POLYELECTROLYTE MONOLAYERS AT THE MICA AIR INTERFACE - MECHANICALLY INDUCED REARRANGEMENTS AND MONOLAYER ANNEALING/

We have carried out a series of experiments on the mobility of a polye lectrolyte monolayer (thickness: 0.7 nm) in a nitrogen atmosphere with the surface force apparatus. If two polyelectrolyte monolayer covered surfaces come into contact, we observe a polyelectrolyte meniscus sur rounding the contact area. After separation of the surfaces, a polyele ctrolyte ring tracing the rim of the former contact area can be found. The monolayer anneals within minutes. (To observe the isolated monola yer, the optics of the surface forces apparatus had to be further deve loped.) From wetting and photobleaching experiments with fluorescent-l abeled monolayers, we deduce that the annealing is a monolayer nux dri ven by the change in surface energy. We find that the relative humidit y (rh) mainly influences the annealing time if rh less than or equal t o 80%. However, at rh approximate to 100%, not a polyelectrolyte but a water meniscus is observed. Polyelectrolyte bilayers can be deformed plastically, yet they do not anneal.