Ultra-high performance photoluminescent polarizers based on melt-processedpolymer blends

Photoluminescent polarizers that comprise uniaxially oriented photoluminesc ent species which absorb and emit light in highly linearly polarized fashio n, 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 orienta tion behavior of a poly(2,5-dialkoxy-p-phenyleneethynylene) derivative (EHO -OPPE), 1,4-bis(phenylethynyl)benzene, and 1,4-bis(4-dodecyloxyphenylethyny l)benzene was systematically compared in different polyethylene grades. Exp eriments suggest that if phase-separation between the photoluminescent gues t 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. I n connection with this finding, an optimized, melt-processed blend based on 1,4-bis(4-dodecyloxyphenylethynyl)benzene and linear low-density polyethyl ene was developed that allows efficient manufacturing of photoluminescent p olarizers which at draw ratios of only 10 exhibit dichroic ratios exceeding 50.