Influence of graphene oxide incorporation and chemical cross-linking on structure and mechanical properties of layer-by-layer assembled poly(Vinyl alcohol)-Laponite free-standing films

Abstract

Functional fillers in multilayered films provide opportunity in tailoring the mechanical properties through chemical cross‐linking. In this study, Laponite‐graphene oxide co‐dispersion was used to incorporate graphene oxide (GO) easily into polyvinyl alcohol (PVA)/Laponite layer‐by‐layer (LBL) films. The LBL films were found to be uniform and the layer thickness increased linearly with number of depositions. The process was extended to a large number of depositions to investigate the macroscopic mechanical properties of the free‐standing films. The LBL films showed remarkable improvements in mechanical properties as compared to neat PVA film. The GO‐incorporated LBL films displayed higher enhancements in the tensile strength, ductility, and toughness as compared to that of PVA/Laponite LBL films, upon chemical cross‐linking. This suggests the advantageous effects of GO incorporation. Interestingly, cross‐linking of LBL films for longer time period (>1 h) and higher temperature (∼80 °C) was not found to be much beneficial. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016, 54, 2377–2387

Crosslinked PVDF‐HFP‐based hydrophobic membranes incorporated with CNF for enhanced stability and permeability in membrane distillation

“…Moreover, few more peaks were observed at 509.7 and 836.2 cm −1 , which could be attributed to a phase β of PVDF‐HFP . In addition, the OH stretching of H‐bonding and CH stretching appears at 3300–3500 cm −1 and 3000 cm −1 that confirms the successful modification of PVDF‐HFP/CNF with glutaraldehyde crosslinked with collagen …”

“…MD laboratory‐scale system was utilized by considering NaCl aqueous solution of 30 g/L concentration as the feed stream solution. As per our previous studies, the feed stream solution temperature has been maintained at 70 °C in a hot‐water bath, whereas the cold permeate side was controlled at 20 °C by re‐circulating distilled water . It was observed that the effective membrane area was 100 cm 2 (with specifications: 10 cm × 10 cm).…”

“…27,28 In addition, the OH stretching of H-bonding and CH stretching appears at 3300-3500 cm −1 and 3000 cm −1 that confirms the successful modification of PVDF-HFP/CNF with glutaraldehyde crosslinked with collagen. 29 The surface hydrophobicity has determining effects on the permeate flux and membrane fouling in MD system. Typically, a higher tendency for water to wet the membrane can be associated with a lower angle of contact.…”

Custom-Made Ion Exchange Membranes at Laboratory Scale for Reverse Electrodialysis

“…This membrane was superficially modified immersing it alternately in PEI and GA solutions. The spectra of both modifying solutions are shown after the AEM (panels d and e), along with their principal peaks [55,56,57,58]; finally, panel f presents the spectrum for the modified-AEM. The GA can react with the primary and secondary amines of the PEI; this process allows the assembling of the subsequent PEI layers [41,59].…”

Study of the Crosslinking of PVA with Glyoxal in LbL Nanocomposites

“…Their remarkable reactivity results in a high crosslinking density, reducing thus considerably the free volume in the film. Other than the gas barrier, crosslinking improves also the mechanical properties [10] due to the modification of the polymer structure with the established covalent bonds [11]. The acetal formation and crosslinking reaction is known to be reversible, which could be avoided with acidic conditions.…”