Energy down-converting LaPO4 nanoparticles highly dispersed into poly(lactic acid) electrospun fibers: microstructural and optical properties

Abstract Electrospinning technique was used to obtain a new class of biopolymer/inorganic nanoparticle hybrid fibers fabricated by using poly(lactic acid) (PLA) as the biopolymer matrix and lanthanum phosphate nanoparticles (LaPO4) as energy down-converting materials. Before being incorporated and electrospun with the PLA, the LaPO4 nanostructures obtained from microwave-assisted hydrothermal method were studied to have a depth understanding related to their synthesis parameters, since it is known they adopt different structures and morphologies with the temperature and pH. Highly hydrophobic samples of LaPO4 nanoparticles in hexagonal and monoclinic phases with mixed morphologies (rods and semi-spherical) were detected in samples calcined at 400 °C while those calcined at 600 °C consisted mainly in monoclinic phase with semi-spherical morphologies. Smallest particles in semi-spherical and orthorhombic morphologies obtained at pH 1 and 11 were detected after processing them through electrospinning technique and distributed uniformly into the PLA. The vibrational analysis suggested that the ester group (RCOOR') in PLA plays a key role in the interaction with the LaPO4 nanoparticles. These materials can find practical applications in biomedical areas for replacing conventional polymers.