Phase transitions and collective chain dynamics in a model biomembrane C₁₀H₂₁NH₃Cl

Proton nuclear magnetic resonance (NMR) was employed to investigate the nature of the phase transitions and collective chain dynamics in a model biomembrane C₁₀H₂₁NH₃Cl undergoing an irreversible structural change. The phase transitions were manifest in the second moment and laboratory frame spin-lattice relaxation rate measurements, with a hysteresis upon heating and cooling. The dimensionality and its crossover were explicitly confirmed as well. In addition, the rotating frame spin-lattice relaxation measurements revealed a low-frequency critical collective chain dynamics in the kHz regime, which is associated with the interdigitated to noninterdigitated chain configurational phase transition.