Well-ordered structure of N-octadecanoyl-l-alanine Langmuir–Blodgett film studied by FTIR spectroscopy

N-Octadecanoyl-l-alanine Langmuir–Blodgett films have been studied by FTIR grazing angle reflection and transmission measurements. The N–H and CO (in amide and carboxylic acid) groups are oriented almost parallel to the substrate surface. The hydrocarbon chains are tilted regularly with a preferred orientation of C–C–C planes parallel to the substrate surface. The anisotropic arrangement of enantiomeric molecules that twist from neighbor to neighbor gives the aggregate chirality in the two-dimensional condensed state.