title: Nanoscale molecular transport: the case of dip-pen nanolithography.
abstract: In dip-pen nanolithography experiments, many groups have observed that different tips deliver the same ink at different rates. This article presents a quantitative model for understanding this phenomenon and, importantly, a way of controlling it. An inkjet printer is used to deliver controlled amounts of 16-mercaptohexadecanoic acid (MHA) to atomic force microscope tips in an array. Ink transport from each tip is studied as a function of the number of drops delivered. We show a nonlinear dependence of transport rates on the number of drops that arises from surface-area-dependent dissolution of MHA. From this work, MHA dissolution attempt frequencies were calculated to be between 1.3 x 10(9) and 4.4 x 10(9) Hz.
authors.affiliation: Department of Materials Science and Engineering, International Institute for Nanotechnology, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208-3113, USA.
authors.forename: Louise R
authors.initials: LR
authors.lastname: Giam
authors.forename: Yuhuang
authors.initials: Y
authors.lastname: Wang
authors.forename: Chad A
authors.initials: CA
authors.lastname: Mirkin