Superfast responsive ionic hydrogels with controllable pore size

Supermacroporous chemically cross-linked poly(aspartic acid) hydrogels

“…Thus, in practice, we have a wider temperature range to prepare cryogels in DMSO than in water, which may provide better control over morphology and make available a wider range of pore sizes. Lower gelation temperatures resulted in larger pores (Table 1), in agreement with Okay et al [21]. The explanation is based on the thermodynamic interpretation of solid-liquid phase separation.…”

Tough organogels based on polyisobutylene with aligned porous structures

“…The variation of the internal morphology of the organogels depending on the gel preparation temperature T prep was monitored by electron microscopy. Previous works show that, in crosslinking copolymerization of hydrophilic monomers in frozen aqueous solutions, macroporous structures start to appear at polymerization temperatures about 8 C below the freezing point of the reaction system [13,14]. Assuming this condition is also valid for the solution crosslinking of PIB, macroporous organogels should form at about À1.5 C in cyclohexane.…”

“…This principle is a consequence of the insolubility of the salts in ice compared to their excellent solubility in water. In cryogelation reactions, aqueous reaction solution containing the monomers and the initiator is cooled below the freezing point of the system; since the monomers and the initiator will be enriched in the unfrozen microzones surrounded by ice crystals, the polymerization reactions only proceed in these unfrozen regions containing a high concentration of monomer [9][10][11][12][13][14]. After polymerization and after removing the ice, macropores appear that are templated from the spaces occupied by the ice crystals.…”

Preparation of macroporous cryostructurated gel monoliths, their characterization and main applications

“…Thus, the required functionality is incorporated in situ during the synthesis of cryogel with single freezing–thawing cycle. Typically, the functional co‐monomer is added to the reaction mixture at a concentration of 5–10 mol% to the total concentration of main monomers 7, 29, 33, 34. Both commercially available 7, 33, 34, 48 and in‐house synthesized 29, 44, 47, 60 functional co‐monomers or cross‐linkers were used for the preparation of functionalized macroporous cryogels.…”