Polyampholytes derived from

We investigated the syntheses and viscosity behavior of polyampholytes derived from cationic-anionic monomer pairs of the type shown in Figure 2. It should be noted that the cationic-anionic monomer pairs that are under consideration contain no nonpolymerizable ions. 

This chapter reports the syntheses and viscosity behavior in aqueous salt solution of two recently prepared polyampholytes. These polymers, derived from cationic-anionic vinyl monomer pairs, exhibit viscosity behavior in salt solution that is contrary to that of normal polyelectrolytes. The intrinsic viscosity is found to increase with increasing salt concentration for one of the samples and remain virtually unchanged for the other. Also, a modified form of the EinsteinSimha equation is observed to correlate especially well with the experimental data, where, in some cases, the Huggins equation apparently is not appropriate. In the context of these findings, some previous results with regard to the behavior of a polyvinylimidazolium sulfobetaine are discussed. 

This study confirms the concept that polyampholytes take an expanded conformation in aqueous salt solutions which is in contrast to typical polyelectrolyte behavior. Viscosity determinations in conjunction with light scattering studies has provided a general confirmation of the polyampholyte effect in the polymers derived from the ion-pair comonomer in aqueous salt solutions. This effect is related to the ion-binding capabilities of the added electrolytes. 

Dhar N, Akhlaghi SP, Tam KC. Biodegradable and biocompatible polyampholyte microgels derived from chitosan, carboxymethyl cellulose and modified methyl cellulose. Carbohydr Polym 2012 87 101-109. 

Several 3-vinyl- and 1,3-divinyl-hydantoin derivatives have been prepared and converted to polymers having pendant hydantoin groups, e.g. (66) (B-74MI11100). Interesting spiro hydantoin polymers (67) are readily prepared from the very reactive 5-methylenehydantoin, hydrolysis of which cleanly produces polymers containing a-aminoacrylic acid units and having corresponding polyampholytic properties. 

Salt-tolerant polyampholytes with potential for viscosity maintenance (or increase) at low concentration in the presence of simple electrolytes such as NaCl include polymers formed by equamolar incorpomtion of sulfonate and quaternary ammonium mer units (Type A) or those formed by the copolymerization of a zwitterionic sulfobetaine monomer with a water-soluble monomer (Type B) as shown in Scheme 1. Usually, a water-soluble mer unit, W, is included for adequate hydration. Key features of polyampholytes from sulfonated quaternary ammonium monomers (Types A and B) are discussed here, although corresponding carboxylate (4-9), phosphonate (10-14), or tertiary ammonium derivatives have been syndiesized and are responsive to pH. 

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