text: Capillary condensation bridges two surfaces together, with the formation of a meniscus, as is stated above.  In the case of atomic-force microscopy (AFM) a capillary bridge of water can form between the tip and the surface, especially in cases of a hydrophilic surface in a humid environment when the AFM is operated in contact mode. While studies have been done on the formation of the meniscus between the tip and the sample, no specific conclusion can be drawn as to the optimum height away from the sample the tip can be without meniscus formation.  Scientific studies have been done on the relationship between relative humidity and the geometry of the meniscus created by capillary condensation.  One particular study, done by Weeks, illustrated that with the increase in relative humidity, there is a large increase in the size of the meniscus.  This study also states that no meniscus formation is observed when the relative humidity is less than 70%, although there is uncertainty in this conclusion due to limits of resolution.
  The formation of the meniscus is the basis of the Dip-Pen Nanolithography technique.