title: Bubble-raft collapse and the nonequilibrium dynamics of two-state elastica.
abstract: We report on the collapse of bubble rafts under compression in a closed rectangular geometry. A bubble raft is a single layer of bubbles at the air-water interface. A collapse event occurs when bubbles submerge beneath the neighboring bubbles under compression, causing the structure of the bubble raft to go from single-layer to multilayer. We studied the collapse dynamics as a function of compression velocity. At higher compression velocity we observe a more uniform distribution of collapse events, whereas at lower compression velocities the collapse events accumulate at the system boundaries. We propose that this system can be understood in terms of a linear elastic sheet coupled to a local internal (Ising) degree of freedom. The two internal states, which represent one bubble layer versus two, couple to the elasticity of the sheet by locally changing the reference state of the material. By exploring the collapse dynamics of the bubble raft, one may address the basic nonlinear mechanics of a number of complex systems in which elastic stress is coupled to local internal variables.
authors.affiliation: Department of Physics and Astronomy, University of California, Irvine, California 92697, USA.
authors.forename: Chin-Chang
authors.initials: CC
authors.lastname: Kuo
authors.affiliation: Department of Physics & Astronomy, University of California, Los Angeles, California 90095, USA.
authors.forename: Devin
authors.initials: D
authors.lastname: Kachan
authors.affiliation: Department of Physics & Astronomy, University of California, Los Angeles, California 90095, USA.|Department of Chemistry & Biochemistry, University of California, Los Angeles, California 90095, USA.|Department of Biomathematics, University of California, Los Angeles, California 90095, USA.
authors.forename: Alex J
authors.initials: AJ
authors.lastname: Levine
authors.affiliation: Department of Physics and Astronomy, University of California, Irvine, California 92697, USA.|Institute for Complex Adaptive Matter, University of California, Irvine, California 92697, USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Dennin