Hydrophobic effect

The hydrophobic effect is the observed tendency of nonpolar substances to aggregate in an aqueous solution and to be excluded by water.

Detergents are composed of amphiphiles that allow hydrophobic molecules to be solubilized in water by forming micelles and bilayers (as in soap bubbles).

Some argue that the hydrophobic interaction is mostly an entropic effect originating from the disruption of highly dynamic hydrogen bonds between molecules of liquid water by the nonpolar solute.

[16] A hydrocarbon chain or a similar nonpolar region of a large molecule is incapable of forming hydrogen bonds with water.

Generally, this leads to significant losses in translational and rotational entropy of water molecules and makes the process unfavorable in terms of the free energy in the system.

The partition coefficients can be transformed to free energy of transfer which includes enthalpic and entropic components, ΔG = ΔH - TΔS.

The hydrophobic effect was found to be entropy-driven at room temperature because of the reduced mobility of water molecules in the solvation shell of the non-polar solute; however, the enthalpic component of transfer energy was found to be favorable, meaning it strengthened water-water hydrogen bonds in the solvation shell due to the reduced mobility of water molecules.

A droplet of water forms a spherical shape, minimizing contact with the hydrophobic leaf.
Cocoa powder, an example of a "hydrophobic substance".
Dynamic hydrogen bonds between molecules of liquid water, the shape of the molecules is sometimes compared to that of boomerangs.