A monolayer Him of 3-aminopropyltriethoxysilane (gamma-APS) was prepared by contact printing with featureless PDMS stamp. First, gamma-APS ink solutions in dry toluene were prepared in a dry nitrogen-filled glove box and immediately used for spin coating onto a PDMS stamp, followed by printing on a silicon wafer. Next, water contact angles and film thicknesses were measured as a function of ink concentration (5-100 mM) and printing time (1-60 min) after printing, as well as after aging in toluene for 24 h. In addition, surface covet-age, topology, RMS roughness and Surface amine density were also evaluated, while the chemical structure of gamma-APS monolayer was analyzed by FT-IR/ATR. Optimum conditions for gamma-APS monolayer with complete coverage were determined to be ink concentration of 20 mM and printing time of 30 min, which resulted in a water contact angle of 93 degrees, film thickness of 0.78 nm and surface amine density of 7.6 molecules/nm(2) (C) 2009 Elsevier Inc. All rights reserved.