Nanofiber-guided orientation of electrospun carbon nanotubes and fabrication of aligned CNT electrodes for biodevice applications
Nanofiber-guided orientation of electrospun carbon nanotubes and fabrication of aligned CNT electrodes for biodevice applications
复制标题
DOI：
10.1016/j.matchemphys.2020.122745
复制
发表时间：
2020-04
影响因子：
4.6
通讯作者：
H. Sakamoto;I. Fujiwara;E. Takamura;S. Suye
中科院分区：
文献类型：
--
作者：
H. Sakamoto;I. Fujiwara;E. Takamura;S. Suye
碳纳米管具有很大的比表面积和很高的电子转移速率。因此，他们预计是有价值的高功率生物装置，如生物传感器和生物燃料电池的建设。然而，由于产生电阻的货车范德华力，CNT倾向于聚集。它们的性能的最佳使用不能简单地通过将CNT并入电极来实现。因此，迫切需要一种用于在电极表面上定向CNT的技术。在这项研究中，我们的目的是开发一种CNT对齐方法，以最大限度地提高固有的导电和结构性能的碳纳米管。我们使用聚（乙烯-共-乙酸乙烯酯）（PEVA）纳米纤维在静电纺丝过程中引导CNT取向。将PEVA和CNT的混合溶液旋涂到Au基底的表面上。在静电纺丝之后，在400 °C下的燃烧使PEVA纳米纤维热解，仅在基底上留下CNT。燃烧后，用扫描电子显微镜（SEM），场发射SEM，和拉曼光谱的碳纳米管的形态和化学状态进行了评价。然后我们将酶固定到修饰的碳纳米管上，并评估其电化学性能。燃烧后对纺成的CNT-PEVA芯-鞘纳米纤维的检查证实CNT在纤维方向上取向。固定化酶电极的阻抗测量结果表明，与随机取向的碳纳米管相比，与定向的碳纳米管的电荷转移电阻较低。在循环伏安法测试中评估酶电化学反应。我们发现碳纳米管在电极表面的排列增加了酶-底物氧化还原反应的电流。
Carbon nanotubes (CNTs) have quite large specific surface areas and high electron transfer rates. They are thus anticipated to be valuable for the construction of high-power biodevices, such as biosensors and biofuel cells. However, CNTs tend to aggregate due to van der Waals forces, which generates electrical resistance. Optimal use of their properties cannot be achieved simply by incorporating CNTs into electrodes. A technique for orienting CNTs on electrode surfaces is thus urgently needed. In this study, we aimed to develop a CNT alignment method to maximize the intrinsic conductive and structural properties of CNTs. We used poly(ethylene-co-vinyl acetate) (PEVA) nanofibers to guide CNT orientation during electrospinning. A mixed solution of PEVA and CNT was spun onto the surfaces of Au substrates. Following electrospinning, combustion at 400 °C pyrolyzed the PEVA nanofibers, leaving only CNTs on the substrates. After combustion, the morphology and chemical state of the CNTs were evaluated with scanning electron microscopy (SEM), field-emission SEM, and Raman spectroscopy. We then immobilized enzyme onto modified the CNTs and evaluated their electrochemical performance. Examination of the spun CNT-PEVA core-sheath nanofibers following combustion confirmed that the CNTs were oriented in the direction of the fibers. Impedance measurements of the enzyme-immobilized electrodes showed that the charge transfer resistance was lower with the aligned CNTs than with randomly oriented CNTs. The enzymatic electrochemical reaction was evaluated in cyclic voltammetry tests. We found that the CNT alignment on the electrode surface increased the current in enzyme-substrate redox reaction.