INTERLAYER STRUCTURE AND MOLECULAR ENVIRONMENT OF ALKYLAMMONIUM LAYERED SILICATES

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