Figure 4 Conceptual model of structures of films cast from insoluble surfactants and myoglobin.

Films of Mb and phosphatidylcholines had symmetric peak shapes and relatively small peak separations (Figure 5) [25, 26]. Peak symmetry, equal heights of oxidation and reduction peaks, and linear increases in peak height with scan rate were characteristic of thin-layer voltammetry. Unlike Mb-DDAB, films of phosphatidylcholines became thinner after soaking in buffer for about 1 hr, but then remained stable. Scanning electron microscopy cross-sections suggested thicknesses after thinning less than or equal to 0.5 µm. Midpoint potentials of the CVs (Figure 5) shifted negative with increasing solution pH, as with all Mb-