Structural coloration of polyester fabrics with electrostatic self-assembly of (SiO2/PEI)n

(SiO2/PEI)(n) films with structural colors on polyester fabrics were fabricated using negatively charged SiO2 nanoparticles and positively charged polyethyleneimine (PEI) using the electrostatic self-assembly approach. The bright and variable structural colors of polyester fabrics coated with a (SiO2/PEI)(n) film were investigated through the color photos captured by a digital camera, and also through the reflectance spectra and the images measured by a DigiEye system and a multi-angle spectrophotometer. The morphological structure of (SiO2/PEI)(n) films was characterized by scanning electron microscopy (SEM), and the electrostatic self-assembly process and the driving forces of fabricating the (SiO2/PEI)(n) films were investigated and schematically illustrated. The results showed that the structural colors varied with the various assembly cycles and viewing angles; both the optical properties indicated by the structural colors and the morphological structures illustrated by the SEM images confirmed that the (SiO2/PEI)(n) film on a polyester fabric was a homogeneous porous composite monolayer, with structural colors originated from single thin film interference; the self-assembly process of (SiO2/PEI)(n) film on a polyester fabric was driven by multi-forces, with dominant forces equilibrium of electrostatic attraction and repulsion.