Effect of TiO₂ nanoparticles on the assembly of a copolymer-clay dispersion

Nanocomposites based on copolymer and clay minerals are attracting increasing attention as they are appropriate for extensive applications. In this work, we present results from an experimental study on the effects of TiO₂ nanoparticles on a pluronic-F127/laponite water solution in the sol state. Differential Scanning Calorimetry (DSC), Dynamic Light Scattering (DLS) and Fourier Transform Infrared Attenuated Total Reflection Spectroscopy (FTIR-ATR) were used to characterize the systems. By DSC and DLS measurements the occurrence of micellization was first investigated. The temperature induced self-assembly was then studied by DLS identifying three relaxations associated to differently sized diffusing structures. The correlation between dynamics and bonding structure was thoroughly investigated by analyzing some specific infrared vibrational bands. In particular, the study of the characteristic absorption band of the ether groups in the dry state allowed to evaluate the amorphous/crystalline component evidencing the presence of more extended conformations in presence of the higher TiO₂. Finally, the analysis of the bending mode for the residual water provided valuable insight about structural OH groups enabling a distinction between different types of water molecules associated to the copolymer/nanoparticle systems.