Sum frequency generation imaging microscopy of patterned self-assembled monolayers with terminal -CH3, -OCH3, -CF2CF3, -C=C, -phenyl, and -cyclopropyl groups

Vibrational spectroscopic imaging is demonstrated for a variety of organic monolayer-functionalized surfaces patterned using microcontact printing. The images from sum frequency generation imaging microscopy (SFGIM) are analyzed using different contrast mechanisms in the interpretation of the transition from stamped to backfilled regions of interest. For this experiment, microcontact printing is used to spatially control the surface monolayers by using a patterned stamp and by varying the terminal functional group of the backfilling solutions. Analysis by the three different methods Suggests that significant mixing occurs between the stamped and backfilled regions, which influence the contrast in the images at the resonant peaks. In addition, the interference between the resonant peaks and nonresonant background also has an effect on the appearance of the image.