Perfluorocyclobutyl (PFCB) polymers and copolymers have a unique combination of properties well suited for optical applications such as high temperature stability, precisely controlled refractive index, low moisture absorption, excellent melt and solution processability, a variable thermo-optic coefficient, and low transmission loss at 1300 and 1550 nm. Electro-optical devices from polymers of ring locked polyene chromophores are attractive due to their thermal, mechanical, optical and dielectric properties. Polyene chromophores with highest hyperpolarizability are covalently attached to trifluorovinyl aryl ether containing moieties and copolymerized with other monomers. The resulting polymers display imrpoved thermal stability, solubility and good film forming capabilities.
Polymer-stabilized ferroelectric liquid crystal (PSFLCs) are made by photopolymerizing a small amount of reactive mesogenic monomer on a quasi-bookshelf texture of ferroelectric liquid crystals (FLCs). We observed the templated submicron-scaled polymer fibrils from the two- dimensionally ordered host. The polymer fibrils capture the orientation of the host with thin polymer fibrils interweaving the smectic layers that act as additional surfaces for controlling the reorientation of FLC molecules. T he SEM study shows the difference in morphology of the polymer fibrils depending on the polymerization conditions and FLC hosts. Improvements in electro-optical properties such as, the increase in spontaneous polarization, the fast switching at a lower applied field, and the voltage independent of switching time are achieved by PSFLCs using a mesogenic monomer and FLC with a smectic A phase. The polymer networks suppress the symmetric rotation of FLC under applied field and result in PSFLCs exhibiting the thresholdless switching behavior.
A series of dendron-modified nonlinear optical (NLO) chromophores and multiple chromophore-containing crosslinkable NLO dendrimers have been developed. The enhancement of poling efficiency (40%) in the dendritic NLO chromophore/polymer guest/host system was obtained due to the significant minimization of intermolecular electrostatic interactions among chromophores by the dendritic effect. Multiple NLO chromophore building blocks can be further placed into a dendrimer to construct precise molecular architecture with predetermined chemical composition. The site-isolation effect, through the encapsulation of NLO moieties by dendrons, can greatly enhance the performance of electro-optic (E-O) materials. A very large E-O coefficient (r33=60 pm/V at 1.55 micrometers ) and high temporal stability (85 degree(s)C for more than 1000 h) were achieved in a NLO dendrimer developed through the double-end functionalization of a 3D shape phenyl-tetracyanobutadienyl (Ph-TCBD)- containing NLO chromophore with thermally crosslinkable trifluorovinylether-containing dendrons.