Аңдатпа
Abstract This study investigated the interface-induced structuring of water on polymer surfaces under conditions of a strong electrolyte background, reflecting typical real-world aqueous environments where dissolved salts are constantly present. The ionic perfluorosulfonic acid polymer Nafion and the hydrophilic polysaccharide polymer carboxymethyl cellulose, formed as thin films on hydrophilic substrates, were used as models. The interfacial state of water was studied in 1 M NaCl, KCl, KI, and K 2 SO 4 solutions at room temperature using LC microscopy as a visual indicator of lateral heterogeneity and orientation effects, as well as pH and redox potential measurements as integral markers of charge redistribution. In this approach, LC microscopy provided spatial information on interfacial microstructure, whereas Raman spectroscopy revealed molecular-level changes in hydrogen bonding and ion hydration, allowing the microstructural and spectroscopic responses to be directly correlated. The molecular level of changes was assessed using Raman spectra and compared with the observed microstructure. Nafion in chloride electrolytes was shown to cause pronounced acidification and an increase in ORP, consistent with the formation of a strong interfacial charge zone and accompanied by more contrasting and directional textures in LC microscopy, as well as a noticeable restructuring of the O–H region profile in Raman spectra. A different scenario was revealed for CMC, in which ion specificity plays a key role, especially in KI, where the most pronounced oriented LC patterns and differences in the Raman signatures of the hydrogen network are observed in the absence of extreme pH and ORP values. Characteristic ionic markers are detected in Raman spectra in the sulfate system, confirming the involvement of hydration shells and the ionic subsystem in the formation of the interfacial organization. The obtained results demonstrate that the properties of interfacial water are determined by the combined action of the polymer interface chemistry and the nature of the electrolyte, which is important for understanding membrane, sorption, and interfacial catalytic processes in saline waters.