  We demonstrate that a highly charged polyelectrolyte confined in a spherical
cavity undergoes reversible transformations between amorphous conformations to
a four-fold symmetry morphology as a function of dielectric mismatch between
the media inside and outside the cavity. Surface polarization due to dielectric
mismatch exhibits an extra "confinement" effect, which are most pronounced
within a certain range of the cavity radius and the electrostatic strength
between the monomers and counterions and multivalent counterions. For cavities
with a charged surface, surface polarization leads to an increased amount of
counterions adsorbed in the outer side, further compressing the confined
polyelectrolyte into a four-fold symmetry morphology. The equilibrium
conformation of the chain is dependent upon several key factors including the
relative permittivities of the media inside and outside the cavity, multivalent
counterion concentration, cavity radius relative to the chain length, and
interface charge density. Our findings offer insights into the effects of
dielectric mismatch in packaging and delivery of polyelectrolytes across media
with different relative permittivities. Moreover, the reversible transformation
of the polyelectrolyte conformations in response to environmental permittivity
allows for potential applications in biosensing and medical monitoring.
