ORGANIC FILM FORMATION INVESTIGATED BY ATOMIC-FORCE MICROSCOPY ON THENANOMETER-SCALE

The formation of ultrathin, amorphous organic films on solids is studi ed for an application-oriented model system. A prepolymer or a copolym er of a cyanate-based high-temperature adhesive is spin cast or dip co ated onto silicon wafers or aluminium coatings to produce firms as thi n as possible. The mean thickness ranges from 1 to ii nm. After a thor ough substrate characterisation by imaging and spectroscopic methods, the various films were investigated by atomic force microscopy (AFM). Besides imaging, for discontinuous films AFM was also utilised to meas ure the ''borderline angle'' introduced in this paper. The borderline angle characterises the slope of the surface of an isolated adsorbed o rganic object near the substrate. Thus, it is the geometric equivalent to the classical contact angle of a lying liquid drop. However, the p henomena leading to these angles are different. Nevertheless, the bord erline angle is related to the affinity of the organic phase to the su bstrate and thus will play an important role in future investigations of film formation and adhesion on the nanometre scale.