Strong, Lightweight, and Shape‐Memory Bamboo‐Derived All‐Cellulose Aerogels for Versatile Scaffolds of Sustainable Multifunctional Materials

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2024-01, Vol.20 (4), p.e2305857-n/a
• Main Authors: Dong, Hongping, Li, Xiazhen, Cai, Zhiyong, Wei, Song, Fan, Shutong, Ge, Yanglin, Li, Xianjun, Wu, Yiqiang
• Format: Article
• Language: English
• Subjects: Aerogels; all‐cellulose aerogel; anisotropic; Bamboo; Carbon nanotubes; Cellulose; Cellulose fibers; Electromagnetic interference; Electromagnetic shielding; Freezing; Hydroxyapatite; Lightweight; Microfibers; Modulus of elasticity; multifunction; Multifunctional materials; regenerated cellulose; Scaffolds; Shape memory; Structural design; Thermal insulation
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.202305857

Strong, lightweight, and shape‐memory cellulose aerogels have great potential in multifunctional applications. However, achieving the integration of these features into a cellulose aerogel without harsh chemical modifications and the addition of mechanical enhancers remains challenging. In this study, a strong, lightweight, and water‐stimulated shape‐memory all‐cellulose aerogel (ACA) is created using a combination strategy of partial dissolution and unidirectional freezing from bamboo. Benefiting from the firm architecture of cellulose microfibers bridging cellulose nanofibers /regenerated cellulose aggregated layers and the bonding of different cellulose crystal components (cellulose Iβ and cellulose II), the ACA, with low density (60.74 mg cm−3), possesses high compressive modulus (radial section: 1.2 MPa, axial section: 0.96 MPa). Additionally, when stimulated with water, the ACA exhibits excellent shape‐memory features, including highly reversible compression‐resilience and instantaneous fold‐expansion behaviors. As a versatile scaffold, ACA can be integrated with hydroxyapatite, carboxyl carbon nanotubes, and LiCl, respectively, via a simple impregnation method to yield functionalized cellulose composites for applications in thermal insulation, electromagnetic interference shielding, and piezoresistive sensors. This study provides inspiration and a reliable strategy for the elaborately structural design of functional cellulose aerogels endows application prospects in various multifunction opportunities. A combination strategy of partial dissolution and unidirectional freeze is developed for the fabrication of strong, lightweight, and shape‐memory all‐cellulose aerogel with the unique anisotropic structure of cellulose microfibers bridging nanofibers/regenerated cellulose aggregated layers. As a versatile scaffold, the aerogel holds great promise for applications in thermal insulation, electromagnetic interference shielding, and piezoresistive sensors.