Monomer Definition and Examples

A monomer is a molecule that forms the basic unit for polymers, which are the building blocks of proteins. Monomers bind to other monomers to form repeating chain molecules through a process known as polymerization. Monomers may be either natural or synthetic in origin.

Oligomers are polymers consisting of a small number (typically under 100) of monomer subunits. Monomeric proteins are protein molecules that combine to form multi-protein complexes. Biopolymers are polymers consisting of organic monomers found in living organisms.

Because monomers represent a huge class of molecules, they are commonly categorized into various subgroups such as sugars, alcohols, amines, acrylics, and epoxides. The term "monomer" combines the prefix mono-, which means "one," and the suffix -mer, which means "part."

Glucose, vinyl chloride, amino acids, and ethylene are examples of monomers. Each monomer may link in different ways to form a variety of polymers. In the case of glucose, for example, glycosidic bonds may link sugar monomers to form such polymers as glycogen, starch, and cellulose.

When only a few monomers combine to form a polymer, the compounds have names:

• Dimer: Polymer consisting of two monomers
• Trimer: Three monomer units
• Tetramer: Four monomer units
• Pentamer: Five monomer units
• Hexamer: Six monomer units
• Heptamer: Seven monomer units
• Octamer: Eight monomer units
• Nonamer: Nine monomer units
• Decamer: 10 monomer units
• Dodecamer: 12 monomer units
• Eicosamer: 20 monomer units