in the contact line uses low melting temperature metal melted and deposited onto micro/nano structured surfaces. When the metal cools and solidifies, it is removed from the surface. flipped, and inspected for contact line micro geometry. There have been a few efforts in fabricating a surface with tunable wettability. For the purpose of spontaneous droplet mobility, a surface can be fabricated with varying tower widths and spacings to gradually increase the free energy of the surface. The trend shows that as tower width increases, the free energy barrier becomes larger and the contact angle drops, lowering the hydrophobicity of the material. Increasing tower spacing will increase the contact angle, but also increase the free energy barrier. Droplets naturally move towards areas of weak hydrophobicity, so to make a droplet spontaneously move from one spot to the next, the ideal surface would consist of small width towers with large spacing to large width towers with small spacing. One caveat to this spontaneous motion is the resistance of stationary droplets to move. Initial droplet motion requires an external stimulus, from something as large as a vibration of the surface or as small as a simple syringe “push” as it is released from the needle. An example of readily tunable wettability is found with special developed fabrics. By stretching a dip-coated commercial fabric, contact angles were typically allowed to increase. This is largely caused by an increase in tower spacing. However, this trend does not continue towards greater hydrophobicity with higher strain. Eventually, the Cassie-Baxter state reaches an instability and transitions to the Wenzel state, soaking the fabric. An example of a biomimetic superhydrophobic material in nanotechnology is nanopin film. In one study a vanadium pentoxide surface is presented that can switch reversibly between superhydrophobicity and superhydrophilicity under the influence of UV radiation. According to the study any surface can be modified to this effect by application of a suspension of rose-like particles for instance with an inkjet printer. Once again hydrophobicity is induced by interlaminar air pockets (separated by 2.1 nm distances). The UV effect is also explained. UV light creates electron-hole pairs, with the holes reacting with lattice oxygen creating surface oxygen vacancies while the electrons reduce to . The oxygen vacancies are met by water and this water absorbency by the vanadium surface makes it hydrophilic. By extended storage in the dark, water is replaced by oxygen and hydrophilicity is