Effect of n-Hexanol and n-Hexylamine on the Micellar Solutions of Pluronic F127 and P123 in Water and 1M NaCl

Abstract

The micelles from aqueous solution of two ethylene oxide(EO)-propylene oxide(PO) triblock copolymers, Pluronic P123 [(EO)₂₀(PO)₆₉(EO)₂₀] and F127 [(EO)₉₉(PO)₆₉(EO)₉₉], with identical PPO but different PEO in the presence of n-hexylamine and n-hexanol were examined using viscosity and dynamic light scattering (DLS) measurements. Micelles of more hydrophilic F127 did not show any noticeable growth or transition in the presence of n-hexylamine in water or in 1 M NaCl solutions, while those of P123 showed significant growth after a certain hexylamine concentration, with the effect being more pronounced in salt solutions. Similar behavior was observed in the presence of n-hexanol, which showed greater effect in comparison to n-hexylamine. The effect of n-hexylamine on F127 has been examined using small-angle neutron scattering (SANS) method also, which showed good agreement with viscosity and DLS results. n-Hexylamine and n-hexanol affect the micellar environment in different ways as per their individual solubility rankings.

Keywords:

• Micelles
• scattering
• solubility

Acknowledgments

P. B. thanks UGC, New Delhi [(F31-145/2005) SR] for financial support.

Notes

R_HS = hard sphere radius (nm), R_c = core radius (nm), N_agg = aggregation number.