Acrylic monomers and polymers with perfluoroalkylated biphenyl side groups: synthesis and phase transitions
Résumé
New perfluoroalkylated acrylic monomers with a biphenyl core and hydrocarbon spacer (CH2)m of various length (m = 0, 6, 11) were synthesized from biphenol. Phase transitions of monomers and intermediates isolated in the course of the synthesis were studied by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). Whereas most fluoroacrylic monomers and low molecular weight precursors displayed thermotropic behavior (whatever the length of the spacer), the polymers did not retain the ability to form mesophases. Moreover, the bulk organization of the fluorinated side groups was diminished strongly for polymers in comparison with the corresponding fluorinated monomers. Nevertheless, it was demonstrated that an intermediate length of the spacer (–CH2)6, could favor the organization of the rigid perfluoroalkylated biphenyl side groups in the bulk.