Poly(N-vinylpyrrolidone)–Laponite XLG Nanocomposite Hydrogels: Characterization, Properties and Comparison with Divinyl Monomer-Crosslinked Hydrogels

Abstract

The present work investigates, for the first time, the synthesis and properties of some nanocomposite (NC) hydrogels obtained by the aqueous solution free radical polymerization of N-vinylpyrrolidone (NVP) in the presence of Laponite XLG (XLG) as a crosslinker, in comparison with the corresponding hydrogels prepared by using two conventional crosslinking divinyl monomers: N,N’-methylenebisacrylamide (MBA) and tri(ethylene glycol) divinyl ether (DVE). The structure and properties of the hydrogels were studied by FTIR, TEM, XRD, SEM, swelling and rheological and compressive mechanical measurements. The results showed that DVE and XLG are much better crosslinking agents for the synthesis of PNVP hydrogels than MBA, leading to larger gel fractions and more homogeneous network hydrogels. The hydrogels crosslinked by either DVE or XLG displayed comparable viscoelastic and compressive mechanical properties under the experimental conditions employed. The properties of the XLG-crosslinked hydrogels steadily improved as the clay content increased. The addition of XLG as a second crosslinker together with a divinyl monomer strongly enhanced the material properties in comparison with the hydrogels crosslinked by only one of the crosslinkers involved. The FTIR analyses suggested that the crosslinking of the NC hydrogels was the result of two different interactions occurring between the clay platelets and the PNVP chains. Laponite XLG displayed a uniform distribution within the NC hydrogels, the clay being mostly exfoliated. However, a small number of platelet agglomerations were still present. The PNVP hydrogels described here may find applications for water purification and in the biomedical field as drug delivery systems or wound dressings.

Laponite/magnetite nanoparticles including waterborne latexes and effect of conditions for stable composite latexes

“…The images show a core‐shell structure consisting of LAM surrounded by copolymer compatible with MNP (core)‐polymer (shell) morphology 38,44 . This indicates that polymerization takes place from the outside of the monomer droplets to the inside 40,45–47 . From the contrast between the core and shell parts of LAM, the lighter parts indicate cross‐linked polymers and the darker parts indicate LAM nanoparticles 1,48 .…”

“…38,44 This indicates that polymerization takes place from the outside of the monomer droplets to the inside. 40,[45][46][47] From the contrast between the core and shell parts of LAM, the lighter parts indicate cross-linked polymers and the darker parts indicate LAM nanoparticles. 1,48 When the images were examined, it was observed that some polymeric beads melted under the effect of electron bombardment.…”

An injectable chitosan/laponite hydrogel synthesized via hybrid cross‐linking system: A smart platform for cartilage regeneration

“…The faces of laponite are negatively charged while their slices are positively charged. These properties allow them to form a hydrogel with controlled gelling properties resembling a “house of cards” structure 31 …”

“…These properties allow them to form a hydrogel with controlled gelling properties resembling a "house of cards" structure. 31 Table 1 shows the calculated gelation time for each formulation using an inverted test tube. According to the obtained results, the incorporation of laponite into the chitosan decreased the gelling time of the hydrogels.…”

Drug delivery systems based on polyethylene glycol hydrogels for enhanced bone regeneration

“…Interestingly, the addition of nanomaterials to PEG crosslinked hydrogels can also delay the degradation rate and increase stability. Laponite is the most commonly used nanoclay, which is composed of SiO 2 , MgO, Li 2 O, Na 2 O ( Podaru et al, 2022 ). Zhai et al (2018) obtained a PEG diacrylates-clay nanocomposite hydrogel by modifying the hydroxyl group of PEG and crosslinking with nanoclay.…”