13C NMR study of the structural phase transition in C10H21NH3Cl

Abstract The temperature dependence of the order parameter for the rotational motion of the alkyl chains between two equilibrium orientations separated by 90° has been measured by 13 C NMR in C 10 H 21 NH 3 Cl. The results show that the onset of rotations together with a partial melting of the chains makes the effective chain diameter eventually larger than half the low temperature lattice distance thus driving the transitions from an intercalated to a non-intercalated structure.