Interactions between Poloxamers in Aqueous Solutions:  Micellization and Gelation Studied by Differential Scanning Calorimetry, Small Angle X-ray Scattering, and Rheology

Abstract

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.

What can isothermal titration microcalorimetry experiments tell us about the self‐organization of surfactants into micelles?

“…The self-organization of surfactants into micelles is a widely studied phenomenon and many techniques have been used to explore this process, including surface tension measurements (Zhang et al, 2008), Fourier transformed infrared spectroscopy (Su et al, 2002), 1 H-NMR relaxation studies (Cau and Lacelle, 1996;Ma et al, 2007), dynamic light scattering, fluorescence spectroscopy (Jiang et al, 2008), and differential scanning calorimetry experiments in which the enthalpy change related to the micellization process can be calculated from the integration of the heat capacity versus temperature (Alexandridis and Hatton, 1995a;Artzner et al, 2007).…”

Monitoring the aggregation behaviour of self-assembling polymers through high-resolution ultrasonic spectroscopy

“…In previous studies, the aggregation and the structural characteristics of micelles were investigated with the aid of different techniques, such as static and dynamic light scattering (DLS), small angle neutron scattering (SANS) (Mortensen, 1996;Artzner et al, 2007), transmission electron microscopy, laser doppler anemometry (Govender et al, 2001) and 1 H nuclear magnetic resonance (NMR) (Hagan et al, 1996). While all these techniques are necessary for deeper understanding of the systems, they are quite complex and required highly specialized researchers and dedicated instruments.…”

“…While all these techniques are necessary for deeper understanding of the systems, they are quite complex and required highly specialized researchers and dedicated instruments. For more general characterization of the basic behaviour of systems, for example, to determine the CMC and the CMT, researchers use more common and widespread methodologies such as spectroscopy techniques (Alexandridis et al, 1994;Alexandridis and Hatton, 1995;Gaisford et al, 1998), light scattering (Yoshida, 2003;Sharma et al, 2007), surface tension (Rodriguez et al, 2007;Sharma et al, 2007) and in particular, differential scanning calorimetry (DSC) (Alexandridis et al, 1994;Wanka et al, 1994;Paterson et al, 1997;Artzner et al, 2007;Trong et al, 2008).…”

In vitro prolonged gastric residence and sustained release of atenolol using novel clay polymer nanocomposite

“…1d), suitable for oral administration, widely used as wetting and solubilizing agent was employed in the present work as stabilizing agent (Kabanov et al, 2002;Adams et al, 2003;Artzner et al, 2007;Zhao et al, 2012;Seema and Datta, 2014).…”