Nanoindentation and tapping mode AFM study of phase separation in poly(ethyl acrylate-co-hydroxyethyl methacrylate) copolymer networks

According to our previous results the free radical copolymerization of ethyl acrylate and hydroxyethyl methacrylate gives rise to a system having chain composition and morphology different from that of the random mixture in the original solution. Besides, structural relaxation experiments revealed the existence of composition heterogeneity in the material. In this work, a deeper insight in the structure of this system is gained using atomic force microscopy (AFM) in the tapping mode and nanoindentation experiments. The material architecture of the copolymerized system is revealed to be formed by nanoaggregates as a consequence of the non-random polymerization process of the comonomers.