Transcript Construction of a toolbox for analysis of dummy toy models

How to walk on water and survive
bullet impacts?
Rheology of complex fluids and simulated polymer gels
Explore SDSU 2012
Joris Billen
PhD Candidate Computational Science
San Diego State University & Claremont Graduate University
Supervisor: Prof A. Baljon,
Department of Physics (SDSU)
What is a complex fluid?
• Complex fluids are everywhere:
• Kitchen (chocolate, mayonaise, milk,
ketchup)
• Human body (blood, mucus)
• Products (Cosmetics, liquid crystals,
Shaving cream)
• Fluids showing non-linear viscous
behaviours, as well as viscoelastic materials,
are Complex Fluids.
• But …what is non-linear viscous and
viscoelastic behavior?
Visco-elastic behavior
After application of a stress…
Permanent deformation: Viscous
Restores initial configuration: Elastic
Temporary restoration: Visco-elastic
• Tendons, ligaments, polymers, toothpaste,
gels,…
Non-linear viscous behavior:
Newtonian VS non-Newtonian?
Slope=
viscosity
Non-linear viscous behavior:
Newtonian VS non-Newtonian?
shear thickening
shear thinning
How to walk on water?
viscosity
Shear
thickening
How to survive bullet impacts?
viscosity
Shear
thickening
Shear thinning
viscosity
Polymers
Polymer = repeating units of monomers
Associating polymer gels
Polymer chains in a solvent
Reversible Network
Rheological response gel
Shear
thinning
Viscosity
Newtonian
Shear
thickening
[J.Sprakel et al.,
Soft Matter (2009)]
Shear rate
Contact lenses
Wound dressings
Paintball fill
Applications
Cartilage replacement / implants
Actin filaments
Controlled
drug delivery
Injectable gels
Self-healing materials
So … what do you do all day?
Modeling the physics of a
polymer gel
Computer simulations of
polymer gels
1000 polymer chains
of 8 beads long
However …we don’t
work with pictures
but with files of
-coordinates of
atoms
-connections in
network
Computer simulations of
polymer gels
Calculate
properties that
are impossible
to measure
experimentally
6
3
2
3
5
4
Our work on the cover of a
magazine
Structure gel
network
similar
to robust
computer
networks
J. Billen, M. Wilson, A.
Rabinovitch, A. R. C.
Baljon,
Europhys. Lett. 87 (2009)
68003.
Thank you for your attention!
Non-Newtonian Dubstep