Norbornene-dicarboximide (NDI) has been selected to be utilized as promising alternative for electro-optic (EO) application. Herein, NDI unit was incorporated to hexyl as well as FTC chromophore substituent for controlling thermal-physical properties and achieving EO activity, respectively. NDI monomers with different pendants were thoroughly polymerized to obtain EO copolymers with high EO chromophore loading density, appropriate molecular weight, as well as high glass transition temperature. This work will be discussed about the EO polymers with distinct design and its effect to physical properties and device characteristics.
Electro-optic (EO) polymers have been extensively considered as promising organic materials providing adjustable EO coefficient according to their designs. In addition, EO polymers comprehensively show well compatibility toward other optical components. However, thermal resistance of organic EO polymers still remains challenging for a range of application. To overcome this issue, we have selected norbornene-dicarboximide (NDI) to be utilized as based backbone for our EO polymer. This is because NDI polymer showed excellent properties toward EO applications, such as high glass transitional temperature and good optical transparency. Therefore, by attaching distinct EO chromophores to NDI backbone, both effective EO coefficient and thermal stable EO polymer could be adequately modified. In this study, the polymerisation was performed by ring opening metathesis polymerisation (ROMP). Grubbs catalyst was used to mildly initiate propagation. As the main NDI derivative was linked to cyclohexyl as it offers high thermal properties, NDI with phenyl vinylene thiophene (FTC) chromophore pendant was necessarily investigated to accomplish high chromophore loading density. Moreover, several conditions were considerably performed to afford polymer in high yield and excellent characteristics without unexpected side-reactions. Preliminary results showed that the obtained EO polymer prepared by ROMP at room temperature showed high chromophore loading density over 30% and yield more than 80%. Further investigations remain to be discussed to afford appropriate quality EO polymer for device fabrication.