Tuning the Properties of Polyether Alkyl Urea Derivatives as Rheology Modifiers in Cosmetic Solvents

Polyether alkyl urea derivatives were synthesized, and their properties as gelators in solvents commonly used in cosmetic formulations such as Labrafac cc, isopropyl myristate, and isododecane were investigated. A solvent-free larger-scale (up to 70 g) hydrophobic functionalization of the polyetheramines was carried out by one-step reaction with alkyl or aryl-containing isocyanates, which resulted in the formation of urea-functionalized polyethers. Systematic structural studies were conducted by varying the nature and molecular weight of the polyether backbone and the length of the linker and the side chain. The gels obtained have an appearance varying from opaque to transparent, and their properties were characterized by rheological measurements and small-angle X-ray scattering (SAXS) studies. Rheological analysis indicated the dependence of the gel properties on the hydrophobicity of the alkyl end groups and the type of polyether backbone. SAXS measurements revealed a topological description of the network structures of these materials wherein the gels obtained in Labrafac cc form defined structures from the fiber bundles, while those in isopropyl myristate produce clusters. The results obtained in this study offer potential applications in perfume and cosmetic formulations.