Silk fibres attract great interest in materials science for their biological and mechanical properties. Hitherto, the mechanical properties of the silk fibres have been explored mainly by tensile tests, which provide information on their strength, Young’s modulus, strain at break and toughness modulus. Several hypotheses have been based on these data, but the intrinsic and often overlooked variability of natural and artificial silk fibres makes it challenging to identify trends and correlations. In this work, we determined the mechanical properties of Bombyx mori cocoon and degummed silk, native spider silk, and artificial spider silk, and compared them with classical commercial carbon fibres using large sample sizes (from 10 to 100 fibres, in total 200 specimens per fibre type). The results confirm a substantial variability of the mechanical properties of silk fibres compared to commercial carbon fibres, as the relative standard deviation for strength and strain at break is 10–50%. Moreover, the variability does not decrease significantly when the number of tested fibres is increased, which was surprising considering the low variability frequently reported for silk fibres in the literature. Based on this, we prove that tensile testing of 10 fibres per type is representative of a silk fibre population. Finally, we show that the ideal shape of the stress–strain curve for spider silk, characterized by a pronounced exponential stiffening regime, occurs in only 25% of all tested spider silk fibres.

Artificial and natural silk materials have high mechanical property variability regardless of sample size / Greco, Gabriele; Mirbaha, Hamideh; Schmuck, Benjamin; Rising, Anna; Pugno, Nicola M.. - In: SCIENTIFIC REPORTS. - ISSN 2045-2322. - 12:1(2022), pp. 1-9. [10.1038/s41598-022-07212-5]

Artificial and natural silk materials have high mechanical property variability regardless of sample size

Greco, Gabriele;Mirbaha, Hamideh;Pugno, Nicola M.
2022-01-01

Abstract

Silk fibres attract great interest in materials science for their biological and mechanical properties. Hitherto, the mechanical properties of the silk fibres have been explored mainly by tensile tests, which provide information on their strength, Young’s modulus, strain at break and toughness modulus. Several hypotheses have been based on these data, but the intrinsic and often overlooked variability of natural and artificial silk fibres makes it challenging to identify trends and correlations. In this work, we determined the mechanical properties of Bombyx mori cocoon and degummed silk, native spider silk, and artificial spider silk, and compared them with classical commercial carbon fibres using large sample sizes (from 10 to 100 fibres, in total 200 specimens per fibre type). The results confirm a substantial variability of the mechanical properties of silk fibres compared to commercial carbon fibres, as the relative standard deviation for strength and strain at break is 10–50%. Moreover, the variability does not decrease significantly when the number of tested fibres is increased, which was surprising considering the low variability frequently reported for silk fibres in the literature. Based on this, we prove that tensile testing of 10 fibres per type is representative of a silk fibre population. Finally, we show that the ideal shape of the stress–strain curve for spider silk, characterized by a pronounced exponential stiffening regime, occurs in only 25% of all tested spider silk fibres.
2022
1
Greco, Gabriele; Mirbaha, Hamideh; Schmuck, Benjamin; Rising, Anna; Pugno, Nicola M.
Artificial and natural silk materials have high mechanical property variability regardless of sample size / Greco, Gabriele; Mirbaha, Hamideh; Schmuck, Benjamin; Rising, Anna; Pugno, Nicola M.. - In: SCIENTIFIC REPORTS. - ISSN 2045-2322. - 12:1(2022), pp. 1-9. [10.1038/s41598-022-07212-5]
File in questo prodotto:
File Dimensione Formato  
20228-SCIREP-Artificial_and_natural_silk_materials.pdf

accesso aperto

Tipologia: Versione editoriale (Publisher’s layout)
Licenza: Creative commons
Dimensione 2.27 MB
Formato Adobe PDF
2.27 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11572/334973
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 26
  • ???jsp.display-item.citation.isi??? 29
  • OpenAlex ND
social impact