Surface-area-to-volume ratio

About: Surface-area-to-volume ratio is a research topic. Over the lifetime, 1197 publications have been published within this topic receiving 20466 citations. The topic is also known as: sa/vol & SA:V.

Surface free energy and its effect on the elastic behavior of nano-sized particles, wires and films

Abstract: Atoms at a free surface experience a different local environment than do atoms in the bulk of a material. As a result, the energy associated with these atoms will, in general, be different from that of the atoms in the bulk. The excess energy associated with surface atoms is called surface free energy. In traditional continuum mechanics, such surface free energy is typically neglected because it is associated with only a few layers of atoms near the surface and the ratio of the volume occupied by the surface atoms and the total volume of material of interest is extremely small. However, for nano-size particles, wires and films, the surface to volume ratio becomes significant, and so does the effect of surface free energy. In this paper, a framework is developed to incorporate the surface free energy into the continuum theory of mechanics. Based on this approach, it is demonstrated that the overall elastic behavior of structural elements (such as particles, wires, films) is size-dependent. Although such size-dependency is negligible for conventional structural elements, it becomes significant when at least one of the dimensions of the element shrinks to nanometers. Numerical examples are given in the paper to illustrate quantitatively the effects of surface free energy on the elastic properties of nano-size particles, wires and films.

Covalent surface modification of oxide surfaces.

Abstract: The modification of surfaces by the deposition of a robust overlayer provides an excellent handle with which to tune the properties of a bulk substrate to those of interest. Such control over the surface properties becomes increasingly important with the continuing efforts at down-sizing the active components in optoelectronic devices, and the corresponding increase in the surface area/volume ratio. Relevant properties to tune include the degree to which a surface is wetted by water or oil. Analogously, for biosensing applications there is an increasing interest in so-called “romantic surfaces”: surfaces that repel all biological entities, apart from one, to which it binds strongly. Such systems require both long lasting and highly specific tuning of the surface properties. This Review presents one approach to obtain robust surface modifications of the surface of oxides, namely the covalent attachment of monolayers.

Equilibrium bicontinuous structure

Abstract: For certain ranges of phase-volume ratio, there are two-phase structures in which both phases are continuous and interfacial area is less than in dispersions of globular units having the same volume ratio and average repeat distance. Included are bicontinuous structures defined by multiply connected minimal surfaces of very high genus and everywhere saddleshaped.

Physical chemistry of glass surfaces

Abstract: Six typical problem areas requiring improved understanding of glass surfaces are identified. Results obtained from several surface-analysis instruments show that five types of surfaces are characteristic of a silicate glass at any time in its history. The type of surface is dependent on the environmental history of the glass and may be defined in terms of surface compositional profiles. Several important glass surface topics of current interest are discussed. These include: corrosion mechanisms; mixed-alkali effect; surface passivation with solution ions; protective film formation; the role of CaO, R 2 O/SiO 2 and Al 2 O 3 in glass corrosion; glass surface area to solution volume ratio; relevance of autoclave procedures in durability tests; and bioglass-bone bonding mechanisms.