Effect of Organic Solvent on (EO)₇₈(PO)₃₀(EO)₇₈ F68 Tri-Block Copolymer: Viscosity and Dynamic Light Scattering Measurements

Abstract

The aggregation process of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) copolymer, (EO)₇₈(PO)₃₀(EO)₇₈ (Pluronic F68) in methanol and acetonitrile was characterized by using viscosity and dynamic light scattering measurements. For low concentrations (4 < C < 10 mg/mL), we assumed that we had a swelling of unimers when they came into contact with an organic solvent. Increasing this concentration to 10 < C < 20 mg/mL favored the association of the unimers into micelles. For $20<$ C $<$40 mg/mL, the hydrodynamic radii increased, suggested to be due to an aggregation process of the micelles with themselves. For 40 mg/mL, we assume that the association of compact micelles is completed. For higher concentrations (C $\ge$50 mg/mL), the increases in R_H for F68/methanol and for F68/acetonitrile were attributed to the large micelle formation.

Keywords:

• acetonitrile
• aggregation
• dynamic light scattering measurements
• methanol
• Pluronic F68
• viscosity

Additional information

Funding

We would like to thank Deanship of Scientific Research at Majmaah University for supporting this work under Project Number No R-2021-321.