Electrospinning of biopolymer nanofibers encapsulated with functional nanoparticles toward core-shell fluorescence encoding

Photochromism has been an efficient approach to improve authenticity of commercial products. In order to prepare an authentication nanofibrous film with mechanical reliability, it has been crucial to improve the engineering production route of the authentication materials. Herein, we electrospun photoluminescent nanofibrous film with a fiber diameter of 50–200 nm from the environmentally-friendly polylactic acid embedded with nanoparticles of rare-earth activated strontium aluminate (NRESA; 10–15 nm). The created nanocomposite film was colorless in daylight, and became an intense green in ultraviolet light. The strontium aluminate photochromic agent must be applied in the nanoparticle form to ensure film transparency by enhancing its dispersion without aggregation in the electrospun polylactic acid nanofiber bulk. An emission peak was observed at 518 nm after excitation of the pigment-polylactic acid nanofibers at 365 nm. Raising NRESA ratio increased the hydrophobic properties of the pigment-polylactic acid nanofibers without changing their visual or mechanical properties. The transparent films showed high photochromic reversibility without exhaustion under numerous exposure cycles of ultraviolet light and darkness. The nanofibrous mats were elastic and flexible. The current technique is an effective strategy for making a variety of anti-counterfeiting substances.