Synthesis and Properties of Polyelectrolyte Gels with Embedded Voids

Abstract

Summary: “Swiss‐cheese” polyelectrolyte gels, i.e., gels containing isolated voids filled with water were synthesized and studied. The gels were obtained by three‐dimensional copolymerization of neutral and charged monomers in the presence of oil/water emulsion stabilized by ionic surfactant. After removal of the surfactant and droplets of oil from the gel, the latter contains voids surrounded with charged swollen polymer network. Experiments were performed with slightly cross‐linked gels of copolymers of sodium‐2‐acrylamide‐2‐methyl‐1‐propanesulfonate with acrylamide. The gel containing voids absorbs much more anionic dyes than the control gel with the same chemical composition of the network obtained in homogeneous solution. This effect is due to strongly inhomogeneous distribution of the low molecular weight anions between the voids and the anionic matrix of the gel. The study of diffusion of the dyes in the gels with and without voids and of the kinetics of their swelling and collapse shows that the voids in the gel are isolated.

Intelligent Gels and Cryogels with Entrapped Emulsions

“…Thus, the gel collapse was unable to induce squeezing out of lipophilic phase when the emulsion droplets were “isolated” from each other by the continuous phase of the hydrogels cross-linked network. Yet more evidence in favor of TD droplets being separated from each other in the course of three-dimensional polymerization performed in the presence of emulsion has also been obtained earlier . For cryogel 3 and composite cryogel 4 the extent of the collapse was the same as for the control gel 1.…”

“…The incorporation of diverse particles in the gels often imparts them new properties. Gels with entrapped magnetic particles are responsive to magnetic field, and gels containing clays have improved mechanical and adsorption properties. , Gels having isolated pores filled with water effectively trap linear macromolecules and low-molecular-weight multicharged ions …”

“…We have recently synthesized a series of gels with incorporated emulsions. These gels were used for the preparation of polyelectrolyte gels containing voids, in particular, gels with voids having charged walls . It was demonstrated that composite gels that contain entrapped emulsions are effective absorbers of liposoluble organic substances .…”

Structural design of PNIPA-based intelligent hydrogels via porous silica templates

“…Gels with entrapped magnetic particles are responsive to magnetic fields [6], gels containing clays have improved mechanical and adsorption properties [7]. Gels having isolated pores filled with water effectively trap linear macromolecules [8] and low-molecular-weight multi-charged ions [9][10]. Nevertheless, together with these advantages, the extensive study of smart gels demonstrated principal imperfections hampering their applications.…”

Intelligent gels and cryogels with embedded emulsions of various oils

“…These systems are expected to be of significant practical interest as effective drug delivery systems 11. Besides, these composites were used for the preparation of polyelectrolyte networks containing voids or channels, so called “swiss‐cheese” gels 12–14. As it was showed, polymer matrix of composite gels can be formed either by the network of cross‐linked synthetic polymers, for instance, poly(acrylamide),12,13 or by physical gels, for instance, agarose‐based 15.…”