Densely packed monolayers of a charged virus are sandwiched in multila
yer films of charged polyelectrolytes by successive adsorption of mole
cules of opposite charges. By small-angle X-ray scattering it is shown
that films of well-defined thickness (+/-10 Angstrom) and with roughn
ess of about 10 Angstrom can be prepared. It is demonstrated that the
surface roughness created by particle deposition is smoothed by the fo
llowing polymer adsorption steps. Very precise data on the lengths of
sublayers are derived from suitable model fitting.