丙酮蒸气诱导PS-b-PMMA薄膜的去润湿行为

In this paper, the dewetting behavior in ultrathin films of diblock copolymer polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA, denoted as SMMA51K) induced by acetone vapor was studied. Thin films of SMMA51K with a thickness of 4 nm were prepared by spin coating and characterized by atomic force microscopy (AFM). The morphology evolutions of the films in acetone vapor were mainly investigated and the probable mechanisms of the dewetting were given. Results indicate that the dewetting in the 4-nm-thick film of SMMA51K occurs by the spinodal dewetting mechanism when the films are annealed in acetone vapor. There are two dewetting processes, a slow dewetting of the polymer layer occurs at the substrate's surface, and a fast one occurs on the top of this layer. The size of the droplets first increases, then decreases, and finally increases again with the increase of annealing interval.