Reflective mode of HPDLC with various structures of polyurethane acrylates

Holographic polymer dispersed liquid crystals were prepared from photo-curable polyurethane acrylate of various structures and a nematic liquid crystal mixture upon curing the reactive diluents and hydroxy ethyl acrylate terminated (HEA) polyurethane prepolymers. fects of prepolymer molecular structure were studied in terms of reflection efficiency, polymer volume shrinkage and electro-optic properties. Emphases have been made to improve the reflection efficiency and shrinkage of holographic grating during fabrications by modifying soft segment length and hard segment structures of the prepolymer. It was found that polyurethanes with short soft segment and flexible hard segment gave high reflection efficiency and volume shrinkage as well.