Fig. 4.
Membrane elastic and viscous properties determined from measurements of the collective thickness fluctuations. (A) Relative area compressibility moduli for the mixed and pure lipid bilayers calculated from the thickness fluctuation amplitude (B) normalized coupling constant (β/βDMPC) calculated by combining the results for the bending modulus and thickness fluctuation amplitude, and (C) calculated membrane viscosity from the compressibility moduli and thickness fluctuation relaxation time τ. Data are at the same relative temperature, T – Tm = 20 °C. The values for xDSPC = 1.0 at T – Tm = 20 °C were extrapolated from the temperature-dependent data. All other compositions were measured at the specified temperature. Solid lines are the arithmetic average of the corresponding properties measured for the single-component membranes.