| 초록 |
Photonic crystals are periodic optical nanostructures that possess photonic bandgap. Opals are composed of close-packed colloidal crystals with a face-centered cubic lattice, which exhibit photonic bandgap properties. The negative replica of opals, which is referred to as inverse opals, also reflect structural colors. As the inverse opals provide enhanced mechanical stability and high degree of freedom in material selection, they have been widely studied. Here, we create inverse opals made of biodegradable polymer, poly(lactic-co-glycolic acid) (PLGA), to use them as colorimetric period indicators for drugs and cosmetics. For fabrication, we first deposit silica opal on the surface of PLGA film and anneal at elevated temperature. The opal is spontaneously embedded into the film, which yields well-defined inverse opal after removal of opal template. As PLGA matrix is biodegradable, the structure gets thinner in aqueous environment and gradually lose the structural colors. |
