Cuticle - Designed by nature for the sake of the hair / Steven Breakspear in INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Vol. 44, N° 3 (06/2022)  

[article]  inINTERNATIONAL JOURNAL OF COSMETIC SCIENCE > Vol. 44, N° 3 (06/2022) . - p. 343-362 Titre : Cuticle - Designed by nature for the sake of the hair Type de document : document électronique Auteurs : Steven Breakspear, Auteur ; Dimitri A. Ivanov, Auteur ; Bernd Noecker, Auteur ; Crisan Popescu, Auteur ; Martin Rosenthal, Auteur Année de publication : 2022 Article en page(s) : p. 343-362 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Allwörden, Réaction d' Cheveux -- Soins et hygiène Cuticule Diffractométrie de rayons X Index. décimale : 668.5 Parfums et cosmétiques Résumé : - Objective : The cuticle of human hair has been examined, via a range of analytical methods, in order to reveal previously unknown information about its structure and to deepen understanding of its contribution to fibre properties. - Methods : Cross-sections of hair fibre have been examined with X-ray microdiffraction oriented perpendicular to the surface of the cross-sections. AFM investigations were carried out for further investigating and deciphering the structure of the cuticle. Moisture sorption analytics of cuticle separated from fibre and mechanical tests of decuticled fibres against virgin fibres were used for understanding the role of the cuticle in the economy of hair fibre. - Results : Previously unknown swelling behaviour of the hair cuticle during moisture sorption has been revealed, as has an increased significance of the cuticle's role in moisture management at higher values of relative humidity. Through AFM investigation, the reaction of hair cuticles with chlorine water has further strengthened the idea that the Allwörden membrane does not exist, and is actually an artefact of the delamination of the A-layer and exocuticle from the underlying endocuticle. Using decuticled fibres for stress-strain tests, and by comparing the results with those of virgin fibres, the effect of the cuticle on the post-yield area of the hair fibre stress-strain diagram has also been demonstrated. Finally, X-ray microdiffraction and AFM investigations suggest that the cuticle possesses a small-scale ordered structure, based on possibly not fully crystalline and irregularly arranged α-helices oriented almost perpendicular to the growth axis of the fibre and enhancing the general description of cuticle as the protective layer of the fibre. - Conclusion : The role of the cuticle for the hair fibre is more complex than previously thought. The cuticle is demonstrated not only to possess a hidden rod-matrix structure, that supports its protective nature, but also to play specific roles in the fibre's response to moisture, and in fibre mechanical behaviour. Note de contenu : - METHODS AND MATERIALS : Materials - Treatment of the fibres - Analytical tools - RESULTS AND DISCUSSION : The birth of cuticle - Morphology of the cuticle - Cuticle layers - Architecture of the cuticle - ROLE OF CUTICLE : Swelling and moisture management - Mechanics DOI : https://doi.org/10.1111/ics.12782 En ligne : https://drive.google.com/file/d/18550p7loA6ry6JACwyFCk9ZIdFpyWBeR/view?usp=shari [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38138 [article]

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Learning from hair moisture sorption and hysteresis / Steven Breakspear in INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Vol. 44, N° 5 (10/2022)  

[article]  inINTERNATIONAL JOURNAL OF COSMETIC SCIENCE > Vol. 44, N° 5 (10/2022) . - p. 555-568 Titre : Learning from hair moisture sorption and hysteresis Type de document : document électronique Auteurs : Steven Breakspear, Auteur ; Patrick Frueh, Auteur ; Anna Neu, Auteur ; Bernd Noecker, Auteur ; Crisan Popescu, Auteur ; Qi Uellner, Auteur Année de publication : 2022 Article en page(s) : p. 555-568 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Absorption Adsorption Cheveux -- analyse Cheveux humides Désorption Hystérésis L'hystérésis (ou hystérèse) et signifiant "après" ou "plus tard", est la propriété d'un système qui tend à demeurer dans un certain état quand la cause extérieure qui a produit le changement d'état a cessé. Justification de l'allégation Mesure Index. décimale : 668.5 Parfums et cosmétiques Résumé : - Objective : The process of moisture sorption and desorption by human hair was analysed for extracting hints on the hair structure. - Methods : The isotherms of moisture sorption and desorption by hair were recorded for untreated and chemically treated (permed and bleached) hair. Data of swelling were also considered. - Results : By examining the swelling and moisture sorption of keratin fibres, it is possible to conclude that hysteresis is quite improbably caused by capillary condensation. The mobility of the protein chains and the strength of the bonds binding water molecules to the active sites inside the matrix are proposed as causes instead. The concept of “breaking symmetry”, derived from moisture sorption– desorption data, and the method of evaluating this parameter, is proposed as a way of characterizing the chemical treatment of hair. The results show that bleaching produces a larger breaking of symmetry than perming, and this is suggested to be due to new hydrogen bonds, created as a result of the chemical treatment, replacing the original disulphide bonds, which are of different strength compared to the bonds of untreated hair. The quantitative sorption data matched well to the model of grains of matrix enveloped in layers of water molecules at increasing relative humidity, up to 100%. The analysis suggested that, aside from the glass transition event occurring at around 60%–70% relative humidity, there is another, less examined, transition occurring at around 30% relative humidity, assigned to the opening of the hair inner structure, and accommodation of more water molecules. Both transitions are reflected by corresponding changes in the fibre mechanical behaviour. - Conclusion : The moisture sorption-desorption by hair was shown to not only allow a quantitative differentiation among various cosmetic treatments of the hair but to also provide valuable information on the structure of the fibre. Note de contenu : - Materials - Treatments - Measurements - Table 1 : Areas of “Old” and “New” hysteresis for untreated and chemically treated hairs - Table 2 : The internal surface of monolayer and of multilayer of water molecules calculated by Equations (7) and (8) for untreated, permed and bleach-treated hairs DOI : https://doi.org/10.1111/ics.12806 En ligne : https://drive.google.com/file/d/1EJKhn9ZqClfhXHP7W6fv4gqOUXFf0fu1/view?usp=shari [...] Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=38153 [article]

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