Nonadditivity of nanoparticle interactions: Understanding the nanoscale

http://www.sciencemag.org/content/350/6257/1242477.abstract

 

Science 9 October 2015:
Vol. 350 no. 6257
DOI: 10.1126/science.1242477

Nonadditivity of nanoparticle interactions

1. Carlos A. Silvera Batista¹,²,
2. Ronald G. Larson¹,²,³,*,
3. Nicholas A. Kotov¹,²,³,⁴,*

+ Author Affiliations

1. ¹Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
2. ²Biointerfaces Institute, University of Michigan, Ann Arbor, MI 48109, USA.
3. ³Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
4. ⁴Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109, USA.

Abstract

Understanding interactions between inorganic nanoparticles (NPs) is central to comprehension of self-organization processes and a wide spectrum of physical, chemical, and biological phenomena. However, quantitative description of the interparticle forces is complicated by many obstacles that are not present, or not as severe, for microsize particles (μPs). Here we analyze the sources of these difficulties and chart a course for future research. Such difficulties can be traced to the increased importance of discreteness and fluctuations around NPs (relative to μPs) and to multiscale collective effects. Although these problems can be partially overcome by modifying classical theories for colloidal interactions, such an approach fails to manage the nonadditivity of electrostatic, van der Waals, hydrophobic, and other interactions at the nanoscale. Several heuristic rules identified here can be helpful for discriminating between additive and nonadditive nanoscale systems. Further work on NP interactions would benefit from embracing NPs as strongly correlated reconfigurable systems with diverse physical elements and multiscale coupling processes, which will require new experimental and theoretical tools. Meanwhile, the similarity between the size of medium constituents and NPs makes atomic simulations of their interactions increasingly practical. Evolving experimental tools can stimulate improvement of existing force fields. New scientific opportunities for a better understanding of the electronic origin of classical interactions are converging at the scale of NPs.