Eluent gel permeation chromatography : a new method for study of the micellisation of block copolymers in solution

A new method is described for the study of micellar solutions of block copolymers by gel permeation chromatography. Results are presented for the micellisation of a poly(oxyethylene/oxypropylene/oxyethylene) triblock copolymer (Synperonic F87) in aqueous solution and compared with those obtained by a conventional light scattering method. The characteristic feature of Eluent GPC is the use of the block copolymer solution as the eluent instead of simply the pure solvent. The equilibrium behaviour of the eluent solution is probed by injecting an additional small volume of copolymer solution into the system. Measurements showed that changes in concentration of the injected probe solution did not affect the relative areas of the micelle and molecule (unassociated chain) peaks. The areas of the peaks were essentially governed by the equilibrium within the eluent solution and provided a direct measure of the weight concentrations of the micelles and molecules in the eluent.