Size-Dependent Properties

While microscale objects (objects with dimensions one-millionth of a meter in size) are widely used, they haven't caused the same excitement as nanoscale materials. The reason is that microscale objects have essentially the same properties as bulk material. However, at the nanoscale the fundamental properties of materials depend on their size, shape, and composition in a way that they don't at any other scale. So, the nanoscale is a different kind of small.

Size-dependent properties are the reason that nanoscale objects have the potential to significantly impact both science and industry.

Examples of size dependent properties include:

• Catalytic properties – how the material enhances chemical reactions
• Electrochemical properties – how the material transfers electrons to other chemical constituents
• Melting properties – how the material transitions from solid to liquid
• Magnetic properties – how the electrons interact to induce magnetic poles
• Optical properties – how the material interacts with light (e.g., its color)

It is difficult to predict at what size a particular material will transition from bulk to size-dependent properties. This threshold is different for each material and each property. For example, nanoscale gold will have different colors throughout the nanoscale size range, but the size-dependent catalytic properties do not dramatically change until gold features are smaller than five nanometers.