Effect of emulsifiers on drying stress and intercellular cohesion in human stratum corneum / F. Ansari in INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Vol. 42, N° 6 (12/2020)  

[article]  inINTERNATIONAL JOURNAL OF COSMETIC SCIENCE > Vol. 42, N° 6 (12/2020) . - p. 581-589 Titre : Effect of emulsifiers on drying stress and intercellular cohesion in human stratum corneum Type de document : document électronique Auteurs : F. Ansari, Auteur ; C. McGuiness, Auteur ; B. Zhang, Auteur ; Reinhold H. Dauskardt, Auteur Année de publication : 2020 Article en page(s) : p. 581-589 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cohésion intercelullaire Cosmétiques -- Analyse Couche cornée Emulsifiants Formulation (Génie chimique) Peau -- Soins et hygiène Produits hydratants Séchage Index. décimale : 668.5 Parfums et cosmétiques Résumé : - Objectives : Emulsifier molecules, with their amphiphilic character, are ubiquitous in moisturizing creams and primarily serve to disperse the water-insoluble molecules such as emollients, oils, lipids and fats in water. The objective of this study was to investigate the effect of emulsifier molecules on the barrier and biomechanical properties of human stratum corneum (SC) and to compare the efficacy of emulsifier molecules when used in a fully formulated moisturizing cream. - Methods : We employed methods based on thin-film mechanics to measure the drying stress and intercellular cohesion in the SC. The emulsifier molecules or moisturizing creams formulated with them were applied to a fully hydrated SC adhered to a glass substrate. In-plane stress developed in the SC during drying was then measured by tracking changes in the curvature of the glass substrate. The intercellular cohesion within the SC was measured by means of a double cantilever beam (DCB) set-up, where the treated or untreated SC was sandwiched between two substrates, and the delamination energy calculated by measuring the force required to drive a crack through the SC. Moisturizing cream diffusivity through the stratum corneum was measured by spectroscopic technique and related to internal SC stress and fracture energy. - Results : We observe significant differences in the biomechanical behaviour of SC when moisturizing creams with different emulsifier molecules are applied on isolated stratum corneum ex vivo. The reduction in maximum stress varied between 12% and 26% depending on the emulsifier molecules used in the formulation. The intercellular cohesion and the diffusion of molecules in the formulated moisturizing creams through the SC were also found to be strongly dependent on the type of emulsifier molecule used in the formulation. - Conclusions : The biomechanical and barrier properties of the human stratum corneum show strong dependence on the emulsifier molecule used in the moisturizing creams, even when the creams included only ~3 weight% emulsifier molecules. Moreover, we found that the reduction in SC peak stress was strongly correlated with the formulation diffusivity into the SC. The moisturizing creams diffusing fastest into the SC had the largest reduction in peak stress and vice versa. Note de contenu : - MATERIALS AND METHODS : Formulated moisturizing creams - Tissue preparation - Drying stress measurement - SC cohésion - Diffusivity measurement - RESULTS AND DISCUSSION : Drying stress - Diffusion - SC cohesion - Table 1 : Important parameters of the moisturizing creams investigated in this study - Table 2 : Relevant physical properties of the emulsifier and emollient molecules used in this study DOI : https://doi.org/10.1111/ics.12643 En ligne : https://drive.google.com/file/d/1B7LGHeaNR4IpitcqVdB81A-RufWdxkVs/view?usp=shari [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35424 [article]

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Flow properties and morphology of PC/LCP blends affected by the addition of glass fiber and resulted mutual influences / X. Zheng in INTERNATIONAL POLYMER PROCESSING, Vol. XVIII, N° 1 (03/2003)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XVIII, N° 1 (03/2003) . - p. 3-11 Titre : Flow properties and morphology of PC/LCP blends affected by the addition of glass fiber and resulted mutual influences Type de document : texte imprimé Auteurs : X. Zheng, Auteur ; B. Zhang, Auteur ; J. Zhang, Auteur ; Y. Xue, Auteur ; J. He, Auteur Année de publication : 2003 Article en page(s) : p. 3-11 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : In-situ hybrid composites containing matrix polycarbonate, glass fiber and LCP are prepared. The morphology of LCP and the rheological behavior of the composites are described. The relationship between flowability and morphology is discussed. It is interesting to find that in some hybrid systems, composites containing more glass fiber have better flowability than composites containing less glass fiber. Glass fiber aspect ratio is an important factor that determines the flowability. Materials with short glass fiber have lower viscosities than the materials with long glass fiber. LCP morphology is another important parameter that determines the flowability of the composites. If LCP forms fibrils, the composites have better flowability. If spheres dominate the morphology of LCP, the materials have larger viscosity. The addition of glass fiber brings about new factors that influence the morphology of LCP. The LCP morphology is not only affected by LCP content, but also by glass fiber content and glass fiber length. LCP fibrils are promoted in some in-situ hybrid composites. A model is proposed to describe how fibrillation of LCP is promoted due to the addition of glass fiber DOI : 10.3139/217.1716 En ligne : https://drive.google.com/file/d/15xKO4djAM7tuKucLP7HGKWPi5zsf5bzM/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=15845 [article]

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Preparing of homogeneous solution of ultrahigh molecular weight PAN / B. Zhang in INTERNATIONAL POLYMER PROCESSING, Vol. XX, N° 1 (03/2005)  

[article]  inINTERNATIONAL POLYMER PROCESSING > Vol. XX, N° 1 (03/2005) . - p. 3-7 Titre : Preparing of homogeneous solution of ultrahigh molecular weight PAN Type de document : texte imprimé Auteurs : B. Zhang, Auteur ; J. Zhao, Auteur ; Y. Zhang, Auteur ; N. Yang, Auteur ; C. Wu, Auteur Année de publication : 2005 Article en page(s) : p. 3-7 Note générale : Bibliogr. Langues : Anglais (eng) Index. décimale : 668.9 Polymères Résumé : Based on torque measurement via a device specially developed by our group, the shearing torque of the mixture of UHMWPAN with swelling agent or solvent during shearing process at various temperatures could be recorded as torque-temperature diagram in the swelling and dissolution process. The temperature where the torque of the mixture began to rise as showed in the torque-temperature diagram was considered as key parameter. UHMWPAN could be swollen fully and the homogeneous solution could be easily prepared if the mixture was heated progressively and was kept for a certain period of time at the every constant temperature. In the case of UHMWPAN (content >-), the parameters of the swelling and dissolution process were finally obtained. DOI : 10.3139/217.1848 En ligne : https://drive.google.com/file/d/1qN_F7L8nKup2P22k1Fh1f0x9gsjo7Alc/view?usp=drive [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=3083 [article]

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