Ultraviolet laser-induced submicron spatially resolved superhydrophilicity on single crystal lithium niobate surfaces

Lithium niobate crystal surfaces become superhydrophilic after ultraviolet laser irradiation. The crystal surface hydrophilicity, which was assessed by the contact angle of a sessile drop of de-ionized water, was found to undergo a transition from mildly hydrophobic (contact angle theta(E)approximate to 50 degrees) to a superhydrophilic state (theta(E)< 5 degrees). Patterning of the hydrophilicity at the micron and submicron ranges has been achieved by spatially modulating the illuminating laser beam. (c) 2007 American Institute of Physics.