Effects Of Di And Tetra Functional Epoxy Monomers Structure On The Morphology And The Electro-Optical Properties Of Polymer-Dispersed Liquid Crystal Films

Abstract- Polymer dispersed liquid crystal PDLC films were prepared by polymerization induced separation PIPS method with nematic liquid crystal LC content as low as 40 wt and the electro-optical properties were carefully investigated. To accomplish this epoxy curable monomers structure with different composition ratio of two mixtures was examined in PDLC films. The electro-optical properties and morphologies of the PDLC films were strongly influenced by the chemical structure of curable monomers di functional ethylene glycol diglycidyl ether EGDE and tetra functional Pentaerythritol tetraglycidyl ether PTTGE. Higher driven voltage and contrast ratio were achieved when the PDLC films showed a reducing morphology with suitably distributed small holes of LC domain size. The detailed characteristics and morphology of polymer network of PDLC films were analyzed by employing liquid crystal device LCD parameters tester and scanning electron microscopy SEM.It was found that the LC domain size of the polymer network could be regulated by adjusting the structure and composition ratio of curable epoxy monomers then the electro-optical of PDLC films could be optimized which is beneficial to decrease the total LC content in PDLC devices.