Synthesis of multifunctional high strength, highly swellable, stretchable and self‐healable pH‐responsive ionic double network hydrogels

Abstract

The multifunctional double network (DN) soft hydrogels reported here are highly swellable and stretchable pH‐responsive smart hydrogel materials with sufficient strength and self‐healing properties. Such multifunctional hydrogels are achieved using double crosslinking structures with multiple physical and chemical crosslinks. They consist of a copolymer network of acrylamide (AM) and sodium acrylate (Na‐AA) and other reversible network of poly(vinyl alcohol)–borax complex. They were characterized by Fourier transform IR analysis and studied for their hydrogen bonding and ionic interaction. The degree of equilibrium swelling was observed to be as high as 5959% (at pH 7.0) for a hydrogel with AM/Na‐AA = 25/75 wt% in the network (GS‐6 sample). The highest degree of swelling was observed to be 6494% at pH 8.5. The maximum tensile strength was measured to be 1670, 580 and 130 kPa for a DN hydrogel (GS‐2 sample: AM/Na‐AA =75/25 wt% with 20, 40 and 60 wt% water content, respectively). The self‐healing efficiency was estimated to be 69% for such a hydrogel. These multifunctional DN hydrogels with amalgamation of many functional properties are unique in hydrogel materials and such materials may find applications in sensors, actuators, smart windows and biomedical applications. © 2018 Society of Chemical Industry

Self‐healing Polyol/Borax Hydrogels: Fabrications, Properties and Applications

“…Similarly, another pH-responsive DN hydrogel was prepared by replacing the second network with MBA-crosslinked poly(acrylamide-co-sodium acrylate). [82] The swelling degree of hydrogel was highly affected by AAm/NaAA ratio and pH of the medium. Increasing the more hydrophilic NaAA content, increased both swelling rate and swelling degree.…”

“…second network improved mechanical properties [81] PVA/P(AAm-co-SA) -second network improved mechanical and pH-responsive properties [82] PVA/AG -AG boost self-healing and improved mechanical strength [83] LBG/Gg pH-driven shape memory ultrafast self-healing with high mechanical properties [84] PVA/CST -CST improved machinal properties [85] HA-DP Corsslinked PAAm strain sensors mussel-inspired flexible, wearable, and self-adhesive [86] Other types of borax-based hydrogels oxidized-alginate gelatin injectable in situ forming biodegradable scaffolds for cartilage regeneration and/or treatment of meniscal injuries gelatin create dynamic imine crosslinking with oxidized alginate [87][88][89] PVA/PSA/PNIPAAm thermoresponsive touch sensors PSA/PNIPAAm improved mechanical properties; induce thermo-sensitivity Although the history for the synthesis of polyol/B hydrogels, such as PVA/B [33,40] and galactomannan/B [41] hydrogels, is turned back to the 20 th century, more detailed studies have been performed on the characteristics of these hydrogels in recent years. The stability evaluation of scleroglucan (Sclg)/B hydrogels in aqueous media showed that in high acidic and high alkaline media the stability is reduced significantly.…”

“…By increasing the water content, the ultimate tensile strength was decreased probably due to the increase in volume which in turn lead to the weakening of the secondary interactions/crosslinking formation between first and second networks. Similarly, another pH‐responsive DN hydrogel was prepared by replacing the second network with MBA‐crosslinked poly(acrylamide‐ co ‐sodium acrylate) . The swelling degree of hydrogel was highly affected by AAm/NaAA ratio and pH of the medium.…”

Engineering bioactive synthetic polymers for biomedical applications: a review with emphasis on tissue engineering and controlled release

“…For this reason, chemically responsive actuators are a more appealing option for tissue engineering applications. 258,[295][296][297][298][299][300][301] Chemically responsive bioactuators often respond to ionic strength charges or pH changes. The basic understanding of polymer-polymer, polymer-solvent, and polymer-solute interactions may lead to the engineering of SyPs-based actuators that undergo mechanical and shape transformations after responding to various external stimuli.…”

Preparation of MPASP‐PAA/Fe3+ Composite Conductive Hydrogel with Physical and Chemical Double Crosslinking Structure and Its Application in Flexible Strain Sensors

“…However, the conductive hydrogels prepared by only using chemical bonds have the shortcomings of being hard and brittle, easy to break under pressure. Once the chemical bonds are broken, they cannot be restored, [3,4] which will reduce the mechanical properties of the hydrogel and shorten the service life. [5,6] At present, the construction of physics and chemistry double network hydrogel has become a research hotspot.…”