Preparation of transparent electrospun nanofibrous membrane from long‐persistent phosphor‐reinforced polymer for security authentication

Abstract

Photochromic inks have been a tempting authentication method to make commercial items more resistant to counterfeiting. However, recent studies have shown that photochromic inks have major drawbacks, such as expensiveness and low durability. Herein, we report the development of new photochromic nanofibers for cutting‐edge anti‐counterfeiting uses. Lanthanide‐doped strontium aluminate nanoparticles (LSAN) were synthesized and immobilized onto electrospun polyurethane nanofibers (PUNF). Anti‐counterfeiting materials encapsulated with inorganic photochromic agent can guarantee photostability and durability. LSAN function as an efficient inorganic photochromic agent whereas PUNF function as a hosting matrix. Both of photostability and reversibility of the prepared UV‐induced photochromic LSAN@PUNF were found to be rather high. Applying varying ratios of LSAN resulted in the development of polyurethane nanofibers with distinct emission properties depending on the LSAN content. The nanofibrous films showed green emission under UV illumination, and whereas no traces were detected in visible daylight. LSAN displayed diameters of 3–6 nm, whereas LSAN@PUNF nanofibers had diameters of 150–450 nm. Transparency was indicated by an excitation peak at 347 nm, and a green color was indicated by an emission peak of 530 nm. The current approach can be presented as an efficient technology to prevent forgery of commercial products.