Chapter 10: Chemo-mechanical Effects for Information Processing with Camphor Particles Moving on a Water Surface

We discuss the potential applications of self-propelled camphor particles that move on the water surface for information processing. We consider the case in which camphor particles play a double function. They are used for information coding and they are information carriers. The binary information coding is assumed: the presence of a camphor disk at a given point of space and at a specific time is interpreted as the logic TRUE variable, the absence is associated with the logic FALSE. We have demonstrated, both in experiments and in numerical simulations, that the flow of information coded as described above can be forced and controlled by dynamically changing the geometry of the channel where camphor disks move. The coupling between a camphor disk and channel geometry is achieved by movable elements that adjust their positions according to the local value of the surface tension. We described construction of a signal diode for information coded in camphor disks. It allows for disk propagation in one direction, but blocks the disk motion in the reverse direction. Interactions between disks and movable elements of the channel allow the design of systems that function as logic gates. Here we describe construction of the XOR gate and discuss its reliability.