multimolecular

Multimolecular is an adjective used in chemistry and related fields to describe assemblies, processes, or species that involve or consist of many molecules. In colloid and surface science, the term is often applied to aggregates formed by the association of multiple molecules, as opposed to unimolecular systems in which a single molecule adopts the relevant structure.

Common examples include multimolecular micelles, in which surfactant molecules self-assemble into a spherical or ellipsoidal aggregate with a hydrophobic core and a hydrophilic shell. These assemblies are dynamic, exchanging molecules with the surrounding solution, and typically exist above the critical micelle concentration. Multimolecular layers can also form at interfaces when several molecules adsorb to a surface, producing adsorption layers that are thicker or more complex than those created by a single molecule.

The concept is distinct from unimolecular micelles, where a single macromolecule folds or organizes into a micelle-like structure without the need for multiple molecules to come together. Multimolecular assemblies are widespread in natural and industrial contexts, contributing to processes such as emulsification, stabilization of suspensions, and substance transport.

In applications, multimolecular assemblies are used for drug encapsulation, catalysis, and controlled release, with properties governed by composition, concentration, temperature, and solvent. Their behavior is often studied under dynamic conditions, reflecting exchange of constituent molecules with the surrounding environment.

Analytical techniques used to study multimolecular systems include dynamic and static light scattering, small-angle X-ray or neutron scattering, cryo-electron microscopy, and nuclear magnetic resonance, which help characterize size, morphology, and molecular exchange dynamics.