Switching of macroscopic molecular recognition selectivity using a mixed solvent system.

The formation of macroscopic assemblies based on molecular recognition is promising in a wide variety of fields of materials science. Switching of the selectivity of macroscopic assemblies is of increasing importance to produce highly functional materials. Here we show macroscopic assembly based on molecular recognition using polyacrylamide gel modified with pyrenyl (Py) moiety (Py-gel) and gels possessing CD moieties (αCD-gel, βCD-gel and γCD-gel) in a mixed solvent of water and dimethyl sulfoxide. Changing the composition of the mixed solvent can switch the selectivity of Py-gel, because the fractions of the monomer and dimer of the Py moieties on the gel surface depend on the mixed solvent composition. The monomer and dimer of the Py moieties prefer βCD and γCD moieties, respectively.