We describe the miscibility of blends involving poly(ethylhexyl methacrylate) [PEHMA] latex copolymers using the direct nonradiative energy transfer (DET) technique. When the polymers in both components of a blend are PEHMA homopolymers, we obtain a fully mixed film. When one of the components in the blend is replaced with a PEHMA copolymer containing 5 mol % tert-butylcarbodiimidoethyl methacrylate (tBCEMA), we also obtain a fully mixed film. However, if a PEHMA copolymer containing 11 mol % methacrylic acid (MAA) is mixed with PEHMA homopolymer, the miscibility between the polymers is limited and is reduced further when the amount of MAA is increased to 20 mol %. Using a distribution model for energy transfer, we were able to determine the evolution of the interface thickness with annealing time. The maximum interface thickness attained in these blends decreases from delta = 15 nm to delta = 8 nm when the content of MAA in the blends increases from 11 mol % to 20 mol %. A freshly formed solvent-cast film prepared from a 1:1 blend of the PEHMA copolymer containing 11 mol % MAA and the PEHMA copolymer containing 5 mol % tBCEMA exhibits some polymer segregation. This persists in the solid film when the film is annealed for short times (20 min) at 60 degrees C. Over longer times, mixing of the copolymers occurs and reaches completion. We attribute this increase in miscibility to the formation of graft copolymer, which serves as a compatibilizing agent, through the reaction between the -COOH and -N=C=C- groups. When a film of the same composition is prepared from a blend of the two latex dispersions and annealed, a fully mixed film also results.