Strong forces between hydrophilic macromolecules: Implications in biological systems

The concept of hydrophilic (HφI) interaction between small HφI molecules or groups is extended to large molecules containing such groups. The Gibbs energy change associated with pairs, triplets, and quadruplets HφI interactions is estimated. The corresponding forces derived from these interactions are shown to be stronger and of longer range compared with the HφI forces between two HφI groups. Some implications of these forces and interactions in biological systems are outlined.