Figure 1. Chemical structures of gels.

The figure shows the chemical structures of a host gel (α- and β-CD-gels), a guest gel (Azo-gel), and a host/guest coexisting gel (α-CD-co-Azo-gel). The molar ratios of the acrylamide, the host-modified or the guest-modified acrylamide, and the N,N′-methylenebis(acrylamide) are indicated as x, y, and z. Host gels with a mol% x/y/z of 93/5.0/2.0 were used. In this study, guest gels with different Azo group contents (y) were prepared. The character r in the main chain of the polymers indicates that each monomer was copolymerized randomly.