Influence of Polycarboxylate Ether Type and Dosage on Electrokinetic and Hydrodynamic Descriptors of Graphene Oxide Suspensions in an Alkaline Model Medium

Abstract

Polycarboxylate ether (PCE) superplasticizers are widely used in cementitious systems. They are also used to disperse solid particles in aqueous suspensions, including cement particles and nano-additives such as graphene oxide (GO). Their performance depends on both polymer formulation and dosage. This study compared four commercial PCEs in a NaOH-adjusted alkaline model medium. The electrokinetic and hydrodynamic behavior of GO suspensions was evaluated over GO:PCE mass ratios from 1:0 to 1:6. Zeta potential (ZP) and dynamic light scattering (DLS) were used as comparative descriptors. The control GO suspension showed a mean ZP of −58 mV, a Z-average hydrodynamic size of 531 nm, and a polydispersity index (PDI) of 0.37. After PCE addition, the PDI decreased to 0.26–0.30, indicating lower DLS-derived apparent heterogeneity relative to the control suspension. The response depended on PCE formulation. ACE 300 and MC-PowerFlow 2695 gave the most negative ZP values, reaching −76 mV and −65 mV, respectively, at a GO:PCE ratio of 1:5. At 1:6, the magnitude decreased relative to the peak values. By contrast, the ViscoCrete series showed a more moderate ZP response, from −53 to −58 mV, while the smallest apparent sizes were obtained with the ViscoCrete series, reaching 477 nm. These results show that GO dispersion in this alkaline model medium cannot be inferred from a single descriptor or from applying a single dosage rule across different PCE formulations. Joint interpretation of electrokinetic and hydrodynamic measurements is therefore needed for comparative screening.