Preparation and characterization of hybrid organic-inorganic composite materials using the amphoteric property of amino acids:: Amino acid intercalated layered double hydroxide and montmorillonite

Deprotonated and protonated forms of L-tyrosine or L-phenylalanine were intercalated by Zn-Al hydrotalcite (HT) and Na-montmorillonite (Na-mont), respectively. The intercalated materials were characterized by powder X-ray diffraction, BET measurements, and FT-IR spectroscopy. Intercalation was successful as the increased basal spacings attested. For hydrotalcite this increase was always significantly larger than for montmorillonite. This fact indicated that the spatial arrangement of the amino acid moieties was very different. A model for this arrangement has been suggested. A variety of methods showed that L-Tyr(Phe)-HT was thermally less stable than HT, while the heat resistance of L-Tyr(Phe)-mont did not change.