Liquid metal imbalance of the surface tension induces a pressure difference between the rear and the head, which produces a thrust to drive the droplet toward the head; at the same time, the hydrogen produced in the electrochemical reaction process also further raises the thrust. The discovery of this phenomenon laid the technical foundation for the development of intelligent motors, vascular robots, fluid pumping systems, flexible actuators and even more complex liquid metal robots. Liquid metal Liquid metal consists of alloys with very low melting points which form a eutectic that is liquid at room temperature. The standard metal used to be
Liquid crystal by moving electric charges, permanent magnetic dipoles are produced by electrons moving about atoms. When a magnetic field is applied, the molecules will tend to align with or against the field. Electromagnetic radiation, e.g. UV-Visible light, can influence light-responsive liquid crystals which mainly carry at least a photo-switchable unit. In the absence of an external field, the director of a liquid crystal is free to point in any direction. It is possible, however, to force the director to point in a specific direction by introducing an outside agent to the system. For example, when a thin polymer coating (usually a