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Specially pretreated chitosan macromolecules possess limited solubility in supercritical carbon dioxide. When deposited on mica substrate from such solutions they adopt somewhat extended conformation. The adsorbed macromolecules become mobile on the interface when exposed to water vapour as revealed by environmental scanning force microscopy. During the exposure in the presence of coadsorbed water layer the chitosan strands demonstrate slight tendency to adopt more compact but still two‐dimensional conformation on the substrate.

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We deposited single individual macromolecules of chitosan directly from their solutions in supercritical carbon dioxide onto a substrate surface and applied SFM method to analyze the macromolecular conformation. By means of image processing of many different SFM‐contours of the visualized individual macromolecules, we determined the scaling exponent ν, which describes the correlation between mean square end‐to‐end distances and contour lengths of the adsorbed macromolecules. It was revealed, that the macromolecules, deposited from scCO2 and visualized by SFM, tended to adopt rather extended conformation. The scaling exponent ν was found to be in range of 0.78–0.8, which was slightly above the 3/4 value, corresponding to 2D self‐avoiding walk statistics. Good adhesion of chitosan coatings directly deposited from scCO2 is expected.

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