Phase Behavior of Poloxamer 188 Aqueous Solutions at Subzero Temperatures: A Neutron and X-ray Scattering Study

Published

February 11, 2021

Author(s)

Xiaoda Yuan, Susan T. Krueger, Michael Sztucki, Ronald L. Jones, Joseph E. Curtis, Evgenyi Shalaev

Abstract

Phase transitions of poloxamer P 188 aqueous solutions during cooling and heating are investigated using small angle neutron scattering (SANS) and small- and wide-angle X-ray scattering (SAXS and WAXS). It is shown that P 188 solution (10 % (w/w)) undergoes the following sequence of the phase transitions during cooling from 25 to -150 °C: micelle solution, solution of monomers, two-phase mixture of cubic mesophase + ice, and finally crystalline P 188 + ice. Formation of the cubic phase during freezing is likely to be triggered by water freezing to ice and corresponding freeze-concentration of the remaining solution. Cubic-to-crystalline P 188 transformation is a relatively slow process, which takes place on minutes and hours timescale. During heating of the frozen solutions, the sequence of the phase transitions is reversed: crystalline P 188 + ice, mesophase + ice, monomer solution + ice, monomer solution, and finally micelle solution. Similar phase transitions are detected for dilute solutions of P 188 (1 % (w/w)) except that micelle formation is not observed at 25 °C, consistent with literature reported critical micelle concentration (CMC) at this temperature.

Citation

Journal of Physical Chemistry B

Volume

125

Issue

5

Pub Type

Journals

Keywords

P 188, poloxomer, phase transition, sub-zero temperature, small-angle neutron scattering, small-angle x-ray scattering, wide-angle x-ray scattering

Citation

Yuan, X. , Krueger, S. , Sztucki, M. , Jones, R. , Curtis, J. and Shalaev, E. (2021), Phase Behavior of Poloxamer 188 Aqueous Solutions at Subzero Temperatures: A Neutron and X-ray Scattering Study, Journal of Physical Chemistry B (Accessed December 21, 2024)