ИСТИНА

The purpose of the lecture is to demonstrate a variety of scenarios according to which the confrontation between the long-range Coulomb and short-range van der Waals interactions in polyelectrolytes results in destroying the homogeneous (disordered) state and formation of ordered phases and complexes. The basic issues to be discussed in the lecture are as follows. 1. Polyelectrolytes are the area of fluctuation effects: if the fluctuations were absent the total charge profile would be zero (due to electroneutrality) and, thus, electrostatic energy would equal zero either. 2. The electrostatic blob notion and distinction between the weakly and strongly charged polyelectrolytes (the blob is big in weakly charged ones). 3. Screening by non-point-like objects and different types of screening in polyelectrolytes (conventional screening, recharging and oscillating screening). 4. Polyelectrolytes in poor solvent: microphase vs macrophase separation. Phase diagrams. 5. Macrophase separation in polyelectrolyte solutions and polyelectrolyte complexes as the minimal droplets of the condensed phase. 6. Why could be the Debye-Hückel estimate of the electrostatic energy not always correct. The necessary extension. 7. Polyelectrolyte complexes and ordered polyelectrolyte complexes. Phase diagrams. 8. The polydispersity effects and charge fractionation. Why and how the polyelectrolyte polydispersity with respect to the linear charge density leads to the fact that the microphase separation is accompanied by the macrophase separation into the stronger and weaker charged polyelectrolyte chains (with the corresponding counterion dendities). 9. Necklace model and microphase separation.