Spiropyran doped rewritable cholesteric liquid crystal polymer film for the generation of quick response codes

With the rapid development of modern information technology, massive amounts of data are stored that require an information security. Here, we introduce a spiropy ran doped polymer dispersed cholesteric liquid crystal film based rewritable medium that can produce high quality visual two-dimensional barcodes for anti-counterfeiting, authentication and security purposes. The prepared film exhibits excellent photochromic properties, improved photosensitivity, high spatial resolution, and numerous rapid write/erase capabilities. Such rewritable material can be efficiently printed over 70 cycles without compromising its readability. Furthermore, the fabricated film is mechanically resistant to small stresses and, hence, it can be directly handled.