Zwitterionic Sulfonium Sulfonate Polymers: Impacts of Substituents and Inverted Dipole

Abstract

Research involving polymer zwitterions typically involves the preparation of ammonium-based structures and their study as coatings or gels that impart hydrophilicity and/or antifouling properties to substrates and materials. More recent synthetic advances have produced a significant expansion in polymer zwitterion chemistry, especially with respect to the composition of the cationic moieties that open new possibilities to examine polymer zwitterions as amphiphiles, functional surfactants, and components of complex emulsions. This article describes the synthesis of new zwitterionic sulfonium sulfonate monomers and their use as starting materials in controlled free radical polymerization to yield the corresponding polymers. These novel polymer zwitterions bear sulfonium sulfonate groups, that possess an inverted dipole directionality relative to prior examples that yields different and unexpected physical and chemical properties. For example, the polymer zwitterions described here are soluble in a wide range of nonaqueous solvents and possess significantly greater stability against nucleophiles relative to their dipole-inverted counterparts. Additionally, the amphiphilic character of these sulfonium sulfonate polymers makes them amenable to use as surfactants for stabilizing oil-in-water emulsions, a feature that is not possible using conventional ultrahydrophilic polymer zwitterions.

Zwitterionic Materials for Enhanced Battery Electrolytes

“…[32] However, sulfobetaine may not be the optimal ZI type for a given electrolyte environment; within at least one popular ILE, other ZI chemistries (carboxybetaine, phosphorylcholine) yielded better performance enhancements. [7] Several additional ZI chemistries have been shown to be synthetically accessible (e. g. trimethylamine N-oxide, [6] sulfonium sulfonates, [33] fluorinated choline phosphates, [34] etc. ), yet most of these have not yet been examined for their potential use in battery electrolytes.…”

“…Several additional ZI chemistries have been shown to be synthetically accessible ( e. g . trimethylamine N ‐oxide, [6] sulfonium sulfonates, [33] fluorinated choline phosphates, [34] etc. ), yet most of these have not yet been examined for their potential use in battery electrolytes.…”

Stimuli‐Responsive Polymers for Engineered Emulsions

“…Polymer zwitterions are characterized by their covalently linked cationic and anionic functionalities that give charge neutrality throughout the polymer chain. [ 71 ] Furthermore, zwitterion‐zwitterion pairing can occur between the oppositely charged groups of zwitterions in close proximity, giving rise to intra‐ and inter‐ molecular associations which can ultimately dictate physical properties of a system. However, the ionic nature of these associations makes them prone to dissociation in the presence of salt solutions which screen charge.…”

Anti‐Fouling Polymer or Peptide‐Modified Electrochemical Biosensors for Improved Biosensing in Complex Media

“…For example, Brown et al recently showed that reversing the dipole orientation from poly(sulfothetin styrene) to poly(sulfonium sulfonate styrene) led to higher stability against nucleophiles due to a reduction in inter-zwitterion interactions, which are shielded in the case of poly(sulfonium sulfonate styrene) by the n-butyl groups extending from the chains. [48]…”