Britannica
Sources used in this answer
How are polymers different from ordinary small molecules?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
polymer
Industrial polymers are synthesized from simple compounds joined together to form long chains. For example, polyvinyl chloride is an industrial homopolymer synthesized from repeating units of vinyl chloride.
Polymers are distinguished from ordinary small molecules primarily by their immense size and the resulting physical properties. While a typical small molecule, such as water, has a low molecular weight, polymers—often called macromolecules—possess average molecular weights ranging from tens of thousands to several million atomic mass units.12
Key differences include:
- Composition: Polymers are formed by the chemical linkage of many smaller units called monomers. A single polymer molecule may incorporate thousands of these units, whereas small molecules consist of a fixed, limited number of atoms.132
- Physical Properties: The vast size of polymers leads to unique characteristics not found in small molecules, such as elasticity, high tensile strength, and the ability to form fibres.1
- Intermolecular Forces: While all molecules experience electrostatic forces, these forces are significantly stronger in polymers due to their large size. These strong interactions allow polymers to be molded into permanent shapes (as in plastics) or drawn into fibres.2
- Structural Complexity: Polymers can exhibit complex architectures, including linear, branched, and network structures, which dictate their behavior, such as whether they are thermoplastic or thermosetting.145