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Cellulose nanofibers/polyurethane shape memory composites with fast water-responsivity†
Journal of Materials Chemistry B ( IF 6.1 ) Pub Date : 2018-02-22 00:00:00 , DOI: 10.1039/c7tb03069j
Yongzhen Wang 1, 2, 3, 4, 5 , Zhongjun Cheng 3, 4, 5, 6 , Zhenguo Liu 1, 2, 3, 4, 5 , Hongjun Kang 1, 2, 3, 4, 5 , Yuyan Liu 1, 2, 3, 4, 5
Affiliation  

Water-responsive shape-memory materials, especially cellulose nanofibers (CNF)–polymer composite materials, have been rapidly developed in recent years for designing new generation water-responsive sensors, actuators, biomedical devices, etc. However, achieving fast-responsivity is still a challenge. Herein, by simply incorporating CNF into a thermoplastic elastomer polyurethane (PU) matrix, we report a material, namely, PU/CNF nanocomposite, which has a good shape memory effect (SME) and fast responsivity. The effects of the CNF content on water absorption, shape memory behavior and mechanical properties of the composites are studied, and it can be found that when the CNF content reaches 30%, materials with good SME, such as high shape fixing and shape recovery ratio (higher than 90%) and fast responsivity (less than 1 min), can be obtained. The excellent SME can be ascribed to the combined effect of the good elastic recovery property of the PU matrix, high modulus of CNF and the rapid water uptake behavior of PU/CNF, based on which a rigid CNF percolation network in the elastomeric PU can be formed/destroyed by the desorption/absorption of water molecules repeatedly. Finally, based on the excellent rapid water-triggered shape memory performance, we also demonstrate some applications of the material, for example, as a “mechanical hand” to grasp solid objects in water and as a smart sealing film to build a controllable release system.

中文翻译:

具有快速水响应性的纤维素纳米纤维/聚氨酯形状记忆复合材料

近年来,水响应形状记忆材料特别是纤维素纳米纤维(CNF)-聚合物复合材料得到了快速发展,用于设计新一代水响应传感器,执行器,生物医学设备等。但是,实现快速响应仍然是一个挑战。本文中,通过简单地将CNF掺入热塑性弹性体聚氨酯(PU)基质中,我们报道了一种材料,即PU / CNF纳米复合材料,它具有良好的形状记忆效果(SME)和快速的响应性。研究了CNF含量对复合材料的吸水率,形状记忆性能和力学性能的影响,发现当CNF含量达到30%时,具有良好的形状,固着性和形状回复率等良好的SME材料(高于90%)和快速响应(少于1分钟),即可获得。优异的SME可以归因于PU基质的良好弹性回复性能,CNF的高模量以及PU / CNF的快速吸水行为的综合效果,基于此,通过重复地解吸/吸收水分子,可以在弹性体PU中形成/破坏刚性CNF渗滤网络。最后,基于出色的快速水触发形状记忆性能,我们还展示了该材料的一些应用,例如,作为“机械手”来抓住水中的固体物体,以及作为智能密封膜来构建可控的释放系统。
更新日期:2018-02-22
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