Evolution of Conformational Order During Self-Assembly of n-Alkanethiols on Hg Droplets: An Infrared Spectromicroscopy Study

Abstract

This Letter describes Fourier-transform infrared spectroscopy evidence for the evolution of conformational order and coverage during the formation of n-alkanethiol monolayers on microdroplets of mercury from the solution phase. At the highest coverages obtained by self-assembly, the monolayer is characterized by predominantly all-trans conformational order. For partial monolayers obtained at arbitrarily quenched incubation periods, we find a continuous evolution of the chain conformational order with monolayer coverage. Analyzing these results in light of previously reported models from X-ray scattering reveals a complex self-assembly process in which the density-dependent evolution of the chain conformational order is coupled with that of molecular orientation and density.

Surface tension of liquid mercury: a comparison of density-dependent and density-independent force fields

“…On the other hand, liquid mercury represents a particular interest in electrowetting applications enabling the construction of highly conducting metallic nanowires inside carbone nanotubes, which is actively studied by both experiment and computer simulation [9][10][11][12]. Because of its seamless surface liquid mercury also enables the creation of high quality defectless self-assembled monolayers (SAMs) of various organic molecules [13][14][15]. Therefore the surface of liquid mercury serves as a model system for the experimental study of universal (free of the underlying crystal substrate) properties of numerous organic films [16][17][18][19][20][21][22][23][24][25][26].…”

“…Therefore the surface of liquid mercury serves as a model system for the experimental study of universal (free of the underlying crystal substrate) properties of numerous organic films [16][17][18][19][20][21][22][23][24][25][26]. Moreover, the unique properties of liquid mercury, especially its high surface tension, make Hg droplets superior to other metals for producing metal-SAM-metal [13,27] and metal-SAM-semiconductor [28,29] junctions. This property motivates the wide usage of liquid mercury in organic electronics [27][28][29][30][31][32][33][34], and even in the design of mixed organic-metal systems for information processing [35].…”

Computer simulation and analysis of self-assembled alkylthiol monolayers on the surface of liquid mercury

“…Low density 2D gas phase of thiols on liquid Hg was deduced from the fits by the Volmer isotherm of the data for the thiol surface coverage lower than the one of the first completely filled layer of laying molecules [64]. Fourier-transformed infrared spectroscopy results have also confirmed an increasing ordering in the alkylthiol SAMs on liquid Hg with the increase in the thiol surface coverage [52], but no interpretation of this data in terms of the molecular packing and respective unit cells has been given.…”

“…One could also cover a Hg droplet electrode with an organic layer prior to putting it into contact with the other SAM on the crystalline electrode. Such a technique is applied in order to inhibit the amalgamation of the crystalline electrode by mercury [52]. All these features serve for the wide usage of thiol SAMs in the rapidly expanding field of organic electronics [50][51][52][53][54][55].…”

“…Such a technique is applied in order to inhibit the amalgamation of the crystalline electrode by mercury [52]. All these features serve for the wide usage of thiol SAMs in the rapidly expanding field of organic electronics [50][51][52][53][54][55].…”