ABSTRACT

The driving force of hydrophobic attraction between (especially) low-polarity molecules or particles, immersed in water, is not a mystery: it is simply the hydrogenbonding (Lewis AB) free energy of cohesion of the water molecules that surround these molecules or particles, see Table IV-2. A synonym for “hydrophobic attraction” is “The Hydrophobic Effect,” although the “hydrophobic” part remains a misnomer (see Chapter XVIII). The expression: “hydrophobic effect” sounds more impressive and also more mysterious than “hydrophobic attraction,” but it is the same thing and it is really solely caused by Lewis acid-base force-induced (which in the case of water, means hydrogen-bond-driven) cohesion between the water molecules. A similar polar cohesion of liquid molecules also occurs in other dipolar liquids, such as glycerol, formamide, ethylene glycol, etc., but the free energy of polar cohesion in these non-aqueous dipolar liquids is much weaker than the polar cohesion of water. In such non-aqueous dipolar organic liquids the interaction is not called “hydrophobic” but, equally unfelicitously, “solvophobic.”