Strain and Strain Recovery of Human Hair from the Nano- to the Macroscale

Autor(en)

Brigitte Waldmann, Martin Florian Timotheus Haßler, Alexander Müllner, Stephan Puchegger, Herwig Peterlik

Abstrakt

In this study, in operandi SAXS experiments were conducted on samples of human hair with a varying degree of strain (2% within the elastic region and 10% beyond). Four different features in the SAXS patterns were evaluated: The intermediate filament distance perpendicular to and the distance from the meridional arc in the load direction, as well as the distances of the lipid bilayer peak in and perpendicular to the load direction. From the literature, one concludes that polar lipids in the cuticle are the origin of the lipid peak in the SAXS pattern, and this study shows that the observed strain in the lipids is much lower than in the intermediate filaments. We support these findings with SEM micrographs, which show that the scales in the cuticle deform much less than the cortex. The observed deformation of the intermediate filaments is very high, about 70% of the macrostrain, and the ratio of the transverse strain to the longitudinal strain at the nanoscale gives a Poisson ratio of νnano = 0.44, which is typical for soft matter. This work also finds that by varying the time period between two strain cycles, the typical strain recovery time is about 1000 min, i.e., one day. After this period, the structure is nearly identical to the initial structure, which suggests an interpretation that this is the typical time for the self-healing of hair after mechanical treatment.

Organisation(en)

Mathematische Physik, Dynamik Kondensierter Systeme, Fakultätszentrum für Nanostrukturforschung

Journal

Life

Band

13

Anzahl der Seiten

16

ISSN

2075-1729

DOI

https://doi.org/10.3390/life13122246

Publikationsdatum

11-2023

Peer-reviewed

Ja

ÖFOS 2012

103015 Kondensierte Materie

Schlagwörter

ASJC Scopus Sachgebiete

Ecology, Evolution, Behavior and Systematics, Allgemeine Biochemie, Genetik und Molekularbiologie, Palaeontology, Space and Planetary Science

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/4246990e-e291-49f4-b3ac-262172f30d19