topographic (left) and phase (right) images of a patterned self-assembled monolayer with alternating COOH-terminated and CH3 stripes taken using a nitrogen atmosphere topographic (left) and phase (right) images of a patterned self-assembled monolayer with alternating COOH-terminated and CH3 stripes taken at 60% RH
topographic (left) and phase (right) images of a patterned self-assembled monolayer with alternating COOH-terminated and CH3 stripes taken at 15% RH topographic (left) and phase (right) images of a patterned self-assembled monolayer with alternating COOH-terminated and CH3 stripes taken at 90% RH

A patterned SAM with alternating COOH-terminated and CH3 stripes was used to study the effect of relative humidity (RH) on phase image contrast. As the relative humidity of the imaging environment was increased from 0% (nitrogen atmosphere -- top left image set) to 90% RH (bottom right image set), the phase contrast (see right image in each image set) between the hydrophilic and hydrophobic stripes was enhanced. The two other image sets shown above were taken using imaging environments with 15% RH (bottom left image set) and 60% RH (top right image set). Note that the topographic image (left image in each image set) remained relatively featureless, except for some patterning artifacts, as the relative humidity was changed.

This study was done in collaboration with the Polymers Division of NIST's Materials Science and Engineering Laboratory.

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