State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science and Laboratory of Advanced Materials , Fudan University , Shanghai 200433 , P. R. China.
ACS Appl Mater Interfaces. 2018 Nov 7;10(44):38466-38475. doi: 10.1021/acsami.8b14521. Epub 2018 Oct 26.
Owing to their promising applications in flexible electronics, researchers have extensively explored flexible and conductive gels. However, these gels have unsatisfactory strength and flexibility as well as easily dry in air. Herein, a rationally designed robust regenerated silk fibroin (RSF)-based gel with significant flexibility and strength, favorable conductivity, and excellent air stability is fabricated by inducing the conformation transition of RSF from random coil to β-sheet in ionic liquid (IL)/water mixtures. We found that such RSF-based gels have a unique homogeneous network structure of RSF nanofibers, which is likely formed because of evenly distributed cross-links dominated by small-sized β-sheet domains created during the conformation transition of RSF. Although the unique homogeneous nanostructure/network contributes toward improving the mechanical properties of these gels, it also provides pathways for ionic transport to help the gels preserve high conductivity of ILs. The prepared RSF-based gels display a remarkable air stability and reversible loss/absorption water capability in a wide humidity range environment primarily because of the distinguished combination of the IL and water. Therefore, the novel RSF-based gels hold a great potential in various applications as multifunctional, flexible, conductive materials, which are dispensed with encapsulation.
由于在柔性电子产品中有很好的应用前景，研究人员广泛探索了柔性和导电凝胶。然而，这些凝胶的强度和柔韧性较差，而且在空气中容易干燥。在此，通过在离子液体（IL）/水混合物中诱导丝素蛋白（RSF）构象从无规卷曲向β-折叠转变，设计并制备了一种具有显著柔韧性和强度、良好导电性和优异空气稳定性的合理设计的稳健再生丝素蛋白（RSF）基凝胶。我们发现，这种基于 RSF 的凝胶具有 RSF 纳米纤维的独特均匀网络结构，这可能是由于在 RSF 构象转变过程中形成的均匀分布的交联，由小尺寸β-折叠结构域主导。虽然独特的均匀纳米结构/网络有助于提高这些凝胶的机械性能，但它也为离子传输提供了途径，有助于凝胶保持 IL 的高导电性。所制备的基于 RSF 的凝胶在很宽的湿度范围内具有出色的空气稳定性和可逆的失/吸水能力，这主要是由于 IL 和水的独特组合。因此，新型基于 RSF 的凝胶作为多功能、灵活、导电材料具有很大的应用潜力，无需封装。
