Study of capillary rise in biodegradable porous poly (l-lactic acid) electrospun nano/micro fiber yarns

Abstract

Specific surface and surface porosity are governing factors in the penetration rate and the amount of liquid rise into the yarn. In this work, porous and non-porous fiber yarns of poly (l-lactic acid) (PLLA) were fabricated via electrospinning and twist insertion. The surface of PLLA electrospun fibers became porous after evaporation of highly volatile solvent in controlled humidity and temperature and changing the concentration of PLLA solution, resulted in the fibers with different surface porosity. Smooth PLLA nanofibers were obtained using non-volatile solvent. Consequently, capillary rise was investigated in both the porous fiber yarns and smooth nanofiber yarn. Experimental evidences revealed that two morphological characteristics of fibers, i.e. surface porosity and fineness of fibers in the electrospun yarn have a governing effect on the capillary rise phenomenon. Liquid penetration in electrospun yarn was increased by increasing the fiber fineness and/or decreasing the surface porosity. The results of this work suggest that finer fiber and smooth surface would be more beneficial for wicking.