| Abstract
| - Numerous previous studies have established that the addition of a microphase-ordered AB diblockcopolymer to a thin homopolymer A (hA) film can slow, if not altogether prevent, film rupture and subsequentfilm dewetting on a hard substrate such as silica. However, only a few reports have examined comparablephenomena when the hA/AB blend resides on a soft B-selective surface, such as homopolymer B (hB). Inthis work, the dewetting kinetics of thin films composed of polystyrene (PS) and a symmetric poly(styrene-b-methyl methacrylate) (SM) diblock copolymer on a poly(methyl methacrylate) substrate is investigatedby hot-stage light microscopy. Without the SM copolymer, the dewetting rate of the PS layer is constantunder isothermal conditions and exhibits Arrhenius behavior with an apparent activation energy of ∼180kJ/mol. Addition of the copolymer promotes a crossover from early- to late-stage dewetting kinetics, asevidenced by measurably different dewetting rates. Transmission electron microscopy reveals themorphological characteristics of dewetted PS/SM films as functions of film thickness and SM concentration.
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