Smart Stimuli-Responsive Polylactic Acid-Hydrogel Fibers Produced via Electrospinning

In this research we propose a new type of smart microfibers, distinguished by moisture management and pro-active temperature and pH controlled release activity. Hydrogel with submicron-sized particles based on poly(N-isopropylacrylamide) (poly-NiPAAm) and chitosan (PNCS hydrogel) was incorporated into the structure of poly(lactic acid) (PLA) microfibers using the electrospinning technique. Composites with different PLA to PNCS hydrogel ratios were prepared, and the chemical and morphological properties of the samples were studied using SEM, FT-IR and Raman mapping. Additionally, the moisture management properties, which were provided by the temperature and pH-related phase change transition of the incorporated PNCS hydrogel, were studied by determining the temperature-related static contact angle, thin-layer wicking, moisture content and pH-related water uptake. The loading and release abilities of the incorporated PNCS hydrogel were studied using fluorescent microscopy. The increased concentration of the PNCS hydrogel in spinning solutions resulted in greater variations in fiber thickness and deterioration of the mechanical properties of the fibers; thus, the highest concentration of the PNCS hydrogel that could be incorporated within the fibers was found to be 20 % of the spinning mass. The composite sample showed temperature and pH responsiveness, a successful fluorescent-dye loading ability and its controlled release at predetermined conditions.