Stabilisation Effect of Calcium Ions on Polymer Network in Hydrogels Derived from a Lyotropic Phase of Hydroxypropylcellulose

Abstract

The process of crosslinking of the hydrogel, derived from lyotropic liquid crystalline (LLC) phases of hydroxypropylcellulose/acrylic acid‐water, by calcium ions was studied by means of Raman and dielectric spectroscopy. Formation of salt by poly(acrylic acid) and calcium ions, resulting in hydrogel crosslinking, induces differences in Raman spectra of the hydrogel before and after the crosslinking. The crosslinking results in significant increase in the activation energy of β‐relaxation of poly(acrylic acid). This is a direct consequence of restriction in motions of carboxylic groups of poly(acrylic acid) due to calcium salt formation. Thus, the crosslinking improves polymer network stability in the hydrogel in the swollen state.

Surface modification of garnet fillers with a polymeric sacrificial agent enables compatible interfaces of composite solid-state electrolytes

“…The peak at 1670 cm −1 associated with the carboxyl group disappears, but a new peak corresponding to the symmetric vibration of –COO − appears at 1423 cm −1 and a peak belonging to –CH 2 or –CH is present at 2926 cm −1 . 26 Both FTIR and Raman spectra indicate that the surface treatment of LLZTO can effectively remove Li 2 CO 3 content. Specifically, the carbonate group on the surface of LLZTO will react with the carboxyl group of PAA, which is represented by the following equation,CO 3 2− + 2 − COOH → 2COO − + H 2 O + CO 2 …”

Effect of calcium neutralization on elastic and swelling properties of crosslinked poly(acrylic acid) - correlation to inhomogeneities and phase behaviour

“…However, it has been shown that Ca 2+ can stabilize PAA hydrogels by preventing the dissolution of the gel by crosslinking the PAA. This increases the activation energy for relaxation of the polymers [12]. Infrared spectroscopy has distinguished several stable forms of Ca 2+ binding to the carboxyl groups and computer simulations have found two stable conformations of Ca 2+ binding to short chains of PAA, one where Ca 2+ is coordinated to one or two carboxylate groups and one where the Ca 2+ is coordinated through a water molecule [13].…”