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Natural eutectic systems as emerging green multifunctional ingredients: A sensory-related perspective

Year: 2025

Type: article

Abstract: Natural Deep Eutectic Solvents (NaDES) are emerging as sustainable alternatives to conventional solvents, with increasing relevance in soft matter applications such as cosmetics. In this study, eleven NaDES were compared to standard cosmetic ingredients to evaluate their sensory-related potential. Surface tension, viscosity, rub-out friction, spreadability, stickiness, and gloss were assessed as instrumental proxies for key sensory attributes. These properties help predict user perception and guide their application as cosmetic ingredients. Surface tension values ranged from 48 to 70 mN/m for hydrophilic NaDES, while lipophilic systems exhibited values close to those of natural oils (27.8 ± 1.5 mN/m). Viscosity profiles revealed strong differentiation: BetGly and UreaGly displayed intermediate viscosities (500–900 mPa·s), similar to glycerin, whereas CitrAcidGlu exhibited high viscosity (5740.3 ± 167.2 mPa·s), coupled with pronounced stickiness (1.12 ± 0.03 g· sec ) and spreading resistance (15.1 ± 0.0 mm 2 /μL/min)—suggesting potential use in adhesive or film-forming formulations like hair care products. Most lipophilic NaDES showed low viscosity (<250 mPa·s) and minimal tack (0.058–0.089 g· sec ), closely resembling emollient esters and oils. Gloss performance highlighted compounds such as ProGlyGlu, BetGly, MentOcta, and C12Ment as analogues to commonly used emollients, like DUB CO (16.5 ± 2.1 AU), while other lipophilic NaDES and BetGlyGlu (hydrophilic) mimic dimethicone (6.5 ± 0.26 AU). Principal Component Analysis (PCA) revealed two distinct sensory-related clusters: hydrophilic NaDES aligned with humectants such as glycerin, while lipophilic NaDES grouped with emollients like jojoba oil. These results highlight the multifunctionality and tunability of NaDES for interfacial design in soft materials.

Source: Journal of Molecular Liquids

DOI: 10.1016/j.molliq.2025.128277