Aggregation behavior of tri(trimethylsiloxy)silyl-propylpyridinnium chloride in non-aqueous solution

The effect of solvent (N,N-dimethylformamide, dimethyl sulfoxide, and 1,4-dioxane) on the micellization of tri(trimethylsiloxy)silylpropylpyridinnium chloride (Si4PyrCl) in aqueous solution were investigated by surface tension, electrical conductivity, dynamic light scattering (DLS), and 1H NMR. The solvents can obviously affect the aggregation behavior of Si4PyrCl. However, Si4PyrCl has excellent surface activity (20–22 mN m−1) in all investigated solvents-water solutions. At lower concentration of solvents, Si4PyrCl has lower CMC values compared with in pure water solution. The self-aggregation of Si4PyrCl is restricted (higher CMC values) by increasing the solvents concentration. The CMC values of Si4PyrCl increase with decreasing in solvophobic parameters (DMSO > DMF > DO) of the solvents attributed to the solvophobic effect which was confirmed by 1H NMR. DLS results show the size of the Si4PyrCl aggregates at 10% organic solvent mixed solution increase owing to the swelling of aggregates by the incorporation of solvent molecules into the aggregates.