Molecular dynamics simulation of self-assembly of one-component nanocrystals grafted with end-functionalized polymers

Abstract

The self-assembly of polymer-grafted nanocrystals (PGNCs) is an important approach to construct new nanomaterials with tunable properties and novel applications, which has attracted considerable attention recently. Introducing functional groups at the ends of polymer chains is an attractive strategy for the self-assembly of PGNCs. The end functional groups introduce unique interaction enthalpy, which, when combined with the rich conformational entropy of polymer chains, can lead to unexpected assembled structures and provide remarkable control and flexibility over the fabrication of nanostructured materials. In this study, we investigated the phase behavior and the ligand organizations’ structural characteristics of terminal-modified one-component polymer-grafted nanocrystal systems through coarse-grained molecular dynamics (CGMD) simulations. Under a series of self-complementary potential well depth and chain rigidity conditions, we successfully achieved the self-assembly of BCC superlattices from a disordered initial state and constructed the phase diagrams as a function of grafted chain length and grafting density. Interestingly, the self-assembly process is accompanied by the maximization of the hybridization-like binding of terminal self-complementary beads. After forming a stable superlattice, the ordered superlattice system displays multivalent cluster properties analogous to those of NCTs, with penetration occurring between grafted polymer chains. Moreover, the structural properties of ligand organizations in BCC superlattices show different variations with design parameters (grafting density, grafted chain length, chain rigidity, and potential well depth). Our research not only provides insights into the self-assembly behavior of terminal-modified one-component polymer-grafted nanocrystal systems but also offers theoretical guidance for achieving ordered superlattice structures in NCT-like nanoparticle systems.