The surface lateral diffusion properties of a range of pure phospltolipid-stabilized black foam films (BFF) were studied by fhoresence recovery after photobleaching. The thin films were formed in a specially constructed chamber and fluorescent-labeled by inclusion of low levels of the anionic surfactant 5- (\mathrm{N}) (octadecanoyl) aminofluorescein. A systematic investigation of temperature dependence of the surface diffusion coefficient in the range (8-85^{\circ} \mathrm{C}) was undertaken with phospholipid BFFs stabilized by DMPG, DMPC, DMPE, DLPE, DPPE, DOPE, and DPPA along with some mixtures (DMPC/DMPG and DLPE/ DPPA). It was found that the diffusion coefficient was dependent on the lipid phase state. With the exception of negatively charged DMPG, surface mobility of all lipids in the gel state was due to flow rather than to diffusion. In contrast, above the liquid crystalline phase transition, diffusion predominated and increased with temperature from about (2 \times 10^{-8}) to (9 \times 10^{-8} \mathrm{~cm}^{2} / \mathrm{s}), with a different slope for the different lipids. Increases in the hydrophobic chain length of the phospholipids resulted in a decrease in the diffusion coeflicient for values obtained at any given temperature above the phase transition, in the order DLPE (>) DMPE (>) DPPE. In the case of unsaturated C18:1 DOPE, measurable diffusion extended down to (15^{\circ} \mathrm{C}) compared to (24^{\circ} \mathrm{C}) for DMPC and (45^{\circ} \mathrm{C}) for the other PEs. The relative importance of the effects of molecular chain length, unsaturation, and charge is discussed. 1994 Academic Press, Inc.