- Investigating the effect of small aromatic compounds on the sphere-to-rod transition in block copolymer micelles. M Sharp, SW Prescott, SM King and T Cosgrove. American Conference on Neutron Scattering, Ottawa, Canada, June 2010.
Small aromatic compounds are strongly solubilised by Pluronic block copolymers, which are triblock copolymers comprising ethylene oxide (EO) and propylene oxide (PO) in the form (EO)n-(PO)m-(EO)n and are soluble in aqueous solution. Such aromatic compounds are used in the pharmaceutical industry to aid drug delivery. It is therefore important to gain a better understanding of the changes that occur upon the addition of such compounds to the micellar solutions of Pluronics, which are of interest as potential drug delivery vehicles. While a significant amount of work ahs been done using both X-ray and neutron scattering on this type of system, the focus has been on the ternary systems at 25°C only. However, due to their potential use in the pharmaceutical industry, it is important to also investigate the effect of raising the temperature of the micellar solutions from room temperature to body temperature. While the effect of several aromatic compounds and Pluronics has been investigated, the focus of this presentation shall be on the effect that benzyl alcohol has on Pluronic P105. A combination of diffusion NMR, small-angle neutron scattering, ultra-small-angle neutron scattering and small-angle neutron scattering under shear was used to obtain information about the structure and dynamics of the micelles. While detailed structural information could be obtained from the static SANS measurements, the shear-SANS measurements allow us to show unambiguously that the micelles undergo a transition from spherical to rod-like micelles as the temperature and benzyl alcohol concentration are increased, as well as allowing the structural properties of the rod-like micelles to be determined.
Last edited: Friday September 10, 2010
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