FIGURE 3.

Relaxation after a rapid change in surface pressure below π_e. Films of POPC spread to 5 ± 4 mN/m were compressed at 74 ± 6 min⁻¹ to 41 ± 1 mN/m and then held at constant surface pressures. Area is expressed relative to the initial value when the film first reached its isobaric surface pressure. The split time and area scales distinguish the initial rapid compression from the subsequent isobaric relaxation. The curve shown is representative of four experiments. Symbols indicate mean ± SD at selected times.