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Two-dimensional synthesis: Ultrathin porous membranes. Final report, December 1, 1993--November 30, 1996

Description: The proposed proof of concept has been accomplished. We have synthesized an ultrathin (7 {angstrom}) covalent molecular grid of the proposed type, composed of 2.5 nm x 2.5 run squares with 1.5 nm x 1. 5 nm square openings, we have demonstrated that it is sturdy (boiling with alcoholic HCl and surface-to-surface transfer), and we have obtained its spectral and STM characterization. The synthesis was based on the originally proposed two-dimensional linear cross-coupling of oriented molecular connectors mounted on pedestals that were constrained to a two-dimensional liquid mercury surface, but the molecules actually used in the successful experiment were different from those intended originally. In this first attempt, only small sheets of the grid were made (up to 0.15 {mu} x 0.15 {mu}), and they did not have long-range order. Both of these problems were undoubtedly caused by the use of an irreversible coupling reaction in the polymerization process, and by the use of a coupler that was not strictly linear and thus permitted easy formation of defects (pentagons instead of squares, etc.). Neither of these limitations are inherent, and we have already submitted research proposals in which we outline how we propose to do the polymerization in a reversible way, yet produce a sturdy polymeric grid, and suggest chemical structures for linear couplers. Patent protection for these results has been applied for by the University of Colorado (following up on a previous conceptual patent already granted) and several publications have been written.
Date: May 28, 1997
Creator: Michl, J.
Partner: UNT Libraries Government Documents Department