Dilatational yielding of solid Langmuir monolayers

S. ALIASKARISOHI; TH. M. FISCHER ; N WILKE

AMER CHEMICAL SOC

Año: 2011 vol. 115 p. 11631 - 11631

n a previous work, Muruganathan and Fischer observed laserinducedlocal collapse of a methyl stearate monolayer. These experimentsopened the possibility of studying the collapse mechanism in a highlycontrolled manner, since the laser intensity can be easily varied and collapsehappens in a definite place (the laser focus). In this paper we extended thework presented by Muruganathan et al., describing the local yielding as analternative pathway toward monolayer collapse competing with the globalcollapse of the monolayer. We first corroborated that the laser-inducedcollapse is a thermocapillary effect and afterward determined the thresholdlaser power necessary for the local pathway to win over the global collapse.We show that the laser threshold is determined more by the gradients intemperature and pressure than by the global pressure and temperature. We propose that the flow of material into the focus of thelaser is