Shape memory effect on electrospun PLA-based fibers tailoring their thermal response

Abstract

A research on the thermally-activated shape memory behavior of electrospun nanofibers based on polylactic acid (PLA) plasticized with its oligomer (OLA) was conducted with the purpose of obtaining a suitable material to be used in potential biomedical applications. Three different PLA-OLA formulations with 70:30, 80:20 and 90:10 ratios were processed by electrospinning and studied in order to decrease the PLA glass transition temperature to a temperature closer to the human body. For each electrospun formulation mat, the average diameter of electrospun fibers was found to be 757 ± 193 nm for neat PLA and 768 ± 207 nm, 620 ± 121 nm and 476 ± 80 nm for PLA-OLA 90:10, 80:20 and 70:30 ratios, respectively and correlate it with their mechanical response. First of all, the PLA capability to present shape memory behavior even in non-woven electrospun fibers form has been studied at 60 °C. Thus, two values of switching temperatures (45 °C and 40 °C) were selected in order to evaluate their shape memory response, being temperatures close to the human body temperature. The recovery and fixity ratio of PLA-OLA formulations studied here showed suitable shape memory behavior of the electrospun systems with excellent values of strain fixity as well as strain recovery ratios indicating these materials appropriate for potential biomedical application.