The present invention discloses preparation of an ultrafine polyimide nanofiber membrane at high voltage and use of the membrane in high-temperature filtration. By using a metal wire needleless-type electrospinning technology, a nanofiber membrane with an average fiber diameter of lower than 130 nm is prepared at a high voltage of 80 kV Such a fine fiber structure not only enhances interception efficiency for fine particulate matter (PM0.3) to achieve a filtration efficiency of above 99.97%, but also significantly reduces filtration resistance to 189.18 Pa through a slip effect, thus having better performance than conventional commercial glass fiber filtration materials. The ultrafine polyimide nanofiber membrane prepared by the present invention has the advantages of high filtration efficiency, low resistance, good thermal stability, and hydrophobicity, thus having a broad application prospect in the field of high-temperature filtration of PM.

The present invention provides a nanofiber membrane with dual-scale porosity, fabricated through a phase-separation electrospinning process. The membrane consists of interconnected inter-fiber and surface pores, enhancing air permeability, diffusion rates, and filtration performance. The method employs solvents with distinct evaporation rates to induce phase separation during electrospinning, resulting in a highly porous structure. The nanofiber membrane is applicable in air filtration, medical dressings, drug delivery systems, and diagnostic test strips, offering improved performance characteristics such as reduced pressure drop, enhanced diffusion, and increased sensitivity in diagnostics. The process enables scalable, cost-effective production with consistent fiber morphology.

A nano silk fibroin fibrous membrane with directional water transport and a preparation method thereof are provided. Firstly, renewable pure silk fibroin is extracted from natural silkworm cocoons. A silk fibroin film with a nanofibrous structure is prepared by an electrostatic spinning method, and a methanol treatment method is used to induce a secondary structure transformation of the silk fibroin film. Then, a spraying process is used to spray octadecyltrichlorosilane (OTS) onto the silk fibroin fibrous membrane, and a uniformly and regularly arranged mesh hydrophobic inner layer and mesh water transport channels are deposited on one side.