Molecular Organization, Structural Orientation, and Surface Topography of Monoacylated β-Cyclodextrins in Monolayers at the Air−Aqueous Interface

Abstract

The surface behavior of monoacylated beta-cyclodextrins, with hydrocarbon chains of 16, 14, and 10 carbons, has been assessed by the measurement of the surface pressure, surface (dipole) potential, optical reflectivity, and surface topography in monolayers at the air-water interface. For all the derivatives studied, the intermolecular organization adopted along compression-decompression isotherms reveals a rich variety of packing states which imply profound reorganization of the hydrophobic and hydrophilic moieties of the beta-cyclodextrin derivatives in the film, depending on the lateral surface pressure. The intermolecular arrangements are consistent with the adoption of a different and defined orientation of the cyclic oligosaccharide unit, relative to the interfacial plane and the aqueous subphase. This is different from the behavior of the per-substituted derivatives, and none of the changes exhibited by the monosubstituted forms are consistent with the oligosaccharide ring remaining in a fixed orientation along the interface when the surface pressure is varied.

Alkyl esters of l-ascorbic acid: Stability, surface behaviour and interaction with phospholipid monolayers

“…(S1) and (S2)). Such phenomena are not often found in lipid films in the LE state, but have been reported for protein or lipid-protein and lipid-nanoparticles films [33][34][35] and for synthetic amphiphilic molecules able to establish intermolecular H-bonds [36,37].…”

Spontaneous catanionic vesicles formed by the interaction between an anionic β-cyclodextrins derivative and a cationic surfactant

“…Mod-β-CD14 is generated by reaction between 2-tetradecen-1-yl succinic anhydride and β-CD as a mixture of two isomers (1b and 1c in Scheme 1 ). 15 We obtained ModCD14-BHD using a 1 : 1 molar mixture of the cationic and anionic surfactants and after elimination of the counterions as is described in the ESI. † Our goal was to explore the behavior of ModCD14–BHD in water in order to generate self-assemblies such as vesicles that integrated a macrocyclic structure large enough to play the role of a host for small molecules in their hydrophobic core.…”

“…12,13 In our lab, we have synthetized amphiphilic CD derivatives from the esterication of one of the OH groups with an alkenyl succinic acid. 14 These CDs resemble surfactants molecules and form micelles in water, monolayers at the air-aqueous interface 15 and can be solubilized in reverse micelles. 16,17 We considered that this type of molecules might be good candidates to form catanionic surfactants with a peculiar feature, they have an additional recognition site, namely the cavity of cyclodextrin, which might be important for the interaction of the organized structures with a desired guest.…”

Molecular organization and recognition properties of amphiphilic cyclodextrins

“…We have studied the Mod-CD (Cn) compounds at the air-water interface [55]. We found that compounds with 10, 14, and 16 carbon atoms form stable monolayers which upon compression are arranged in different phase states as is evident from the observation of the surface pressure, surface potential, the compression modulus, and the perpendicular dipolar moment (Fig.…”