Yanbo Liu

This article reviews wood microstructure and component features, analyzes modification mechanisms, explores applications of modified wood, and suggests optimizing technologies and lowering costs to promote sustainable wood industry development.

In this study, a high-load self-supporting thick carbon electrode (35.2 mg cm⁻²) was constructed by hot-pressing densification combined with KOH activation of natural wood. Its hierarchical pore structure synergistically optimizes energy storage performance (3.5 F cm⁻²) and provides a new strategy for the practical application of supercapacitors.

As a unique structural form, helical structures have a wide range of application prospects. In the field of biology, helical structures are essential for the function of biological macromolecules such as proteins, so the study of helical structures can help to deeply understand life phenomena and develop new biotechnology. In materials science, helical structures can give rise to special physical and chemical properties, such as in the case of spiral nanotubes, helical fibers, etc., which are expected to be used in energy, environment, medical and other fields. The helical structure also has unique charm and application value in the fields of aesthetics and architecture. In addition, helical fibers have attracted a lot of attention because of their tendrils’ vascular geometry and indispensable structural properties. In this paper, the development of helical fibers is briefly reviewed from the aspects of mechanism, synthesis process and application. Due to their good chemical and physical properties, helical fibers have a good application prospect in many fields. Potential problems and future opportunities for helical fibers are also presented for future studies.

The research progress of strong cellulose-based materials from the “bottom-up” and “top-down” approaches are summarized.

Electrospinning is an effective method to prepare nanofibers at present. Aiming at problems such as low spinnable viscosity and the low productivity of the traditional multi-needle, a radial nozzle was proposed in this paper. In order to solve the problem of end effects in multi-nozzle electrospinning, COMSOL Multiphysics 6.0 software was used to simulate the electric field in electrospinning with seven radial nozzles. And the influence on the electric field intensity and distribution of the structural parameters of the radial nozzle, including the number, length, tip-shape, and tip-pointing direction of the vanes, were studied. Then, the electric field intensity of any point on the central axis of a radial nozzle was obtained based on the principle of electric field superposition, and then the rotation angle of the vanes corresponding to the minimum Coulomb repulsion force on the target point was deduced. At last, the method of electric field homogenization of a rotating vane arrangement was obtained. In the simulation, the strength and homogenization of the electric field were taken as the research objective, and the optimum structure parameters of the radial nozzle were obtained; the uniform theory of the electric field based on the orientation of the vanes was verified. Then, electrospinning with seven radial nozzles was performed, and it was found that each radial nozzle can produce multiple jets during electrospinning, and the prepared electrospun membranes have even thickness and high porosity. What is more, the fibers are relatively finer and more uniform.

The rapid development of piezoelectric sensors has been studied extensively, owing to their good flexibility, wearability, high sensitivity and low cost. However, some inorganic materials with good piezoelectricity cannot make sensors flexible, and the organic materials with good flexibility have a weak output electrical signal and low strength. In order to explore and optimize the preparation technology of piezoelectric sensors, a BaTiO₃@polyacrylonitrile (PAN)/poly(vinylidene fluoride) (PVDF) nanofibrous composite membrane (NCM) was prepared by cross-electrospinning technology and the central combination design (CCD) method. The morphology, structure, hydrophobicity, mechanical properties and piezoelectricity of the BaTiO₃@PAN/PVDF NCMs were investigated. The BaTiO₃@PAN/PVDF NCMs had the better hydrophobicity and mechanical properties compared with the pure PAN/PVDF NCM. The 5BaTiO₃@PAN/PVDF NCM designed by CCD had a more uniform fiber diameter, and a more stable output voltage with a 46% improvement. With the help of cross-electrospinning technology and the CCD method, the NCM will be outstanding for the development of fabricating flexible wearable piezoelectric sensors.