Electrospinning is a process that generates nanofibres. Temperature and humidity affect this process. In this article the influence of humidity and temperature on the formation and the properties of nanofibres are studied using cellulose acetate (CA) and poly(vinylpyrrolidone) (PVP) as target materials. The experiments indicate that two major parameters are dependent of temperature and have their influence on the average fibre diameter. A first parameter is the solvent evaporation rate that increases with increasing temperature. The second parameter is the viscosity of the polymer solution that decreases with increasing temperature. The trend in variation of the average nanofibre diameter as a function of humidity is different for CA and PVP, which can be explained by variations in chemical and molecular interaction and its influence on the solvent evaporation rate. As the humidity increases, the average fibre diameter of the CA nanofibres increases, whilst for PVP the average diameter decreases. The average diameter of nanofibres made by electrospinning change significantly through variation of temperature and humidity

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In comparison with conventional structures, nanofibrous structures have unique characteristics, such as higher surface-to-volume ratios, smaller pores, and higher porosity. Their hydrophilic nature is a key characteristic for many applications. However, because of their high porosity, it is difficult to measure the hydrophilicity of nanofibrous structures with contact-angle measurements. Therefore, characterization through wicking behavior is more appropriate. The International Organization for Standardization norm on wicking needs some refining to account for the specific nature of highly porous nanofibrous structures. A refined method was used on several structures that differed in the fiber diameter and the polyamide type. The structures with the thickest nanofibers had the highest wicking rates. At equilibrium, the wicking heights of structures of different polyamide types with the same average fiber diameter followed the trend expected from their intrinsic hydrophilicity. In the initial phase, the capillary forces established the wicking behavior. Later in the process, the wicking behavior was determined by the capillary forces and the hydrophilicity. In conclusion, the hydrophilicity of nanofibrous structures can be successfully determined by an optimized wicking procedure, and the fiber diameter is the dominant parameter for the resulting wicking height at equilibrium.