Amphiphile

In chemistry, an amphiphile (from Greek αμφις (amphis) 'both' and φιλíα (philia) 'love, friendship'), also referred to as an amphipath, is a dipolar chemical compound possessing both hydrophilic (water-loving, polar) and lipophilic (fat-loving, nonpolar) properties within the same molecule. Such compound is called amphiphilic or amphipathic. This dipolar characteristic implies the existence of different chemical groups forming spatially segregated regions with contrasting surface polarity. Amphiphilic compounds include surfactants, detergents, block copolymers, and Janus particles. In aqueous solutions, amphiphiles are able to self-assemble to form a wide range of supramolecular structures, including micelles, lamellae, nanofibers, and biological membranes. Phospholipid amphiphiles constitute a significant class of biological amphiphiles composed of a polar-phosphate based head group and two hydrophobic fatty acid chains. Phospholipid bilayers are the major structural component of cell membranes, and serve as the basis for a number of research areas including chemistry and biochemistry, notably that of lipid polymorphism. Organic compounds containing hydrophilic groups at both ends of the molecule are called bolaamphiphiles. They are distinguished from the conventional head-tail amphiphiles by the prolate geometry of the micelles they form in aggregation.