title: Spreading properties of cosmetic emollients: Use of synthetic skin surface to elucidate structural effect.
abstract: The study focuses on the impact of structural and physicochemical properties of emollients on their spreadability. Fifty-three emollients, among which esters, silicones, vegetable and mineral oils, have been characterized. Their viscosity, surface tension, density and spreadability have been measured. Vitro-skin®, an artificial skin substitute, was used as an artificial porous substrate to measure spreadability. Two different methods have been selected to characterize spreadability, namely contact angle and spreading value. Dynamic contact angle measurements showed that emollient spreadability is first governed by spontaneous spreading and that, in a second phase, absorption and migration into the porous substrate becomes the driver of the extension of the spreading area. Statistical analysis of physicochemical and spreading value data revealed that viscosity has a major impact on the spreading behavior of emollients whatever their chemical type. A special emphasis was placed on the ester family in which chemical diversity is very wide. The results highlighted a difference between "high viscosity esters" for which viscosity is the main factor impacting spreadability and "low viscosity esters" for which structural variations (mono/diester, saturated/unsaturated chain, linear/branched chain) have to be considered in addition to viscosity. Linear regressions were used to express spreading value as a function of viscosity for each of the four emollient families tested (esters, silicones, vegetable and mineral oils). These regressions allowed the development of reliable predictive models as a powerful tool for formulators to forecast spreadability of emollients.
authors.affiliation: Normandie Univ., UNILEHAVRE, FR 3038 CNRS, URCOM, 76600 Le Havre, France.
authors.forename: Marine
authors.initials: M
authors.lastname: Douguet
authors.affiliation: Normandie Univ., UNILEHAVRE, FR 3038 CNRS, URCOM, 76600 Le Havre, France. Electronic address: celine.picard@univ-lehavre.fr.
authors.forename: Céline
authors.initials: C
authors.lastname: Picard
authors.affiliation: Normandie Univ., UNILEHAVRE, FR 3038 CNRS, URCOM, 76600 Le Havre, France.
authors.forename: Géraldine
authors.initials: G
authors.lastname: Savary
authors.affiliation: Stearinerie Dubois, 696 rue Yves Kermen, 92658 Boulogne-billancourt Cedex, France.
authors.forename: Fabien
authors.initials: F
authors.lastname: Merlaud
authors.affiliation: Stearinerie Dubois, 696 rue Yves Kermen, 92658 Boulogne-billancourt Cedex, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Loubat-Bouleuc
authors.affiliation: Normandie Univ., UNILEHAVRE, FR 3038 CNRS, URCOM, 76600 Le Havre, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Grisel
mesh_terms: D003358:Cosmetics / Q000737:chemistry*; D004548:Elasticity; D004643:Emollients / Q000737:chemistry*; D004952:Esters / Q000737:chemistry*; D006801:Humans; D008899:Mineral Oil / Q000737:chemistry*; D010938:Plant Oils / Q000737:chemistry*; D012828:Silicones / Q000737:chemistry*; D017768:Skin, Artificial; D013500:Surface Tension; D014783:Viscosity
chemical_list: D003358:Cosmetics; D004643:Emollients; D004952:Esters; D010938:Plant Oils; D012828:Silicones; D008899:Mineral Oil
keywords: Contact angle; Emollients; Esters; Spreadability; Surface tension; Viscosity