How does phospholipid react in water?

Phospholipids are amphipathic molecules with a hydrophobic tail and hydrophilic head. In water, phospholipids spontaneously form lipid bilayers due to their amphipathic nature, with the hydrophobic tails facing inward and hydrophilic heads facing outward towards the water. This forms the basic structure of cell membranes, which separate the internal and external environments of cells.