Cation/polymer interactions

Water-soluble pAM-DAA-HCl and pAM-DAEA-HCl cationic polymers interact with ions by the following mechanisms ... 

Mg has been studied in a polyelectrolyte system where the counterion is a phosphazene-bound sulphonate group. In this case the finite but low conductivity is due to Mg migration. A large increase in conductivity is noted when a bicyclic ligand, crypt [2.1.1.], is introduced (Hancock and Martell, 1988). Apparently, the cation-anion and cation-polymer interactions are reduced by complex formation, resulting in a more mobile cation, despite its larger effective radius. 

W. Huang, R. Freeh, P. Johansson, J. Lindgren, Electrochim. Acta 1995, 40, 2147-2151. Cation-polymer interaction and ionic association in diglyme-LiCFsSOs and diglyme-propylene carbonate-LiCF3S03 complexes. 

As in the case of a conventional (liquid) solution, the ion association dynamics in a polymer electrolyte will be driven by the relative strength of the different interactions present, namely cation-anion, cation-polymer, and anion-polymer, which can be understood in the conceptual framework of the Pearson s HSAB model [152-154]. In the most general situation, oxygen atoms in a polyether can be considered as hard bases. This means that they interact strongly with hard acids (i.e., cations such as Li, Mg, Na, Ca, or Cu ). However, the cation-polymer interaction win be weak with soft cations Ag, Sn, Pb, or Hg ". In the case of anions, the main characteristic that seems to control the... 

RHODES c p and frech r, Cation-anion and cation-polymer interactions in (PE0) NaCF3S03 (n = 1-80) , Solid State Ionics, 1999,121,91-99... 

Cationic samples can be adsorbed on the resin by electrostatic interaction. If the polymer is strongly cationic, a fairly high salt concentration is required to prevent ionic interactions. Figure 4.18 demonstrates the effect of increasing sodium nitrate concentration on peak shapes for a cationic polymer, DEAE-dextran. A mobile phase of 0.5 M acetic acid with 0.3 M Na2S04 can also be used. 

Anionic and neutral polymers are usually analyzed successfully on Syn-Chropak GPC columns because they have minimal interaction with the appropriate mobile-phase selection however, cationic polymers adsorb to these columns, often irreversibly. Mobile-phase selection for hydrophilic polymers is similar to that for proteins but the solubilities are of primary importance. Organic solvents can be added to the mobile phase to increase solubility. In polymer analysis, ionic strength and pH can change the shape of the solute from mostly linear to globular therefore, it is very important to use the same conditions during calibration and analysis of unknowns (8). Many mobile phases have been used, but 0.05-0.2 M sodium sulfate or sodium nitrate is common. 

Water-soluble pAANa anionic polymer interacts with ions through cation and anion exchange mechanisms. 

The apparent hypochromieities of cationic analogs with polynucleotides are compiled in Table 2. As is clear from the table, some of the cationic models interact strongly with polynucleotides. The hypochromieities of the polymers with polynucleotides are similar to that reported for some neutral model compounds21-23, or fairly higher than those of most neutral and anionic models hitherto synthesized (see Sections 2.1. and 2.3.). The large hypoehromieity values of the cationic models... 

In 1956 Brown, in a series of patents(68-75), disclosed that clays could be treated with di-, tri-, or tetra-substituted ammonia derivatives. Later, McLaughlin, et al.(76,77), introduced cationic polymers as permanent clay protective chemicals. A series of published results describing laboratory and field applications soon became available(78-81). Structural details of the cationic polymers appeared in patents(82-85). In general the polymers are polyamine derivatives, mostly quaternary in nature. Theng(86,87) has discussed how the multiple cationic centers in these polymers can interact and permanently protect clays. Callaway(88) et al. has noted that cationic polymers may interfere with the performance of crosslinked fracturing fluids. 

Cationic accelerants vary in their efficacy [161]. Other types of accelerant have also been evaluated. In one study [162], comparisons were made between tetra-ethylammonium bromide, benzyltriethylammonium chloride, polyfdiallyldimethylammonium chloride) and the diethyldimethylammonium derivative of a benzenesulphonate polyglycol ester. It was found that the cationic polymers had a greater effect than the simple quaternary ammonium compounds of lower molecular mass. This effect was attributed to the capability of the polymers to enter into hydrophobic interaction with the fibre surface. Ethylenediamine has also been found to accelerate the alkaline hydrolysis of polyester [163]. 

Tang MX, Szoka FC (1997) The influence of polymer structure on the interactions of cationic polymers with DNA and morphology of the resulting complexes. Gene Ther 4 823-832... 

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