Graphical Scratch the surface : Co 2 V 2 O 7 hollow cylinders were prepared from hexagonal prisms using hydrogen peroxide as an etching agent and Co(NH 2 ) 2 as the release rate controlling agent. The material exhibits enhanced lithium storage properties. The construction of hollow structures has been used as an efficient strategy to improve electrochemical properties in lithium-ion batteries (LIBs). In this paper, novel Co 2 V 2 O 7 hollow cylinders have been fabricated via a unique etching process, in which H 2 O 2 and CO(NH 2 ) 2 were selected as the etching agent and the release rate controlling agent, respectively. The formation process for the hollow structure and the etching mechanism have been investigated. Benefiting from the improved diffusion and transport of Li + , the Co 2 V 2 O 7 hollow cylinder electrode demonstrates higher electrochemical performance as an anode material for LIBs than that of Co 2 V 2 O 7 solid hexagonal prisms. Under a current density of 0.4 A g −1 , the cycling capacity can be improved to 2.5 times greater than that of non-etched hexagonal prisms.
Mechanoluminescent (ML) materials emit light by trapping and releasing charge carriers under mechanical stress. However, previous studies do not fully reveal the relationship between emitting light intensity and mechanical stress, thereby affecting the accuracy of stress measurement. This study addresses this gap by systematically investigating ML cylinders with various sizes and loading paths using theoretical analysis and simulations, focusing on the maximum contact stress, equivalent stress distribution, and the relationship between the strain energy density and light intensity at the point of maximum contact stress. In combination with experiments, the mechanical behavior and optical responses of ML cylinders under normal compressive forces reveal that the luminescence intensity is closely related to cylinder size and loading path, effectively reflecting stress distributions in objects of different sizes under complex stress conditions. Particularly, within the elastic range and under ideal conditions where lateral stress is ignored, the maximum contact stress is nearly equal to the equivalent stress. The equivalent stress is linearly related to the light intensity, while the strain energy density at the maximum contact stress point is proportional to the square root of the light intensity. This work promotes the application of ML materials in structural health monitoring and stress visualization.
Because of the advantageous properties, the photoresponsive bioinspired polymers are of great interest for many applications. In this study, we synthesized a new family of photoresponsive poly(ethylene glycol)-block-poly(o-nitrobenzyl-l-glutamate) diblock copolymers, which can self-assemble into spherical micelles in aqueous solution. Upon UV irradiation, an interesting photoinduced morphology transition from spheres to cylinders was observed arising from the disruption of amphiphilicity induced by the cleavage of o-nitrobenzyl groups on the side chains. A couple of techniques including proton nuclear magnetic resonance (1H NMR) and ultraviolet–visible absorption spectra measurement (UV–vis) were used to track the process of photolysis. A systematic study on the effects of pH, molecular weights, and secondary structure on the self-assembly of diblock copolymers was performed. We demonstrate that the secondary conformation transition with pH variation dominates the sphere-to-cylinder transition. Remarkably, the hierarchical nanostructures with various dimensions can be obtained from preassembled units with the addition of metal ions.
Sun Hui,Chen Shuai,Li Xiao,Leng Ying,Zhou Xiaoyan,Du Jianzhong
The precise control of the shape, size and microstructure of nanomaterials is of high interest in chemistry and material sciences. However, living lateral growth of cylinders is still very challenging. Herein, we propose a crystallization-driven fusion-induced particle assembly (CD-FIPA) strategy to prepare cylinders with growing diameters by the controlled fusion of spherical micelles self-assembled from an amphiphilic homopolymer. The spherical micelles are heated upon glass transition temperature ( T g ) to break the metastable state to induce the aggregation and fusion of the amorphous micelles to form crystalline cylinders. With the addition of extra spherical micelles, these micelles can attach onto and fuse with the cylinders, showing the living character of the lateral growth of cylinders. Computer simulations and mathematical calculations are preformed to reveal the total energy changes of the nanostructures during the self-assembly and CD-FIPA process. Overall, we demonstrated a CD-FIPA concept for preparing cylinders with growing diameters.
危险品化学品经营许可证（带存储）