82 research outputs found
Cross-linking patterns and their images in swollen and deformed gels
Using the theory of elasticity of polymer gels we show that large-scale
cross-link density patterns written into the structure of the network in the
melt state, can be revealed upon swelling by monitoring the monomer density
patterns. We find that while isotropic deformations in good solvent yield
magnified images of the original pattern, anisotropic deformations distort the
image (both types of deformation yield affinely stretched images in
solvents). We show that in ordinary solids with spatially inhomogeneous profile
of the shear modulus, isotropic stretching leads to distorted density image of
this profile under isotropic deformation. Using simple physical arguments we
demonstrate that the different response to isotropic stretching stems from
fundamental differences between the theory of elasticity of solids and that of
gels. Possible tests of our predictions and some potential applications are
discussed.Comment: 16 pages, 3 figure
Chemically Active Nanodroplets in a Multi-Component Fluid
We introduce a model of chemically active particles of a multi-component
fluid that can change their interactions with other particles depending on
their state. Since such switching of interactions can only be maintained by the
input of chemical energy, the system is inherently non-equilibrium. Focusing on
a scenario where the equilibrium interactions would lead to condensation into a
liquid droplet, and despite the relative simplicity of the interaction rules,
these systems display a wealth of interesting and novel behaviors such as
oscillations of droplet size and molecular sorting, and raise the possibility
of spatio-temporal control of chemical reactions on the nanoscal
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