A NONLEAK TROUGH FOR MONOLAYERS AT THE AIR WATER INTERFACE/

The problem of barrier leakage in surface pressure-surface area measur ements has been overcome with a trough wherein the sample is compresse d inside a band of teflon-covered spring steel strip. A computer-contr olled stepping motor drive applies force to one side of the band, defo rming it from a rounded triangle to a ''v'' shape. The compression ran ge extends up to 4:1 and is repeatable to +/-2%. Calibration is conven iently and accurately done with a computer-interfaced video imaging an d analysis system. The design greatly simplifies the construction of s urface troughs and completely obviates the possibility of leakage at h igh surface pressures. The trough is useful for investigations involvi ng high surface pressures and/or requiring long times.