Toughening of poly(ionic liquid)-based ion gels with cellulose nanofibers as a sacrificial network
Toughening of poly(ionic liquid)-based ion gels with cellulose nanofibers as a sacrificial network
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DOI：
10.1039/d3sm00112a
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发表时间：
2023-03-23
期刊：
影响因子：
3.4
通讯作者：
Ono，Tsutomu
中科院分区：
文献类型：
--
作者：
Watanabe，Takaichi;Oe，Emiho;Ono，Tsutomu
离子凝胶具有广泛应用的潜力，如二氧化碳分离膜和软电子产品。然而，它们的低机械强度限制了它们的实际应用。在这项研究中，我们开发了由具有疏水性基团的tempo氧化纤维素纳米纤维（TOCNF）和交联聚[1-乙基-3-乙烯基咪唑双（三氟甲磺酰基）亚胺]（PC2im-TFSI）网络组成的双网络（DN）离子凝胶。随着凝胶中TOCNF含量的增加，凝胶的机械强度增加到6 wt%。此外，发现含有6 wt% TOCNF的DN离子凝胶的断裂能比PC2im-TFSI单网络（SN）离子凝胶高19倍。循环应力应变测量表明，由于凝胶中物理交联的TOCNF网络的破坏，凝胶上的载荷能量消散。由于所有成分的热稳定性，DN离子凝胶也表现出约400°C的高分解温度。此外，TOCNF/聚离子液体（PIL） DN离子凝胶的断裂能是我们之前研究的二氧化硅纳米颗粒/PIL DN离子凝胶的两倍[Watanabe et al., Soft Matter, 2020, 16, 1572-1581]。这表明纤维状纳米材料比球形纳米材料更能有效地提高离子凝胶的力学性能。这些结果表明，TOCNF可以用于增韧基于pil的离子凝胶，从而扩大其应用范围。
Ion gels have the potential to be used in a broad range of applications, such as in carbon dioxide separation membranes and soft electronics. However, their low mechanical strength limits their practical applications. In this study, we developed double-network (DN) ion gels composed of TEMPO-oxidized cellulose nanofibers with hydrophobic groups (TOCNF) and cross-linked poly[1-ethyl-3-vinylimidazolium bis(trifluoromethanesulfonyl)imide] (PC2im-TFSI) networks. The mechanical strength of the gel increased as the amount of TOCNF in the gels increased up to 6 wt%. Moreover, the fracture energy of the DN ion gels with 6 wt% TOCNF was found to be 19 times higher than that of the PC2im-TFSI single network (SN) ion gels. Cyclic stress–strain measurements of the DN gels showed that the loading energy on the gels dissipates owing to the destruction of the physically cross-linked TOCNF network in the gels. The DN ion gels also exhibited a high decomposition temperature of approximately 400 °C because of the thermal stability of all components. Additionally, the fracture energy of the TOCNF/poly(ionic liquid) (PIL) DN ion gel was two times higher than that of the silica nanoparticles/PIL DN ion gel developed in our previous study [Watanabe et al., Soft Matter, 2020, 16, 1572–1581]. This suggests that fiber-shaped nanomaterials are more effective than spherical nanomaterials in enhancing the mechanical properties of ion gels. These results show that TOCNF can be used to toughen PIL-based ion gels and hence broaden their applications.