Fourier transform infrared (FTIR) spectroscopy has been used to probe the organization of the organic fragmentsin lamellar bridged silsesquioxanes with organic substructures based on alkylene chains of various lengthsand urea groups [O1.5Si(CH2)3NHCONH(CH2)nNHCONH(CH2)3SiO1.5] (n = 6, 8−12). The structure andintermolecular interactions (hydrophobic and H-bonding) of these well-defined self-structured hybrid silicasare discussed in relation to their powder X-ray diffraction patterns. The degree of structural order is determinedby the length and parity of the alkylene spacer. A concomitant enhancement in the degree of condensation ofthe inorganic component and a decrease in the strength of the hydrophobic interactions between the organiccomponents are demonstrated. The strength and directionality of the H-bonding are directly correlated to thecrystalllinity of the organic−inorganic hybrid materials.
