Interpolyelectrolyte complexes: advances and prospects of application

Advances in the development of water-soluble nonstoichiometric polyelectrolyte complexes, which are characterized by high stability and can be involved in competitive interpolyelectrolyte reactions, are summarized and analyzed. The complexes remain stable over a wide range of external conditions (pH, ionic strength, temperature), but show a rapid, reversible and highly sensitive response to environmental changes outside this range by changing the phase state. The review considers methods of preparation and properties of nonstoichiometric polyelectrolyte complexes formed by interactions between oppositely charged polyelectrolytes. These reagents can be used for controlled modification of various surfaces, the preparation of soluble complexes functionalized by different molecules, the suppression and prevention of protein aggregation. The review briefly summarizes new types of soluble polyelectrolytes and polyelectrolyte complexes of different nature and with different structures, including biopolymers and dendrimers, suitable for solving problems in medicine and agricultural biotechnology. In order to evaluate the results achieved, there is a need to integrate and analyze the data on interpolyelectrolyte reactions, which are of most interest for a wide range of researchers.

The bibliography includes 118 references.

Particle Size in Secondary Particle and Magnetic Response for Carrageenan Magnetic Hydrogels

The relation between the number of magnetic particles and the change in storage modulus induced by a magnetic field was investigated for weak hydrogels containing carbonyl iron, iron oxide, and barium ferrite particles with different diameters in primary particles while maintaining the magnetization of magnetic particles. The change in storage modulus exhibited a power dependency against the number of magnetic particles, which was nearly independent of the magnetic particles. The change in storage modulus was successfully scaled by the reduced number of magnetic particles using the diameter of secondary particles. Microphotographs revealed that iron oxide and barium ferrite particles form aggregations while carbonyl iron particles are well dispersed in carrageenan gels. The diameter of secondary particles determined by a relation between the change in storage modulus and the reduced number of magnetic particles showed similar values with those observed in microphotographs.

Polymeric stabilizers for protection of soil and ground against wind and water erosion

The article is devoted to the design, development and application of a new generation of binders for various dispersed systems, including soil, ground, sand, waste rock and others. The binders are formed by interaction of oppositely charged polyelectrolytes, both chemically stable and (bio)degradable. The fundamental aspects of interpolyelectrolyte reactions are discussed; the IPC structure and properties of the resulting interpolyelectrolyte complexes (IPCs) allow considering them as unique and universal binders. Numerous results of laboratory experiments and field trials of the IPC formulations are presented. In particular, large-scale tests have been done in the Chernobyl accident zone where the IPC binders were shown to be effective means to suppress water and wind erosion thereby preventing a spread of radioactive particles (radionuclides) from contaminated sites. Ecologically friendly IPC compositions are described, including those based on commercially available polymers; prospects for improving their efficiency and extending the range of their possible use are discussed.