The hydrophobic effect is the common expression for processes where no
npolar groups in molecules are spontaneously removed from water. Therm
odynamic analysis of hydrocarbon solubility in water, micellization an
d adsorption of surfactants show that the hydrophobic effect can be un
derstood in terms of two contributions. The first contribution is attr
ibuted to the structuring, or rearrangement, of water molecules in the
vicinity of a hydrophobe. This contribution is favorable, and hence i
ncreases the solubility of hydrocarbons in water, increases the cmc, a
nd decreases the adsorption of surfactants. The second contribution is
attributed to the formation of a cavity in the water in order to acco
modate the hydrophobe. This contribution dominates over the first one
and is unfavorable, i.e. it decreases the solubility of hydrocarbons i
n water, decreases the cmc, and increases the adsorption of surfactant
s. Thus, the cause of the hydrophobic effect is to be found in the lar
ge energy required to form a cavity in the water. On the other hand th
e temperature dependence of the hydrophobic effect is entirely determi
ned by the water structuring, or rearrangement, in the vicinity of a h
ydrophobe.