Tailoring the morphology and crystallinity of poly(L-lactide acid) electrospun membranes

[EN] Biodegradable poly(L-lactic acid) (PLLA) microfibers were prepared by electrospinning by varying the applied potential, solution flow rate and collector conditions. PLLA fibers with smoothly oriented and random morphologies were obtained and characterized by scanning electron microscopy. The optimum fiber orientation was obtained at 1000 rpm using a 20.3 cm diameter collecting drum, while for higher and lower drum rotation speeds, the rapid random motion of the jets resulted in a random fiber distribution. The deformation of the jet with rapid solidification during electrospinning often results in a metastable phase. PLLA electrospun fibers are amorphous but contain numerous crystal nuclei that rapidly grow when the sample is heated to 70-140 °C. In this way, the degree of crystallinity of the fibers can be tailored between 0 and 50% by annealing. Infrared transmission spectra revealed that the processing conditions do not affect the PLLA samples at the molecular level and that the crystallinity of the samples is related to the presence of ¿-crystals. © 2011 National Institute for Materials Science.SEM observations were conducted by the authors with the kind help of Jose Carlos Rodriguez from the Microscopy Service of Universidad Politecnica de Valencia, whose advice is greatly appreciated. We thank Centro for Nano and Microtechnologies (CeNTI), Famalicao, Portugal, for technical support and the Portuguese Foundation for Science and Technology (FCT) Grants PTDC/CTM/73030/2006, PTDC/CTM/69316/2006 and NANO/NMed-SD/0156/2007. VS thanks FCT for the SFRH/BPD/63148/2009 grant and CR thanks IINL for a PhD grant. JLGR acknowledges the support by the Spanish Ministry of Education through project No. MAT2010-21611-C03-01 (including FEDER financial support), by Centro de Investigacion Principe Felipe in the field of Regenerative Medicine through the collaboration agreement with Conselleria de Sanidad (Generalitat Valenciana) and Instituto de Salud Carlos III (Ministry of Science and Innovation).Ribeiro, C.; Sencadas, VJGDS.; Miguel Costa, C.; Gómez Ribelles, JL.; Lanceros-Mendez, S. (2011). Tailoring the morphology and crystallinity of poly(L-lactide acid) electrospun membranes. SCIENCE AND TECHNOLOGY OF ADVANCED MATERIALS. 12:15001-15009. https://doi.org/10.1088/1468-6996/12/1/015001S15001150091