Application of Force Fields in Materials Science

With this basic understanding of the various types of force fields, how they were derived, parameterized, and what they can be used for, we now consider the application of these force fields in the area of materials science. 

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In the remainder of this chapter, we take a detailed look at the physical reasoning behind the use of force fields, at the derivation of force field parameters, and at a number of applications of force fields in the materials science area. 

In this chapter we have shown how force fields can be utilized in materials science applications. There are similarities between force fields used in life science and in materials science. Owing to the variety of molecules studied in materials science, however, there are several complementary approaches to modeling such systems. Molecular mechanics force fields as used in life science (i.e., in biomolecules) can also be applied to organic materials such as polymers or liquid crystals. Ionic materials such as oxides are better described by means of ion pair or shell model potentials. For some systems with ionic as well as covalent character in their bonds (e.g, zeolites), both approaches are feasible. 

Twenty years ago Car and Parrinello introduced an efficient method to perform Molecular Dynamics simulation for classical nuclei with forces computed on the fly by a Density Functional Theory (DFT) based electronic calculation [1], Because the method allowed study of the statistical mechanics of classical nuclei with many-body electronic interactions, it opened the way for the use of simulation methods for realistic systems with an accuracy well beyond the limits of available effective force fields. In the last twenty years, the number of applications of the Car-Parrinello ab-initio molecular d3mam-ics has ranged from simple covalent bonded solids, to high pressure physics, material science and biological systems. There have also been extensions of the original algorithm to simulate systems at constant temperature and constant pressure [2], finite temperature effects for the electrons [3], and quantum nuclei [4]. 

In the colloidal realm, given the large surface-to-volume ratio and the relatively small range of force that can sway the disposition of a colloidal particle, it is easy to appreciate the importance of controlling surface properties. Research literature abounds with the characteristics of colloid systems and model systems that mimic colloid surfaces. Applications permeate the fields of materials processing, adhesion, coatings, food science, and medicine. 

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