The interaction of organic additives with alumina surfaces was studied using a typical tape casting composition for alumina: solvent mixture trichloroethylene/ethanol, polyvinylbutyral (PVB) as binder and fish oil as dispersant.
The characterization of the single components revealed why the dispersant Menhaden fish oil has such excellent dispersing properties for colloids and slurries. Menhaden fish oil used for wet-chemical processing was found to be a chemically polydisperse polymer with a dispersity of D=45 (by GPC) and a molecular weight of Mw=28,000.
The investigation of the interaction in the highly concentrated colloidal slurry indicates that the high molecular weight fraction of fish oil is preferentially adsorbed and that an onion like supramolecular structure is formed by the ceramic particle/dispersant/binder system. The sequence in this nanostructure can be controlled by the sequence of addition of the compounds and is guided by polymer effects. The results gained on powders are supported by experimental data from surface plasmon resonance spectroscopy (SPR).