Autophobic dewetting of polystyrenes on the substrates grafted with chemically identical polymers

We present the autophobic dewetting behavior of polymer melt droplets on chemically identical brushes. The polymer model layers were set to define the interface between polystyrenes (PSs) and corresponding brushes having variable chain lengths (or molecular weights), and then thermally annealed above the glass transition temperature. Autophobic dewetting of polymer melts in a dry brush regime was characterized by well-defined PS melt droplets that dewetted the brushes upon thermal annealing. The contact angle (θ) of PS droplets on the brushes and interfacial tension (γ_m/b) between the PS melts and brushes significantly increased as the chain length of PS brushes decreased and grafting density increased. We speculated that the γ_m/b increasingly converges on the maximum interfacial tension (γ_m/b^∗) at the extremely short and dense PS brush, indicating the super autophobicity of the PS melt on the corresponding brush.