Environmental Engineering Reference
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size dependence. The sequence from solid-liquid interface energy γ sl (section 2), solid-solid
interface energy γ ss (section 3), solid-vapor interface energy γ sv (section 4), and liquid-vapor
interface energy γ lv (section 5). The section 6 provides a summary and future prospect.
Overview
At materials sizes of nanosize range (interface size at least in one dimension is also in this
size range), which are above the atomic scale and below the macroscopic scale, the
corresponding materials properties could not be readily interpreted based on ″classical″
atomic or solution theories, and the regions of space involved were beyond the reach of
existent experimental techniques [1]. Science to interpret these phenomena has taken a firm
theoretical and experimental hold on the nature of matter at its two extremes: at the
molecular, atomic, and subatomic levels, and in the area of bulk materials, including their
physical strengths and weaknesses and their chemical and electrical properties. Between those
two extremes lies the world of nanometer size range, or called as mesoscale, and even with
the latest advanced techniques for studying the phases and the region between phases, a great
many mysteries remain to be solved. That ″region″ of the physical world represents a bridge
not only between chemical and physical phases, but also plays a vital but often unrecognized
role in other areas of physics, chemistry, materials science, biology, medicine, engineering,
and other disciplines [1].
″Interfacial″ phenomena may be defined as those related to the interaction between one
phase (solid or liquid) with another phase (solid, liquid, or gas) or a vacuum in the narrow
region in which the transition from one phase to the other occurs. As will quickly become
apparent, the two classes of phenomena are intimately related and often cannot be
distinguished [1].
Our understanding of the nature of the interfacial region and the changes and transitions
that occur in going from one chemical (or physical) phase to another has historically lagged
behind that in many other scientific areas in terms of the development and implementation of
both theoretical and practical concepts. Great strides were made in the theoretical
understanding of interactions at interfaces in the late nineteenth and early twentieth centuries
by thermodynamics [1]. Modern computational and analytical techniques made available in
the last few years have led to significant advances toward a more complete understanding of
the unique nature of interfaces and the interactions that result from their unique nature due to
the rapid increase of computation ability/price ratio of computers [2]. The so-called
computation materials science considers the interface properties from three different size
scales [2]:
1.
From atomic scale with the ab initio calculation based on the first principle, which
considers many-body interaction behavior of several ten to hundreds molecules
together;
2.
From nanosize scale with molecular dynamics and Monte Carlo methods, which
considers many-body interaction behavior of several thousands to several million
molecules;
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