Polymer nano-adhesion promoted by surface molecular motion

Polymer nano-adhesion was studied. Polystyrene (PS) bilayer was prepared by attaching original two PS film surfaces together, and was annealed at a temperature between surface and bulk glass transition temperatures for a given time. Discernible interfacial adhesion strength (G) was observed, and was proportional to the interfacial width of a few nanometers measured by dynamic secondary ion mass spectrometry. This means that G at the (PS/PS) bilayer interface is mainly governed by interfacial thickening. Then, nano-adhesion test in between PSs was made using scanning force microscopy. The G value so obtained was much larger than that for the bilayer. The difference was accounted for by the completeness of the interfacial formation.