pH-dependent appearance of chiral structure in a langmuir monolayer

Grazing incidence X-ray diffraction studies on a heneicosanoic (C21) acid monolayer with cadmium ions in the subphase, at near-zero surface prssure and ~9 degree celsius, show that there exists a pH 'window' within which the monolayer takes on a chiral structure and an ordered superlattice is observed.