We measured the frequency dependence of the longitudinal viscosity and the layer compression modulus of homeotropically aligned multilamellar film of hydrated dimyristoyl phosphatidylcholine (DMPC) at low frequencies from 10 Hz to 1 kHz, varying temperature (T) and relative humidity (RH) systematically. We have, for the first time, demonstrated unambiguously that in the Lα phase (the lyotropic smectic-A phase) the longitudinal viscosity diverges as 1/ω when the circular frequency goes to zero. In addition, we were able to construct the T-RH phase diagram of the Lα-Lβ′ transition of hydrated DMPC, based upon the T and RH dependences of the layer compression modulus. The phase boundary thus determined agreed well with that obtained by X-ray scattering by Smith et al. (J. Chem. Phys. 92 (1990) 4519).
|Journal||Japanese Journal of Applied Physics, Part 2: Letters|
|Issue number||11 A|
|Publication status||Published - 1992 Nov 1|
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)