Accordingly, all hydrophobized KPHIs are also completely selectively dispersed in the organic top layer of the biphasic H2O/1-octanol system (Figure ). The synthesized KPHI shows a typical X-ray diffraction (XRD) pattern with the maxima at ca. 28.3 and 8.1 corresponding to the (002) and (001) crystal planes of KPHI, respectively (Figure ). The sol-gel modification of the parent material with SiO2 does not significantly alter the diffraction pattern, with an exception that the peak intensities become lower, owing to the dilution of KPHI with silica, and a slight shift of the (002) reflection can be observed. The latter effect is ascribed to the partial ion-exchange of K + for H + and to the protonation of the polyheptazine structure leading to the changes in - stacking. This shift of the peak towards lower 2 values is even more pronounced for the KPHI-HTS and KPHI-OTS samples, resulting in the (002) peak position of ca. 27.4, while the XRD pattern of KPHI-HMDS does not manifest such a displacement (Figure ). This further peak displacement observed for KPHI-HTS and KPHI-OTS is possibly due to a higher degree of protonation and of the extent of exchange of K + for H + in the chloroalkylsilanes-modified materials, which can be explained by the protonation effect of HCl evolved during the hydrophobization as the result of the silylation agent reaction with silanols.