Effect of Chemical Structure and Charge Distribution on Behavior of Polyzwitterions in Solution

Abstract

Summary: The hydrodynamic and conformational properties of polyelectrolyte poly(N,N‐diallyl‐N,N‐dimethylammonium chloride) and its corresponding polybetaine poly(2‐diallyl(methyl)ammonio)acetate) molecules in aqueous solutions with various ionic strength and pH, were studied by viscometry, static and dynamic light scattering methods. It was established that a 1 M NaCl solution is a thermodynamically good solvent for poly(N,N‐diallyl‐N,N‐dimethylammonium chloride). In water solutions conformation of poly(2‐diallyl(methyl)ammonio)acetate) molecules corresponds to polymer coil under θ–conditions. An increase in the concentration of NaCl in water and 0.1M NaOH solutions from 0 to 1 mol/l brings about a sharp gain in the intrinsic viscosity of the polymer and in the hydrodynamic radius of molecules. This effect results from the decomposition of zwitterion pairs responsible for the compact conformation of polymer molecules in water and 0.1 M NaOH. The Kuhn segment length for poly(2‐diallyl(methyl)ammonio)acetate) molecules A = 6.3 nm determined in water and in 0.1 M NaOH solutions practically coincided with A value 6.6 nm, received in 1 M NaCl and in 0.1 M NaOH/1M NaCl. For poly(N,N‐diallyl‐N,N‐dimethylammonium chloride) molecules in 1 M NaCl solutions A = 3.9 nm.

Polymeric Delivery of Therapeutic Nucleic Acids

“…As an added benefit, zwitterionic polyplexes showed enhanced resistance to destabilization from increasing salt concentration. Zwitterionic polymers are known to be unstable or form collapsed coils in water but gain stability with increasing ionic strength from salt ions . Zwitterionic polymers are not a catch-all replacement for PEGylation.…”

“…Zwitterionic polymers are known to be unstable or form collapsed coils in water but gain stability with increasing ionic strength from salt ions. 601 Zwitterionic polymers are not a catch-all replacement for PEGylation.…”

Interactions between Biomolecules and Zwitterionic Moieties: A Review

“…In general, the solubility of a zwitterionic polymer depends on its molecular weight, concentration, and the salt composition of the solution . Though hydrophilic, zwitterionic polymers can be insoluble in pure water because the electrostatic attractions between the charged functional groups cause the zwitterionic polymers to take a collapsed-coil form . The solubility of zwitterionic polymers increases with the addition of salt, which obstructs the electrostatic attractions between zwitterions, allowing the zwitterionic polymers to dissolve and take on chain-like conformations. − Changes in salt concentration do not affect different zwitterions equally.…”

Structures and Synthesis of Zwitterionic Polymers

“…In fact, it seems that nearly the full spectrum of polymerizable groups suited for radical polymerization has been used to make polyzwitterions in the past, including not only styrenes, vinylpyridines, vinylimidazoles or vinylesters [124], but also rather uncommon polymerizable groups such as dienoic acids [123,124,[131][132][133][134][135][136][137][138][139], vinylcyclopropanes [124,134] or isocyanides [69], and cyclopolymerizing species such as diallylammonium [64,87,88,124,134,[140][141][142][143][144][145][146][147][148][149][150][151][152][153] and closely related divinyl monomers [93,94]. Moreover, a number of monomers confined exclusively to (often alternating) radical copolymerization, such as vinylethers [124,134], fumarates and maleates [124,134,[154][155][156], isobutylenes [157] and ...…”

“…This has resulted in a continuous interest in zwitterionic diallylammonium carboxy-, phosphono-and sulfobetaines (cf. Figure 16, P-68 and P-69) [64,87,88,124,134,[140][141][142][143][144][145][146][147][148][149][150][151][152][153]431,433].…”