Gaseous Hole Closing in a Polymer Langmuir Monolayer
The hole-closing phenomenon is studied in a polymer Langmuir film with coexisting gaseous and liquid phases both as a test of hydrodynamic theories of a two-dimensional fluid embedded in a three-dimensional one and as a means to accurately determine line tension, an important parameter determining size, shape, and dynamics within these and other membrane model systems. The hole-closing curve consists of both a universal linear regime and a history-dependent nonlinear one. Improved experimental technique allows us to explore the origin of the nonlinear regime. The linear regime confirms previous theoretical work and yields a value λ = (0.69 ± 0.02) pN for the line tension of the boundary between the gaseous and liquid phases. The observed hole closing also demonstrates that the two-dimensional polymer gas must be taken as having a small, probably negligible elasticity, so that line-tension measurements assuming that both phases are incompressible should be re-evaluated.
© 2009 American Chemical Society
Gaseous Hole Closing in a Polymer Langmuir Monolayer. Lu Zou, Andrew J. Bernoff, J. Adin Mann Jr., James C. Alexander, Elizabeth K. Mann. Langmuir 2010 26 (5), 3232-3236.