nn0c04298_si_004.avi (3.96 MB)
Highly Elastic Hydrated Cellulosic Materials with Durable Compressibility and Tunable Conductivity
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posted on 2020-08-06, 22:20 authored by Chaoji Chen, Jianwei Song, Jian Cheng, Zhenqian Pang, Wentao Gan, Gegu Chen, Yudi Kuang, Hao Huang, Upamanyu Ray, Teng Li, Liangbing HuAnisotropic
cellular materials with direction-dependent structure
and durable mechanical properties enable various applications (e.g., nanofluidics, biomedical devices,
tissue engineering, and water purification), but their widespread
use is often hindered by complex and scale-limited fabrication and
unsatisfactory mechanical performance. Here, inspired by the anisotropic
and hierarchical material structure of tendons, we demonstrate a facile,
scalable top-down approach for fabricating a highly elastic, ionically
conductive, anisotropic cellulosic material (named elastic wood) directly
from natural wood via chemical treatment. The resulting
elastic wood demonstrates good elasticity and durable compressibility,
showing no sign of fatigue after 10 000 compression cycles.
The chemical treatment not only softens the wood cell walls by partially
removing lignin and hemicellulose but introduces an interconnected
cellulose fibril network into the wood channels. Atomistic and continuum
modeling further reveals that the absorbed water can freely and reversibly
move inside the elastic wood and therefore helps the elastic wood
accommodate large compressive deformation and recover to its original
shape upon compression release. In addition, the elastic wood showed
a high ionic conductivity of up to 0.5 mS cm–1 at
a low KCl concentration of 10–4 M, which can be
tuned by changing the compression ratio of the material. The demonstrated
elastic, mechanically robust, and ionically conductive cellulosic
material combining inherited anisotropic cellular structure from natural
wood and a self-formed internal gel may find a variety of potential
applications in ionic nanofluidics, sensors, soft robots, artificial
muscle, environmental remediation, and energy storage.