Characteristic Features of Amphiphilic P-Functionalized Calixarene Monolayers at the Air/Water Interface

Abstract

The combined application of surface pressure−area (π−A) isotherms, Brewster angle microscopy (BAM), and grazing incidence X-ray diffraction (GIXD) offers a powerful possibility to characterize the amphiphilic P-functionalized calix[4]arene monolayers at the air/water interface. The studies are performed with two calix[4]arene bisphosphonates 1 and 2, which are phosphorylated in the same way at the upper rim and differ only in the number of alkyl chains at the lower rim (compound 1 with four n-dodecyl chains; compound 2 with two n-dodecyl chains in opposite positions). Significant differences exist in the π−A isotherms of the two calix[4]arene bisphosphonates 1 and 2 monolayers. In the case of derivative 1, they resemble those of usual amphiphiles with the characteristic temperature dependence and a coexistence region between a fluid and condensed phase. The π−A isotherms of derivative 2 deviate considerably from those of typical amphiphilic monolayers having no temperature dependence and no “plateau” regi...