AVS 51st International Symposium
    Surface Science Tuesday Sessions
       Session SS2-TuM

Invited Paper SS2-TuM3
High Resolution Mapping of Compositional Differences and Reactions at Buried Interfaces by Electric Force Microscopy

Tuesday, November 16, 2004, 9:00 am, Room 210C

Session: Self Assembled Monolayers
Presenter: M.D. Porter, Iowa State University
Authors: H. Takano, University of Pennsylvania
G. Edwards, Iowa State University
A.J. Bergren, Iowa State University
J. Driskell, Iowa State University
R.J. Lipert, Iowa State University
M.D. Porter, Iowa State University
Correspondent: Click to Email
The ability to interrogate the chemical composition of organic films is of vast importance to many areas in interfacial and surface science (e.g., electrocatalysis, corrosion inhibition, organic electronic devices, and biocompatability). This presentation describes two sets of results that demonstrate the ability of electric force microscopy (EFM) to map compositional differences of organic monolayers buried under thick polymer films. The first example examines the compositional mapping of organic monolayers buried under an ~430 nm film of polystyrene. The underlying adlayer was patterned onto a gold surface using the microcontact printing of CH3(CH2)16SH followed by solution deposition of HO(CH2)16SH. This procedure results in alternating domains of different terminal groups. Results show that the imaging mechanism exhibits sufficient contrast to function as a mapping methodology for buried functional groups. The second example presents the results from monitoring photochemical reactions of polymeric films deposited on organic monolayer-covered metal substrates. UV-light was irradiated on the polymer/monolayer/metal composites through a photomask, resulting in alternating domains. These findings show not only that EFM can distinguish the domains of reacted and non-reacted portions, but also that EFM can provide sufficient contrast as a subsurface mapping technique. Issues related to the imaging mechanism are also examined. Models that explore the fundamental basis of this capability are also discussed.