I am an application engineer for Laurell Technologies. We manufacture spin coaters as mentioned in keithwms 12:38am post. Spin coating is used with all types of monomers and polymers, aqueous solutions, solutions with suspended nanoparticles, epoxies, optical lens coatings, paint, colloids, etc... Round, square, rectangular and irregular shapes can be used within a spin coater. Coating uniformity, when using a square or rectangular substrate, can be maximized out to the edges, when using a properly designed substrate chuck. Spin speeds can be up to 12,000rpm. If anyone has questions about spin coating, feel free to contact me at pgrasso[at]laurell.com