Neutron spin–echo investigations of membrane undulations in complex fluids involving amphiphiles

Abstract

The intermediate functions I( Q, t) obtained from neutron spin–echo (NSE) experiments were well fitted to I(Q,t)=I(Q,0) exp[−(Γt) 2/3] for the bicontinuous microemulsion and the lamellar phases of the C 12E 5/ n-octane/water system and also for the lamellar phase of the DPPC/water/CaCl 2 system. The relaxation rate Γ increased as Q 3. These results support the theory presented by Zilman and Granek [Phys. Rev. Lett. 77 (1996) 4788]. Bending modulus of the membrane ϰ was estimated in the C 12E 5/ n-octane/water system and in the DPPC/water/CaCl 2 system using their theory.