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Structure Evolution in Hair Fibres During Strain and the Effect of Relative Humidity.
Paul D A Pudney1, Adrian Voda2, Kenneth S Lee1
1Unilever R&D, Port Sunlight Laboratory, Port Sunlight, Wirral CH63 3JW, UK.
Applied Spectroscopy
|May 26, 2026
Summary
This study reveals how hair
Area of Science:
- Biomaterials Science
- Protein Chemistry
- Structural Biology
Background:
- Hair's mechanical properties stem from its protein composition, primarily keratin.
- Keratin undergoes conformational changes, including alpha-helix to beta-sheet transitions, under stress.
- The exact conditions and humidity's role in these transitions are not fully understood.
Purpose of the Study:
- To investigate the in situ molecular changes in hair during mechanical stress.
- To determine the influence of humidity on keratin's structural transitions.
- To correlate molecular alterations with applied strain using advanced spectroscopic and scattering techniques.
Main Methods:
- Raman spectroscopy and wide-angle X-ray scattering (WAXS) were employed to monitor structural changes.
- In situ measurements were conducted under controlled strain and humidity conditions.
- Two-dimensional correlation spectroscopy (2D-COS) and PCMW2D analyzed the relationship between molecular changes and strain.
Main Results:
- Two distinct alpha-helix to beta-sheet transitions were observed for the first time using both Raman and WAXS.
- These transitions were found to be humidity-dependent and proceed through a disordered intermediate state.
- Water content significantly influences the hair matrix, affecting the strain at which intermediate filaments unfold.
Conclusions:
- Humidity plays a critical role in modulating hair's mechanical response by altering the keratin matrix.
- The observed transitions provide new insights into the molecular mechanisms of hair deformation.
- Findings contribute to a better understanding of hair structure-property relationships and proposed mechanical models.
Keywords:
2D correlation methods, hair2D-COSPCMW2DRaman spectroscopyWAXDkeratinkeratin associated proteins (KAPs)perturbation correlation moving window two-dimensional correlation spectroscopywide angle X-ray diffractionMore Related Videos
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