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

Abstract

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 (γm/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 γm/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. Autophobic dewetting of polymer melts was characterized by well-defined polystyrene (PS) melt droplets that dewetted chemically identical brushes upon thermal annealing. The contact angle (θ) of PS droplets on the brushes and interfacial tension (γm/b) between the PS melts and brushes significantly increased as the chain length of PS brushes decreased and grafting density increased. The super autophobicity of the PS melt at the extremely short and dense PS brush was evaluated when the γm/b increasingly converges on the maximum interfacial tension (γ*m/b).