Self-Assembled Vesicles from Mixed Brush Nanoparticles in Solution

Abstract

The self-assembly of binary polymer-grafted nanoparticles (NPs) in a selective solvent is investigated using coarse-grained simulations. Simulations are performed using theoretically informed Langevin dynamics (TILD), a particle-based method that employs a particle-to-mesh scheme to efficiently calculate the nonbonded interactions. The particles are densely grafted with two immiscible polymers, A and B, that are permanently bound to the NP either at random grafting sites (random-grafted) or with all the A chains on one hemisphere of the NP and all the B chains on the other hemisphere (Janus-grafted). For NPs with random grafting, the polymers phase-separate on the surface of the NP to form Janus-type structures in dilute solution, even though some of the chains have to stretch around the particle to form the Janus structure. When the solvent quality is sufficiently poor for the solvophobic chains, the binary grafted NPs assemble into various structures, including double-walled vesicles. In particular, vesicles are formed when the solvophilic volume fraction is between 0.2 and 0.3, in a similar range to that required for vesicle formation in diblock copolymers in a selective solvent. For mixed-grafted NPs, there is considerable variation in the structure of each individual NP, but nevertheless, these NPs form ordered vesicles, similar to those formed by Janus-grafted NPs.

Controlling the two components modified on nanoparticles to construct nanomaterials

“…On this basis of a lot of work on theoretical simulations of single-component polymer grafted nanoparticles, 22,61,62,[64][65][66][67][68][69][70][71][72][73] theoretical simulations of two-component polymer grafted nanoparticles has also gradually attracted attention. Koski et al 12 used the theoretically-informed Langevin dynamics (TILD) to study the self-assembly of nanoparticles modified with different polymers to form different structures of vesicle, droplet and dispersed, respectively (Fig. 3C).…”

“…In particular, the system of multiple modifications of nanoparticles through different kinds of chains has attracted increasing attention because of its ability to take into account different properties. Different modified components can be DNA segments of different sequences, 6,7 DNA strands and block copolymers, 8,9 DNA strands and homopolymers, 10 hydrophilic and hydrophobic polymers, 11,12 organic molecules with different functional groups, 13 etc. According to the different combinations of modified components, the main research directions of two-component modified nanoparticles can be divided into five categories (Fig.…”

Self-assembled morphologies of polyelectrolyte-grafted nanoparticles directed by oppositely charged polymer matrices

“…They pointed out that the phase separation of NPs was driven by the chemical mismatch between the inorganic core and the organic ligands, even though the graft and matrix chains were chemical identical. Very recently, Koski and Frischknecht 23 investigated the self-assembly of NPs coated with two neutral immiscible homopolymers (solvophobic and solvophilic chains) in a selective solvent by using Langevin dynamics (LD) simulation. Various well-ordered structures, including double-walled vesicles, were formed when the solvent quality was sufficiently poor for the solvophobic ligands.…”

“…5,8 Comprehensive understanding and documenting the selfassembled structures of polymer-graed NPs is essential to predict and control macroscopic properties of PNCs. So far, a series of experimental, [11][12][13][14] theoretical, [15][16][17][18][19] and simulation [20][21][22][23] studies have investigated the phase behavior of NPs coated by uncharged macromolecules. Akcora et al 11 investigated the selfassembled structure of spherical silicon NPs uniformly coated with polystyrene (PS) chains dispersed in corresponding homopolymer matrix.…”

Phase Behavior of Polymer-Grafted Nanoparticles in Homopolymer Blends from Simulations

“…A hybrid particle-field method called theoretically informed Langevin dynamics (TILD) was recently shown to be able to determine phase behavior and self-assembly of polymer-grafted NPs. ,− TILD uses Langevin dynamics to sample the dynamic partition function of the system. The coordinates of each polymer and NP are explicitly tracked using a particle representation, while the nonbonded interactions are calculated using density fields generated from a particle-to-mesh scheme.…”