Visco-Elasto-Capillary
Thinning
With J. Crest,
Introduction
The aim of this project is to create nano-fibers.
The proposed approach is based on capillary-driven thinning of drying visco-elastic filaments. This method allows for fibers that
are orders of magnitude smaller that those created using current processes. We
developed a fast numerical method to simulate the dynamics of such fibers using
a Giesekus model. The main contributions was to be able
to predict the equilibrium radius (and stability) of fibers. We compute a map
of equilibrium radii as a function of the two main parameters; The
Elasto-Capillary number Ec and the Processability
number P.
Experiments
[Click
on the pictures below for movies in DIVX format]
CABER Experiments using PMMA– J. Crest and G. McKinley
Numerical
Solutions
Numerical simulation of a stable fiber – Processability number= 0.000345
Numerical simulation of a breaking fiber – Processability number= 0
Numerical simulation of a stable fiber with opening phase
Predicted equilibrium fiber radius map:
As a function of the Elasto-capillary number (Ec) and the Processability Number P
Relevant Publications:
J.
Crest, J.C. Nave,
drying viscoelastic filaments”, submitted to J. of Non-Newtonian Fluid Dynamics, PDF
Last Modified by Jean-Christophe Nave - July
2009