Estimation of contact area of nanoparticles in chains using continuum elastic contact mechanics

The key challenge to understand the nanomechanical behavior of nanoparticle chain aggregates (NCA) is strongly dependent on accurate determination of the contact area between individual particles. Experimental determination of the contacting radius is extremely difficult and often not reliable. We present calculations based on elastic contact mechanics models, that predict the contact radii of nanoparticles. The model considers important parameters, such as the particle size, the elastic property of the materials and the effect of humidity that intervenes between the contacts. Calculations carried out for four selected materials show that there is a large difference between the radii of contacts formed in vacuum and in ambient conditions. In vacuum, the surface energy of the material is higher compared to that in ambient condition and the contact formation is dominated by the strong interactions between the surfaces. In ambient condition, the contact is dominated by the Laplace pressure due to the condensed water meniscus between the contacts. Calculations presented in this article show that the contact radius between nanoparticles depends on materials properties and the environment.