Supramolecular chemistry is finding a lot of uses in the field of self-assembly. But, say Gerardo Odriozola and Marcelo Lozada-Cassou of the Mexican Petroleum Institute, it's still explained using intuitive concepts such as molecular complementarity and recognition. The pair decided to use statistical mechanics to try and define the physical basis for the mechanism, comparing their findings with experimental data.

Odriozola and Lozada-Cassou say in their paper that while 'terms such as "molecular recognition and complementarity" in the SMC [supramolecular chemistry] field are intuitively appealing', they are probably misleading, as the concept of recognition usually involves memory and intelligence, which molecules don't have. Instead, say the pair, the solvent's role is key. As assembly occurs, there is an increase in the volume available to the solvent and that and entropic gain rules the interaction.