Claudine Biver

A novel elastomer/liquid crystal polymer nanocomposite created in situ from controlled radical graft-polymerization

We present the original design and properties of a novel, all-polymer hierarchical composite comprising an elastomer and a fluorinated liquid crystal polymer. The material follows from the phase separation between the two highly incompatible components, occuring in situ during the controlled radical graft-polymerization of the liquid crystal monomer onto functionalized elastomeric chains. We demonstrate that the composite remarkably combines the mechanical properties, static and dynamic, of both an elastomer and a semi-crystalline polymer. We thereby illustrate how the careful choice of a graft can provide a simple rubbery material with original and antonymic functionalities. Here, the temperature-sensitive liquid crystal polymeric domains act as hard particulate fillers under their fusion temperature and liquid softening inclusions above, with fast reversible transitions from one state to another. A variety of composites combining physico-chemical features difficult to marry otherwise may be designed following this simple method.