Interaction between Polymer-Grafted Particles

Abstract

Previous self-consistent field theory (SCFT) calculations have predicted that the steric interaction between two polymer-grafted particles in good solvent can become attractive, but this conclusion has since been questioned. Here we reexamine the problem with a new numerical scheme using multiple coordinate systems, and find that the interaction remains repulsive regardless of the particle size, brush thickness, or particle separation. The erroneous attraction in the earlier calculations can be attributed to numerical inaccuracy and a subtle issue with how the chains were grafted to the particles. Using our corrected SCFT solution, we also investigate the accuracy of a previous calculation based on strong-stretching theory (SST) and the applicability of the Derjaguin approximation, where the interaction between large particles is estimated from the one-dimensional uniform compression of polymer brushes.

Communication: Unusual dynamics of hybrid nanoparticles and their binary mixtures

“…The interactions between grafted polymer chains on a surface in bad or theta solvent does indicate the presence of an attractive interaction between two surfaces, 23 while the interactions are completely repulsive in a good solvent under all conditions. [24][25][26] For our hybrid nanoparticles, this could be the origin of the dynamical arrest for samples with low f, driven by such attractive interactions. However, we believe that the observed dynamical arrest in low f͑Ͻ10͒ system is driven by van der Waals attractive interactions between gold nanoparticle cores.…”

Hairy nanoparticle assemblies as one-component functional polymer nanocomposites: opportunities and challenges

“…They then used this model to explore the phase diagram of star polymer solutions using Monte Carlo simulations [27] and found a number of crystal structures, including face-centered cubic (FCC), body-centered cubic (BCC), and diamond lattices. An explicit treatment of HNPs in good solvents by Kim and Matsen [28] using a self-consistent field theory bears out the general assumption that in the densely grafted limit, the interaction potential for the particles is purely repulsive, and is soft when the two particles begin to impinge on each other. These methods of inherent structure formation resulting from coronamediated potentials open up new avenues (complementing mesophase-templated concepts such as BCP-nanoparticle blends) yet to be fully explored to create ordered, organic-inorganic superlattices.…”

Unusual dynamical arrest in polymer grafted nanoparticles

“…This is very close to the value of R B / R A ͑1.8Ϯ 0.2͒, further confirming the starlike morphology of our polymer grafted nanoparticle samples. 22 This difference in morphology also leads to a significant difference in the dynamics of these systems, as discussed below. In Fig.…”