Material Characterization of Fluid-loaded Lycopodium Membran
EMSL Project ID
2382
Abstract
This work is to provide the experimental component for an applied mathematics research proposal, which is being submitted to DOE/MICS. The title of that proposal is, Fluid-Solid Interaction for Multi-Scale Computational Science. Therein, it is argued that a fluid-loaded lycopodium membrane is similar to the cell membrane in many respects.Lycopodium is a 20 micron grain, which is covered with fluorinated silanes. The honeycomb-like grains are two-sided, with one side being hemispherical and the opposite side being cut-off with a strongly geometric 120? tri-limbed super-structural feature. The lycopodium particles are pollen-like, and may be dispersed in a fine layer on the free surface of water in a beaker. Fluid-filled water droplets, which are encased in a lycopodium membrane, may be formed by placing a drop of water on the surface of the lycopdium layer and gently rolling the water droplet until it is entirely coated with lycopodium. The resulting lycopodium-encapsulated water droplet will remain on the lycopodium-coated surface of the water for rather indefinite periods of time. This fluid-loaded fluid-filled membrane is quite similar to both a cell membrane and to the transport vesicles of endocytosis/exocytosis. Further, if one was to gently blow a bubble of air into the lycopodium-coated water, a lycopodium-coated air bubble will sit on the surface of the beaker. Looking into the glass beaker at the bottom of the air bubble, a minicus is evident; this miniscus is similar to the miniscus observed in the vesicle formation of the endocytosis process.We conjecture that these similar observations - between cell membranes and lycopodium membranes, between the formation of vesicles and material mixing bubble formation ? are not coincidental. Rather, we argue that the physics and geometry governing these processes is related and we intend to develop this theory via a multi-scale, multi-material, multi-dimensional, multi-physics analysis.We propose to investigate this hypothesis by building a model of the system. In order to do so, we must first characterize the lycopodium membrane. This EMSL User Proposal is to support the experimental material characterization activities.We propose to investigate questions regarding the modeling of the fluid-loaded lycopodium membrane experiment. What gives the membrane its cohesiveness? What is the mechanical relationship between the particles? What is the preferred response of the fluid to the presence of the particles? What are the forces or elastic properties that are required to expand and contract the membrane? What is the ordering of the particles on the surface of the water? Do the particles arrange themselves in multiple layers? Is one side of the lycopodium particle hydrophobic and the other hydrophilic? What are the distances between the centers of mass of the particles? What are the invariant symmetries? Why do the second, third, etc. layers stick to a drop of water? What is the mechanism for surface adhesion?Armed with the answers to these questions, and equipped with a model to describe the dynamics of this system, we will then be in a position to ask similar questions about the nano-scale cellular membrane.
Project Details
Project type
Exploratory Research
Start Date
2002-03-04
End Date
2004-03-09
Status
Closed
Released Data Link
Team
Principal Investigator
Team Members