Large Polycations

The behaviour of ternary systems consisting of two polymers and a solvent depends largely on the nature of interactions between components (1-4). Two types of limiting behaviour can be observed. The first one occurs in non-polar systems, where polymer-polymer interactions are very low. In such systems a liquid-liquid phase separation is usually observed each liquid phase contains almost the total quantity of one polymer species. The second type of behaviour often occurs in aqueous polymer solutions. The polar or ionic water-soluble polymers can interact to form macromolecular aggregates, occasionally insoluble, called "polymer complexes". Examples are polyanion-polycation couples stabilized through electrostatic interactions, or polyacid-polybase couples stabilized through hydrogen bonds. 

These polycations can be further hydrolyzed or react with each other to give a large number of possible polycations. The olatlon reaction occurs without a change In solution acidity but does change the concentration of hydrolyzed species In solution. Dilution causes the reversal of reaction 2 (I.e., depolymerization) and the Introduction of new hydrolyzed species Into solution. The new species formed can then re-equilibrate through the hydrolysis reaction. The kinetics of aging depend on the relative rates of the olatlon and hydrolysis reactions. 

The activation parameters are presented in Table 819 For the reactions be between the Co(III) complex2+ and Fe-edta2-, (a) to (c) in Table 8, the activation enthalpy is smaller and the activation entropy larger than for the reduction by Fe2+, (d) to (f), which is a reaction of two cations. A comparison of the parameters for the polymer complex, (b) or (c), with those for the pyridine complex, (a) shows that the acceleration for the PVP or QPVP complex is based on a decrease in activation enthalpy and an increase in activation entropy. This is the opposite of the polyelectrolyte-catalyzed reaction, in which the acceleration is due to an increase in activation entropy (compare(e) with (d)). In the polyelectrolyte-catalyzed system the acceleration and increase in activation entropy are attributed to the increase in the local concentration of the two reactants, the Co(HI)-Py complex2 and Fe2+ 84, whereas in the reaction of the polymer complex the large activation entropy and small activation enthalpy are held to be due to the increase in the local concentration of the reactant Fe(II)-edta2 and the electrostatic attraction between the reactant and the Co(III) complex, which is fixed to the polycation chain. 

Biopolymers as well as synthetic polymers, as polyanions or polycations, exist with the same surface/charge ratio and migrate with almost identical velocity and cannot be separated in a normal electric field without an auxiliary aid. Since these polymers differ greatly in size, however, a gel can be used to influence the mobility of a large polymer more than that of a smaller one. In capillary gel electrophoresis (CGE), the electrophoretic migration of macromolecules is hindered by the gel matrix. The transport of the solutes through the capillary is based on the charge of the macromolecules, but the separation is dependent on the molecular size. It is easy to understand that with this technique EOF should be eliminated because otherwise the gel is extruded from the capillary. 

A large number of macromolecules complementary to PMAA, namely polyvinylpyrrolidone, polyvinylpyridine, polyacrylamide, poly(vinyl alcohol), poly(ethylene oxide), oligoethylenimine, poly(sodium styrene sulfonate), polycations of the integral type ionen (2X) were used as P2 and P3. The pH of the media strongly influences the studied reactions of complex formation. For example, in PVPy + PVP + PMAA or OEI + PEO + PMAA systems in the add region, where weak polybases are completely protonized and PMAA does practically not dissodate, complexes with hydrogen bonds (PMAA-PVP or PMAA-PEO) are formed. In neutral medium weak polybases are partially ionizated and polyelectrolyte complexes (PMAA-PVPy, PMAA-OEI) are generated. In the alkaline medium formation of complexes has not been observed. 

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