Materials

Materials means different things to different people. To a seamstress material means fabric but to an artist it means the media used to create with. In science, by materials we mean solid substances, specifically those that behave in an interesting manner.

There are three broad categories of materials - polymers, inorganic continuous solids and organic or inorganic molecular materials. The general area of materials science is a fairly new area of study. Polymers have really boomed in the last fifty or so years, to the point where today, a vast variety of polymers are in use in everyday life. The study of continuous solids has been an area of considerable interest over the last decade or so, particularly since the discovery of the YBa2Cu3O7 superconductor in 1987, though ceramics were studied and have been in use for sometime before that. One of the most recent areas of research has been in the area of molecular materials, where there has been growing interest as many of these have been shown to exhibit interesting physical phenomena like second harmonic generation (SHG) and liquid crystallinity.

Structures

Structure is the fundamental arrangement of the atoms that make up materials. There are two broad categories of materials - crystalline and amorphous. Crystalline materials have "long range order", which means that a pattern of atoms keeps repeating - like the pattern on wallpaper. Amorphous materials do not repeat in a regular array, but may have short range order". This means that if you look at the structure over a long rangethere is no regular pattern , if however you look closely, there may be similarities - like leaves on a tree, the leaves are all the same, but they are randomly arranged on the tree.

So the structure of a material is the arrangement of the atoms within it. Now when a material is cooled it gets smaller, which means that the atoms get closer together. However, in some cases atoms can't get closer together easily, so the structure may have to change and therefore the way it behaves, i.e. the material's properties, may change too.

So, the structure of a material is an important indication of why it behaves the way that it does, and materials science is the study of the way that atoms interact with each other under different physical conditions.

Properties

Materials can have many different properties from diamagnetism to the more interesting phenomenon of superconductivity. Many of the appliances in the home rely on physical properties to work. For example, magnetism is a fundamental property used in the hard disk of the computer you are sitting at! Many other appliances in the home rely on the physical properties of the materials used to make them too.

Such properties are usually related to the structure of the material and understanding this relationship helps us to design smaller, more efficient more powerful devices for everyday use. It is for this reason that structure property relationships are studied.

Last updated 29 October, 2002