranged from 3.5 to 18.1 m^(2)/g,BJH total pore volume was from 0.00234 to 0.01338 cm^(3)/g,DA specific surface area of micropores vaired from 1.3 to 7.3 m^(2)/g,and DA pore volume ranged from 0.00052 to 0.00273 cm^(3)/g.The specific surface area of micropores in the shale accounted for 23.1%-80.2%of total specific surface area with an average of 50.3%,and the pore volume of micropores accounted for 12.1%-48.5%of total pore volume with an average of 32.3%.Micropore was the main storage space in shale reservoir for methane adsorption,that because capacities of specific surface area provided by micropores were considerably greater than those provided by mesopores and macropores.Pore size distribution of the shale was complex,and multiple different peaks occurred in the pore size curves,showing two or three peaks in the range from 0 to 100 nm and four peaks occasionally.TOC had a good linear relationship with pore structure parameters of micropores,mesopores t macropores and total pores in the shale,indicating that TOC was the most important control factor for micron-to nano-pore structure in the shale.After normalization of pore structure parameters to TOC,the pore structure parameters of total pores and mesopores t macropores,had positive linear relationships with content of clay minerals but negative linear relationships with content of brittle minerals,indicating that clay minerals and brittle minerals mainly controlled development of mesopores and macropores in the shale.
基金the National Natural Science Foundation(No.52073187)NSAF Foundation(No.U2230202)for their financial support of this project+3 种基金National Natural Science Foundation(No.51721091)Programme of Introducing Talents of Discipline to Universities(No.B13040)State Key Laboratory of Polymer Materials Engineering(No.sklpme2022-2-03)support of China Scholarship Council
文摘Pre-polymerized vinyl trimethoxy silane(PVTMS)@MWCNT nano-aerogel system was constructed via radical polymerization,sol-gel transition and supercritical CO_(2)drying.The fabricated organic-inorganic hybrid PVTMS@MWCNT aerogel structure shows nano-pore size(30-40 nm),high specific surface area(559 m^(2)g^(−1)),high void fraction(91.7%)and enhanced mechanical property:(1)the nano-pore size is beneficial for efficiently blocking thermal conduction and thermal convection via Knudsen effect(beneficial for infrared(IR)stealth);(2)the heterogeneous interface was beneficial for IR reflection(beneficial for IR stealth)and MWCNT polarization loss(beneficial for electromagnetic wave(EMW)attenuation);(3)the high void fraction was beneficial for enhancing thermal insulation(beneficial for IR stealth)and EMW impedance match(beneficial for EMW attenuation).Guided by the above theoretical design strategy,PVTMS@MWCNT nano-aerogel shows superior EMW absorption property(cover all Ku-band)and thermal IR stealth property(ΔT reached 60.7℃).Followed by a facial combination of the above nano-aerogel with graphene film of high electrical conductivity,an extremely high electromagnetic interference shielding material(66.5 dB,2.06 mm thickness)with superior absorption performance of an average absorption-to-reflection(A/R)coefficient ratio of 25.4 and a low reflection bandwidth of 4.1 GHz(A/R ratio more than 10)was experimentally obtained in this work.
