Scanning tunneling microscopy studies of corrosion passivation and nanometer-scale lithography with self-assembled monolayers /
possible applications of organomercaptan self-
| Main Author: | |
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| Format: | Thesis Book |
| Language: | English |
| Published: |
[Place of publication not identified] :
[publisher not identified] ;
1998.
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| Subjects: | |
| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=733037041&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | possible applications of organomercaptan self- assembled minelayers (SAMs) for corrosion castigation and nanometer-scale lithography. We examined linear- chain n-alkanethiol and aromatic SAMs in these studies and used scanning tunneling microscopy (STM) as the main tool for surface characterization. the corrosion castigation properties of SAMs were studied on Au in aqueous CN' and Br' solutions and on undemotentially deposited Cu (CU-UPD) in aqueous HClO4. All the SAMs studied reduce the rate of corrosion and shift the potential for corrosion positive of its onset on the unmodified metals. Corrosion of SAM- modifed metals usually begins at defects in the manslayer and the morphology of the corroding metal surface depends on the functional end group of the SAM. The chain length and functional end group of SAMs were varied to determine which factors lead to the most corrosion pagination. SAMS with longer chain lengths and more hydrophilic functional end groups (OH and COOH) protect the best. Corrosion castigation by linear-chain and aromatic SAMs was compared. We found that if the thickness and functional end group are the same, aromatic SAMs are superior. One goal of this research was to improve the barrier properties of SAMS. This can be achieved by depositing one layer of Cu on Au before adsorbing the SAM. We also used SAMs as resists in STM lithography experiments. An Ag- coated STM tip was used to pattern a SAM-modified Au surface by removing thiol molecules selectively under the tip. Patterns having critical dimensions of 25 nm were formed in this way. Next, Ag was electrochemically deposited from the tip into the pattern. Nanometer- sized metal deposits were created on the surface in a controlled fashion with this two-step approach. The SAM patterning and Ag deposition were the result of Faradaic electrochemistry occurring between the tip and the surface. The nano-scale electrochemical cell was completed by nanodroplets of water condensed from the humid air. |
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| Item Description: | Vita. "Major Subject: Chemistry". |
| Physical Description: | xiv, 144 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilm Inc. |
| Bibliography: | Includes bibliographical references (leaves 121-140). |