In the case of the OA-Gly-OH copolymer aqueous solution, the emission spectra of pyrene revealed a concentration-dependent change in the I₁/I₃ ratio. Plotting the I₁/I₃ ratio against surfactant concentration yielded CAC values of 47 mM for OA-Gly-OH, 6 mM for OA-Phe-OH, and 15 mM for OA-Thr-OH. These results demonstrate the effect of the amino acid structure to the self-assembly behaviors. . The results indicate that the CAC dramatically decreases with the increase of the self-assembly propensity of the amino acids.