Charged Polymer Colloids via Flash NanoPrecipitation: Formulation, Stability, and Functionality

Abstract

Polymer colloids represent a promising class of materials for use in applications ranging from macroscopic coatings, emulsions, and composites to nanoscopic drug delivery vehicles and structured assemblies. However, to realize the advantages of colloids in these applications, a scalable and versatile fabrication platform is required to not only produce colloids at industrial scales, but also tune requisite dispersion properties through the unconstrained design of formulations. To this end, flash nanoprecipitation (FNP) has been demonstrated as a capable fabrication platform in both academic and industrial settings, enabling the continuous and scalable production of nanoparticles and nanocarriers from a wide library of material inputs. Nevertheless, current formulation approaches compatible with FNP, especially those for producing charged particle dispersions, present challenges in achieving adequate scalability while also controlling dispersion stability and particle surface properties.In this dissertation, new insights into both formulation approaches and dispersion property relationships are presented, enabling the production of charged polymer colloids by FNP. Using the design of Pickering emulsifiers as a motivating application requiring the production of concentrated dispersions of charged particles, ionomers are demonstrated as effective electrostatic stabilizers, minimizing the tradeoff between processing throughput and final particle size. Next, a novel relation between the polymer glass transition (Tg) and the stability of polymeric colloidal dispersions is presented, providing a new approach for tuning particle adsorption and differentiating the interactions of hydrophobic polymers in aqueous dispersions. Finally, by combining learnings from these studies, FNP is demonstrated as an efficient prototyping platform for engineering structured charged colloids to yield highly stable Pickering emulsions.