Encouraged by the porous and stable structure of cold-resist animals’hair or feather,bio-inspired hierarchical structure yarns combining polyacrylonitrile(PAN)nanofibers and polypropylene(PP)hollow microfibers have b...Encouraged by the porous and stable structure of cold-resist animals’hair or feather,bio-inspired hierarchical structure yarns combining polyacrylonitrile(PAN)nanofibers and polypropylene(PP)hollow microfibers have been developed by a modified conjugate electrospinning technology.Physical cross-linking has been built to increase fibers adhesion and construct interlayer support for nanofibrous assembly.The nanofibers and hollow microfibers construct a stable porous structure with porosity of 62%,providing excellent thermal insulating ability[temperature difference(|ΔT|)between skin and yarn surface is 4.9℃]as well as good mechanical property.More interestingly,the water transfer ability(infiltrate the yarn in 10 s)of synthetic fibers has been improved greatly by the combination of thin diameter nanofibers to the yarn.It is believed that the research lays the foundation for bio-inspired engineering technology in the manufacture of thermal comfort.展开更多
In this work,hierarchical hybrid composites consisting of porous three-dimensional reduced graphene oxide(3D-rGO)skeleton and lamellar boron nitride(BN)/silicon carbide(SiC)coatings are prepared by chemical vapor infi...In this work,hierarchical hybrid composites consisting of porous three-dimensional reduced graphene oxide(3D-rGO)skeleton and lamellar boron nitride(BN)/silicon carbide(SiC)coatings are prepared by chemical vapor infiltration(CVI)process.The graphene framework prepared by 3D printing and frozen self-assembly exhibits a lightweight structure and a perforated conductive network,which extends the transmission path of incident microwaves.The introduced ceramic coatings can effectively tune the impedance matching degree and supply a lossy phase,and the hierarchical structure of the composites enhances the multiple scattering of the incident microwaves.As expected,the 3D-rGO/BN/SiC composites possess an excellent absorbing performance with a minimum reflection loss value of–37.8 dB,and the widest effective absorbing bandwidth(RL<–10 dB)of 5.90 GHz is obtained.The controllable fabrication of composites can provide a guideline for rational design and fabrication of high-performance electromagnetic waves absorbing materials in practical applications.展开更多
基金This work was supported by the Major Scientific and Technological Innovation Project of Shandong Province,China(No.2019JZZY020218).
文摘Encouraged by the porous and stable structure of cold-resist animals’hair or feather,bio-inspired hierarchical structure yarns combining polyacrylonitrile(PAN)nanofibers and polypropylene(PP)hollow microfibers have been developed by a modified conjugate electrospinning technology.Physical cross-linking has been built to increase fibers adhesion and construct interlayer support for nanofibrous assembly.The nanofibers and hollow microfibers construct a stable porous structure with porosity of 62%,providing excellent thermal insulating ability[temperature difference(|ΔT|)between skin and yarn surface is 4.9℃]as well as good mechanical property.More interestingly,the water transfer ability(infiltrate the yarn in 10 s)of synthetic fibers has been improved greatly by the combination of thin diameter nanofibers to the yarn.It is believed that the research lays the foundation for bio-inspired engineering technology in the manufacture of thermal comfort.
基金supported by the National Natural Science Foundation of China(No.51772310)National Natural Science Foundation of China(No.52222202)+3 种基金Chinese Academy of Sciences Key Research Program of Frontier Sciences(No.QYZDYSSWJSC031)Key Deployment Projects of the Chinese Academy of Sciences(No.ZDRW-CN2019-01)Shanghai Sailing Program(No.21YF1454600)Outstanding Chinese and Foreign Youth Exchange Program of China Association of Science and Technology.
文摘In this work,hierarchical hybrid composites consisting of porous three-dimensional reduced graphene oxide(3D-rGO)skeleton and lamellar boron nitride(BN)/silicon carbide(SiC)coatings are prepared by chemical vapor infiltration(CVI)process.The graphene framework prepared by 3D printing and frozen self-assembly exhibits a lightweight structure and a perforated conductive network,which extends the transmission path of incident microwaves.The introduced ceramic coatings can effectively tune the impedance matching degree and supply a lossy phase,and the hierarchical structure of the composites enhances the multiple scattering of the incident microwaves.As expected,the 3D-rGO/BN/SiC composites possess an excellent absorbing performance with a minimum reflection loss value of–37.8 dB,and the widest effective absorbing bandwidth(RL<–10 dB)of 5.90 GHz is obtained.The controllable fabrication of composites can provide a guideline for rational design and fabrication of high-performance electromagnetic waves absorbing materials in practical applications.
