2026 ASEE Annual Conference & Exposition

When comparing bond strengths, Van der Waals forces are at least an order of magnitude smaller than that of primary bonds, yet Van der Waals interactions can still play a very important role in materials properties. One exciting example is that of geckos, who use van der Waals interactions to climb up vertical walls and even walk upside-down on the ceiling. This “Activities with Impact” demonstration engages students in exploring how atomic bonding and structure of materials relate to emergent macroscopic properties.
To really make the content stick, I bring in a subject matter expert who is well-versed in Van der Waals Bonding. [This expert is my pet gecko, Diesel Truck.] I also bring a USB mini-microscope, which I can plug in and project to the room: we use this to observe the structure of his footpads. This reveals the mechanism he uses to climb up walls: while each van der Waals interaction is small, the hierarchical structure of gecko feet enables millions of interactions, the sum of which creates a large effect. We also compare how Diesel Truck interacts with different material surfaces: he can easily climb on cloth, plastic, wood, and even up a vertical ceramic plate, but he slips when trying to climb up a Teflon-coated pan. Students use this to connect bonding and surface properties.
In a complementary project, students measure the contact angle of water droplets on different surfaces, creating a connection between molecular interactions, wetting behavior, and adhesion. The activity integrates biological inspiration, materials characterization, and surface science in a fun and memorable way!