(642e) Rational Design of Tailor-Made Threshold Scale Inhibitor Dendrimers and Dendrons

For years, water-based industries have been facing operational challenges as a result of sparingly soluble salt formation and adhesion to unit operations, referred to as scaling, increasing heat, mass, and momentum transfer resistances. Macromolecular additives, often decorated with negatively charged functional groups such as carboxylates, sulfates, and phosphates may interact with the early stages of precipitating inorganic polymorphs, thermodynamically destabilize and dissolve them back to their ionic constituents (threshold effect). Despite significant effort 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 (backbone flexibility) influence the antiscaling properties of macromolecules. Here, we design and synthesize two new families of dendrimers and dendrons with precisely tailored structures to shed light on the structure-antiscaling property relationships. 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 increasing the generation of dendrimers and dendrons, partial substitution of anionic functional groups with soluble inert moieties, and altering the molecular core directly affect the antiscaling properties. This work may set the stage for rational design of next generation threshold scale inhibitors, which will globally benefit water industry.