Previous studies of covalently attached, homopolymer films encompass a variety of practical applications - including antifouling and antifogging materials - but creating films of multiple homopolymers edicts a new frontier. Mixed polymer brushes, or surfaces composed of more than two polymers, provide an intriguing new pathway to tailor responsive surfaces. Such surfaces can undergo a reversible change in response to their environment, providing advantages in protein adsorption, drug delivery, and catalysis. With typical polymer brushes, two radical polymerizations are unable to run side-by-side due to the adverse side reactions from the reactive radicals. In a system that combines two different polymerization approaches, selective activation provides access to mixed brushes that would otherwise undergo side reactions. This work encompasses a single method of mixed polymer brush synthesis - dual reversible addition-fragmentation chain transfer polymerization - with the goal of optimizing the individual polymerizations before synthesizing the mixed polymer brush. Successful formation of mixed brushes is evidenced by variable angle spectroscopic ellipsometry and x-ray photoelectron spectroscopy.