The process outlined in this study
utilizes a natural phenomenon coined the “coffee ring effect”20
to draw particles to the edge of a droplet of suspension. The rate
of drying dictates the mass transfer rate of particles toward the
contact line, which is stationary or “pinned” as a result of the
deposited colloids. Instead, by drawing the meniscus across a
substrate this natural process has been utilized for controlled
deposition, known as rapid convective deposition,21 a process
seemingly similar to but distinctively different than the
Langmuir-Blodgett technique for creating monolayer films.22
Although many recently developed processes take advantage of
this technique, primary questions remain regarding the fundamental
physics involved with particle convection and self-assembly.