We demonstrated that viscosity measurement using a spinning laser-trapped microsphere depends on the hydrophobicity or hydrophylicity of a spherical material. Reduction in viscous drag was observed in hydrophobic liquid crystal droplets. Rheology on a liquid crystal surface with D2O was demonstrated by spinning and stopping a laser tweezed droplet. The importance of nonslipping boundary conditions in viscosity measurements is discussed.
Japanese Journal of Applied Physics,
Vol. 45, no. 2A (2006), pp. 977-982