NRC Postdoctoral Research Associateship Program, Naval Research Laboratory, Washington, DC 20375, USA.
ACS Nano. 2013 Jun 25;7(6):4746-55. doi: 10.1021/nn304267b. Epub 2013 May 16.
This work demonstrates the production of a well-controlled, chemical gradient on the surface of graphene. By inducing a gradient of oxygen functional groups, drops of water and dimethyl-methylphosphonate (a nerve agent simulant) are "pulled" in the direction of increasing oxygen content, while fluorine gradients "push" the droplet motion in the direction of decreasing fluorine content. The direction of motion is broadly attributed to increasing/decreasing hydrophilicity, which is correlated to high/low adhesion and binding energy. Such tunability in surface chemistry provides additional capabilities in device design for applications ranging from microfluidics to chemical sensing.
这项工作展示了在石墨烯表面上产生良好控制的化学梯度的方法。通过诱导氧官能团的梯度，水滴和二甲甲基膦酸酯（神经毒剂模拟物）被“拉”向氧含量增加的方向，而氟梯度则“推动”液滴向氟含量降低的方向运动。运动的方向主要归因于亲水性的增加/减少，这与高/低粘附力和结合能相关。这种表面化学的可调节性为从微流控到化学传感等应用的器件设计提供了额外的功能。
