纳米二氧化硅基虹彩膜的设计与表征.

SiO2 has been widely used in the assembly of photonic crystals due to its excellent optical properties. Currently, many studies have been focused on the structural color of monodispersed silica photonic crystals, yet there are few reports on the poly-dispersed ones. In this study, SiO2 particles (450～650 nm) with normal size distribution was prepared by the improved St9ber method. Pouring self-assembly method was used for the film fabrication. Polyvinyl alcohol (PVA) with flexible macromolecular chains was introduced into the gap of SiO2 microspheres, and polyvinylpyrrolidone (PVP) with strong polar groups was introduced into the surface of the microspheres to enhanced film flexibility and better orderliness respectively. It was found that integral film is shown while the mass ratio of 0. 3% SiO2 to 8% PVA is 2∶1. Best iridescent film is shown at the PVP dosage of 1. 75%. The film fabricated in this paper has flat surface and good mechanical properties. The large and small silica microspheres are arranged alternately to form different photonic band gap, which results in iridescent color under point light, while colorless and transparent under natural light. The research results will provide potential application in optical anti-counterfeiting, optical encryption and decoration. [ABSTRACT FROM AUTHOR]