10^-6 - 10^-5 dyne×sec/cm
||Evan. Evans, David. Needham, Physical properties of surfactant bilayer membranes: thermal transitions, elasticity, rigidity, cohesion and colloidal interactions. J. Phys. Chem., 1987, 91 (16), pp 4219–4228 DOI: 10.1021/j100300a003 link p.4220 right column 3rd paragraph
|| Derzko Z, Jacobson K. Comparative lateral diffusion of fluorescent lipid analogues in phospholipid multibilayers. Biochemistry. 1980 Dec 23 19(26):6050-7.  Saffman PG, Delbrück M. Brownian motion in biological membranes. Proc Natl Acad Sci U S A. 1975 Aug72(8):3111-3.  Galla HJ, Hartmann W, Theilen U, Sackmann E. On two-dimensional passive random walk in lipid bilayers and fluid pathways in biomembranes. J Membr Biol. 1979 Jul 31 48(3):215-36.  Evans, E. Hochmuth, R. M. In Current Topics in Membranes and Transport, Vol. 10. Bronner, F., Kleinzeller, A,, Eds. Academic: New York, 1978 p.1.PubMed ID7470449, 1059096, 40032
||"Surface diffusivity measurements of fluorescent membrane probes."
||p.4220 right column 3rd paragraph: "Surface diffusivity measurements of fluorescent membrane probes
can be used to estimate the surface shear viscosity of lipids in the
liquid state the results are on the order of 10^-6-10^-5 dyn×s/cm [primary sources]. On the other hand, dynamic deformations of cell-size vesicles provide extremely useful methods for study of bilayer yield and flow in the frozen (solid) state. Here, the shear viscosity is so large that measurements of probe diffusivity become unreliable."