Polymer/Clay Nanocomposites: Influence of Ionic Strength on the Structure and Adhesion Characteristics in Multilayered Films

Abstract

The aim of the present contribution is to understand how ionic strength, brought by the addition of salt to laponite/PEO nanocomposite dispersions, influences the texture and adhesion characteristics at nano‐ and microscales in multilayered nanocomposite films prepared from such dispersions. At the nano‐scale, SAXS and XRD measurements indicated that the clay platelets orient parallel to the film plane and that the polymer chains intercalate the clay platelets regardless of salt addition. A gradual transition from an agglomerated structure, containing polymer‐rich and clay‐rich domains, to a fine‐balanced structure with smaller distinct details without excess PEO was observed, via AFM, on the exposed edges of cryo‐microtomed films with increasing ionic strength.magnified image

Supramolecular ionic strength-modulating microstructures and properties of nacre-like biomimetic nanocomposites containing high loading clay

“…Like most references, 6,[10][11]22 in this study, a water-soluble PVA was chosen as an organic binder to fabricate clay-polymer composites in the form of a membrane in which clay sheets are in the form of stacked bricks. There are three kinds of water-based polymer systems: water-soluble, waterborne, and water-dispersed.…”

“…6 Considering Sample C as an example, the photograph in Fig. This phase change results from the fact that while partial PVA repeating units connect with clay sheets via a hydrogen bond (O-H/O-), the connection points become hydrophobic because of the lack of active sites with water molecules.…”

“…1 In this hybrid system, inorganic aragonite platelets, the crystal form of CaCO 3 , are stacked orderly in the organic protein matrix. 25 Mg 0.75 )(Si 8 O 20 )(OH) 4 ] and Laponite1 RD 6 with the molecular formula of Na 0.7 [(Mg 5.5 Li 0.3 )(Si 8 O 20 )(OH) 4 ] have been used. 3 The nacre-like microstructures inspired us to develop new inorganic/organic hybrid composites to satisfy the need of modern advanced materials, such as gas barrier membranes, electric insulation, flame-retardant building or furniture materials, the large-scale preparation of biomimetic materials is also of preeminent importance for future construction and coating applications.…”

Effect of Ionic Species on the Structures and Properties of Salt‐Containing PEO/Montmorillonite Nanocomposites

“…Within such systems, the clay stacks are poorly wrapped in polymer and agglomerate to form larger clay‐rich clusters. The excess polymer forms a mesh that covers these large agglomerates, generating a polymer‐rich area outside the clusters 26…”

“…It has been shown that in PEO‐montmorillonite nanocomposites the heterogeneous nucleation of PEO competes with the PEO coordination to sodium ions, which inhibit PEO crystallinity 23–25. Recently, we have shown, via AFM studies, that when no electrolyte salt is added to the PEO/clay system the polymer/clay interactions in solution are diminished and the final structure of the resultant multilayered film is a combination of polymer‐rich and clay‐rich domains 26. Within such systems, the clay stacks are poorly wrapped in polymer and agglomerate to form larger clay‐rich clusters.…”