A versatile approach to develop porous hydrogels with a regular pore distribution and investigation of their physicomechanical properties

Abstract

Porous polyacrylamide (PAAm) hydrogels with enhanced mechanical properties and regular pore distribution have been synthesized by a unique and facile methodology, which involves formation of the hydrogel pores by leaching out chemically modified silica particles. To improve the pore distribution and mechanical properties of the hydrogel network, porogen particles have been modified with PAAm chains chemically attached to the silica surface. Grafting polymerization initiated by peroxide groups immobilized on the particle surface has been used for this modification. The grafted PAAm layer on the silica surface improves the dispersibility of the porogen material in the hydrogel composition, and simultaneously forms pore ''walls'' reinforcing the hydrogel network, after leaching out the silica particles. The proposed synthetic way for the development of porous hydrogels includes three steps: (i) tethering of PAAm chains to silica particles due to the grafting polymerization initiated by an adsorbed polyperoxide macroinitiator (PPM), (ii) simultaneous crosslinking of grafted PAAm chains and PAAm forming hydrogel network, and (iii) pore formation by leaching out silica particles in the presence of hydrofluoric acid. The PPM has been synthesized by a free radical copolymerization of the peroxide monomer (PM) N-(tert-butylperoxymethyl)acrylamide with acrylamide. Both PM and PPM have been developed in our lab, and applied for the synthesis of porous polymeric hydrogels.

Optical properties of hydrogels filled with dispersed nanoparticles

“…As reported earlier [14,15], the formation of PAm hydrogels via polycondensation mechanism proceeds according to Fig. 2.…”

“…Previously we have described the synthesis of polyacrylamide hydrogels and studied their properties [14][15][16]. Such hydrogels are promising as sensor-materials, providing the opportunity to measure the change in glucose concentration in the media of interest.…”

Crosslinking of hydrophilic polymers using polyperoxides

“…The signals at 1.26 and 1.47 ppm are assigned to CH 3 protons (signals 1, 2, Fig. 2b) of PM [60,61]. The peak at 0.97 ppm is attributed to the methyl group of BA (signal 11, Fig.…”

Microfluidic hydrogels for tissue engineering

“…Therefore, it is crucial to control the various pore features (e.g., pore size, porosity, pore distribution and interconnectivity) within hydrogels. Various methods have been developed to fabricate porous hydrogels, including solvent casting/particle leaching [31,37,38], freeze drying [39,40], gas foaming [41,42], polymer phase separation [43], frontal polymerization [44], and electrospinning [45,46], as summarized in table 1.…”