A collection of objects are called monodisperse or monosized if they have the same size, shape and mass. A sample of objects that have an inconsistent size, shape and mass distribution are called polydisperse. In practice, monodisperse collections are uncommon because the technological challenges that must be overcome in order to produce such collections are often enormous. Examples

• Polymers: Most will possess a distribution of molecular mass
• Particles: Most manufactured particles will possess a wide distribution of size, surface area and mass
• Thin-films: Most thin-films will possess a varied distribution of film thickness.

Polymers

The term is used for polymer chains made by anionic polymerization, a method which results in chains of the same length. The catalyst used to initiate chains is anionic in nature. The technique is also known as living polymerization. It is used commercially for the production of block copolymers.

See also

• Polydispersity index

External links

• Polymer structure