Phase Transitions in a Lipid Bilayer Embedded in a Crystalline Matrix

Abstract

The hydrocarbon part of (C 10 H 2 iNH 3 )2CdCl 4 represents a smectic lipid bilayer exhibiting two structural phase transitions in analogy to biomembranes. Single-crystal 13 C NMR and 14 N nuclear quadrupole resonance and x-ray data show that the first transition is connected with a disordering of the polar heads whereas the second represents a partial melting of the lipid chains. A Landau theory describing the melting of bilayer membranes in terms of order parameters used in the theory of liquid crystals has been constructed to explain the obtained results.

Magnetic ordering in two-dimensional Heisenberg antiferromagnets with variable interlayer distances

“…5 In any case some types of chain defects occur at the transition. Previous studies have successfully described the structural phase transitions in the light of the Landau model similar to those in the liquid crystals, 6 and the critical dynamics related to the structural order parameter has recently been reported by the authors. 7,8 When M is Cu or Mn, the magnetic behavior of CnM exhibits a two-dimensional character.…”

Distinct critical fluctuations and molecular motions manifest in a model biomembrane

“…The first systematic studies on the layer structure intercalation compounds including C10Cd were made by Blinc and coworkers using magnetic resonance. Measurements of the order parameters by 35 Cl and 14 N NQR and 1 H and 13 C NMR made possible a consistent understanding of phase transitions and dynamics of the NH 3 and the hydrocarbons using a Landau theory similar to that in the liquid crystal [13,14]. In a 2 H NMR study of C4Cd [17], the evolution of orientational and conformational orders of the hydrocarbon chain was shown to be similar to those in lipid membranes, although the order parameter tensor was not uniaxial and the value in the high temperature phase was two times greater than that in the L a phase.…”

“…In contrast to the case of bis-n-alkylammonium tetrachlorometallates (n-C n H 2nC1 NH 3 ) 2 MCl 4 with MZCd, Cu, Mn and Zn (CnM) [13][14][15][16][17], little information is available on the phase transitions in CnSn [4][5][6][7][18][19][20]. The first systematic studies on the layer structure intercalation compounds including C10Cd were made by Blinc and coworkers using magnetic resonance.…”

On the Order‐Disorder Phase Transition of Anilinium Halides. VI. Phase Transition in 4‐RC6H4NHX⊖, and C6H5NR'HX⊖, X = Br,I. A 79,81 Br and 127I NQR Study

“…Fecher et al studied the high temperature phase of C,H,NH?Br' by X-ray and neutron diffraction [4] and determined the structure of the low temperature phase at T = 100 K by neutron diffraction [5]. 79Br NQR spectroscopy was used by Pies and Weiss [6] to study the mechanism of the phase transition in C6H5NH?Bre. Microscopic observa-*) Permanent address: Kotagodum School of Mines, Osmania University, Kotagodum-507101, India.…”