Temperature-dependent adsorption of surfactant molecules and associated crystallization kinetics of noncentrosymmetric Fe(IO3)3 nanorods in microemulsions

• Crystallization of Fe(IO3)3 in microemulsions probed by hyper-Rayleigh scattering.
• A faster growth and a better shape control of nanorods are obtained at 80 °C.
• Different persistent cell deformations are related to the crystallization kinetics.
• A temperature-dependent adsorption of surfactants on nanorods is suggested.

Aggregation-induced crystallization of iron iodate nanorods within organic–inorganic aggregates of primary amorphous precursors is probed by time-dependent hyper-Rayleigh scattering measurements in Triton X-100 based-microemulsions. In the context of a growing interest of noncentrosymmetric oxide nanomaterials in multi-photon bioimaging, we demonstrate by a combination of X-ray diffraction and electron microscopy that an increase in the synthesis of temperature results in faster crystallization kinetics and in a better shape-control of the final Fe(IO3)3 nanorods. For initial microemulsions of fixed composition, room-temperature synthesis leads to bundles of 1–3 μm long nanorods, whereas shorter individual nanorods are obtained when the temperature is increased. Results are interpreted in terms of kinetically unfavorable mesoscale transformations due to the strong binding interactions with Triton molecules. The interplay between the nanorod crystallization kinetics and their corresponding unit cell deformation, evidenced by lattice parameter refinements, is attributed to a temperature-dependent adsorption of surfactants molecules at the organic–inorganic interface.

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