Various driving mechanisms for generating motion of colloidal particles

Driven colloidal particles exhibit a number of interesting nonequilibrium effects. In order to study these effects the driving mechanisms have to be understood in detail. In this paper we show three different driving mechanisms: driving by gravity, by a gradient in a magnetic field, and by a local chemical reaction. The first mechanism can be used to drive a large variety of particles, while the latter two require specially designed particles. We will describe the design of such particles and discuss differences and similarities of the driving mechanisms.