Controlling the level of dispersion of silicate layers in polymer matrices through intermolecular
interactions and exploiting these interactions to enhance thermomechanical behavior are key challenges in the
field of polymer nanocomposites. In this investigation, unmodified Laponite platelets are dispersed in a segmented
polyurethane containing a polar, hydrophilic soft segment and a hydrophobic hard segment using a novel solvent
exchange method and compared to polyurethane nanocomposites containing more hydrophobic hard and soft
domains. It was determined that the silicate layers were preferentially, but not exclusively, attracted to the
hydrophilic, polar soft domains. An apparent microphase-segregated morphology was observed in transmission
electron microscopy for this system, revealing regions of exfoliation and intercalation. According to polarizing
optical microscopy, strain-induced alignment is inhibited for this polyurethane nanocomposite, which is reflected
in dramatic reductions in tensile strength and ultimate extensibility. In comparison, the Laponite disks appear to
be preferentially, but not exclusively, embedded within the hard domains in the segmented polyurethanes containing
more hydrophobic hard and soft domains. Exfoliation of the clay platelets leads to enhanced modulus and toughness
without a reduction in extensibility. This study provides clues for exploiting silicate-polymer interactions to
tune material properties without chemical modification.