Interactions between poloxamers in aqueous solutions: micellization and gelation studied by differential scanning calorimetry, small angle X-ray scattering, and rheology.
Poloxamers F88 (EO97PO39EO97) and P85 (EO27PO39EO27) are triblock copolymers of ethylene oxide (EO) and propylene oxide (PO), which have the same hydrophobic PO block. We studied aqueous solutions of these two copolymers by the conjoint use of differential scanning calorimetry (DSC), rheology, and small-angle X-ray scattering (SAXS). The results showed that the temperature-induced micellization of aqueous solutions of F88 and P85 was a progressive process followed by gelation for sufficiently concentrated samples. Gelation was due to the ordered packing of micelles under a hexagonal compact (HC) structure for P85 and a body-centered cubic (BCC) phase for F88. Importantly, the phase diagram of F88/P85 mixtures in water was elucidated and showed the destabilization of the HC phase upon addition of small amounts of F88.
Artzner
Franck
F
UMR CNRS 8612, Univ Paris-Sud, Faculté de Pharmacie, 5 rue JB Clément, 92296 Châtenay-Malabry Cedex, France.
Geiger
Sandrine
S
Olivier
Audrey
A
Allais
Cécile
C
Finet
Stéphanie
S
Agnely
Florence
F
D002152:Calorimetry, Differential Scanning / Q000379:methods; D005782:Gels / Q000737:chemistry; D008823:Micelles; D020442:Poloxamer / Q000737:chemistry*; D012212:Rheology; D053838:Scattering, Small Angle; D012680:Sensitivity and Specificity; D012996:Solutions / Q000737:chemistry; D013499:Surface Properties; D014867:Water / Q000737:chemistry; D014961:X-Ray Diffraction
D005782:Gels; D008823:Micelles; D012996:Solutions; D014867:Water; D020442:Poloxamer