Enthalpy penalty

The stability of block copolymer microphases results from a balance between the enthalpy penalty for curvature of the interface between microdomains, the entropy associated with localizing junctions between the blocks at the interface and the entropy associated with maintaining a uniform density, which leads to the stretching of chains to fill space. Again, considering AB diblock copolymers as the simplest case, in a... 

Surprisingly, the low solubility of small-sized particles does not stem from a weak interaction of particles with their surrounding water environment (77). For example, the heat of solvation of methane in water at ambient temperature is of similar magnitude as the heat of vaporization of pure liquid methane (80). The positive solvation free energy of small apolar particles at low temperatures is the consequence of negative solvation entropy, which overcompensates for the negative solvation enthalpy. It is widely believed that this entropy penalty is caused by the orientation order introduced to the hydration-shell water molecules as they try to maintain an intact hydrogen bond network (77). Parallel to the entropy decrease observed for low... 

In 1993 Blokzijl and Engberts published an important review article on hydrophobic effects. In 1992, Smith, Zhang and Haymet showed that hydrophobic association of uncharged solutes in water is almost entirely an entropy effect. Haymet went on to point out that experimental data show that methane likes water about as well as it likes any other solvent from the point of view of enthalpy. This view is underlined by the experimentally high solubility of water in cryogenic solvents such as liquid methane. Hydrophobicity in fact arises from the entropy penalty incurred by the water. The methane is not hydrophobic the water is methophobic . 

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