关键词: 微型静电纺丝仪, 纳米纤维, 有限元分析, 电场强度, 速溶补水面膜

Abstract: In recent years, with the rising living standards in China, consumer attitudes have gradually shifting. Women and even men have an increasing high pursuit of skin care, and the consumer base for facial masks has been expanding. Owing to their high porosity, large specific surface area, high air permeability, and small pore size within the fibers, nanofibrous membranes prepared by electrospinning technology have the characteristics of great specific surface area, excellent porosity, perfect adhesive biocompatibility, good moisture retention and water holding capacity. Therefore, it is of great significance to build a micro-typed electrospinning instrument to prepare nanofiber-based facial masks to occupy the high-end facial mask market in China. The micro-typed electrospinning instrument studied in this project is small in size, convenient to carry or move, and the charge will tend to gather at the position with the largest curvature and the strongest adsorption force (namely needle tip). It enables continuous and stable electrospinning, and it does not require disassembly of the device for battery replacement, so it can be directly charged and used, and the electrospinning can be used continuously. It marks a significant advancement in the nanofiber production technology via electrospinning, and its application in medical aesthetic masks promises to be a breakthrough in the field of nanofiber masks. 
Based on the design scheme of a mobile electrospinning device with current extraction, this study used COMSOL finite element analysis software to analyze and discuss the electric field uniformity of the liquid surface at the outlet of the nozzle with different spinning-methods, explored the influence law of electrospinning voltage and collection distance on the electric field strength, and determined the optimal data of spinning-methods. Soluble nanofiber facial masks were fabricated by using the electrospinning method, and the effects of different solution ratio, applied voltage, collection distance and liquid supply speed on the surface morphology of nanofiber were explored. Then the properties of nanofiber facial mask were comprehensively analyzed to highlight the advantages of the nanofiber facial mask. 
When the diameter of the conical spinning head was 0.6 mm, the length was 8 mm, the receiving distance was 120 mm, and the spinning voltage was 25 kV, the average electric field strength was 1.2×10^8 V/m. A water-soluble nanofiber membrane was prepared by mixing PEG-14M, HA, and 1,3-BDO in a 40:1:4 ratio to form the spinning solution. Subsequently, various properties of the fiber membrane were analyzed. Using a 10% PEG/HA/BDO (PHB) solution, the liquid supply speed was 0.2 ml/h, the receiving distance was 200 mm, and the spinning voltage was 25 kV. The average fiber diameter was 284.8 nm, with a CV value of 19.8% and exhibiting uniform fiber distribution, resulting in an 81% increase in skin moisture. It dissolved completely in deionized water within 6 seconds. Therefore, the PHB facial mask developed by the micro-typed electrospinning instrument is a convenient and economical instant nanofibrous facial mask, where the effective small molecules can be quickly absorbed by the skin, resulting in shortening the skin care time. 

Key words: micro-electrospinning instrument, nanofiber, finite element analysis, electric field strength, instant hydrating mask