- Main
Cavitation: Testing the Eulerian and Lagrangian Descriptions of the Dynamics of Soft Materials
- Little, Justin
- Advisor(s): Bruinsma, Robijn F
Abstract
The systems encountered in biophysics typically straddle the line between solidand fluid, and are thus subject to large deformations even at modest stress val- ues. This, along with the presence of material properties such as visco-elasticity and strain hardening, necessitate the use of non-linear elasticity when describ- ing the physics of these systems. In this dissertation, we explore the use of non-linear elasticity theory in describing soft matter physics, with a focus on the specific example of cavitation in polymer gels and similar systems. We first look at cavitation in the context of equilibrium mechanics. In sim- ple materials that obey neo-Hookean elasticity, we show that compressibility effects strongly enhance cavitation. On the other hand, cavitation phenom- ena in gels of flexible polymers in a binary solvent that phase separates are surprisingly similar to those of incompressible materials. We find that, as a function of the interfacial energy between the two solvent components, there is a sharp transition between cavitation and classical nucleation-and-growth. Fi- nally, biopolymer gels are characterized by strain hardening, and even very low levels of strain hardening are shown to suppress cavitation in polymer gel that obey Flory-Huggins theory in the absence of strain hardening. Next, we explore the dynamics of cavitation in non-linear incompressible mate- rials. We find that, while purely elastic systems can be described entirely within either a Lagrangian or Eulerian frame of reference, and viscous fluids with no elasticity can be described entirely within an Eulerian frame, visco-elastic ma- terials such a Maxwell materials cannot be fully described without making use both frames, translating between the two using a known deformation mapping.
Main Content
Enter the password to open this PDF file:
-
-
-
-
-
-
-
-
-
-
-
-
-
-