Nanostructuring Single-Molecule Polymeric Nanoparticles via Macromolecular Architecture

Abstract

Heterogeneous polymer-based nanoparticles comprise a very promising family of materials for a broad range of applications. Here, we present a detailed study of structural heterogeneities in nanostructured single-molecule nanoparticles in various environments by means of atomistic molecular dynamics simulations. The nanoparticles consist of mikto-arm star copolymers with two types of chemically incompatible arms, namely poly(ethylene oxide) (PEO) and polystyrene (PS), (PS) n , (PEO) n , where n is the number of arms. The immiscibility between the two components gives rise to intramolecularly nanostructured particles. The nanostructured objects resemble either "Janus-like" or "patchy-like" particles, depending on the number or the length of the arms (or both) as well as the interaction with the surrounding medium. The degree of intramolecular heterogeneity increases with increasing number of arms and with decreasing affinity of star components to the polymer host. We provide a detailed analysis of the internal structure of the starshaped particles, focusing on the intramolecular packing and the spatial arrangement of the arms. The results of our study can be used to design heterogeneous, internally nanostructured particles with two phases of distinct static properties for challenging specific applications of next-generation materials.

Size and Shape Characteristics of Polystyrene and Poly(ethylene oxide) Star Polymer Melts Studied By Atomistic Simulations

“…Identical behavior was found for the PEO arms of the mikto‐arm stars dispersed in oligomeric PEO matrix. [ 39 ] Therefore, we rule out any possible aggregation of the arms, or arrangement such as the umbrella shape of star polymers in the theta state. [ 20 ]…”

“…[44] Identical structure of the kernel was used before in the simulations of mikto-arm stars. [38][39][40] In Figure 1, we present a schematic illustration of the kernels for f = 8 and f = 32. The kernel is composed of carbon units which we consider as united atoms.…”

“…The initial configuration of the star was created by attaching fully stretched arms to the kernel under a certain angle, minimizing the overlap of the atoms, following the protocol reported for mikto-arm stars model systems. [38][39][40] Then, a series of energy minimization (EM) runs together with very short MD simulations with a reduced time step (of 0.1 fs) were performed to eliminate overlaps. The bonds were constrained during the EM by the LINCS [48] algorithm, to avoid bond stretching.…”

“…As showed in our previous studies on mikto-arm stars, the PS arms with their bulky groups occupy much bigger volume around the star core than the PEO arms, being thus adequate examples of two model polymers with distinct properties. [38][39][40] Both types of stars have been also studied experimentally. [41,42] With our realistic model, we aim to bridge the gap between the general, bead-spring type coarse-grained polymer models and experimentally relevant specific polymer star-like structures.…”

Nanoparticles shape-specific emergent behaviour on liquid crystal droplets

“…Many have documented how NPs can show various degrees of selfassembly, depending on the particle morphology and on the system thermodynamic conditions. [4][5][6][7][8][9][10][11] Bulk NP self-assembly has been investigated [12][13][14] as well as NP self-assembly onto interfaces. [15][16][17][18][19] LCs provide the foundation for mature electronic applications 20 as well as for putative applications as chemical sensors, bacterial detectors, and so forth.…”