Chemical Design of Spherical Polyelectrolyte Brushes for Efficient Scale Inhibition

The addition of scale inhibitors is an effective and economical strategy for mitigating scaling in water treatment. Spherical polyelectrolyte brushes (SPBs) have garnered attention for scale control because of their high specific surface area, tunable interfacial functionality, and ability to accommodate a high density of diverse functional groups. In this work, spherical polyelectrolyte brushes (PS-PCAA) were synthesized via photoemulsion polymerization, using 2-[(carboxymethyl)(prop-2-enyl)amino]acetic acid sodium salt (CAA) as the monomer, which contains one amino and two carboxyl groups. PS-PCAA with controllable size and narrow size distribution, obtained by optimizing the monomer concentration, reaction time, and pH value, exhibits efficient inhibition of calcium sulfate scaling through a threshold effect combined with calcium chelation and crystal dispersion. This work demonstrates that PS-PCAA is well suited for scale inhibition especially in high-temperature and alkaline water systems and provides a rational design strategy for developing advanced, environmentally friendly polymeric scale inhibitors functionalized with multifunctional groups.