Modeling the effect of molecular architecture of comb polymers on the behavior of Al2O3 dispersions using charge/composition factors (CCF)

In this work, we study the effect of periodicity and PEO side-chain length in four PMAA-PEO (sodium salt) comb polymers with known molecular architecture on Al₂O₃ colloidal dispersions in DI water. We introduce here charge composition factors (CCF) representing charge density of the comb polymers defined as (number of charged units in a repeating unit)/(molecular weight of a repeating unit). We find, for the first time to our knowledge, that the CCF can be used along with dispersant dosage to obtain explicit functions predicting the conductivity of the dispersants in solution, the zeta potential behavior during dispersant titrations, and the isoelectric point (IEP) of the dispersions. In addition, the dosage normalized by the CCF provides a basis for comparison for the dispersants to elucidate the trends found in adsorption and potentiometric titrations. Thus, the CCF can be used as a tool for the design of improved and new comb polymer molecular architectures.