Self-Assembly of Gels through Molecular Recognition of Cyclodextrins: Shape Selectivity for Linear and Cyclic Guest Molecules

The molecular recognition of cyclodextrin (CD) for linear and cyclic guest moieties attached to the gels, which led to the specific assembly of gels were investigated. The α-CD-gel bound a gel containing linear alkyl groups to give an association, although β-CD-gel did not bind a cyclic alkyl-gel at all. The mechanical strength of the assembled gel could be regulated by the mole content of guest moiety in the guest gels. The water-soluble guest polymers bearing guest moieties were prepared by copolymerization of acrylamide and alkyl acrylate or alkyl-acrylamide by a radical polymerization using 2,2'-azobis(isobutyronitrile) (AIBN) in dimethyl sulfoxide (DMSO) at 60°C. The mechanical properties of gel-assemblies were measured by the mechanical tension testing system. The interaction between β-CD-gel and cyclohexyl(ester)-gel was found to be controllable by the addition of a soluble competitive host (β-CD) or guest.