From NSDL Materials Digital Library Wiki
Amphiphiles are molecules that consist of both hydrophilic and hydrophobic or lyophilic groups chemically bonded together. These hydrophobic/hydrophilic interactions drive solutions of surfactants to phase separate when in water or oil. For example, when placed in water, the hydrophilic groups will wish to maximize contact with the water molecules, rather than aggregate, where as the water-hating groups will try to minimize their contact with the water and will aggregate [1,2]. Amphiphile is a general term describing molecules that are formed by bonding two or more immiscible blocks together. Surfactants and Block copolymers are two examples of amphiphilic molecules.