"Hairy" Plates: Poly(ethylene oxide)-b-polyisoprene Copolymers in the Presence of Laponite Clay

The morphology and thermal properties have been investigated in laponite/poly(ethylene oxide) (PEO) clay/homopolymer and laponite/poly(ethylene oxide-bisoprene) (PEO-PI) clay/block copolymer nanocomposites using small- and wide-angle X-ray scattering, optical microscopy, transmission electron microscopy, and differential scanning calorimetry. In the laponite/PEO composite, PEO intercalation adjusts the layer spacing and increases the layer correlation length. In the laponite/PEO-PI nanocomposite, the enthalpic interactions between the unlike blocks favoring nanophase separation work in tandem with the entropic interactions favoring polymer/clay intercalation, giving rise to multiple levels of organization. We show that (i) a diblock copolymer can be effectively intercalated within the clay galleries and (ii) the balance of these interactions give rise to a case where one block of the copolymer is intercalated and the other forms a spring that keeps the clay platelets apart, i.e., "hairy" plates