Macroporous hydrogels are water-swollen polymer networks with porous structures beyond the mesh size.They provide high specific surface areas and hieratical mass transfer channels which are desired for emerging applic...Macroporous hydrogels are water-swollen polymer networks with porous structures beyond the mesh size.They provide high specific surface areas and hieratical mass transfer channels which are desired for emerging applications including cell culturing,bio-separation,and drug delivery.A variety of approaches have been developed to fabricate macroporous hydrogels,including gas foaming,porogen templating,phase separation,3D printing,etc.Alternatively,ice templating utilizes the crystallization of water as the porogenation mechanism which doesn't need the leaching of porogens.展开更多
With the innovation of microelectronics technology, the heat dissipation problem inside the device will face a severe test. In this work, cellulose aerogel(CA) with highly enhanced thermal conductivity(TC) in vertical...With the innovation of microelectronics technology, the heat dissipation problem inside the device will face a severe test. In this work, cellulose aerogel(CA) with highly enhanced thermal conductivity(TC) in vertical planes was successfully obtained by constructing a vertically aligned silicon carbide nanowires(SiC NWs)/boron nitride(BN) network via the ice template-assisted strategy. The unique network structure of SiC NWs connected to BN ensures that the TC of the composite in the vertical direction reaches 2.21 W m^(-1) K^(-1) at a low hybrid filler loading of 16.69 wt%, which was increased by 890% compared to pure epoxy(EP). In addition, relying on unique porous network structure of CA, EP-based composite also showed higher TC than other comparative samples in the horizontal direction. Meanwhile, the composite exhibits good electrically insulating with a volume electrical resistivity about 2.35 × 10^(11) Ω cm and displays excellent electromagnetic wave absorption performance with a minimum reflection loss of-21.5 dB and a wide effective absorption bandwidth(<-10 dB) from 8.8 to 11.6 GHz. Therefore, this work provides a new strategy for manufacturing polymer-based composites with excellent multifunctional performances in microelectronic packaging applications.展开更多
Herein,we report the synthesis of interconnected hierarchical pore biochar(HTB)via an ice-templating strategy using bio-waste(tofukasu).The abundance of N-and O-containing functional groups in tofukasu makes it easy t...Herein,we report the synthesis of interconnected hierarchical pore biochar(HTB)via an ice-templating strategy using bio-waste(tofukasu).The abundance of N-and O-containing functional groups in tofukasu makes it easy to form hydrogen bonds with water molecules and water clusters,resulting in nano-micro structures like ice clusters and snow crystals during freezing process.More importantly,tofukasu will be squeezed by micron-scale snow crystals to form coiled sheet-like structures,and its surface and interior will be affected by needle-like ice nanocrystals from several nanometers to tens of nanometers to form transverse groove needles and mesopores.The ice crystals are then removed by sublimation with tofukasu,leaving the interconnected pore structure intact.Therefore,the ice template synthesis strategy endowed the interconnected hierarchical pore structure of HTB with a large specific surface area(SBET,733 m^(2)⋅g^(−1))and hierarchical porosity(30.30%for mesopores/total pore volume ratio),which is significantly higher than the normal dry treated tofukasu biochar(TB),which had a SBET of 436 m^(2)⋅g^(−1) and contained 1.53%mesopores.In addition,the sheet-like structure with interconnected pores of HTB favors high exposure of active sites(N-and O-containing functional groups),and a fast electron transport rate.As a result,HTB had an excellent adsorption capacity of 159.65 mg⋅g^(−1),which is 4.7 times that of typical block biochar of TB(33.89 mg⋅g^(−1))according to Langmuir model.Electrochemical characterization,FTIR and XPS analysis showed that the mechanism of Cr(Ⅵ)removal by HTB included electrostatic attraction,pore filling,reduction and surface complexation.展开更多
基金supported by the National Natural Science Foundation of China(grant Nos.52273112,U20A6001,22105167)the Start-up funding of Ningbo Research Institute of Zhejiang University(grant No.20201203Z0193).
