Swelling Behavior of Chitosan Hydrogels in Ionic Liquid−Water Binary Systems

Abstract

The swelling behavior of chitosan hydrogels in ionic liquid-water binary systems was studied using hydrophilic room-temperature ionic liquids (RTILs) to elucidate the swelling mechanism of chitosan hydrogels. No penetration of RTIL into a dry chitosan material was observed. Swelling was achieved by soaking in water-RTIL binary mixtures, with larger swelling observed at higher water contents. In one instance, the binary mixture was acidic and produced larger than expected swelling due to the dissociation of the amine groups in the chitosan. The equilibrium binary system content behavior of the chitosan hydrogels depended upon the amount of free water, which is a measure of the number of water molecules that do not interact with the ionic liquid. After evaporation of water, remnant RTIL remained in the chitosan network and hardness testing indicated a plasticization effect, suggesting that the RTIL molecularly mixed with the chitosan. Chitosan hydrogels containing only RTIL were prepared by dropping pure RTIL onto a fully preswollen hydrogel followed by water evaporation. This method may be a useful means for preparing air-stable swollen chitosan gels.

Study of the PVA hydrogel behaviour in 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid

“…We could assume that BMIMBF 4 acts as a dehydrating agent for the swollen PVA hydrogels. This behaviour does not seem to be unique, as similar phenomena have been noted and reported also for chitosan hydrogels, when in contact with BMIMBF 4 [24]. So, in case the practical interest is to load the PVA hydrogel with BMIMBF 4 , we have to use more highly diluted IL solution for the gel immersion.…”

“…[11,12,33,34]. The behaviour of hydrogels with different compositions, in the presence of different ionic substances has been studied [13,18,[23][24][25]32]. PVA is a widely used polymer, due to its exceptional properties such as non-toxicity, non-carcinogenity, water solubility, biodegradability, biocompatibility, good mechanical and optical properties that could generate hydrogels by physical and chemical ways.…”

DNA Hydrogel Fiber with Self‐Entanglement Prepared by Using an Ionic Liquid

“…We have found that room-temperature hydrophilic ionic liquids (RTILs) can produce suitable conditions. The feasibility of using RTILs was suggested by our previous work, [14] which showed that 100 % of RTILs will absorb water even when bound to a polymer network. Moreover, some RTILs can create low-pH conditions when in contact with water, and such acidic conditions have been used to promote coagulation in the wet spinning of DNA fibers.…”

Functionalized assembly of solid membranes for chiral separation using polyelectrolytes and chiral ionic liquid

“…This is because some of the PEI/PAA may have swelled and partly peeled off, due to the b-CD-IL assembly process. [30][31][32] It was clear that although the b-CD-IL can be assembled on to the PEI/PAA due to the electrostatic adsorption force, the b-CD-IL will, to Figure 7. UV-vis spectra of (PAA/IL) n films with n 5 1-6 on quartz substrates.…”