Well-Defined Zwitterionic Microgels: Synthesis and Application as Acid-Resistant Microreactors

Abstract

This paper describes the synthesis, swelling behavior, and applications of well-defined narrowly dispersed zwitterionic (ZW) microgels prepared by dispersion polymerization in aqueous media. Microgel stability was achieved through precise control of the dispersant composition, timely addition of a cross-linker after the nucleation stage, and the utilization of ionic initiators. Dispersion polymerization allowed for incorporation of both hydrophilic and hydrophobic comonomers, including acrylamide (AAm) and dopamine methacrylamide (Dopa-MA). The broad variety of compositions created many opportunities for practical applications such as encapsulation of mineral acids and synthesis of metal nanoparticles. The swelling behavior of ZW-co-AAm microgels in 6 M HCl was particularly interesting: whereas ZW moieties remained stable in contact with the strong acid, the amide groups underwent hydrolysis to carboxylic acid, resulting in microgel contraction and acid release. Zw-co-Dopa-MA microgels were employed as particulate microreactors, where the ZW moieties played a role of an osmotic pump delivering Ag ions to the DOPA moieties for conversion to silver nanoparticles uniformly dispersed inside the microgel particles.

Hydrogels Based on Poly(aspartic acid): Synthesis and Applications

“…On the other hand, high ion concentration shields the network charge and lowers swelling (Yang et al, 2006). Additionally, by changing crosslinking density, mechanical properties and swelling could be tuned (Vatankhah-Varnoosfaderani et al, 2016). More importantly, PASP hydrogels can be readily modified with a wide variety of species to meet the need of any given application.…”

Exploring the Long-Term Hydrolytic Behavior of Zwitterionic Polymethacrylates and Polymethacrylamides

“…Also, it is generally accepted that hydrolysis is accelerated by increasing temperature, as well as by acidic or basic conditions. Still, particularly for the most widely employed antifouling polymers that bear oligo(ethylene glycol) or zwitterionic moieties in their side chains, experimental studies on their hydrolysis are scarce [22,23,24,25,26]. Moreover, they consider typically short periods only, that is, a few days at most.…”

Anti‐bacterial poly(vinyl alcohol) nanocomposite hydrogels reinforced within situsynthesized silver nanoparticles

“…Hydrogels have widely been used in various areas of biomedical engineering such as drug delivery , scaffolds for cell culture , wound dressings , embilizaing agents , substitutes for cartilage micro‐reactors . Among all hydrogels, those based on polyvinyl alcohol (PVA) has drawn a great deal of attention due in particular to low toxicity, biocompatibility, biodegradability, and good water uptake capability.…”