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

Abstract

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 E40B8, EgoB8 and diblock copolymers. Here E represents an oxyethylene, -[CH2CH20]- unit while B an oxybutylene, 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, 1) 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, 1) were responsive to nonspheroidal shape of aggregates and become more elongated with increasing the E-block length