Synthesis of Monodisperse Glycerol Dimethacrylate-Based Microgel Particles by Precipitation Polymerization

Abstract

A new, single-stage precipitation polymerization was proposed for the synthesis of monodisperse crosslinked glycerol dimethacrylate (GDMA)-based microgel particles carrying hydroxyl and carboxyl functionalities, from nanometer to micrometer size range. The synthesis of monodisperse microgel spheres in the size range of 30-1500 nm was possible by the proposed method. In the polymerizations, glycerol dimethacrylate was copolymerized with methacrylic acid (MAA) in the medium containing toluene and acetonitrile without using a stabilizing agent. The effects of polymerization conditions on the final monomer conversion, polymerization kinetics, and MAA distribution in the microgel particles were investigated. The hydrodynamic size, the size distribution characteristics, and the mass charge density of microgel particles were also determined. Highly monodisperse and spherical microgel particles were obtained particularly with low GDMA feed concentrations. A marked increase in the hydrodynamic size was observed with the decreasing polarity (i.e., increasing toluene concentration) in the continuous medium. The distribution of MAA in the particles and the effect of pH on the swelling behavior in the aqueous medium indicated that the microgel particles contained a swellable shell and a nonswellable core. Most of the MAA charged was buried within the core part of the microgel particles. The swelling of microgel was controlled by the ionization of the carboxyl groups located on the shell layer. The swellable character, the presence of functional groups for surface derivatization, and the similarity of microgel to a biocompatible structure, poly(hydroxyethyl methacrylate), make the new microgel a promising material for biomedical applications.

Porous polymer particles—A comprehensive guide to synthesis, characterization, functionalization and applications

“…It should be noted that commercial DVB is technical, composed of either 55% or 80% DVB with the rest being mostly ethyl styrene monomer. Methacrylate crosslinkers are also polymerized via precipitation polymerization with a low percentage of added monomer [50][51]. As a result, precipitation polymerized particles are rich in remaining double bonds that can be efficiently utilized in post-functionalization [52] (see further functionalization section).…”

“…As a result of the fact that the nuclei do not overlap, highly monodisperse particles, generally in the size range of 1-5 µm, are obtained [54]. Recently, monodisperse nanoparticles are also reported [50]. As one of the unique properties of this technique, particles grow constantly and the polymerization can be stopped when the desired particle size is reached.…”

“…Oppositely, surface charge is not desired for self-assembly purposes [289]. Charged particles are generally obtained by using acid [50] or base [191] monomers, yielding negative or positive charge, respectively. pH of the medium is also important: a carboxylic acid particle will not be charged at low pH.…”

Synthesis and characterization of hydrophilic and spherical poly(glycerol dimethacrylate-co-glycerol-1,3-diglycerolate diacrylate) microbeads

“…Saracoglu et al [26] reported that monodisperse cross-linked poly(glycerol dimethacrylate) (poly(GDMA))-based microgel particles carrying hydroxyl and carboxyl functionalities from nanometer to micrometer size range were synthesized by single-stage precipitation polymerization. The authors claimed that the produced poly (GDMA) microbeads could be used widely as a promis-ing material for biotechnological and biomedical applications.…”

Thiol-ene and thiol-yne chemistry in microfluidics: a straightforward method towards macroporous and nonporous functional polymer beads

“…However, like in seeded suspension polymerization the obtained beads are in the range of 0.1-10 micrometer, which is not suitable for solid phase synthesis and catalysis applications due to handling problems. Also, the incorporation of functional monomers can be problematic or impossible 29 , because of the delicate mechanism of growing polymer chain precipitation during the polymerization.…”