Optimization of holographic polymer dispersed liquid crystal for ternary monomers

✍ Scribed by Cho, Y H; Kim, B K; Park, K S

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 325 KB
• Volume: 48
• Category: Article
• ISSN: 0959-8103
• DOI: 10.1002/(sici)1097-0126(199911)48:11<1085::aid-pi235>3.0.co;2-o

✦ Synopsis

Polarized optical micrography (POM) images of gratings and UV±visible spectra of holographic polymer dispersed liquid crystals (HPDLC) are reported for a ternary monomer system composed of dipentaerythritol hydroxypentaacrylate/trimethylolpropanetriacrylate/N-vinylpyrrolidone (DPHPA/TMPTA/NVP) = 7/2/1 by weight. Gratings were written by irradiation with an argon ion laser (l = 488 nm) at various intensities (20±200 mW cm À2 ) on monomer/liquid crystal (LC) composite ®lms of various compositions (75/25, 70/30, 65/35, 62/38, 60/40). Re¯ection ef®ciency±irradiation intensity±®lm composition relationships are obtained in three dimensional plots which show that maximum re¯ection moves from high LC content (38%) at low irradiation intensity (20 mW cm À2 ) to low LC content (25 wt%) at high irradiation intensity (200 mW cm À2 ).