Stability of Aliphatic Dithiocarboxylic Acid Self-Assembled Monolayers on Gold

Abstract

Self-assembled monolayers (SAMs) were prepared by the adsorption of aliphatic dithiocarboxylic acids (ADTCAs) onto the surface of gold. The films were characterized using a variety of analytical techniques: ellipsometry, contact angle goniometry, polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS), and X-ray photoelectron spectroscopy (XPS). These studies found that the ADTCAs attach to the surface of gold via equivalent binding of both sulfur moieties in the dithiocarboxylic acid headgroup. The stability of these highly orientated SAMs was examined at room temperature under a variety of atmospheric conditions (i.e., under argon, oxygen, air, and humid air) and compared to the stability of related SAMs derived from n-alkanethiols. The ADTCA-based SAMs were observed to decompose relatively rapidly via oxidation of the sulfur headgroups, as judged by XPS. The rate of desorption of the SAMs was observed to vary as a function of the atmospheric conditions as well as the chain length of the ADTCA adsorbates.

Self-assembly mechanism of thiol, dithiol, dithiocarboxylic acid, disulfide and diselenide on gold: an electrochemical impedance study

“…[1][2][3] The stability of self-assembled monolayers (SAMs) is very important in determining their applications. 4 While easily removable protective overlayers are good for soft lithographic patterning, stable SAMs are desirable for corrosion prevention and thin-film lubrication. [4][5][6][7][8] Chelating SAMs derived from chelating dithiols are very stable due to their stabilization by the chelate effect and the energetically disfavored formation of highly strained cyclic disulfides.…”

A regenerating ultrasensitive electrochemical impedance immunosensor for the detection of adenovirus

“…EIS biosensors are typically constructed using either SAMs or electrodeposited conducting polymer base-layers to immobilize the bioactive material (antibody, antigen, DNA) on the surface of the electrode (Amano and Cheng, 2005;Caygill et al, 2012;Fang et al, 2010;Hejazi et al, 2010;Jarocka et al, 2014;Jiang and Spencer, 2010;Li et al, 2013;Park et al, 2010;Tang et al, 2004;Cui and Martin, 2003). The long term stability of both approaches has been problematic (Cui and Martin, 2003;Cometto et al, 2012;Cooper and Legget, 1998;Lee et al, 2004;Nishida et al, 1996;Schoenfisch and Pemberton, 1998;Shadnam and Amirfazli, 2005;Yan et al, 2006), as is regeneration of the antibody. While electrochemical reductive desorption of self-assembled alkanethiols from gold electrodes is common (Pensa et al, 2012;Williams and Gorman, 2007;Mandler and Kraus-Ophir, 2011) and proven to be quite effective, studies pertaining to electrochemical removal of large proteins and pathogens covalently immobilized to self-assembled alkanethiols are infrequent.…”

A ruthenium(II) complex with bis(3,5-dimethylpyrazol-1-yl)dithioacetate built layer-by-layer on silver and gold surfaces

“…Nevertheless, very few studies related to self-assembled monolayers (SAM) of dithiocarbamates and dithiocarboxylates, and only on gold surfaces, have been reported [4][5][6][7]. Even more, no report on SAM of metal complexes with ligands containing dithiocarboxylate terminal groups has been found.…”