Effect of the Hydrophilic Block Length on the Micellar Properties of Oxyethylene-Oxybutylene Diblock Copolymers in Aqueous Solution: Density and Viscosity Studies

摘要

Density and viscosity measurements, over a wide range of concentration and temperature, were implied to investigate the effect of hydrophilic block length on the micellar properties of the aqueous solution of E_(40)B8, E_(80)B8 and E_(120)B8 diblock copolymers. Here E represents an oxyethylene, -[CH2CH2O]- unit while B an oxybutylene, -[CH(C2H5)CH2O]- unit and the subscripts denote the number-average block length. To calculate the intrinsic viscosities and solute- solvent interaction parameter viscosity measurements were made. Besides that the hydration value of micelle plus shape factor, v of aggregates were evaluated by combining the results of density and viscosity. The effects of varying E-block length and temperature on all calculated parameters were elucidated. Values calculated for shape factor, v were responsive to nonspheroidal shape of aggregates and become more elongated with increasing the E-block length.