文摘Macroporous hydrogels are water-swollen polymer networks with porous structures beyond the mesh size.They provide high specific surface areas and hieratical mass transfer channels which are desired for emerging applications including cell culturing,bio-separation,and drug delivery.A variety of approaches have been developed to fabricate macroporous hydrogels,including gas foaming,porogen templating,phase separation,3D printing,etc.Alternatively,ice templating utilizes the crystallization of water as the porogenation mechanism which doesn't need the leaching of porogens.
基金financial support from National Natural Science Foundation of China(21704096,51703217)the China Postdoctoral Science Foundation(Grant No.2019M662526)financial support from Taif University Researchers Supporting Project Number(TURSP-2020/135),Taif University,Taif,Saudi Arabia。
文摘With the innovation of microelectronics technology, the heat dissipation problem inside the device will face a severe test. In this work, cellulose aerogel(CA) with highly enhanced thermal conductivity(TC) in vertical planes was successfully obtained by constructing a vertically aligned silicon carbide nanowires(SiC NWs)/boron nitride(BN) network via the ice template-assisted strategy. The unique network structure of SiC NWs connected to BN ensures that the TC of the composite in the vertical direction reaches 2.21 W m^(-1) K^(-1) at a low hybrid filler loading of 16.69 wt%, which was increased by 890% compared to pure epoxy(EP). In addition, relying on unique porous network structure of CA, EP-based composite also showed higher TC than other comparative samples in the horizontal direction. Meanwhile, the composite exhibits good electrically insulating with a volume electrical resistivity about 2.35 × 10^(11) Ω cm and displays excellent electromagnetic wave absorption performance with a minimum reflection loss of-21.5 dB and a wide effective absorption bandwidth(<-10 dB) from 8.8 to 11.6 GHz. Therefore, this work provides a new strategy for manufacturing polymer-based composites with excellent multifunctional performances in microelectronic packaging applications.
基金National Natural Science Foundation of China(51602281)Innovative Science and Technology Platform Project of Cooperation between Yangzhou City and Yangzhou University,China(No.YZ202026308)+1 种基金Yangzhou University self-made experimental equipment special fund(YZUZZ2022-13)Yangzhou University High-end Talent Support Program,the“Qinglan Project”of Jiangsu University and Postgraduate Research&Practice Innovation Program of Jiangsu Province(SJCX22_1735)。
文摘Herein,we report the synthesis of interconnected hierarchical pore biochar(HTB)via an ice-templating strategy using bio-waste(tofukasu).The abundance of N-and O-containing functional groups in tofukasu makes it easy to form hydrogen bonds with water molecules and water clusters,resulting in nano-micro structures like ice clusters and snow crystals during freezing process.More importantly,tofukasu will be squeezed by micron-scale snow crystals to form coiled sheet-like structures,and its surface and interior will be affected by needle-like ice nanocrystals from several nanometers to tens of nanometers to form transverse groove needles and mesopores.The ice crystals are then removed by sublimation with tofukasu,leaving the interconnected pore structure intact.Therefore,the ice template synthesis strategy endowed the interconnected hierarchical pore structure of HTB with a large specific surface area(SBET,733 m^(2)⋅g^(−1))and hierarchical porosity(30.30%for mesopores/total pore volume ratio),which is significantly higher than the normal dry treated tofukasu biochar(TB),which had a SBET of 436 m^(2)⋅g^(−1) and contained 1.53%mesopores.In addition,the sheet-like structure with interconnected pores of HTB favors high exposure of active sites(N-and O-containing functional groups),and a fast electron transport rate.As a result,HTB had an excellent adsorption capacity of 159.65 mg⋅g^(−1),which is 4.7 times that of typical block biochar of TB(33.89 mg⋅g^(−1))according to Langmuir model.Electrochemical characterization,FTIR and XPS analysis showed that the mechanism of Cr(Ⅵ)removal by HTB included electrostatic attraction,pore filling,reduction and surface complexation.
