Nelson Jeffrey B, Schwartz Daniel T
Electrochemical Materials and Interfaces Laboratory, Department of Chemical Engineering, University of Washington, Seattle, Washington 98195, USA.
Langmuir. 2007 Sep 11;23(19):9661-6. doi: 10.1021/la701014u. Epub 2007 Jul 19.
Alkanethiol self-assembled monolayers (SAMs) have been used in electrochemical microfabrication processes. The reductive desorption potential of alkanethiol SAMs, Edes, can be comparable to, greater than, or less than the metal reduction potential during electrodeposition, Emet. As a result, the SAM layer can passivate the surface or desorb simultaneously with metal deposition. We show that these electrochemical traits can be combined with a rastering microjet electrode to pattern SAMs directly and create patterned metal films without lithography steps. For the case of copper deposition on 1-octanethiol (OT)- and 1-dodecanethiol (DT)-coated substrates, Edes is significantly negative of Emet, resulting in high-resolution metal patterns with poor nucleation and poor adhesion to the substrate. However, nickel patterns deposited on 1-butanethiol (BT), OT, and DT have traits similar to bare gold (excellent nucleation and adhesion) because Edes is positive of Emet. Substrates with SAMs also suppress adventitious chemistries that occur distant from the rastering microjet electrode, such as oxygen reduction, making samples more corrosion resistant and improving the overall patterning process that we call electrochemical printing.
链烷硫醇自组装单分子层（SAMs）已用于电化学微加工工艺。链烷硫醇SAMs的还原脱附电位Edes，在电沉积过程中可能与金属还原电位Emet相当、大于或小于Emet。因此，SAM层可以使表面钝化，或者与金属沉积同时脱附。我们表明，这些电化学特性可以与光栅微喷射电极相结合，直接对SAMs进行图案化，并在无需光刻步骤的情况下制备图案化金属膜。对于在涂覆有1-辛烷硫醇（OT）和1-十二烷硫醇（DT）的基底上沉积铜的情况，Edes明显低于Emet，导致形成的高分辨率金属图案成核性差且与基底的附着力差。然而，沉积在1-丁烷硫醇（BT）、OT和DT上的镍图案具有与裸金相似的特性（良好的成核性和附着力），因为Edes高于Emet。带有SAMs的基底还抑制了远离光栅微喷射电极处发生的偶然化学反应，如氧还原反应，使样品更耐腐蚀，并改善了我们称为电化学印刷的整体图案化工艺。
