ИСТИНА

The problem of inhomogeneous dielectric permittivity in polyelectrolytes have attracted great attention during the recent decades. It is clear that the solvent shell around charged molecules is already polarized and its response to an external field is somehow shielded. Moreover, conglomerations of non-polar organic molecules or hydrocarbon polymers considerably decrease local dielectric permittivity of water-based solution. Thus it is very important to consider inhomogeneous permittivity in the systems where electrostatic interactions play significant role. Initial model to include the local permittivity in the self-consistent theory of polyelectrolyte gel collapse was proposed by Kramarenko and Khokhlov in 1994. Later several approaches were suggested to study charged polymer chain behavior both in MD simulations and random phase approximation approach. Here we propose a coarse-grained approach to consider inhomogeneous permittivity within the framework of dissipative particle dynamics (DPD). While the general description of the electrostatic interactions was already presented by Groot, we developed a modification of this approach for the case of high charges density. We study the influence of species different permittivity on the coil-to-globule transition and morphological changes in polyelectrolyte block-copolymer melts. For the case of polyelectrolyte melts the phase behavior is studied for a number of chain compositions and interaction strengths; at low dielectric constants, the charge correlation effects cause the formation of a condensed phase formed by the charged species, and the counterion entropy causes the system to adopt bicontinuous structures over a wide compositional window.