A collection of objects are called monodisperse, or monosized, if they have the same size and shape when discussing particles, and the same mass when discussing polymers. A sample of objects that have an inconsistent size, shape and mass distribution are called polydisperse.
Monodisperse collections can be easily created through the use of template-based synthesis, a common method of synthesis in nanotechnology. Monodisperse polymers are typically created through natural processes.
The term is used for polymer chains made by anionic polymerization, a method which results in chains that are similar in 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.