ROBUST FUNCTIONALIZED ORGANIC THIN FILMS ON GOLD: FABRICATION, CHARACTERIZATION, AND THEIR APPLICATIONS

Date

2015-05

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Abstract

Four series of robust, functionalized organic thin films on gold were generated that include custom-designed bidentate adsorbates: (1) a series that features a carboxylic acid-terminated alkanedithiol, (2) a series that demonstrates the utility of a Boc-protected ω-amino alkanedithiol, (3) a series that showcases molecularly mixed films generated from perfluoro-terminated, oligo(ethylene glycol)-terminated, and n-alkyl-terminated alkanedithiols, and (4) a series that highlights the stability of α,ω-difunctional radical initiators having dithiol headgroups. All of these adsorbates utilize dithiol headgroups to enhance their thermal and chemical stability, and a phenyl-based framework to connect these headgroups to a single alkyloxy chain, providing a means of extending the functionality of the tailgroup away from the surface of gold. The structural features of the resulting films were characterized by ellipsometry, X-ray photoelectron spectroscopy, and polarization modulation infrared reflection-absorption spectroscopy and compared to those derived from monodentate adsorbates having each of the featured functional termini. The results of the structural analyses indicate that films derived from bidentate adsorbates are less densely packed than films derived from analogous monodentate adsorbates. However, functionalized organic thin films derived from the featured bidentate adsorbates demonstrated several advantages for use in nanoscale coatings: (1) thermal stability (carboxylic acid-terminated alkanedithiol, Boc-protected ω-amino alkanedithiol, and α,ω-difunctional radical initiator adsorbates having dithiol headgroups), (2) chemical stability (Boc-protected ω-amino alkanedithiol and α,ω-difunctional radical initiator adsorbates having dithiol headgroups), and (3) stable mixed-monolayers (perfluoro-, oligo(ethylene glycol)-, and n-alkyl-terminated alkanedithiols).

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Keywords

functionalized organic thin films, stability

Citation

Portions of this document appear in: Lee, Han Ju, Andrew C. Jamison, Yuehua Yuan, Chien-Hung Li, Supachai Rittikulsittichai, Irene Rusakova, and T. Randall Lee. "Robust carboxylic acid-terminated organic thin films and nanoparticle protectants generated from bidentate alkanethiols." Langmuir 29, no. 33 (2013): 10432-10439. And in: Lee, Han Ju, Andrew C. Jamison, and T. Randall Lee. "Boc-protected ω-amino alkanedithiols provide chemically and thermally stable amine-terminated monolayers on gold." Langmuir 31, no. 7 (2015): 2136-2146.