AFM mercury fountain pen probe

 

This figure shows a novel , in-situ renewable mercury microelectrode integrated into an atomic force microscopy (AFM) cantilever. The approach is based on a fountain pen probe with appropriate dimensions enabling filling with mercury under changing of the applied pressure at a connected mercury supply. The fountain pen probe utilizes a special design with vertical pillars inside the channel to minimize mechanical perturbation.

As the research of the AFM mercury fountain pen probe was novel, so is the image we created for the University of Twente. The image includes many new techniques, which we reused in our later work.
The goal was to create an image which could be displayed on the covers of scientific journals and magazines. A figure which did not explain or describe (as all the other normal infographics), but rather to display the concept of the AFM mercury pen probe. To show it in full action, and display it as beautiful as possible.

We started with the basic idea and shape of the cantilever. We wanted to create the cantilever in a Discovery Channel ‘slit through’ kind of way which showed the internals of the cantilever. We wanted to do this in false 3D, something never did before. False 3D meaning: completely modeling something in 2D, Photoshop, but making it look like it was modeled in 3D.
But instead of sliding through the full cantilever y-axis, which would deny the 3D shape completely, we only show the internals of the front of the tip. Thus the rest of the 3D model stays intact. To further improve the feel of the 3D model, we decided to show a translucent channel in the cantilever.
Also, to show that the cantilever model is very small, we introduced some heavy Depth of Field, which is a realistic representation of how viewing it through a microscope or SEM would look like.

Below is the first version of the image, where we created the plane on which the mercury falls in a ‘look onto the future’ way. The grid which converges into one point on the horizon helps to endorse this feeling.

A few important changes were made on this first version:

• Mercury has a strong cohesion and low surface tension, so it forms almost perfectly round spheres on a microscale level. These spheres were modeled.
• Mercury is a metal, so highly reflective. The reflections on the mercury spheres were drawn by hand in the second version.
• The ground plane distracts from the cantilver in the first version. This undermines the idea that it all is really about the cantilever. So, only a part of the ground plane is shown in the second version. Furthermore, to increase color diversity in the image the color of the ground plane was changed to green.

With these changes, the second (and final) version was created:

The figure has seen a widespread use across the internet, more than was anticipated. It was first published on the website of the University of Twente, where it was quickly shown as a homepage entry. Multiple websites republished the article, including the figure (see above section). Unfortunately, it was not used as the cover image for Analytical Chemistry, where the publication was submitted to. It was however printed in the Dutch newspaper ‘De Volkskrant’.