Polymer chains with electric charges along the chain backbones act extremely sensitive towards the addition of inorganic salts from specifically interacting cations (SIC) or changes of pH and temperature. Typical SICs interacting specifically with the anionic carboxylate residues of polyacrylates are alkaline earth cations or transition metal cations like Ag+ or Pb2+. This is reflected in a drastic change of the polyelectrolyte coil dimensions and eventually in a precipitation of the respective polyelectrolyte salt, once the SIC content is large enough. It is this sensitivity to SICs which makes such polyelectrolytes ideal candidates for responsive materials or modulators in mineralization processes. Our main focus lays on a comparative study of the impact of SICs on polyacrylate and polystyrenesulfonate. The subtle interplay of an added inert salt with appropriate amounts of SIC enables us to select any intermediate state along this shrinking process and to analyse the structural details of such intermediates by our combined scattering techniques. Beyond a precipitation threshold, aggregation of SIC-polyacrylate complexes is analysed by time-resolved LS. A particularly interesting system under current investigation is the solution of Ag+-salts in the presence of long chain polyacrylates, where the anionic chains serve as UV-assisted reducing agent as well as host for the thus prepared Ag-nanoparticles.