Hierarchically non-uniform structures determine the hydro-actuated bending deformation of camel hair

Abstract

Summary: Nature uses efficient strategies to produce complex structures for hydration-induced reversible deformation. One such example is camel hair, a keratinous fiber with remarkable water-triggered shape memory. Herein, we unravel the effect of non-uniform structures on the shape memory of camel hair. By extraction and quantitative analysis of the deformation of camel hair, we describe that the shape memory of camel hair is a bending mode instead of shrinking along the long fiber axis. The shape memory process is based on anisotropic swelling, caused by the non-uniform distribution of disulfide bonds and the non-uniform thickness of the cortex layer along the cross-section. This natural actuation structure inspires the design of complex shape-memory materials with simple simulation strategies and has better biocompatibility to meet the requirements of biological applications.

Keywords

• shape memory
• hair fiber
• structure-property relationship
• FTIR imaging