Electrooptic studies on polymer-dispersed liquid-crystal composite films. III. Poly(methyl methacrylate-co-butyl acrylate)/E7 and poly(methyl methacrylate-co-butyl acrylate)/E8 composites

2008 ◽  
Vol 107 (2) ◽  
pp. 689-699 ◽  
Author(s):  
A. K. Kalkar ◽  
V. V. Kunte ◽  
S. A. Bhamare
Keyword(s):  
Liquid Crystal ◽  
Methyl Methacrylate ◽  
Butyl Acrylate ◽  
Composite Films ◽  
Poly Methyl Methacrylate ◽  
Polymer Dispersed Liquid Crystal ◽  
Polymer Dispersed ◽  
Crystal Composite

PHASE TRANSITION INVESTIGATIONS IN POLYMER/LIQUID CRYSTAL COMPOSITE MATERIALS

1999 ◽  
Vol 13 (21) ◽  
pp. 759-767 ◽  
Author(s):  
DOINA MANAILA-MAXIMEAN ◽  
MAURIZIO FURLANI ◽  
RODICA BENA ◽  
BENGT-ERIK MELLANDER ◽  
CONSTANTIN ROSU ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Liquid Crystal ◽  
Composite Films ◽  
Scanning Calorimetry ◽  
Polymer Dispersed Liquid Crystal ◽  
Polarized Microscopy ◽  
Polymer Dispersed ◽  
Thermally Stimulated Depolarization ◽  
Crystal Composite ◽  
Polymer Liquid Crystal

We prepared polymer dispersed liquid crystal (PDLC) composite films using polymethyl methacrylate (PMMA) and the ferroelectric liquid crystal (LC) Felix 015/000 (Hoechst) by the solvent-induced phase separation method. We studied the phase transitions by the thermally stimulated depolarization currents (TSDC) method and by differential scanning calorimetry (DSC), for the composite film and the corresponding liquid crystal. Polarized microscopy was also used to characterize the phase transitions. When the LC is mixed with the PMMA, its characteristic transition temperatures are shifted down a few degrees and the current peaks revealed by the TSDC method are broadened due to the dispersion of microdroplets and the consequential presence of a large interface between the LC and the polymer matrix.

Effect of Host Polymer Matrices on Electro Optical and Dielectric Behaviour of Polymer Dispersed Liquid Crystal System

2012 ◽  
Vol 584 ◽  
pp. 531-535 ◽  
Author(s):  
Rajendra Deshmukh ◽  
Sanmesh Parab ◽  
Manoj Malik
Keyword(s):  
Liquid Crystal ◽  
Electric Field ◽  
Methyl Methacrylate ◽  
Indium Tin Oxide ◽  
Dielectric Relaxation Spectroscopy ◽  
Sensitive Material ◽  
Poly Methyl Methacrylate ◽  
Polymer Dispersed Liquid Crystal ◽  
Liquid Crystal System ◽  
Polymer Dispersed

The effect on the electrical characteristics of poly (methyl methacrylate) (PMMA) and poly (methyl methacrylate – co – butyl acrylate) (PMMABA) containing liquid crystal (E8) as dispersed material, is investigated in terms of electro optical and dielectric relaxation spectroscopy (DRS) technique. This polymer dispersed liquid crystal (PDLC) composite film is sandwiched between two glass slides with a transparent conductive substrate such as indium tin oxide (ITO). The resulting assembly forms an electro-sensitive material that can be switched from a OFF state to a ON state by the application of an external electric field or thermal ramp. In the present investigation PMMA / E8, PMMABA / E8 and PMMA+PMMABA / E8 composite films of 30/70 wt / wt % were prepared by Solution Induced Phase Separation (SIPS) method. Morphological study showed that homogeneous LC phase is embedded in a spongy – like polymer matrix. Electro optical behavior was determined under the condition of an externally applied AC electric field (0-200Vp-p, 50-1000Hz). DRS has been carried out in the frequency range from 20 Hz to 20 MHz and over the temperature range from 24°C to 75°C.The interfacial charge layer effect and qualitative evaluation of distribution of relaxation time is characterized by Cole-Cole model.

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