Small-angle neutron scattering (SANS) measurements were carried out on the supramolecular complexes formed between sodium dodecylsulfate (SDS) and different generation poly(1,4-diaminobutane) dendrimers. For the first and second generation dendrimers, the scattering data are consistent with the existence of spherical SDS micelles bound to the dendrimers. The aggregation numbers of these bound micelles were determined. When these data are combined with reported data from binding isotherms, information on the molecular composition and structure of the complexes can be obtained. For the first generation dendrimers the complexes comprise three and four dendrimer molecules bound to an SDS micelle. The number of bound dendrimers decreases for the next generation poly(1,4-diaminobutane) dendrimers. The SANS data for the dendrimer/SDS complexes of the third and fourth generation dendrimers are not consistent with small spherical micelles. Indeed the intense scattering observed at low values of wave vector transfer is consistent with the formation of large aggregates. This result was confirmed from viscosity measurements. Fluorescence quenching measurements suggest that the bound SDS in these larger structures have aggregation number of twice those of normal SDS micelles. The overall data suggests that the basic building blocks in these complexes consists of surfactant aggregates linking different dendrimers. Finally SANS measurements were also carried out to study the micelles of hexaethyleneglycol monododecyl ether (C12EO6) in the presence of these dendrimers. The scattering data are consistent with spherical free C12EO6 micelles existing in solution.

CF4 plasma etching of hydrogen-silsesquioxane films on bare silicon substrates was conducted. An increase in average etching rate and a decrease in dielectric constant from 2.9 to 2.7 were observed after a top layer was removed from the surface of the film, indicating that a negative density depth gradient in the film was developed during the cure processing, A small part of the reduction in dielectric constant may be attributed to structural change resulting from the plasma interaction with the films since a small amount of Si-F bonds were identified in the surface layer of the film after plasma etching. There are indications in the x-ray photoelectron spectroscopy (XPS) spectra that traces of fluorocarbon polymer residue have been generated during the plasma etching. The results of this study also indicate a possibility of obtaining a lower dielectric constant HSQ film by plasma etching.