shear stress up to a shear rate of 200 s(-1), but they are easily fragmented by the addition of a neutral surfactant.The association behavior of random copolymers of sodium 2-(acrylamido)-2-methylpropanesulfonate (AMPS) and cholesteryl 6-methacryloyloxyhexanoate (Chol-C-5-MA) in 0.1 M NaCl aqueous solutions was investigated by quasielastic light scattering and fluorescence techniques to gain further insights into the structures and properties of their "intermolecularly bridged flower-type micelles" which we had proposed previously. When the Chol-C5-MA content in the copolymer was as low as 1 mol %, unimers were found to coexist with the interpolymer aggregates independent of the polymer concentration (Cp) in a range 0.1 < Cp < 10 g/L. However, when the Chol-C5-MA content was increased to 5 mol %, virtually all the polymer chains form multipolymer aggregates which can be viewed as an assembly of flower-type micelles where polymer chains are "cross-linked" via Chol associations. The aggregation number of Chol moieties was estimated to be 17-19 for the copolymer of 5 mol % Chol-C-5-MA by a time-resolved fluorescence quenching method. Taken together with our previous results, it is concluded that each intermolecularly bridged flower-type micelle (mass similar to 1.9 x 10(6), hydrodynamic radius similar to 50 nm) formed from the copolymer of 5 mol % Chol-C5-MA is composed of 50 polymer chains in which 175 Chol groups constitute about 10 microdomains (i.e., cross-linking sites), each microdomain consisting of 17-19 Chol groups. The hydrophobic cross-links are stable enough not to be disrupted by applying.