Structural color from layer-by-layer assembled nanoporous multilayers

PMSE 479

Zhizhong Wu, wuz2@mit.edu1, Daeyeon Lee2, Robert E. Cohen3, and Michael F. Rubner, rubner@mit.edu1. (1) Department of Materials Science and Engineering, Massachusetts Institute of Technology, 77 Mass Ave., Cambridge, MA 02139, (2) School of Engineering and Applied Sciences, Harvard University, 40 Oxford St. ESL 202, Cambridge, MA 02138, (3) Department of Chemical Engineering, Massachusetts Institute of Technology, MA
One-dimensional photonic bandgap structures (i.e., Bragg stacks) exhibiting structural color have been fabricated by the layer-by-layer (LbL) deposition of polyelectrolytes and nanoparticles. The LbL assembly of polyelectrolytes and nanoparticles resulted in the formation of nanoporous thin films. High and low refractive index regions of Bragg stacks were generated by incorporating TiO2 and SiO2 nanoparticles, respectively. The porosity and thickness of each stack were characterized by a simple method based on ellipsometry. These Bragg stacks also exhibited potentially useful superhydrophilicity and self-cleaning properties.