A mini-review: How reliable is the drop casting technique?

The simple, easy and rapid technique of "drop casting" is widely used to prepare the surface of chemically modified electrodes in which the modifying layer is composed of particles such as nanotubes or nanoparticles and used for electro-catalysis notably for chemical sensing as well as materials evaluation. However, meaningful voltammetry requires the formation of uniformly modified surfaces for which the coffee ring and its related effects, which are overviewed, present a significant limitation on the reproducibility of the drop casted surfaces. Approaches for amelioration of the coffee ring effect by various methods are discussed.