Controlled deposition of photonic polystyrene-nanosphere films

The objective of this study is to develop a procedure for controlling the deposition of colloidal crystal coatings from nanoparticle suspensions. We experimentally deposited polystyrene nanospheres on glass plates by dragging a small volume of liquid over the substrates. The mechanism governing the deposition is convective assembly. It has been observed that the number of deposited nanosphere layers can be influenced by the deposition speed and the nanosphere volume fraction, as predicted by theory. Crystal coatings of a few square centimeters were deposited in minutes from suspensions of 5 - 20 μL. Our computer simulations of the phenomena generated structures similar to those from experimental films, proving the validity of the model elaborated for the assembly process.