Planar structure spontaneously formed by amphipathic lipids in a polar (aqueous) environment.
Note: Formation of a lipid bilayer is driven by the interaction of the polar heads of lipids with water molecules while minimizing the exposure of the hydrophobic parts of lipids to water. Lipid bilayers represent the basic structure of biological membranes.
Source:
PAC, 2018, 90, 1121. 'Terminology of bioanalytical methods (IUPAC Recommendations 2018)' on page 1179 (https://doi.org/10.1515/pac-2016-1120)