Innovative approach for stabilizing poly( ethylene oxide)-b-poly(propylene oxide)-b-poly( ethylene oxide) micelles by forming nano-sized networks in the micelle

Poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (F- 68) micelles were stabilized by UV-induced free-radical polymerisation of pentaerythritol tetraacrylate (PETA). The polymerisation resulted in the formation of an interpenetrating network of poly(PETA) and polyether chains, which was restricted only to specific nanodomains (nano-networks) within the micelles as shown by the TEM analysis. Depending on the experimental conditions stabilized polymeric micelles (SPMs) with spherical shape and sizes in the 32-50 nm range were obtained. SPMs stability in aqueous media at concentrations significantly lower than the critical micelle concentration (CMC) of free F-68 was demonstrated using dynamic light scattering and the diphenylhexatriene (DPH) solubilization technique. Furthermore, the stabilized F-68 micelles maintained their size and structure even when subjected to 20 kHz ultrasonic irradiation.