FIGURE 1.

Free energy per lipid molecule of the Q_II (μ_Q) and H_II (μ_H) phases relative to the L_α phase as functions of the temperature for a lipid with the curvature energy parameters of DOPE-Me for different values of the L_α phase unbinding energy, g_u. (A) g_u = 0 (i.e., μ_Q and μ_H are determined only by curvature elastic energy via Eqs. 10 and 11, respectively). (B) g_u = 0.01 erg/cm², a value typical of methylated PEs and mixtures of PEs with small mole fractions of PC (Table 1). (C) g_u = 0.15 erg/cm², a value typical of pure PEs (Table 1). The curvature elastic energy parameters for DOPE-Me are from Siegel and Kozlov (14) and Siegel (15).