COEXISTENCE OF BUCKLED AND FLAT MONOLAYERS

The minimum surface tension and respreadability of a surfactant monola yer is limited by a two to three dimensional instability called collap se. Liquid-condensed or solid phase monolayers collapse via fracture f ollowed by loss of material. Liquid-expanded phase monolayers collapse by solubilization into the: subphase. Monolayers that retain a contin uous liquid-expanded phase network surrounding islands of liquid-conde nsed or solid phase collapse at low surface tensions via a localized, large amplitude buckling. The buckled regions coexist with the Aat mon olayer, remain attached to thr interface, and reversibly reincorporate into the monolayer upon expansion. [S0031-9007(98)06943-9].