Combining Precipitation and Vitrification to Control the Number of Surface Patches on Polymer Nanocolloids

Abstract

In an effort to incorporate increasingly higher levels of functionality into soft nanoparticles, heterogeneously structured particles stand out as a simple means to enhance functionality by tailoring only particle architecture. Various means exist for the fabrication of particles with specific structural configurations; however, the tunability of particle morphology is still a challenging and often laborious task, especially in self-assembled systems where a single equilibrium configuration dominates. Improved strategies for multipatch particle assembly are therefore needed to allow for the tailoring of particle structure via a single, continuous assembly route. One means of accomplishing this is through kinetic trapping of particle morphologies along the path to the final equilibrium configuration in precipitation-induced, phase-separating polymer blends. Here, we demonstrate this capability by using rapid nanoprecipitation to control the overall size, composition, and patch distribution of soft colloids. In particular, we illustrate that polymer feed concentration, blend ratio, and polymer molecular weight can all serve as functional handles with which to consistently alter particle patch distributions in a self-assembling homopolymer system without redesigning the starting materials. We furthermore delineate the role of polymer vitrification in the determination of particle structure.

Multi-scale simulations of polymeric nanoparticle aggregation during rapid solvent exchange

“…ν is the Flory exponent, which depends on solvent conditions. For the polystyrene chains with a molecular weight of 16.5 kg/mol studied in the experiments, 11,22,23 our coarse-graining method leads to N b = 23. 11 In addition, the values of ν for different solvent conditions have been calculated from MD simulations and are presented in Fig.…”

“…Compared to other competing methods, e.g., templating, 12,13 particle lithography, 14,15 or Self-Organized Precipitation (SORP), [16][17][18][19] FNP stands out as a one-step continuous process that operates at room temperature, consumes little energy, and has potential to scale up. In addition, it has also been demonstrated both by experiments and by simulations that it is able to access a wide range of structures, including Janus, core-shell, 20,21 patchy, [22][23][24] and concentric lamellar, 25 using different feed materials, with reliable control over particle size, morphology, and composition. This process can make use of electroneutral polymers with no external stabilizing agents.…”

Diverse Particle Carriers Prepared by Co‐Precipitation and Phase Separation: Formation and Applications

“…Sosa et al co-precipitated glassy polymer (PS) and nonglassy polymer (PI) at temperature below the glass transition temperature (T g ) of PS, below which the vitrified PS polymer inhibits the structural change and the two polymers phase-separate into a nonequilibrium structure of heteroaggregate, as shown in Figure 2e. [33] If the particles are annealed at 135°C, which is higher than the T g of PS, PS aggregates start to form a single domain, forming spherical Janus particles. This is because vitrified PS aggregates are able to anneal above T g to reach the thermal equilibrium state.…”

Synthetic advances of internally nanostructured polymer particles: From and beyond block copolymer

“…When mixing polymers with different glass transition temperature, vitrification of polymer blends strongly determines the particle structures ( Figure 5B,C). [37,38] Furthermore, they also found that diblock copolymers with a different molecular weight could form various internal nanostructures ranging from an ordered concentric lamella to a disordered lamellar morphology. The increase of molecular weight led to a disorder in lamella orientation which further caused complex internally structured colloids.…”

“…Reproduced with permission. [37] Copyright 2017, American Chemical Society morphologies were generated when using blends of a BCP and a homopolymer. Additional phase separation and chain kinetic trapping effects lead to complicated situations for the polymer blends.…”