The hydrophobic effect is the solvent-mediated tendency of nonpolar regions to associate in water. Exposing a hydrocarbon region changes how surrounding water molecules can arrange and interact; reducing that exposure can lower the total free energy. Both water and lipids enter the accounting. The effect is not an additional covalent bond between chains. See IUPAC Gold Book: hydrophobic interaction.
At fixed temperature and pressure, compare two candidate organizations by the change in Gibbs free energy, , where is enthalpy, is absolute temperature, and is entropy. An organization with lower is favored in this comparison. Reducing exposed hydrocarbon area is one contribution; changes in chain packing and the entropy of the lipids also matter. This explains why hydrophobicity alone cannot predict every aggregate shape. See 16.4 Free Energy.
Articles by others on the same topic
The hydrophobic effect is a phenomenon in which nonpolar substances aggregate in aqueous solutions, minimizing their exposure to water. This effect is a key principle in biology, particularly in the folding of proteins and the formation of cellular membranes. ### Key Points: 1. **Nonpolar vs. Polar Molecules**: Water is a polar solvent, meaning it has a partial positive charge on one end and a partial negative charge on the other.