INTERLAYER STRUCTURE AND MOLECULAR ENVIRONMENT OF ALKYLAMMONIUM LAYERED SILICATES

Transmission Fourier transform infrared spectroscopy (FTIR) was used t o probe the interlayer structure and phase state of intercalated alkyl ammonium silicates by monitoring frequency shifts of the CH2 stretchin g and scissoring vibrations as a function of interlayer packing densit y, chain length, and temperature. A wide range of molecular environmen ts varying from solidlike to liquidlike was found. In general, as the interlayer packing density or chain length decreases or the temperatur e increases, the chains adopt a more disordered, liquidlike structure. In intermediate cases, the chains are neither solidlike nor liquidlik e but exhibit a liquid-crystalline character.