title: Tailoring the morphology and crystallinity of poly(L-lactide acid) electrospun membranes.
abstract: 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 α-crystals.
authors.affiliation: Centro/Departamento de Física da Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
authors.forename: Clarisse
authors.initials: C
authors.lastname: Ribeiro
authors.affiliation: Centro/Departamento de Física da Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
authors.forename: Vitor
authors.initials: V
authors.lastname: Sencadas
authors.affiliation: Centro/Departamento de Física da Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal; CeNTI - Centre for Nanotechnology and Smart Materials, Rua Fernando Mesquita 2785, 4760-034 Vila Nova de Famalicão, Portugal.
authors.forename: Carlos Miguel
authors.initials: CM
authors.lastname: Costa
authors.affiliation: Centro de Biomateriales e Ingeniería Tisular, Universidad Politécnica de Valencia, 46022 Valencia, Spain; Centro de Investigación Príncipe Felipe, Autopista del Saler 16, 46013 Valencia, Spain; CIBER en Bioingeniería, Biomateriales y Nanomedicina, Valencia, Spain.
authors.forename: José Luís
authors.initials: JL
authors.lastname: Gómez Ribelles
authors.affiliation: Centro/Departamento de Física da Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
authors.forename: Senentxu
authors.initials: S
authors.lastname: Lanceros-Méndez
keywords: PLLA; crystallinity; electrospinning; membranes