Monomer Definition and Examples (Chemistry)

The Building Blocks of Polymers

Polyvinyl chloride (PVC) is a polymer consisting of linked vinyl chloride monomer subunits.
Polyvinyl chloride (PVC) is a polymer consisting of linked vinyl chloride monomer subunits. LAGUNA DESIGN, Getty Images

Monomer Definition

A monomer is a molecule that forms the basic unit for polymers. They may be considered the building blocks from which proteins are made. Monomers may bind to other monomers to form a repeating chain molecule via a process called polymerization. Monomers may be either natural or synthetic in origin.

Oligomers are polymers consisting of a small number (typically under one hundred) of monomer subunits. Monomeric proteins are protein molecules that combine to make a multiprotein complex. Biopolymers are polymers consisting of organic monomers found in living organisms.

Because monomers represent a huge class of molecules, they are commonly categorized. For example, there are sugars, alcohols, amines, acrylics, and epoxides.

The term "monomer" comes from combining the prefix mono-, which means "one", and the suffix -mer, which means "part".

Examples of Monomers

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 the sugar monomers to form such polymers as glycogen, starch, and cellulose.

Names for Small Monomers

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

dimer - polymer consisting of 2 monomers
trimer - 3 monomer units
tetramer- 4 monomer units
pentamer- 5 monomer units
hexamer- 6 monomer units
heptamer- 7 monomer units
octamer- 8 monomer units
nonamer- 9 monomer units
decamer- 10 monomer units
dodecamer - 12 monomer units
eicosamer - 20 monomer units