Xu Hao, Yi Wenhui, Li Dongfan, Zhang Ping, Yoo Sweejiang, Bai Lei, Hou Jin, Hou Xun
Key Laboratory for Information Photonic Technology of Shaanxi Province, Key Laboratory for Physical Electronics and Devices of the Ministry of Education, School of Electronics and Information Engineering, Xi'an Jiaotong University Xi'an 710049 P. R. China
Frontier Institute of Science and Technology, Xi'an Jiaotong University Xi'an 710054 P. R. China.
RSC Adv. 2019 Jan 25;9(7):3558-3569. doi: 10.1039/c8ra09934k.
Silkworm fibers have attracted widespread attention for their superb glossy texture and promising mechanical performance. The mechanical properties can be reinforced with carbon nanofillers, particularly carbon nanotubes (CNTs), depending on the CNT content in the silk fibers. In order to increase the CNT content, lignosulfonate (LGS) was used as a surfactant to ameliorate the CNT solubility, dispersibility, and biocompatibility. The resulting CNT/LGS nano-composite was further processed through an additional purification method to remove excess surfactant and enhance the CNT/LGS ratio. Then the purified biocompatible single and multiple-walled CNTs were fed to silkworms, leading to a large CNT content in the resulting silk fibers. Reinforced silk fibers were produced with a mechanical strength as high as 1.07 GPa and a strain of 16.8%. The toughness modulus is 1.69 times than that of the unpurified group. The CNT-embedded silk fibers were characterized Raman spectrometry and thermogravimetric analysis (TGA), demonstrating that the CNT content in the silk fibers increased 1.5-fold in comparison to the unpurified group. The increased CNT content not only contributed to the self-assembly into buffering knots of silk fibers, but it also enhanced the conductivity of graphitized silk. Our coating and purification strategies provide a potential facile way to obtain natural silk fibers with high mechanical performance.
蚕纤维因其出色的光泽质地和良好的机械性能而备受关注。根据丝纤维中碳纳米管（CNT）的含量，机械性能可以通过碳纳米填料，特别是碳纳米管得到增强。为了增加CNT的含量，木质素磺酸盐（LGS）被用作表面活性剂来改善CNT的溶解性、分散性和生物相容性。所得的CNT/LGS纳米复合材料通过额外的纯化方法进一步处理，以去除过量的表面活性剂并提高CNT/LGS比例。然后将纯化后的生物相容性单壁和多壁CNT喂给蚕，从而使所得丝纤维中含有大量的CNT。制备出的增强丝纤维具有高达1.07 GPa的机械强度和16.8%的应变。韧性模量是未纯化组的1.69倍。通过拉曼光谱和热重分析（TGA）对嵌入CNT的丝纤维进行了表征，结果表明，与未纯化组相比，丝纤维中的CNT含量增加了1.5倍。CNT含量的增加不仅有助于丝纤维自组装成缓冲结，还提高了石墨化丝的导电性。我们的涂层和纯化策略为获得具有高机械性能的天然丝纤维提供了一种潜在的简便方法。
