Experimental method and thermodynamic model for competitive adsorption between polycarboxylate comb copolymers

This study presents a method that establishes the existence of competitive adsorption between polycarboxylate ether (PCE) molecules with different molecular architecture. By combining well-established total organic carbon measurements with UV–Visible absorption, competition between PCEs of different structures could be quantified. Results are interpreted by deriving a fundamental thermodynamic model describing the PCE competition as a dynamic equilibrium between adsorbed and dissolved PCE molecules with different architectures. The model rationalizes the effect of dispersity in charge and backbone length on the adsorption behavior of PCEs and contributes to a fundamental understanding of the PCE working mechanism on the molecular level.