Ultra-high performance photoluminescent polarizers based on melt-processed polymer blends

Photoluminescent polarizers that comprise uniaxially oriented photoluminescent species which absorb and emit light in highly linearly polarized fashion, can efficiently combine the polarization of light and the generation of bright colors. We here report the preparation and characterization of such polarizers by simple melt-processing and solid-state deformation of blends of a photoluminescent guest and a thermoplastic matrix polymer. The orientation behavior of a poly(2,5-dialkoxy-p-phenyleneethynylene) derivative (EHO-OPPE), 1,4-bis(phenylethynyl)benzene, and 1,4-bis(4-dodecyloxyphenylethynyl)benzene was systematically compared in different polyethylene grades. Experiments suggest that if phase-separation between the photoluminescent guest and the matrix polymer is reduced during the preparation of the pristine (i.e. unstretched) blend films, photoluminescent polarizers can be produced which exhibit unusually high dichroic properties at minimal draw ratios. In connection with this finding, an optimized, melt-processed blend based on 1,4-bis(4-dodecyloxyphenylethynyl)benzene and linear low-density polyethylene was developed that allows efficient manufacturing of photoluminescent polarizers which at draw ratios of only 10 exhibit dichroic ratios exceeding 50.