Oligomer
In chemistry, an oligomer (
i) (oligo-, "a few" + -mer, "parts") is a molecular complex that consists of a few monomer units, in contrast to a polymer, where the number of monomers is, in principle, not limited.Dimers, trimers, and tetramers are, for instance, oligomers composed of two, three and four monomers, respectively.
In the context of biochemistry, an oligomer usually refers to a macromolecular complex formed by non-covalent bonding of a few macromolecules like proteins or nucleic acids. In this sense, a homo-oligomer would be formed by few identical molecules and by contrast, a hetero-oligomer would be made of more than one, different, macromolecules. Collagen is an example of a homo-oligomeric protein that is composed of three identical protein chains. The term multimer () (multi-, "more than one" + -mer, "part") is used with a meaning similar to that of oligomer in the context of proteins (although technical restrictions of word sense may exist).
Many oils are oligomeric, such as liquid paraffin. Plasticizers are oligomeric esters widely used to soften thermoplastics such as PVC. They may be made from monomers by linking them together, or by separation from the higher fractions of crude oil. Polybutene is an oligomeric oil used to make putty. Greek prefixes are often used to designate the number of monomer units in the oligomer, for example a tetramer being composed of four units and a hexamer of six.
