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Soft Ultraviolet (UV) Photopatterning and Metallization of Self-Assembled Monolayers (SAMs) Formed from the Lipoic Acid Ester of alpha-Hydroxy-1-acetylpyrene: The Generality of Acid-Catalyzed Removal of Thiol-on-Gold SAMs using Soft UV Light
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Metadata
Document Title
Soft Ultraviolet (UV) Photopatterning and Metallization of Self-Assembled Monolayers (SAMs) Formed from the Lipoic Acid Ester of alpha-Hydroxy-1-acetylpyrene: The Generality of Acid-Catalyzed Removal of Thiol-on-Gold SAMs using Soft UV Light
Author
Pukenas L, Prompinit P, Nishitha B, Tate DJ, Singh NDP, Walti C, Evans SD, Bushby RJ
Name from Authors Collection
Affiliations
University of Leeds; National Science & Technology Development Agency - Thailand; National Nanotechnology Center (NANOTEC); Indian Institute of Technology System (IIT System); Indian Institute of Technology (IIT) - Kharagpur; University of Leeds; University of Leeds
Type
Article
Source Title
ACS APPLIED MATERIALS & INTERFACES
ISSN
1944-8244
Year
2017
Volume
9
Issue
21
Page
18388-18397
Open Access
Green Accepted
Publisher
AMER CHEMICAL SOC
DOI
10.1021/acsami.7b04708
Format
Abstract
Under a layer of 0.1 M HCl in isopropanol, soft ultraviolet (UV) (365 nm) photolysis of the thiol-on-gold self-assembled monolayer (SAM) derived from the lipoic acid ester of alpha-hydroxy-1-acetylpyrene results in the expected removal of the acetylpyrene protecting group. When photolyzing through a mask, this can be used to produce a patterned surface and, at a controlled electrochemical potential, it is then possible to selectively and reversibly electrodeposit copper on the photolyzed regions. Rather surprisingly, under these photolysis conditions, there is not only the expected photodeprotection of the ester but also partial removal of the lipoic acid layer which has been formed. In further studies, it is shown that this type of acid-catalyzed photoremoval of SAM layers by soft UV is a rather general phenomenon and results in the partial removal of the thiol-on-gold SAM layers derived from other omega-thiolated carboxylic acids. However, this phenomenon is chain-length dependent. Under conditions in which there is a similar to 60% reduction in the thickness of the SAM derived from dithiobutyric acid, the SAM derived from mercaptoundecanoic acid is almost unaffected. The process by which the shorter-chain SAM layers are partially removed is not fully understood because these compounds do not absorb significantly in the 365 nm region of the spectrum! Significantly, this study shows that acid catalysis photolysis of thiol-on-gold SAMs needs to be used with caution.
Funding Sponsor
Royal Thai Government; RCUK's Basic Technology Research program
Publication Source
WOS