Instantaneous and time-lag breaking of a two-dimensional solid rod under a bending stress

Abstract

In a Langmuir monolayer of NBD-stearic acid, long rods (∼1 mm long, ∼20 μm wide) of a two-dimensional solid phase are obtained at the liquid-solid phase transition. A rod bent in the plane of the water under the effect of a bending stress breaks after a clearly defined delay. This delay is a function of the strain applied to the rod and of the temperature. For large deformations, a second mode of breaking appears and coexists with the previous one: A fraction of the rods break instantaneously while other break after a delay.