Anisotropic self-assembly of spherical polymer-grafted nanoparticles

Abstract

It is easy to understand the self-assembly of particles with anisotropic shapes or interactions (for example, cobalt nanoparticles or proteins) into highly extended structures. However, there is no experimentally established strategy for creating a range of anisotropic structures from common spherical nanoparticles. We demonstrate that spherical nanoparticles uniformly grafted with macromolecules ('nanoparticle amphiphiles') robustly self-assemble into a variety of anisotropic superstructures when they are dispersed in the corresponding homopolymer matrix. Theory and simulations suggest that this self-assembly reflects a balance between the energy gain when particle cores approach and the entropy of distorting the grafted polymers. The effectively directional nature of the particle interactions is thus a many-body emergent property. Our experiments demonstrate that this approach to nanoparticle self-assembly enables considerable control for the creation of polymer nanocomposites with enhanced mechanical properties. Grafted nanoparticles are thus versatile building blocks for creating tunable and functional particle superstructures with significant practical applications.

Confinement enhances dispersion in nanoparticle–polymer blend films

“…Extensive research has, therefore, been devoted to understand the morphological and dynamical phase diagram of such blends and the consequent role it plays in determining the physical properties of these materials [5][6][7][8][9][10][11][12][13] . On the basis of these studies, various strategies are therefore being devised to enhance the dispersibilty of various functional nanoparticles in PNCs [5][6][7][8][9][10][11][12][13][14][15] . It is believed 4,8,11,13 that a wetting nanoparticle-polymer interface is required for homogeneous nanoparticle dispersion in bulk PNCs.…”

“…On the basis of these studies, various strategies are therefore being devised to enhance the dispersibilty of various functional nanoparticles in PNCs [5][6][7][8][9][10][11][12][13][14][15] . It is believed 4,8,11,13 that a wetting nanoparticle-polymer interface is required for homogeneous nanoparticle dispersion in bulk PNCs. For bulk PNCs it has also been well established 5,6,8,11 that for dewetting grafted chainmatrix chain interface, the T g of nanoparticle-polymer blends decreases with increasing fraction of the nanoparticles, whereas T g for wetting interface increases or remains unchanged.…”

“…We observe confinement-induced enhanced dispersion of otherwise bulk phase-segregated blends of nanoparticles and polymers. To gain insight into the mechanism responsible for enhanced dispersion of nanoparticles at a microscopic level, we used coarse-grained MD simulations, which has been widely used for PNCs 4,13,[28][29][30] . We simulated uniformly grafted nanoparticles in a homopolymer matrix confined between two smooth surfaces.…”

Laser-induced Interaction of Multilevel Quantum Dots

“…The interest to the self-organization of nanoparticles into complex structures is common for these studies, the mechanisms of the former being actively studied [7 ,8]. Self-organization based on selective chemical interactions of molecules is studied in [9][10][11]. Prospective extension of this trend is the self-organization based on physical interactions, allowing to control both the structures' growth process and the resulting shape of them.…”

Programmed self-assembly of DNA origami nanoblocks into anisotropic higher-order nanopatterns

“…For example, anisotropic plasmonic structures can enhance the signal intensity of the Fano resonance [8]. However, it remains a great challenge for the construction of anisotropic structures in nanoscale precisely [9].…”