STRUCTURES OF COLLAPSED POLYSILOXANE MONOLAYERS INVESTIGATED BY SCANNING FORCE MICROSCOPY

Surface pressure-area isotherms of monolayers of cyclolinear polysilox anes on water exhibit several plateaus that have been associated with the formation of multilayers. This stepwise collapse has been studied in one of these polymers by scanning force microscopy under topographi c, frictional, and electric force modes. Topographic images show that the growth of the second layer begins with the nucleation of three-dim ensional islands, which then appear to spread in the form of ribbons 0 .5 mu m wide and 7.5 Angstrom high. The number of ribbons increases as the extent of the second layer increases, but the width of the ribbon s remains constant. Subsequent layers do not exhibit this morphology.