Systematic control of the packing density of self-assembled monolayers using bidentate and tridentate chelating alkanethiols

Joon-Seo Park; Andy Nguyen Vo; David Barriet; Young-Seok Shon; T Randall Lee

doi:10.1021/la0475573

Systematic control of the packing density of self-assembled monolayers using bidentate and tridentate chelating alkanethiols

Langmuir. 2005 Mar 29;21(7):2902-11. doi: 10.1021/la0475573.

Authors

Joon-Seo Park¹, Andy Nguyen Vo, David Barriet, Young-Seok Shon, T Randall Lee

Affiliation

¹ Department of Chemistry, University of Houston, 4800 Calhoun Road, Houston, Texas 77204-5003, USA.

PMID: 15779965
DOI: 10.1021/la0475573

Abstract

The structural and interfacial properties of self-assembled monolayers (SAMs) on gold derived from the adsorption of a series of 1,1,1-tris(mercaptomethyl)alkanes (i.e., CH3(CH2)mC[CH2SH]3, where m = 9, 11, 13, 15) were investigated. The new SAMs, which possess uniformly low densities of alkyl chains, were characterized by ellipsometry, contact angle goniometry, and polarization modulation infrared reflection absorption spectroscopy. Additional analysis of the SAMs by X-ray photoelectron spectroscopy permitted a direct calculation of the packing densities of the SAMs on gold. The results as a whole, when compared to those obtained on SAMs generated from normal alkanethiols (CH3(CH2)m+2SH), 2-alkylpropane-1,3-dithiols (CH3(CH2)mCH[CH2SH]2), and 2-alkyl-2-methylpropane-1,3-dithiols (CH3(CH2)mC(CH3)[CH2SH]2) having analogous chain lengths, demonstrate that the 1,1,1-tris(mercaptomethyl)alkanes afford SAMs with alkyl chains having the lowest packing density and least conformational order.