In the present study, the adsorption capacities of two intercalated smectites, CTAB-saponite and CTAB-montmorillonite with a cationic surfactant, were investigated with three fluorescent dyes namely Rhodamine 640 perchlorate rhodamine (Rho), sulforhodamine B (SR) and Kiton red 620 (KR). The adsorption isotherms fit well with the non-linear Langmuir isotherm model and the maximum adsorption capacities of all the composites are determined. The photophysical properties such as anisotropy and fluorescence lifetime of all the fluorescent dyes over the clay materials are determined. The set of experimental data based on X-Ray diffraction (XRD), transmission electron microscopy (TEM), Thermal analysis (TG-DTA) and fluorescence measurements allow highlighting the presence or the absence of interactions between the dyes and the modified clay minerals.

A water molecule is the foundation of life and is the primary compound in every living system. While many of its properties are understood in a bulk solvent, its behavior in a small hydrophobic nanopore still raises fundamental questions. For instance, a wetting/dewetting transition in a hydrophobic solid-state or a polymer nanopore occurs stochastically and can only be prevented by external physical stimuli. Controlling these transitions would be a primary requirement to improve many applications. Some biological channels, such as gramicidin A (gA) proteins, show a high rate of water and ion diffusion in their central subnanochannel while their external surface is highly hydrophobic. The diameter of this channel is significantly smaller than the inner size of the lowest artificial nanopore in which water drying occurs (i.e. 1.4 nm). In this paper, we propose an innovative idea to generate nanopore wetting as a result of which the application of an external field is no longer required. In a nanopore, the drying or wetting of the inner walls occurs randomly (in experiments and in simulations). However, we have shown how the confinement of gA, in a dried hydrophobic nanopore, rapidly generates a stable wetting of the latter. We believe that this simple idea, based on biomimetism, could represent a real breakthrough that could help to improve and develop new nanoscale applications.