Nanoscale Capillary Bridges Investigated by Friction Force Microscopy Robert Szoszkiewicz School of Physics, Georgia Tech   Tiny bridges of water between grains provide stability to sandcastles and hold initially wet cement grains in the buildings where we (or some of us) live. Atlanta smog is also affected by capillary condensation, but capillary bridges are present in much smaller scales as well. The functioning of micro- and nano- mechanical machines (MEMS and NEMS respectively), as well as dip-pen nanolitography (an expanding area of nanoscale fabrication), are strongly influenced by nanoscopic capillaries. To investigate the nanoscopic capillaries, we studied local nanoscopic friction forces between an atomic force microscope tip and a glass sample in a humid environment [1, 2]. We showed [1] how and why it is possible to tune friction forces in a predictable way by changing either the sample temperature, or the humidity in the experimental chamber. We also found that the water gas-liquid phase diagram is the same at the macroscopic scale as well as at the nanoscopic tip-sample contact. Through detailed friction measurements at varying sample temperature and humidity we extracted information about kinetics of capillary condensation at the nanoscale [2]. At 40 % relative humidity we found that meniscus nucleation times increased from 0.6 ms up to 4.2 ms when temperature decreased from 332 K to 299 K. The nucleation times obeyed an Arrhenius law, in excellent agreement with theoretical predictions. [1] R. Szoszkiewicz, E. Riedo, Appl. Phys. Lett. 87, 033105 (2005) [2] R. Szoszkiewicz, E. Riedo, Phys. Rev. Lett. 95, 135502 (2005)