It is possible that the hydrophobic guest within amphiphilic polymer micelles may leak out and be captured by other species before polymer micelles adhere to the desired focus because of the complexity in an actual release procedure, rendering the reduced efficiency of the nanocarrier system. To describe such a scenario, two water-soluble fluorescent amphiphilic random copolymers of PAV and PAA with photo-cross-linkable coumarin and anthracene pendants, respectively, were chosen to investigate the equilibrating immigration and maleimide-anthracene-based Diels–Alder-trapping of hydrophobic octylmaleimide guest from one type of photo-cross-linked polymer micelles of PAV85% to another of PAA66% in aqueous solution using the emission and absorption spectra techniques.