Dewetting patterns of thin films of charged polymer solutions

Dewetting of thin films of a volatile aqueous solution of charged polymer is investigated using atomic force microscopy. Spontaneous dewetting of films below 10 nm shows a wide range of morphology ranging from holes, polygonal networks, and bicontinuous structures to droplets, depending on film thickness. These morphologies are also shown to depend on polymer charge density and the rate of dewetting. At high polymer charge density, unusual features are observed, including very long fingers around hole rims and cylindrical structures that resist fragmentation. These features, attributed to viscous effects, are enhanced when the dewetting rate is increased.