Supramolecular structures in nanocomposite multilayered films

Abstract

We investigate the multilayered structures of poly(ethylene)oxide/montmorillonite nanocomposite films made from solution. The shear orientation of a polymer-clay network in solution combined with simultaneous solvent evaporation leads to supramolecular multilayer formation in the film. The resulting films have highly ordered structures with sheet-like multilayers on the micrometer length scale. The polymer covered clay platelets were found to orient in interconnected blob-like chains and layers on the nanometer length scale. Inside the blobs, scattering experiments indicate the polymer covered and stacked clay platelets oriented in the plane of the film. The polymer is found to be partially crystalline although this is not visible by optical microscopy. Atomic force microscopy suggests that the excess polymer, which is not directly adsorbed to the clay, is wrapped around the stacked platelets building blobs and the polymer also interconnects the polymer-clay layers. Overall our results suggest the re-intercalation of clay platelets in films made from exfoliated polymer-clay solutions as well as the supramolecular order and hierarchical structuring on the nanometer, via micrometer to the centimeter length scale.

Highly Extensible Bio‐Nanocomposite Films with Direction‐Dependent Properties

“…The directionally dependent mechanical properties of the dried nanocomposite films depend on the nano-and micrometer-sized structural features, on the PEO-Laponite interactions, and on the shear orientation induced by film preparation [31,32] and stretching. For example, the high-molecular-weight polymer (M w ¼ 10 6 g/mol PEO) that is used for making gels and then films, increases the interconnectivity between the Laponite cross-linkers compared to low M w polymers.…”

“…Laponite cross-linked PEO films were prepared via gel/solution exfoliation while optimal solutions were obtained for a particular polymer silicate ratio, pH, and ionic strength [31,32]. For this work, we have prepared hydrogels composed of 2 wt.% PEO and 3 wt.% LRD at ambient temperature.…”

Elongational Rheology of Polymer/Clay Dispersions: Determination of Orientational Extent in Elongational Flow Processes

“…In the past we have adjusted the ionic strength of montmorillonite dispersions by addition of NaCl to screen the electrostatic interactions between charged phyllosilicate platelets. [14] In this work we test the rheological response of polymer/clay gels where ionic strengths were adjusted by means of three different salts.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Highly ordered polymer nanocomposites are complex materials that display a rich morphological behavior because of variations in composition, structure and properties on a nanometer length scale. [6,14,15] Novel physical properties of polymer/clay nanocomposite multilayered films are strongly dependent on the structure and orientation of precursor nanocomposite dispersions and gels. [14,15] The ability to tailor properties to…”

“…[6,14,15] Novel physical properties of polymer/clay nanocomposite multilayered films are strongly dependent on the structure and orientation of precursor nanocomposite dispersions and gels. [14,15] The ability to tailor properties to…”