View source for Nanopin film

'''Nanopin film''' is an experimental material in [[nanotechnology]] developed in 2005 with unusual [[hydrophobic|superhydrophobic]] properties {{Ref|1}}. A droplet of water makes contact with the surface of this film and forms an almost perfect sphere with a [[contact angle]] of 178[[degree (angle)|°]]. This happens because it is covered with [[Nanoscopic scale|nanoscale]], topped-off [[Pin (device)|pin]]s or [[Cone (geometry)|cones]] [[perpendicular]] to the surface. The surface is regarded as a [[composite material]] with mostly air and a small fraction constituted by the tops of the cones. When the [[contact angle]] of the cone material is sufficiently large, [[Cassie's law]] predicts large contact angle values for the composite.

This particular nanopin film is produced with [[borosilicate glass]]. A solution of CoCl<sub>2</sub>•6H<sub>2</sub>O or [[cobalt chloride hexahydrate]] is heated at 60 [[°C]] for 24 hours in a [[chemical bath deposition]] to form a [[brucite]] type [[cobalt(II) hydroxide]] layer with composition
:CoOH<sub>1.13</sub>Cl<sub>0.09</sub>(CO<sub>3</sub>)<sub>0.39</sub>.0.05H<sub>2</sub>0

The top coating is provided by [[lauric acid]] in a separate step. A 3 square micrometer surface now contains on average 166 such cones with cone height of around 100&nbsp;nm, and the cone diameter at the tip is 6.5&nbsp;nm. The [[Cassie's law]] prediction for this material with the [[lauric acid]] [[surface area]] contact fraction of 0.000612 and flat film [[contact angle]] of 75[[degree (angle)|°]] is 177.8[[degree (angle)|°]].

== See also ==
{{Portal|Science|Technology}}

== References ==
# {{Note|1}} ''Superhydrophobic Perpendicular Nanopin Film by the Bottom-Up Process'' Eiji Hosono, Shinobu Fujihara, Itaru Honma, and Haoshen Zhou [[J. Am. Chem. Soc.]]; '''2005'''; 127(39) pp 13458 – 13459 [http://pubs.acs.org/doi/abs/10.1021/ja053745j Abstract]  [http://pubs.acs.org/doi/suppl/10.1021/ja053745j/suppl_file/ja053745jsi20050815_065444.pdf Supporting info with pics]

[[Category:Nanomaterials]]