In
chemistry, an oligomer is a molecule that composed of a few repeating units which could be derived from smaller molecules, monomers. The name stems from Greek, oligo-, meaning “a few,” and -mer, meaning “parts.”
Some biologically important oligomers are macromolecules such as proteins or nucleic acids; for instance, hemoglobin is a protein tetramer. An oligomer of amino acids is called an oligopeptide or a peptide. An oligosaccharide is an oligomer of monosaccharides (simple
sugars).
An oligonucleotide is a short single-stranded fragment of nucleic acid such as DNA or RNA, or similar fragments of analogs of nucleic acids such as peptide nucleic acid or Morpholinos. The units of an oligomer may be connected by covalent bonds, which may be a product of bond rearrangement or condensation reactions, or by weaker forces such as hydrogen bonds.
Oligomers are made up of repeating subunits that occupy a unique area of chemical space between small molecules and higher molecular weight polymers. As a result, this emerging class of materials encompasses research opportunities from both categories, and frequently
presents new directions that cannot be found in either traditional class.
Difference Between Oligomer and Polymer
The main difference between oligomer and polymer is that the oligomer forms when few monomers undergo polymerization, whereas the polymer forms when a large number of monomers experience polymerization.
Polymers are large macromolecules that contain a large number of repeating units; they are called monomers. The monomers undergo a process called polymerization in order to generate a polymer material. An oligomer is also a type of polymer but with a fewer number of repeating units throughout its structure.
Hence, these two materials mainly differ from each other depending on the number of monomers that undergo the formation process. Besides, a difference between oligomer and polymer can be identified based on their properties. In comparison to oligomers, polymers have higher molecular masses and densities.
If the number of monomers is two, it forms a dimer; three monomers form a trimer, four monomers form a tetramer, etc. Therefore, the oligomers can be named accordingly. There are two major forms of oligomers.
Namely, they are the homo-oligomers and heterooligomers. Homo-oligomers form when monomers of the same type undergo oligomerization while heterooligomers form when monomers of different types undergo oligomerization. As for similarities, oligomer and
polymer form from monomers. Therefore, both are polymeric structures. Besides, both are based on chemical bonds between the monomers.
The combination of precise oligomers and catalytically active molecular species is an effective way to improve catalyst activity and selectivity. As catalytic processes are arranged mostly by the orientation of catalyst ansubstrate, control over the nano-environment provided by discrete oligomers is quite useful for enhancing catalyst performance.
Application
Many oils, such as liquid paraffin, are oligomeric. Plasticizers are oligomeric esters typically 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.
Molecular recognition of oligomers is still a research focus with significant inspiration from biological systems such as oligosaccharides. The elucidation and optimization of molecular recognition is a challenging endeavor, and the accumulated knowledge from saccharide and peptide-based recognition and related methods will be quite valuable.
Apart from the recognition of abiotic oligomers with biological systems, the role in small molecule substrate binding to effect catalytic reactions with exquisite selectivity is an opportunity that has tremendous potential.
The significant effect that oligomer structure and sequence can have on catalytic properties have been shown in recent studies and it is expected that more complex reactions and multi-functional oligomer designs will be developed in the future.
Sequence defined oligomers are also anticipated to be valuable in the information storage, which requires well-defined oligomers to correlate molecular structure with the storage of information at ultra-high densities.
As long as they are properly chosen, oligomers provide improved performance in a wide range of applications, such as adhesion, chemical resistance, substrate wetting and weathering.
Sources:
https://onlinelibrary.wiley.com/doi/10.1002/pol.20200862
https://www.differencebetween.com/difference-between-oligomer-and-polymer/
