Can nonadditive dispersion forces explain chain formation of nanoparticles?

Abstract

We study to what extent dielectric nanoparticles prefer to self-assemble into linear chains or into more compact structures. To calculate the Van der Waals (VdW) attraction between the clusters we use the Coupled Dipole Method (CDM), which treats each atom in the nanoparticle as an inducible oscillating point dipole. The VdW attraction then results from the full many-body interactions between the dipoles. For non-capped nanoparticles, we calculate in which configuration the VdW attraction is maximal. We find that in virtually all cases we studied, many-body effects only result in local potential minima at the linear configuration, as opposed to global ones, and that these metastable minima are in most cases rather shallow compared to the thermal energy. In this work, we also compare the CDM results with those from Hamaker-de Boer and Axilrod-Teller theory to investigate the influence of the many-body effects and the accuracy of these two approximate methods.

Nonadditivity of nanoparticle interactions

“…Eq. 1 may also be referred to as the additivity assumption (17,18); it fails as the size of the particles and the distances between them reach nanoscale dimensions. NPs are often made from metals (such as gold, silver, platinum, nickel, and cobalt) or semiconductors (such as PbSe, PbS, and CdTe) with high polarizability that increases the coupling between different interactions, exacerbating the problem.…”

Three-body critical Casimir forces

“…This procedure, however, often generates many-body forces, beyond the linear superposition of basic pairwise forces. This kind of nonadditivity is present in various systems such as colloidal suspensions [1][2][3][4][5][6][7][8], systems governed by quantum-electrodynamic Casimir forces [9][10][11][12][13][14], polymers [15][16][17][18][19], granular systems [20][21][22], nematic colloids [23], and noble gases or nanoparticles with van der Waals forces acting among them [24][25][26][27][28][29][30][31].…”

Self-limiting self-assembly of supraparticles for potential biological applications

“…Electrostatic interactions include repulsive and attractive forces. 25,[78][79][80] When colloidal building blocks are identically charged, electrostatic repulsion will occur between them and result in the overlapping of an electrical double layer surrounding NPs, which can prevent the coagulation or aggregation of the colloids and maintain their stability. 17 Similar to van der Waals force, electrostatic force also plays an important role in the assembly of SPs.…”