Robben Bavo, Strubbe Filip, Beunis Filip, Callens Michiel, Johansson Thomas, Beales Graham, Fleming Robert, Neyts Kristiaan
Electronics and Information Systems Department and Center for Nano and Biophotonics, Ghent University, Technologiepark Zwijnaarde 126, 9052 Zwijnaarde, Belgium.
CLEARink Displays, 3011 North First Street, San Jose, California 95134, United States.
Langmuir. 2020 Jun 16;36(23):6521-6530. doi: 10.1021/acs.langmuir.0c00943. Epub 2020 Jun 5.
The adsorption of charged inverse micelles at the electrode-liquid interface has an important effect on field screening and on the voltage drop over diffuse double layers. Recently, we analyzed the behavior of inverse micelles in a nonpolar liquid close to this electrode-liquid interface. For the fluorocarbon/surfactant system under study, we are in the limit of slow adsorption and negligible desorption of inverse micelles on the electrodes. Upon applying a voltage step, this results in a measurable Stern layer buildup in the time range of hours clearly distinguishable from the diffuse double layer buildup, which happens in less than 1 s. This Stern layer buildup manifests itself by a shift in the voltage drop from the diffuse double layer to the Stern layer until the voltage drop over the Stern layers reaches the applied voltage, leaving a zero bulk field without the diffuse double layer. New measurements of the transients of Stern layer buildup show that the buildup of charges in the Stern layer is more complex. We explain the observed transient behavior by introducing an asymmetry in the adsorption rate of charged inverse micelles. We provide an equivalent electrical network, an analytical solution to explain the behavior in more detail, and simulations within the diffuse double layer limit for a range of adsorption rates.
带电反胶束在电极 - 液体界面的吸附对场屏蔽以及扩散双电层上的电压降有重要影响。最近，我们分析了靠近该电极 - 液体界面的非极性液体中反胶束的行为。对于所研究的氟碳/表面活性剂体系，我们处于反胶束在电极上吸附缓慢且解吸可忽略不计的极限情况。施加电压阶跃后，这会导致在数小时的时间范围内形成可测量的斯特恩层，这与在不到1秒内发生的扩散双电层形成明显不同。这种斯特恩层的形成表现为电压降从扩散双电层转移到斯特恩层，直到斯特恩层上的电压降达到施加电压，此时没有扩散双电层的零体场。斯特恩层形成瞬态的新测量结果表明，斯特恩层中电荷的形成更为复杂。我们通过引入带电反胶束吸附速率的不对称性来解释观察到的瞬态行为。我们提供了一个等效电路、一个用于更详细解释该行为的解析解，以及在一系列吸附速率下扩散双电层极限内的模拟。
