  We develop a new quantitative molecular theory of liquid-phase dipolar
polymer gels. We model monomer units of the polymer network as a couple of
charged sites separated by a fluctuating distance. For the first time, within
the random phase approximation, we have obtained an analytical expression for
the electrostatic free energy of the dipolar gel. Depending on the coupling
parameter of dipole-dipole interactions and the ratio of the dipole length to
the subchain Kuhn length, we describe the gel collapse induced by electrostatic
interactions in the good solvent regime as a first-order phase transition. This
transition can be realized at reasonable physical parameters of the system
(temperature, solvent dielectric constant, and dipole moment of monomer units).
The obtained results could be potentially used in modern applications of
stimuli-responsive polymer gels and microgels, such as drug delivery,
nanoreactors, molecular uptake, coatings, superabsorbents, etc.
