TY - JOUR
T1 - Capillary Force on a Nanoscale Tip in Dip-Pen Nanolithography
AU - Jang, Joonkyung
AU - Schatz, George C
AU - Ratner, Mark A
PY - 2003/1/1
Y1 - 2003/1/1
N2 - Monte Carlo simulation has been used to characterize the capillary force due to the condensation of a liquid meniscus between a tip with a nanoscale asperity and a flat surface. To consider both hydrophobic and hydrophilic molecules coating the tip as a model of dip-pen nanolithography, tips with various wettabilities are studied. The capillary force due to the meniscus is calculated for various saturations (humidities). We have implemented a thermodynamic integration technique that can project the force into energetic and entropic contributions. In most cases, the force is mainly energetic in origin. At the snap-off separation where the meniscus disappears, the tip feels a significant entropic force at high saturation. Our calculation shows nonmonotonic behavior of the pull-off force as a function of saturation, which is in qualitative accord with experiments.
AB - Monte Carlo simulation has been used to characterize the capillary force due to the condensation of a liquid meniscus between a tip with a nanoscale asperity and a flat surface. To consider both hydrophobic and hydrophilic molecules coating the tip as a model of dip-pen nanolithography, tips with various wettabilities are studied. The capillary force due to the meniscus is calculated for various saturations (humidities). We have implemented a thermodynamic integration technique that can project the force into energetic and entropic contributions. In most cases, the force is mainly energetic in origin. At the snap-off separation where the meniscus disappears, the tip feels a significant entropic force at high saturation. Our calculation shows nonmonotonic behavior of the pull-off force as a function of saturation, which is in qualitative accord with experiments.
UR - http://www.scopus.com/inward/record.url?scp=85038312600&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85038312600&partnerID=8YFLogxK
U2 - 10.1103/PhysRevLett.90.156104
DO - 10.1103/PhysRevLett.90.156104
M3 - Article
AN - SCOPUS:85038312600
VL - 90
JO - Physical Review Letters
JF - Physical Review Letters
SN - 0031-9007
IS - 15
ER -