Before revision: We present the first systematic measurement of critical dynamics of a 2D liquid with conserved order parameter embedded in bulk 3D fluid, here a lipid membrane in water . We use scaling to collapse time dependent structure factors at multiple wavenumbers and find the effective dynamic exponent z_{ eff } \approx 3 near the critical point.
After revision: We present the first systematic measurement of critical dynamics of a 2D liquid with conserved order parameter . Here we analyze time-dependent correlation functions of a quasi-2D lipid bilayer in water to show that its critical dynamics agree with a recently predicted universality class. In particular, the effective dynamic exponent z_{ eff } \approx 3 near the critical point.