Tethered Nano Building Blocks:  Toward a Conceptual Framework for Nanoparticle Self-Assembly

Abstract

We perform molecular simulations to study the self-assembly of nanoparticles functionalized with oligomeric tethers attached to specific locations on the nanoparticle surface. We demonstrate that for certain categories of tethered nano building blocks the obtained morphologies may be predicted using concepts from block copolymer microphase separation and liquid-crystal phase ordering, whereas for other categories the unique packing constraints introduced by nanoparticle geometry and by nanoparticle−tether topology lead to structures far richer than those found in conventional block copolymer, surfactant, and liquid-crystal systems. Our results suggest the potential usefulness of considering tethered nano building blocks as a new class of “macromolecule” for assembling novel materials on the nanoscale.

Dynamics of solvent-free grafted nanoparticles

“…Aside from our earlier work, 16,17 previous theoretical and computational studies of oligomer-grafted nanoparticles mainly focused on self-assembly in solution, and often incorporated some degree of asymmetry in the shape of the core building blocks (e.g., spheres, 20, 21 disks, 22 cubes, 23 and rods 24,25 ). Oligomer-grafted nanoparticles have been considered in previous theoretical studies in a phantom solvent to determine the effects of single 26 and multiple grafted chains on their structure, and calculations of the particle-particle potential of mean force of grafted particles have been performed in an explicit polymer matrix.…”

Self-assembly of amphiphilic peanut-shaped nanoparticles

“…(We note that colloidal silica dumbbells can be synthesized by other routes [19], and that micrometer-scale peanuts show potential as Pickering stabilizers of oil-in-water emulsions [20].) In an attempt to answer our posed question we have constructed a model of interacting peanuts whose minimal character is motivated by the insight into self-assembly afforded by similarly simple model systems [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39]. Our model can be evolved with computational efficiency sufficient to allow observation of collective, thermally-driven dynamics on timescales of seconds.…”

Kinetics of hexagonal cylinders to face-centered cubic spheres transition of triblock copolymer in selective solvent: Brownian dynamics simulation

“…Brownian Dynamics is particularly suited for simulating polymer solutions because it correctly models the Langevin dynamics for describing diffusion. 15 The solvent is treated implicitly. In the simulation, the system is coarse-grained such that the elemental unit is not a single molecule or even a single monomer of the polymer, but rather a sphere representing the center of the mass of a cluster of many molecules.…”

“…Thus compared to all atom molecular dynamics, BD is more efficient and saves computational time in simulating the polymer solution system. For example, BD methods have been used for simulating polymer flow, 16 phase diagram in surfactants modeled as sphere tethered to a chain 15,17 and in block copolymer melts, 14 solution, 18 and polymer brushes systems. 11,19 To the best of our knowledge, BD simulation has not been reported to study the kinetics of the HEX cylinders to FCC or BCC spheres transition for block copolymer in a selective solvent system.…”