The next surprising finding that required clarification was the apparent lack of proportionality between the amount of deposited PSiFe particles at the KCl-containing subphase and the occupied area at the interface (Figure ). Applying more material onto the air/water subphase did not increase the occupied area, and the isotherms overlapped when expressed as a function of the trough's area. Such behavior was not observed at pure water, where reasonable proportionality between the amount of particles and their occupied area was observed.