Gold Micropetals Self‐Assembled by Shadow‐Sphere Lithography for Optofluidic Control

The self-assembly of gold micropetals and microfluidic control using their photothermal properties are demonstrated experimentally in this work. Gold fabricated on a glass substrate the shadow-sphere lithography technique. Each micropetal consists two areas with thin films different thicknesses resulting an inhomogeneous optical absorption distribution. property results generation water vapor microbubble when is immersed degassed irradiated by continuous wave laser. By applying temperature gradient to microbubble, Marangoni flow direction parallel successfully induced. varies combination distribution laser power. This variation can be explained position bubble around bubble. Controlling at which generated found important for controlling direction. technique allows microfluids pumped through irradiation light simple intensity spatially arranged micropetals.