Electrospinning of porous polylactic acid fibers during nonsolvent induced phase separation

Abstract

In this study, porous micron‐sized fibers of polylactic acid (PLA) are fabricated via electrospinning of PLA‐dichloromethane (DCM)‐hexane systems with no post treatment involved. Several compositions from the liquid‐liquid phase separated region of the phase diagram of this ternary system are selected and their electrospinnability are investigated throughout their phase separation process before gelation. We show that under constant processing and ambient parameters, there is a phase separation shelf time for each composition wherein the viscoelasticity of the systems is optimum to produce long, uniform porous fibers. For the first time, we investigate the effect of aging time during phase separation on the morphology of the electrospun fibers using scanning electron microscopy (SEM). Based on our results, certain phase separated systems provide a range of viscosity allowing for the production of porous spherical micro beads or fibers via electrospraying and electrospinning, respectively. It is also shown that obtaining long, uniform fibers from electrospinning of highly phase separated systems, e.g., a gel, is not feasible due to the high degree of crystallinity of their polymer‐rich domains and the solid‐like yielding behavior. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44862.

Fabricating porous poly(lactic acid) fibres via electrospinning

“…However, the resultant PLA fibres lacked well-defined pores and uniform structures. In a recent paper, Rezabeigi et al [38] produced porous, micron-sized fibres of PLA by electrospinning PLA-DCM-hexane systems.…”

Preparation and Characterization of Polymeric Microfibers of PLGA and PLGA/PPy Composite Fabricated by Solution Blow Spinning

“…They found that the pore formation and pore morphology, including fiber diameter and surface morphology, depended on the electrospinning parameters, with applied voltage being the most important parameter. Rezabeigi et al produced porous polylactic acid (PLA) microfibers with various morphologies via the one‐step electrospinning of liquid–liquid phase‐separated PLA‐dichloromethane‐hexane systems. The differences in solvent evaporation rates caused composition changes in the electrospinning jet after ejection, leading to the formation of a two‐phase region and, consequently, the formation of pores.…”

The Influence of Pre‐Electrospinning Plasma Treatment on Physicochemical Characteristics of PLA Nanofibers

“…In addition, a slight reduction in surface tension is also observed for this solution, which can be the result of polymer degradation causing a decrease in cohesive forces between the solution molecules. Lower surface tension however is known to positively affect the electrospinnability of a solution . On the other hand, the conductivity and pH values continue to increase and decrease, respectively, during the first 2 days after PEPT.…”