Fabrication and Characterization of Submicrometer- and Nanometer-Sized Double-Barrel Pipets

Abstract

Submicro- and nanometer-sized glass double-barrel pipets have been fabricated by a laser puller with new pulling programs and have been used to support submicro- and nanometer dual liquid/liquid interfaces. The smallest pipet that can be made by this approach is approximately 20 nm in radius. These pipets have been characterized by cyclic voltammetry and scanning electron microscopy. Generation/collection mode of charge-transfer reaction is demonstrated at the submicro- and nanometer dual-liquid/liquid interfaces. The dependence of collection efficiency upon geometric parameters of the pipets has been discussed. Among the micro-, submicro-, and nanopipets, we have found that the submicro-double-barrel pipets have higher collection efficiencies than that of others and are also very close to the values predicted by the theory. Therefore, in terms of G/C mode applications, the optimal size of double-barrel pipets should be in submicrometer scale. As one of the examples of special application, we have also demonstrated that in the case of no supporting electrolyte, only the nanometer double-barrel pipets can provide reasonably good G/C results.

Investigation of transfer behavior of protonated pyridine at the liquid/liquid interface using dual micropipettes

“…The orifice of the dual micropipette consists of two semi-ellipses and r (the radius) is usually not equal to r 1 . As mentioned above, the geometric effects of dual pipettes on collection efficiency have been exhaustively studied [21,22]. One of the conclusions is that the collection efficiency strongly depends upon the d/r.…”

“…The G/C technique, though promising, was once limited due to insufficiently development of theories. Hu nanometer sized pipettes) [21]. This actually provides a guideline to fabricate pipettes with a certain purpose.…”

“…However, most of work reported so far has involved rather simple systems. For instance, some classical simple IT, FIT and ET [17][18][19][20][21] processes. And published work related to this G/C technique can be counted by fingers, and it has not been popularized.…”

Simulation and experimental verification of the dependence of collection efficiency on the shape of a dual micropipette

“…One of the reasons is that such a G/C device usually has more complicated geometry compared with other G/C techniques, such as well-known rotating ring-disk electrodes [8], closed spaced double microelectrodes [9]. As a matter of fact, it is challenging to simulate mass transport in such a system with an irregular geometry, and there has just been a preliminary theory available for characterization of charge transfer reactions using dual micropipettes [7,10]. Fortunately, lots of researches have proved that numerical simulation is an exceptional powerful tool for quantitative analysis of various electrolysis processes at different shapes of electrodes on the basis of the development and application of various numerical computational methods in the electrochemistry, especially the finite difference (FD), finite element (FE) and boundary element (BE) methods [11−19].…”

“…Using the BE method, Fisher et al [17] have simulated similar systems, and discussed in detail the influence of collection efficiencies by various separating distances between these two microelectrodes. However, for such kind of geometry of a dual micropipette (shown in Figure 1), there has been only preliminary theory available [7,10].…”