Rational design of molecularly engineered biomimetic threshold scale inhibitors

Abstract

For years, water-based industries have been facing operational challenges due to the formation of sparingly soluble salts and their adhesion to process units, referred to as scaling, which increases heat, mass, and momentum transfer resistances. Macromolecular additives, often decorated with negatively charged functional groups such as carboxylates, sulfates, and phosphates, interact with the early stages of precipitating inorganic polymorphs, thermodynamically destabilize and dissolve them back to their ionic constituents (threshold effect). Despite significant efforts in developing new macromolecular platforms for scale inhibition, no mechanistic studies have been conducted on how the synergy between the functional groups and molecular conformation influences the antiscaling properties of macromolecules. Here, we engineer the structure of a novel class of dendrimers based on tetraethylene glycol (TEG) at the molecular level to shed light on the relationship between the macromolecular antiscaling properties and the functional groups, solubility, generation, flexibility, and core structure. While phosphonate groups are the most efficient functional moieties to regulate calcium carbonate scaling, the backbone attains an equally imperative role in the macromolecule–scale interactions. We show how the molecular optimization of dendrimer architecture provides essential parameters to design efficient dendron-based additives with exceptional antiscaling properties and a facile large-scale synthesis. This work may set the stage for rational design of next generation threshold scale inhibitors.