Revista de Nanomateriais e Nanotecnologia Molecular

Nanoparticles in a Liquid: New State of Liquid?

Jaroslaw Drelich

Nanoparticles in a Liquid: New State of Liquid?

Atoms at a solid surface have different co-ordination numbers, bond lengths, and bond angles, with manifest differences in chemical and physical properties of surface atoms relative to their counterparts in the bulk material. In materials where the fraction of atoms at or near the surface is relatively small (e.g. most bulk materials) the effects of surface atoms on macroscopic phenomena are often negligible. This is not true when materials are in the form of nanoparticles, where their highly subdivided state leads to a very high fraction of the total atoms residing at or near a surface. For nanoparticles, the differences between the bulk and surface properties of constituent atoms can often dominate the overall properties of the material. These effects manifest themselves as an increase in vapor pressure, a decrease in melting point, and/or an increase in surface tension/ surface energy when compared to their macroscopic counterparts. Nanoparticles also experience significant changes in optical and electronic properties due to quantum size effects and energetic effects initiated by the increasing contribution of the particle surface to the energy of particles.