Tarnish protection of silver by octadecanethiol self-assembled monolayers prepared in aqueous micellar solution

Carborane–thiol–silver interactions. A comparative study of the molecular protection of silver surfaces

“…The former species are significantly more stable toward heating [9], chemical substitution [10], exposure to X-ray radiation [9], and, as we show here, they provide superior protection for silver surfaces. The corrosion of silver in a hydrogen sulphide containing atmosphere is accompanied by colour changes and yellowish brown tints have been noted previously [3,11,12]. In comparison, we have observed well-defined colour changes from lustrous silver, through yellow, violet, blue, and finally to grey.…”

“…For the purposes of a comparison with carboranethiols, we first describe the protective abilities of selected organic derivatives. Three alkanethiols, 1-butanethiol, 1-octanethiol, and 1-dodecanethiol, were used to investigate the influence of alkyl chain length on the capacity of the molecular layer to protect the silver surface, and, in agreement with previous studies [11,12], a better protection was achieved with the longer alkyl group. Fig.…”

Transport of TiO2 nanoparticles in soil in the presence of surfactants

“…where Ф is the volume fraction of coating within the brush layer (d) (1.31 nm, 10 nm, and 3.2 nm respectively for TX-100, SDBS, and CTAB were taken for calculation according to other studies (Liang et al, 2009;Muller et al, 1998;Yuan et al, 2002)), Г max is the maximum attained surface excess concentration (1.0 mg m −2 , 10.0 mg m −2 and 1.5 mg m − 2 for TX-100, SDBS and CTAB, respectively) (Tkachenko et al, 2006;Li and Tripp, 2004), χ is the Flory-Huggins solvency parameter (a value of 0.45 was taken for calculation), M w is the molecular weight of the surfactant (628 g mol − 1 , 348.48 g mol − 1 , and 364.45 g mol −1 for TX-100, SDBS, and CTAB, respectively), ρ is the density of adsorbed surfactant layer (0.98 g cm − 3 , 1.1 g cm − 3 , and 0.95 g cm −3 for TX-100, SDBS, and CTAB, respectively), and v is the volume of a solvent molecule (0.03 nm 3 ) (Wang et al, 2012). The estimation of osmotic and elastic repulsive potentials (defined in the range of d ≥ h N 0) between coated-nTiO 2 and an uncoated flat surface is given in the following expression as (Song et al, 2011):…”

Ancient silver artefacts: corrosion processes and preservation strategies

“…They found after electrochemical testing that the best protection system is offered by polyo-phenetidine in an organic solvent by showing good adherence and protection at applied potential at elevated temperatures. Recent studies by Liang et al [29], McEwan et al [30] and Evesque et al [31] have shown the protective effectiveness of thiol compounds on silver substrates. These compounds have a capacity to form a self-assembled protecting membrane.…”