Facile fabrication and characterization of high-performance Borax-PVA hydrogel

Strong, thermo-reversible salogels with boronate ester bonds as thermal energy storage materials

“…We then aimed to compare our PVA/borax salogels with wellknown PVA/borax hydrogel systems. 14,15,17,20,28,54 For this purpose, salogels and hydrogels containing 3 wt% PVA 90k,98 and 0.16 wt% borax were prepared in CNH and water, respectively. Comparison of the storage moduli in the frequency sweep (Fig.…”

“…In contrast to physically crosslinked gels which lack mechanical strength and covalently crosslinked gels which are irreversible, dynamic covalent bonds confer the strength of a covalent bond resulting in a strong gel network necessary for shape stabilization, while the dynamic nature of the bonds result in reversible deconstruction of the gel network in response to an external stimuli. Boronate ester bonds are well known to modulate strength and impart pH-and temperature responsiveness to solvent-free polymer networks 14 and hydrogels, [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] but their action in the environment of inorganic PCMs remained unexplored. A PCM of choice for this work was calcium nitrate tetrahydrate (Ca(NO 3 ) 2 $4H 2 O, CNH), an inexpensive material with a heat of fusion of 153 kJ kg −1 and low viscosity of 67 mPa s at 323 K above its melting temperature of 42 C which increases its propensity for leakage.…”

Tunable and Self-Healing Properties of Polysaccharide-Based Hydrogels through Polymer Architecture Modulation

“…The pre-gel was formed at 95 °C by stirring for 1 h, and then the rigid hydrogel was finally obtained after the freezing–thawing process (Figure ). The possible interaction model for borax ester bonds as proposed was based on the two diol units of PVA and one borate ion. , Boron in borax possesses an unoccupied molecular orbital, which shows a strong ability to accept electrons to react with the hydroxyl groups of PVA, and the presence of GSG in the hydrogel system further provides abundant hydroxyl groups for connecting with boron, as well as enhanced flexibility relating to its long-chain structure. The broad and strong adsorption from 3100 to 3600 cm –1 , which is related to the symmetrical stretching vibration of the available hydroxyl groups both in GSG and the PVA-borax network, was clearly weakened due to the extensive establishment of hydrogen bonding in the hydrogel system (Figure a) .…”

Highly Stretchable and Stimulus-Free Self-Healing Hydrogels with Multiple Signal Detection Performance for Self-Powered Wearable Temperature Sensors

“…The tensile strength of the CNC-PEDOT:PSS/PVA hydrogels obtained in this paper was higher than that of previously reported PVA network-based hydrogels. 8,32,35,36 To balance tensile strength and strain, 5 wt % CNC-PEDOT:PSS/PVA hydrogel was selected as the optimal sample to further explore its self-healing and sensing properties in the following research.…”