HUANG FengLing, QIU Hu, GUO WanLin. Microstructures and mechanical properties of fiber cells from Echinocactus grusonii cactus spine. Sci China Tech Sci, 2014, 57, 706-712.

Title
Microstructures and mechanical properties of fiber cells from Echinocactus grusonii cactus spine

Journal
Science China Technological Sciences
Volume 57, Issue 4 , pp 706-712

Cover Date
2014-04-01

DOI
10.1007/s11431-014-5504-6

Authors
FengLing Huang (1) (2)
Hu Qiu (1)
WanLin Guo wlguo@nuaa.edu.cn (1)

Author Affiliations
1. State Key Laboratory for mechanics and control of mechanical structures, Key Laboratory for Intelligent Nano Materials and Devices of the Ministry of Education and Institute of Nanoscience, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China
2. Department of Biomedical Engineering, College of Automation Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, China

Keywords
spine
fibers
microstructure
indentation modulus

Abstract
Spine is the sharpest and hardest part of many plants, which contains highly aligned fiber cells. Here, we report the microstructures and mechanical properties as well as their correlation of single spine fiber cells (SFCs) from the cactus Echinocactus grusonii. It is found that the SFCs are 0.32–0.57 mm in length and 4.6–6.0 μm in width, yielding an aspect ratio of 53–124. X-ray diffraction and Fourier transform infrared spectrophotometry show that the spine fiber is mainly made up of cellulose I with a crystallinity index up to ∼76%. Nanoindentation tests show that a natural spine presents a high modulus of ∼17 GPa. Removing hemicellulose and lignin from the SFC significantly reduces its modulus to ∼0.487 GPa, demonstrating the critical role of adhesives hemicellulose and lignin in affecting the mechanical properties of the SFCs. This finding sheds light on designing novel bio-inspired high-performance composite nanomaterials with aligned nanofibers, such as using hemicellulose and lignin as adhesive in making carbon nanotube fibers.

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