Dilute solution properties of poly(α-methylstyrene) in cyclohexane

The lack of details regarding PαMS in poor solvents and the scarcity of information for the transport properties [η] and D_z (except for PS) for chains below theta lead us to study the hydrodynamic behavior of PαMS in the subtheta regime. The initial goals of this work were to: a) evaluate the behavior of [η] and D_z and their associated interrelationships and b) to compare the subtheta collapse of PαMS with PS. Although our measurements do not extend to the globule conformation, owing to the lack of sufficiently high molecular weight samples, the results indicate, outside experimental error, that the collapse of PαMS in cyclohexane is considerably different from that for PS in the same solvent. These results thus indicate that the chemical structure of the chain influences the collapse transition - a result also observed for the variation of draining in good solvents. An implication of the work reported here is that ternary interactions are apparently different for chemically dissimilar chains.