Structural studies of vacuum-deposited thin film of permethyloligosilanes with phenyl end groups

Thin films of permethyloligosilanes with phenyl end groups, Ph(SiMe2)(n)Ph (n = 10, 12), were prepared by vacuum deposition at various temperatures. T he deposited thin films were investigated by X-ray diffractometry in terms of multilayered structures and varying incident-angle absorption spectrosco py in terms of their molecular orientations. The interlayer spacings in the multilayered structures are reasonably well explained by assuming interdig itated structures with the molecules oriented normal to the substrates. Whe n the films were deposited onto cold substrates, another structure appeared , in which molecules are oriented parallel to the substrate. Introduction o f phenyl end groups was found to reduce the domain sizes In thin films.