Synthesis of nanoparticulate anatase and rutile crystallites at low temperatures in the Pluronic F127 microemulsion system

A low-temperature synthesis method for preparing nanosized TiO2crystallites has been developed based on a Pluronic F127 microemulsion system. Both anatase and rutile polymorphs can be prepared, and there exists a temperature window between 40 and 50 °C where the formation of rutile is favored over anatase. At 60 °C and above, anatase is kinetically favored and only very slowly transforms to rutile at 60 °C. The results differ from previous observations regarding formation kinetics and temperature range for rutile formation as well as in the microscopic aggregation of the formed nanoparticles. This development of a low-temperature synthesis of crystalline titania nanoparticles within the Pluronic block copolymer system is an important and enabling step toward devising a direct synthesis route for the formation of ordered mesoporous and crystalline titania.