One variation of a method for directly casting a thin layer onto a substrate includes: combining a prepolymer, a solvent, and a curing agent to define a viscous material; advancing a substrate from a roll across a surface continuously at a first speed; depositing the viscous material at a viscosity through a deposition head onto the substrate, the viscous material flowing laterally across the substrate to form a thin layer of substantially uniform thickness over the substrate over a period of time while the substrate advances along the surface; and, at a distance from the deposition head depositing the viscous material onto the substrate corresponding to a duration of time for the viscous material to flow laterally across the substrate, heating the viscous material to evaporate solvent and to induce reaction between the curing agent and the prepolymer to cure the viscous material to form a layer.