Physical Organohydrogels With Extreme Strength and Temperature Tolerance

Abstract

Tough gel with extreme temperature tolerance is a class of soft materials having potential applications in the specific fields that require excellent integrated properties under subzero temperature. Herein, physically crosslinked Europium (Eu)-alginate/polyvinyl alcohol (PVA) organohydrogels that do not freeze at far below 0 • C, while retention of high stress and stretchability is demonstrated. These organohydrogels are synthesized through displacement of water swollen in polymer networks of hydrogel to cryoprotectants (e.g., ethylene glycol, glycerol, and d-sorbitol). The organohydrogels swollen water-cryoprotectant binary systems can be recovered to their original shapes when be bent, folded and even twisted after being cooled down to a temperature as low as −20 and −45 • C, due to lower vapor pressure and ice-inhibition of cryoprotectants. The physical organohydrogels exhibit the maximum stress (5.62 ± 0.41 MPa) and strain (7.63 ± 0.02), which is about 10 and 2 times of their original hydrogel, due to the synergistic effect of multiple hydrogen bonds, coordination bonds and dense polymer networks. Based on these features, such physically crosslinked organohydrogels with extreme toughness and wide temperature tolerance is a promising soft material expanding the applications of gels in more specific and harsh conditions.

Environment tolerant, adaptable and stretchable organohydrogels: preparation, optimization, and applications

“…74 Specifically, the performance of the organohydrogels prepared by solvent replacement, such as frost resistance, long-term stability, and mechanical properties, can be easily adjusted by changing the immersion time, concentration, or the type of organic agent. 4,86 Based on these advantages, a large number of organohydrogels constructed by the solvent displacement have been reported in the past several years. 55,63,66,87,88…”

“…Moreover, organohydrogels are prone to rupture due to the lack of sufficient energy dissipation mechanism to slow down the propagation of cracks. To address this problem, tremendous improvements have been made to fabricate strong and tough organohydrogels by introducing energy dissipation mechanisms, such as forming a double network (DN), 43,63,87,118 adding nanofillers, 16,84,95,119 introducing other dynamic interactions, 86,120,121 and creating nano-crystalline domains. 88…”

Synthesis Antifreezing and Antidehydration Organohydrogels: One-Step In-Situ Gelling versus Two-Step Solvent Displacement

“…Owing to the distinct antifreezing and antidehydration properties, the organohydrogel has aroused great interest among researchers since it was introduced [ 12 , 13 , 14 , 15 , 22 ]. Various organohydrogels and organohydrogel-based applications have emerged recently, and the glycerol [ 14 , 15 , 22 , 23 , 24 , 25 , 26 ], ethylene glycol (EG) [ 13 , 15 , 27 , 28 , 29 , 30 , 31 ], DMSO [ 32 , 33 ], and sorbitol [ 15 , 34 ] are widely used. There are two popular strategies to fabricate organohydrogels.…”

“…After solvent displacement, the obtained organohydrogels exhibited low temperature tolerance down to −70 °C [ 15 ]. Since then, due to its universality, solvent displacement became another popular strategy to synthesize the environment-adaptable organohydrogels [ 23 , 24 , 27 , 28 , 34 , 40 , 41 , 42 , 43 , 44 , 45 , 46 ].…”