Abstract: In some embodiments, a film forming composition described herein comprises an aliphatic polyisocyanate; an aliphatic polyfunctional nucleophile; a chain extender; a first solvent; and a second solvent, wherein an evaporation rate of the first solvent and an evaporation rate of the second solvent are within 150% of each other, the percentage being based on the larger value. In some embodiments, a method of forming a film on a substrate is described herein, the method comprising combining a polyisocyanate with a polyol to form a polyurethane pre-polymer; combining the polyurethane pre-polymer with a chain extender to form a polymer; and applying the polymer to the substrate.