Department of Electrical and Computer Engineering, Wayne State University, Detroit, MI, USA.
Nanotechnology. 2012 Sep 21;23(37):375501. doi: 10.1088/0957-4484/23/37/375501. Epub 2012 Aug 24.
We report electrowetting on dielectric (EWOD) experiments using graphene; a transparent, flexible and stretchable nanomaterial. Graphene sheets were synthesized by chemical vapor deposition, and transferred to various substrates (including glass slides and PET films). Reversible contact angle changes were observed on the Teflon-coated graphene electrode with both AC and DC voltages. Nyquist plots of the EWOD reveal that the graphene electrode has higher capacitive impedance than gold electrodes under otherwise identical conditions, suggesting a lower density of pin-holes and defects in the Teflon/graphene electrode than in the Teflon/gold electrode. Furthermore, we have observed reduced electrolysis of the electrolyte and smaller leakage current in the dielectric layer (Teflon) on graphene electrodes than on Au electrodes at the same Teflon thickness and applied voltage. We expect that the improved EWOD properties using graphene as an electrode material will open the door to various applications, including flexible displays and droplet manipulation in three-dimensional microfluidics.
我们报告了使用石墨烯的电润湿（EWOD）实验；石墨烯是一种透明、灵活且可拉伸的纳米材料。石墨烯片通过化学气相沉积合成，并转移到各种基底上（包括玻片和 PET 薄膜）。在涂有特氟龙的石墨烯电极上施加交流和直流电压，观察到可逆的接触角变化。EWOD 的奈奎斯特图表明，在其他条件相同的情况下，石墨烯电极的电容阻抗高于金电极，这表明特氟龙/石墨烯电极中的针孔和缺陷密度低于特氟龙/金电极。此外，我们还观察到在相同的特氟龙厚度和施加电压下，石墨烯电极上的电解质电解和电介质层（特氟龙）漏电流都比金电极小。我们期望使用石墨烯作为电极材料可以改善 EWOD 性能，为各种应用开辟道路，包括柔性显示器和三维微流控中的液滴操控。
