Tailoring the structure of hybrid organic inorganic nanomaterials built on tetra- and polyfunctional alco-oxo-titanium clusters in polystyrene

Functional titanium oxo-clusters Ti₁₆O₁₆(OEt)_32-x(OPhCH=CH₂)_x with different numbers of styrenic groups, where x = 4 (tetra) and x = 16 (poly), have been synthesized and copolymerized with styrene. The resulting hybrid nanomaterials present three-dimensional networks in which the inorganic nano-fillers are covalently linked to the inorganic polymer. The influence of the number of functional groups borne by the oxo clusters on the structure of the resulting hybrid nanomaterials has been investigated by a combination of small-angle X-ray scattering, transmission electron microscopy and energy-filtering transmission electron microscopy. Compared with the tetra-functional clusters, the poly-functional clusters were better dispersed in the hybrid phase even at very high cluster content (between 5 and 10 wt%). Independently of the number of functional groups, three structural levels (i.e. largest, intermediate and primary clusters) have been revealed. The size of the aggregates has been found to be reduced by increasing the number of styrenic reactive groups.