Generation of Highly Ordered 3D Vivid Monochromatic Coloured Photonic Crystal Films Using Evaporative Induced Technique

Abstract

Structural coloured crystal films have attracted immense attention because of numerous applications like optical sensing, anti-counterfeiting and photonic fabrics.  Herein, we successfully generated highly periodic three-dimensional (3D) monochromatic structural crystal films with brown, turquoise, blue and yellow colourations from as-synthesized poly(styrene-methyl methacrylate-acrylic acid) or P(St-MMA-AA) colloidal latex via the evaporative induced self-assembly technique. The colours were controlled through the modulation of their crystal lattice by varying their microspheres diameter from 180 nm, 120 nm, and 260 nm to 150 nm. Scanning electron microscope and atomic force microscope (SEM/AFM) analyses showed that the photonic crystal particles readily assembled into an impeccable closely-packed three dimensional (3D) ordered hexagonal structure with multiple monolayer arrangements. Transmission electron microscope (TEM) analysis revealed that the synthesized P(St-MMA-AA) colloidal particles have a core-shell morphology. The ability to deliberately fabricate photonic crystals by synthesizing polymer colloidal particles with a specific desired size for the fabrication of monochromatic colours would be very useful in the field of optical sensing.

Keywords: core-shell; crystal films; photonic crystal films; monochromatic