Question

The gecko is a reptile that has the amazing ability to climb smooth surfaces - even glass. Recent discoveries indicate that geckos stick to smooth surfaces via van der Waals interactions between septae on their feet and the smooth surface. When not selling car insurance, geckos climb smooth surfaces.

a. How is this method of stickiness advantageous to the gecko over covalent interactions?
b. Given that van der Waals forces are among the weakest molecular interactions, how can the gecko's feet stick so effectively?

Answer 1

a) This method of stickiness is advantageous over covalent interactions because it is weak and easily reversible.

b) The feet are equipped with millions of septae which collectively produce a synergistic effect that produces a powerful adhesive effect.

Step-by-step explanation:

Geckos have their feet studded with tiny hair-like substances called septae, and these substances interact with the surfaces on which the Gecko climbs using weak van der Waals forces to produce stickiness.

a) The van der Waals interactions for the purpose of climbing is of more advantage over the covalent method of interaction because climbing involves a repetitive action of adhesion to the surface and destruction of such adhesion, and this involves the creation and the breaking of the bonds between the two surfaces easily. van der Waals forces being easily broken helps to achieve effective climbing. If the method of interaction is with a comparatively strong bond, the speed of creation and destruction of such bond is reduced, and the effectiveness of climbing is reduced.

b) Although van der Waals forces are weak forces, each foot of the wall Gecko has millions of septae that each create a van der Waals interaction, and the collective interactions produce a powerful adhesion causing the feet to stick effectively.