In this project funded by the Macromolecular, Supramolecular and Nanochemistry Program of the Chemistry Division, Paul Weiss of the University of California at Los Angeles will study fundamental surface substrate-molecule interactions that underpin important surface chemistries and engineering. The approach is to synthesize, prepare and characterize self-assembled monolayers (SAMs) of cage thiols that have limited degrees of conformational freedom, to prepare SAMs of bifunctional cage molecules and study their lateral interactions and fundamental reactivities, and to map the surface potentials experienced by asymmetric molecules such as thiophenes on metal surfaces. The broader impacts involve training undergraduate students, graduate students, and postdoctoral researchers, disseminating research results through publications and presentations at national conferences, and enhancing research infrastructure through establishing collaborations with four-year colleges.

This work would advance our fundamental, atomic scale knowledge about how molecules interact with surfaces. The proposed work could have significant impacts on the fields of nanoscience, nanotechnology, and electronic materials and devices and could generate innovations for industries ranging from microelectronics to catalytic chemical manufacturing.

Project Report

We have designed molecules, assembled them, and measured these assemblies at the nanoscale with scanning probe microscopies and spectroscopic imaging, and at the ensemble scale with spectroscopies and other measurements. We have evidence that cage molecules with dipole moment components parallel to the surface outcompete those with dipoles normal to the surface. This indicates that lateral dipoles must align to lead to favorable interactions. Such alignment has never been observed and we have unique tools to test this idea. We have used a combination of spectroscopic imaging and mathematics to test this idea. We have observed domains of aligned dipoles in carboranethiols. We have used molecular dynamics simulations coupled to the experiments. The domain sizes match between experiments and simulation. Further control experiments are required, but the idea that we can align cage molecules is significant in controlling interactions and building off the surface into three dimensions. We have developed a new chemical patterning method as well as a means to create a supported monolayer of metal. Chemical lift-off lithography has been used to make patterns as small as 15 nm with 2 nm precision (limited by the master of the stamp used). Patterns can be made across millimeters of surfaces. Patterns can be made in three different ways - by patterning the stamps, the monolayers, or the substrates.

Agency
National Science Foundation (NSF)
Institute
Division of Chemistry (CHE)
Type
Standard Grant (Standard)
Application #
1013042
Program Officer
Timothy E. Patten
Project Start
Project End
Budget Start
2010-09-01
Budget End
2013-08-31
Support Year
Fiscal Year
2010
Total Cost
$490,000
Indirect Cost
Name
University of California Los Angeles
Department
Type
DUNS #
City
Los Angeles
State
CA
Country
United States
Zip Code
90095