Orientational control of liquid crystal molecules via carbon nanotubes and dichroic dye in polymer dispersed liquid crystal |
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Authors: | Pankaj Kumar Vandna Sharma Chinky Jaggi Praveen Malik Kuldeep Kumar Raina |
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Institution: | 1. Chitkara University Research and Innovation Network, Chitkara University, Patiala, India;2. School of Applied Sciences, Chitkara University, Patiala, Indiapkumartiet@gmail.com;4. School of Applied Sciences, Chitkara University, Patiala, India;5. School of Applied Sciences, Chitkara University, Patiala, India;6. Liquid Crystal Laboratory, Department of Physics, Dr. B. R. Ambedkar National Institute of Technology, Jalandhar, India;7. DIT University, Dehradun, India |
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Abstract: | Polymer dispersed liquid crystals (PDLCs) using nematic liquid crystal and photo-curable polymer (NOA 65) were prepared by polymerisation-induced phase separation technique, in equal ratio (1:1) of polymer and liquid crystal (LC). We demonstrate that doping of small amount (0.125%, wt./wt.) of multiwall carbon nanotubes (CNTs) and orange azo dichroic dye in PDLC generously controlled the molecular orientation, dynamics of LC in droplet and size of droplets. The effects of multiwall CNTs and dye on PDLCs were studied in terms of transition temperature, droplet morphology, transmittance characteristic, contrast ratio and response time. The results exhibited that the values of the threshold electric fields were reduced from 8 V/µm (pure PDLC) to 1.18 and 1.72 V/µm, doped with multiwall CNTs and dye, respectively. The CNTs-doped PDLC shows faster switching response as compared with pure PDLC and dye-doped PDLC. However, dye-doped PDLC shows much higher contrast among all PDLC samples. Further, the results also illustrate that the birefringence value of LC in PDLCs was changed with doping of CNTs and dye. |
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Keywords: | Nematic liquid crystal (NLC) carbon nanotubes (CNTs) orange azo dye polymer dispersed liquid crystal (PDLC) droplet morphology contrast ratio |
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