Polyelectrolytes are often used to prepare highly concentrated dispersions of particles of heterogeneous surfaces of controlled viscosity and stability. However, there is not a satisfactory understanding of the adsorption mechanism of polymers on the surface of heterogeneously charged particles such as kaolin. A systematic investigation of the interaction of silica, alumina, and kaolin, with Na-polyacrylic acid (PAA) polyelectrolyte was performed by conducting adsorption experiments and employing attenuated total reflection infrared spectroscopy (FTIR/ATR) techniques. Adsorption studies indicate that the adsorption density of Na-PAA on the surface of kaolin is considerably smaller than that on alumina particles and there is no indication of adsorption of PAA on the surface of silica particles. FTIR/ATR experiments confirmed that there are specific interactions between PAA and the surface of alumina and kaolin particles as the adsorption bands are shifted to higher wavenumbers.