INCLUSION COMPOUND FROM A SEMIFLUORINATED ALKANE AND BETA-CYCLODEXTRIN

Inclusion compds. (ICs) were obtained for the first time from a semi-fluorinated n-alkane [F(CF2)8(CH2)16H, abbreviated F8H16] with β-cyclodextrin (β-CD) in water. Because of the hydrophobic nature of the two constituent blocks, the semi-fluorinated alkane readily penetrates the hydrophobic CD's cavity, to avoid contact with water, and produces a fine cryst. powder. The F8H16/β-CD inclusion compd. was obtained by spreading some crystals of the semi-fluorinated alkane onto the surface of a concd. β-CD aq. soln. (16 mM), at 70 °C and sonicated. The cryst. ICs were studied through differential scanning calorimetry, Fourier transform IR spectroscopy, X-ray diffractometry, and at. force microscopy (AFM), and they were identified as novel systems, with different structure and behavior from the two parent mols. According to X-ray diffractometry, the host-guest system presents the channel type structure that is typical of polymer-CD inclusion compds. At. force microscopy confirms the presence of tubular structures obtained from dispersion of the F8H16/β-CD inclusion compd. The formation of such supramol. assemblies may be useful for the encapsulation of fluorinated hydrophobic materials and for the insertion of specific polymeric chains onto the surface of cyclodextrin-grafted fibers and textiles. AFM expts. show the presence of large nanotubes in the dried samples, which result from the aggregation of several F8H16/β-CD inclusion compds.