Preparation of a Photobleacheable Dye Capsule Nanocomposite for Reusable Recording Media
A new photobleacheable nanocomposite was developed as a reusable recording media. It is composed of polymer dye capsules containing TiO2 nanoparticles, leuco dyes, and a developer. The polymer dye capsules were prepared using the convenient one-step mini-emulsion polymerization. The morphology of the resultant polymer dye capsules were examined through a scanning electron microscopy (SEM), to show the capsule structure, which averaged 30~ 500 nm in size. The leuco dye was originally colorless, but it acquired color when it reacted with the developer. The blue colored dye capsule solution was stable under ambient conditions and could thus be utilized as a recording composition. The color of the recorded part, by coating the dye capsule solution on to a piece of white paper, was persistent. However, the recorded mark was bleached upon exposure to a UV light. Capsule morphology was not detected in the bleached region as examined by a SEM, indicating that titanium dioxide in the film acted as a photocatalyst to decompose the capsule structure. The bleaching was irreversible so that the recording media was reusable. The bleaching efficiency in photobleaching was shown to be higher than 75%.
Kwang Hwa Chung, Yong Hyeon Shin, Sue-Nie Park, Hyun Sook Cho, Soon-Ae Yoo, Byung Joo Min, Hyo-Suk Lim and Kyung Hwa Yoo
H. Oh and E. Kim, "Preparation of a Photobleacheable Dye Capsule Nanocomposite for Reusable Recording Media ", Key Engineering Materials, Vols. 277-279, pp. 1029-1034, 2005