(445f) Structured Nanoparticles from the Self-Assembly of Polymer Blends through Rapid Solvent Exchange

Structured nanoparticles are important for various scientific and industrial applications. A fabrication process which is simple, scalable and allows for precise control over particle size and morphology is thus highly desirable. Here, we describe molecular dynamics simulations performed to study the rapid mixing of a polymer blend in solution with a miscible nonsolvent, i.e., Flash Nanoprecipitation.¹ In agreement with experiments, we observe that polymers self-assemble into complex nanoparticles, such as Janus and core-shell particles, when the good solvent is displaced by the poor solvent.² The emerging structures can be predicted based on the surface tensions between the polymers, as well as between the polymers and the surrounding liquid. Meanwhile, processing parameters, such as mixing rate, polymer concentration and blend ratio can systematically tune the size and composition of the nanoparticles. In addition, by altering the glass transition temperature of one polymer component, nanoparticle morphologies can be kinetically trapped along the path to the final equilibrium configuration, which gives rise to patchiness. By varying the size of the precipitated nanoparticle, the glass transition temperature and the fraction of the glassy polymer, the number and distribution of surface patches can also be systematically adjusted. Our results demonstrate that this process is highly promising for the production of structured nanoparticles with various surface features in a scalable and controlled way.

References:

1. Sosa, C.; Liu, R.; Tang, C.; Qu, F.; Niu, S.; Bazant, M. Z.; Prudhomme, R. K.; Priestley, R. D. Soft Multifaced and Patchy Colloids by Constrained Volume Self-Assembly. Macromolecules 2016, 49, 3580-3585.

2. Li, N.; Panagiotopoulos, A. Z.; Nikoubashman, A. Structured Nanoparticles from the Self-Assembly of Polymer Blends through Rapid Solvent Exchange. Langmuir DOI: 10.1021/acs.langmuir.7b00291