Scalable Production of Internally-Structured and Surface-Active Polymer Colloids via Flash NanoPrecipitation

Production of polymer nanocolloids with complex internal structures or anisotropic surface functionality on large scales has been a challenge which has hindered their implementation in applications from drug delivery and biosensing to oil and gas recovery. We have developed Flash NanoPrecipitation (FNP) as a scalable process which can be used to generate kilograms of such polymer colloids per day. This solvent-exchange process relies on the rapid mixing of a polymer solution with an antisolvent stream to produce supersaturated conditions which result in monodisperse polymer colloids. Additional complexity can be achieved using the same low-cost equipment by taking advantage of the phase separation of chemically distinct polymers. Janus, core-shell, patchy, and lamellar morphologies have been produced by incorporating a blend of homopolymers or block copolymers into the system, and hydrophilic coronas can be generated via the use of amphiphilic block copolymers. Amphiphilic Janus colloids have recently been created by combining the phase separation behavior of hydrophobic polymers with the adsorption of amphiphilic block copolymers on one domain. These colloids are surface-active in oil-water mixtures and show promise as Pickering emulsion stabilizers.