Impact of the Distributions of Core Size and Grafting Density on the Self-Assembly of Polymer Grafted Nanoparticles

Abstract

It is now well-accepted that hydrophilic nanoparticles (NPs) lightly grafted with polymer chains self-assemble into a variety of superstructures when placed in a hydrophobic homopolymer matrix or in a small molecule solvent. Currently, it is thought that a given NP sample should only assemble into one kind of superstructure depending on the relative balance between favorable NP core–core attractions and steric repulsion between grafted polymer chains. Surprisingly, we find that each sample shows the simultaneous formation of a variety of NP-assemblies, e.g., well-dispersed particles, strings, and aggregates. We show through the generalization of a simple geometric model that accounting for the distributions of the NP core size and the number of grafted chains on each NP (which is especially important at low coverages) allows us to quantitatively model the aggregate shape distribution. We conclude that, in contrast to molecular surfactants with well-defined chemistries, the self-assembly of these NP analogues is dominated by such fluctuation effects.

Interfacial effects on crystallization behavior of polymer nanocomposites with polymer‐grafted nanoparticles

“…Generally, the conformation of absorbed chains is described as trains (tightly bound to the surface), loops (formed by two trains) and tails (one end of the chains anchored on the surface). [24,107] In the case of R g < R NP , adsorption is similar to that on flat surfaces. [108] No crystallization signal is detected due to a predominance of trains of PEO segments.…”

“…Wunder and coworkers studied the conformation, mobility, and crystallization of PEO chains ( R g = 13.6 nm) absorbed on the SiO 2 surface by varying R NP (ie, R NP = 100, 50, 15 nm). Generally, the conformation of absorbed chains is described as trains (tightly bound to the surface), loops (formed by two trains) and tails (one end of the chains anchored on the surface) . In the case of R g < R NP , adsorption is similar to that on flat surfaces .…”

“…The polymer‐grafted NPs (PGNPs) have been increasingly explored in PNCs with semicrystalline polymers. The performance of PNCs is intimately connected to the final crystal structure and morphology .…”

“…[19] A promising strategy for controlling the NPs dispersion state is to graft polymer chains onto NPs, thereby increasing the compatibility with the polymer matrix. [20][21][22][23] The polymer-grafted NPs (PGNPs) [24] have been increasingly explored in PNCs with semicrystalline polymers. The performance of PNCs is intimately connected to the final crystal structure and morphology.…”

Superstructures of Multielement Colloidal Molecules: Efficient Pathways to Construct Reconfigurable Photonic and Phononic Crystals

“…Micro‐ and nanoscale colloidal building blocks provide an attractive platform for directed self‐assembly, a classic problem in soft matter research with the intention of facilitating spontaneous formation of desired structures . Over the past two decades, the scope of self‐assembly with colloidal particles has evolved from close‐packed structures and binary crystals, to more exotic, non‐close‐packed symmetries driven by different forms of anisotropy . These structures present complex and interesting collective behavior at different length scales, and provide the opportunity to carefully engineer functional metamaterials.…”