Polymer-mediated nanorod self-assembly predicted by dissipative particle dynamics simulations

Abstract

Self-assembly of nanoparticles in polymer matrices is an interesting and growing subject in the field of nanoscience and technology. We report herein on modelling studies of the self-assembly and phase behavior of nanorods in a homopolymer matrix, with the specific goal of evaluating the role of deterministic entropic and enthalpic factors that control the aggregation/dispersion in such systems. Grafting polymer brushes from the nanorods is one approach to control/impact their self-assembly capabilities within a polymer matrix. From an energetic point of view, miscible interactions between the brush and the matrix are required for achieving a better dispersibility; however, grafting density and brush length are the two important parameters in dictating the morphology. Unlike in previous computational studies, the present Dissipative Particle Dynamics (DPD) simulation framework is able to both predict dispersion or aggregation of nanorods and determine the self-assembled structure, allowing for the determination of a phase diagram, which takes all of these factors into account. Three types of morphologies are predicted: dispersion, aggregation and partial aggregation. Moreover, favorable enthalpic interactions between the brush and the matrix are found to be essential for expanding the window for achieving a well-dispersed morphology. A three-dimensional phase diagram is mapped on which all the afore-mentioned parameters are taken into account. Additionally, in the case of immiscibility between brushes and the matrix, simulations predict the formation of some new and tunable structures.

Percolation analysis of the electrical conductive network in a polymer nanocomposite by nanorod functionalization

“…It is reported that by employing the integral equation theory, NRs exhibit the contact aggregation, dispersion, bridging, and tele-bridging behavior with tuning the polymer-NR interaction. 45 In our systems, NRs mainly form the contact aggregation and bridging structures at λ A ≤ 0.2, while NRs mainly form the bridging and tele-bridging structures at λ A ≥ 0.4. To intuitively observe the NR dispersion state, the snapshots are shown in Fig.…”

Dissipative Particle Dynamics Simulations of a Protein-Directed Self-Assembly of Nanoparticles

“…Here, K b = 100, r 0 = 0.6 r C is used for gelatin 49 and K b = 20, r 0 = 0.85 r C is used for PVDF. 42 The harmonic angle style potential U θ = K θ (θ – θ 0 ) 2 is applied on two consecutive bonds for both gelatin and polymer chains, where K θ , θ, and θ 0 are the bending constant, inclination angle, and equilibrium angle. For three consecutive skeleton beads (S) of gelatin or three consecutive PVDF beads (P), the bending constant and equilibrium angle are set as K θ = 6 and θ 0 = 180° to keep the chain structures.…”

Dissipative Particle Dynamics Aided Design of Drug Delivery Systems: A Review

“…(II) The nanoparticle is equivalent to a large-volume bead, and other small beads can be modified on the surface of these large beads with bead bonds to change the solvophilicity of those nanoparticles. By virtue of those modeling methods, researchers have completed a series of studies on the self-assembly of liquid crystal polymers (polymer with rigid molecular side chains), − and then nanorods, , nanotubes, ,, and other nanoparticles − were successfully modeled and introduced into the DPD simulation.…”