Micro-rotors in nematic liquid crystal films with a free surface

Thermocapillary flow is defined as the mass transfer through the interface of two materials due to the surface tension gradient arising from temperature differences. Circular thermocapillary flow, in particular, has been reported at a free surface in homeotropically oriented nematic liquid crystals. Here, we present a detailed discussion on its coupling properties with the director field and the topographical structure at the free surface in a nematic liquid crystal. We also suggest its significance to every applicable field concerning material transport and manipulation in fluidic devices and methods.