Solvation Effects on Self-Association and Segregation Processes in tert-Butanol-Aprotic Solvent Binary Mixtures

The present study reveals that the fully miscible binary mixtures consisting of tert-butanol with aprotic solvents form well-defined ordered supermolecular structures, which have been characterized on different length scales. Three different types of microstructures have been determined. They are separated by distinct crossovers that appear as a function of the dilution rate, going from "correlated clusters" to "diluted clusters" and "diluted monomer" microstructures. These observations have been made possible by the combination of Raman vibration spectroscopy, H-1 NMR, and neutron diffraction that probe, respectively, the cluster formation (self-association) and the intercluster correlations (cluster segregation). The solvation effects on both the cluster formation and the intercluster correlations have been assessed by tuning the alcohol-solvent interaction, i.e., changing the chemical nature of the diluting solvent from a purely inert alkane to a weakly interacting aromatic system.