The pH role in casein-carboxymethylcellulose nano/ microparticles formation

Tuning the pH of colloidal dispersions formed by polymer chains can induce different self-aggregation of the particles, since their size and charges can be affected by the physicochemical properties of the systems. Nano -and microparticles formed by carboxymethylcellulose (CMC) and casein (CA) were prepared using the complex coacervation technique at different pH values (pH 4, 5, 6, and 7). The ratio of CA: CMC chains was 1:1 and 1:2, and non-crosslinked and crosslinked particles were obtained. The results showed that the pH and the polymer proportion played an essential role in the morphology, size, charge, rheological, and thermal behavior of the systems. CA: CMC 1:1 particle formed at pH 4 presented larger aggregates, while the CA: CMC 1:2 systems formed at this pH value presented smaller particles. In this scenario, the size, and charges of CA: CMC particles were especially influenced by the pH of the systems, giving by the relation to the colloidal stability of crosslinked and non-crosslinked systems. These results expand the understanding of the potential application of CA: CMC complex coacervates in the storage and controlled release of specific substances in aqueous medium, important for food, cosmetics, pharmaceutical, and wastewater treatment industries.