Tuning the properties of electrospun polylactide mats by ethanol treatment

Highlights: • Ethanol treatment of electrospun PLA mats led to their shrinkage and fibers crimping without an increase of crystallinity • Both free-ends and fixed-ends ethanol-treated PLA mats had a higher elongation at break than the non-treated ones • Stretching of PLA mats in ethanol caused their high alignment while stretching in air led to fibers necking and poor alignment • Ethanol-stretched PLA mats caused contact guidance of HaCaT human keratinocytes -- Abstract: In the present work, we analyzed the changes in structure and mechanical properties of electrospun PLA mats induced by ethanol treatment. The amorphous PLA mats gained elasticity when immersed into ethanol (the elongation at break increased from ~50% in air to ~280% in ethanol) and partly retained it after drying (~110%). At the nanoscale, the ethanol treatment caused crimping of the fibers without crystallinity increase. Stretching of the electrospun mats in ethanol caused high alignment of the fibers (geometrical orientation factor f = 0.92) without the need for a special collector electrode such as a pair of blades, which yielded mats with geometrical orientation factor f = 0.71. The aligned mats prepared by stretching in ethanol caused contact guidance of HaCaT human keratinocytes and did not taint viability and proliferation rate of cells in comparison with the non-aligned ones. Our research demonstrates the tuning of electrospun mats properties by post-treatment without any modification of the chemical structure.