Spontaneous Assembly in Organic Thin Films Spread on Aqueous Subphase: A Scanning Force Microscope (SFM) Study

Abstract

Structure, morphology, and mechanical properties of mono‐ and several‐layer structures of amphiphiles or pure n‐alkane crystallites generated by spontaneous self‐assembly on aqueous subphase have been analyzed by scanning force microscopy (SFM). Pure‐component and heterogeneous mixtures of molecules were allowed to spread and self‐assemble without compression on an aqueous subphase. The self‐assembled films were transferred to an atomically smooth mica substrate by drainage for measurement using SFM. Results were compared with a variety of techniques including cryo‐transmission electron microscopy, grazing incidence X‐ray diffraction, X‐ray reflectivity, and reflectance/absorption infrared spectroscopy. Whereas the collaborative techniques provide spatially‐averaged information, we find that the SFM accesses both individual crystallites and amorphous material, thus providing unique information on the morphology, number of layers, and complementary structural features.

Photochemical activity of organic compounds in ice induced by sunlight irradiation: The Svalbard project

“…The concentration range of the compounds studied was more than 6 orders of magnitude higher than that of the naturally occurred pollutants in polar ice and snow, the molecular aggregation of which could be significantly different. However, a spontaneous aggregation of organic molecules [ Cohen et al , 1996; Trakhtenberg and Naaman , 1998] seems to be probable under natural conditions due to their hydrophobic character. While intramolecular reactions are concentration independent, the formation of dimeric compounds requires two starting molecules being able to reach a close reaction proximity and a proper orientation.…”

Chemical and Biochemical Analysis Using Scanning Force Microscopy

“…have carefully elucidated how differences in cohesive interactions, which affect elasticity, at structures of the same packing density can contribute to the observed adhesion and friction. Other researchers − have also shown that information related to adsorbate orientation and packing density can affect the observed friction. Investigations using SFM to evaluate the interplay between chain length and friction and wear of thiol- and silane-based monolayers have also been conducted. ,,, …”

A review of air–ice chemical and physical interactions (AICI): liquids, quasi-liquids, and solids in snow

“…The role of the disordered interface in promoting chemical reactions and exchange processes has been intensively discussed for decades (Smith and Pounder, 1960;Wang, 1961Wang, , 1964Gross et al, 1987;Dash et al, 1995;Cohen et al, 1996;Finnegan and Pitter, 1997;Petrenko and Whitworth, 1999;Giannelli et al, 2001;Cho et al, 2002;Heger et al, 2005;Vrbka and Jungwirth, 2005;Wren and Donaldson, 2011). A key question that leads to some controversy is whether or not describing the surface in analogy to liquid phase and parameterising processes occurring there based on liquid phase-processes is a valid and realistic picture.…”