Controllable Synthesis Of Morphologically Anisotropic Carbon Nanorings And Its Scaling Up

Compared with isotropic porous carbon materials,their anisotropic counterparts combine essential properties of carbon materials,e.g.good electrical and thermal conductivity,high specific surface area,abundant adjustable pore channels,with anisotropic morphology,thus exhibit unique physicochemical properties,such as complex stacking forms,special contact effects or directional forces.They have become a new type of advanced carbon materials with great potential for application in the fields of energy storage,biomedicine,catalysis and nano devices.Due to the fundamental principle of natural symmetry,the construction of morphologically anisotropic ringy nanoparticles,especially by solution chemistry synthesis method,is still a great challenge.The targeted synthesis of ringy carbon materials with regular morphology and tunable thickness is an important prerequisite for practical application.So,we carried out a study related to the controllable synthesis and scaling up of carbon nanorings based on solution chemistry.1.carbon nanorings with regular morphology and tunable thickness were synthesized by mixing hydrophobic long-chain octadecanol and block copolymer F127.By examining the growth process of the ringy template,the mechanism of ring formation was revealed,which is based on the asymmetric intramicellar phase-transition induced tip-to-tip assembly.This orientational self-assembly relies on the directional interactions brought by the difference in surface hydrophobicity of the intermediates,which can overcome the disordered molecular and nanoparticle motions during ring formation process.By controlling the kinetics of the selfassembly process,a variety of unique nanostructures such as crescent-like,pod-like,wreathlike particles can also be prepared.By regulating the kinetics of the polymerization process,a quadratic function relationship between the thickness of the carbon nanoring and the mole ratio of octadecanol to resorcinol was established,and precise regulation of the thickness of the carbon nanoring can be achieved.This discovery has laid a solid foundation for the construction of complex nanostructures at the nanoscale,which not only promotes the development of basic research but also paves the way for the development of advanced nanodevices.2.Studies related to the large-scale preparation of carbon rings were conducted based on the laboratory-level synthesis of carbon rings to increase the production of carbon nanoring from milligram level to gram level.Based on the reaction characteristics of the benzoxazine polymerization process,a vertical kettle reactor equipped with a turbine stirring paddle and a jacketed heat transfer device was designed and selected as the device for the scale-up preparation,with circulating water as the heat carrier.The actual reaction volume is 8L,which is 40 times bigger than before.The size and morphology of the polymer nanoring,as well as the pore size distribution of carbon nanorings were essentially the same as those of the small kettle synthesis.By further feasibility analysis in terms of yield,raw material cost and safety,it was demonstrated that this process meets the basic requirements for the preparation of chemicals at scale.