Aggregation of Pluronics in Ionic Liquids

Pluronics (PEOy-PPOx-PEOytriblock copolymers) self-assemble in water to form mainly micelles with several potential applications, such as the improvement of the aqueous solubility of drugs, chemical separations and nanoparticle synthesis Room temperature ionic liquids (RTILs) are alternative solvents with characteristic properties, such as non-flammability, low volatility, high thermal stability. RTILs can solubilise both hydrophilic and hydrophobic compounds and influence the aggregation properties of amphiphilic molecules. The aggregation of a series of Pluronics (P85, P105, L121) in some RTILs ([Bmim+] [BF4-], [Bmim+] [PF6-] and [Bmim+] [TF2N-]) has been investigated by using different techniques (UV-NIR spectroscopy, optical microscopy). The critical aggregation concentration (CAC) of the investigated Pluronics has been determined by UV-NIR [3]. The CAC increases in the RTILs in comparison to water, suggesting an higheraffinity of the polymers for the ionic liquids. The values of CAC depends on both the nature of the polymer (PEO/PPO ratio) and the permittivity () of the ionic liquid. Supramolecular structures have been observed by optical microscopy