Dong Hongping, Li Xiazhen, Cai Zhiyong, Wei Song, Fan Shutong, Ge Yanglin, Li Xianjun, Wu Yiqiang
College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, Hunan, 410004, P. R. China.
USDA Forest Products Laboratory, Madison, WI, 53726-2398, USA.
Small. 2024 Jan;20(4):e2305857. doi: 10.1002/smll.202305857. Epub 2023 Sep 13.
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 ), 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.
强韧、轻质且具有形状记忆功能的纤维素气凝胶在多功能应用中具有巨大潜力。然而，在不进行苛刻化学改性和添加机械增强剂的情况下，将这些特性集成到纤维素气凝胶中仍然具有挑战性。在本研究中，通过部分溶解和单向冷冻相结合的策略，从竹子中制备出了一种强韧、轻质且受水刺激的形状记忆全纤维素气凝胶（ACA）。得益于纤维素微纤维桥接纤维素纳米纤维/再生纤维素聚集层的坚固结构以及不同纤维素晶体成分（纤维素Iβ和纤维素II）之间的结合，密度低至60.74毫克/立方厘米的ACA具有较高的压缩模量（径向截面：1.2兆帕，轴向截面：0.96兆帕）。此外，在水刺激下，ACA表现出优异的形状记忆特性，包括高度可逆的压缩回弹和瞬时折叠展开行为。作为一种多功能支架，ACA可以通过简单的浸渍方法分别与羟基磷灰石、羧基碳纳米管和LiCl集成，以制备用于隔热、电磁干扰屏蔽和压阻传感器的功能化纤维素复合材料。本研究为功能性纤维素气凝胶的精细结构设计提供了灵感和可靠策略，赋予了其在各种多功能应用中的广阔前景。
