Synthesis, electro‐optic properties, and performance of novel fluorinated polyurethaneimide

• Published in: Polymer engineering and science 2024-09, Vol.64 (9), p.4371-4378
• Main Authors: Wang, Long‐De, Tong, Ling, Wu, Jian‐Wei, Rong, Jie‐Wei
• Format: Article
• Language: English
• Subjects: Anhydrides; Chemical synthesis; Chromophores; Decomposition reactions; Diamines; Electric properties; electro‐optical materials; Fluorination; Glass transition temperature; Isocyanates; Light reflection; Light transmission; Modulation; Modulators; Monomers; Nonlinear optics; Oligomers; Optical materials; Optical properties; Optics; Polycondensation reactions; Polymers; polyurethaneimide; synthesis; Toluene; Toluene diisocyanates; Urethanes; Waveguides
• ISSN: 0032-3888; 1548-2634
• DOI: 10.1002/pen.26853

Urethane imide anhydride oligomers with terminal groups as anhydride groups were designed and synthesized using second‐order nonlinear optical chromophore molecule, bisphenol AF‐type diethylidene dianhydride, and toluene diisocyanate as monomers. Polyurethaneimide (PUI) second‐order nonlinear optical polymers with the structure of imide and amino ester chain segments were then synthesized by the polycondensation reaction between urethane imide anhydride oligomers and aromatic diamine monomers. The glass transition temperature (Tg) of PUI reached 186°C, and the 5% heat‐loss decomposition temperature was 320°C. The corona‐polarized PUI had an electro‐optic (EO) coefficient (γ33) of 82 pm/V tested by the reflection method. The loss of light transmission of the polymer waveguide prepared with PUI as electro‐optical material was 1.13 dB/cm at 1550 nm. Mach–Zehnder type polymer waveguide electro‐optical modulators have been prepared based on the properties of the electro‐optic material PUI. The fabricated polymer EO modulators had favorable electro‐optic modulation response performance for low‐frequency electrical signals. The good modulation characteristics of the manufactured electro‐optical modulators proved that the synthesized PUI was a waveguide polymer material with good comprehensive performance. Highlights Electro‐optic fluorinated polyurethaneimide was synthesized. Polyurethaneimide as core material, polymer waveguide EO modulators were fabricated. The prepared modulators had good electro‐optic modulation performance. (A) Schematic cross‐section of the designed polymer waveguide electro‐optic modulator. (B) Scanning electron microscope image of waveguide substrate trenches prepared from photoresist SU‐8. (C) Prepared polymer waveguide EO modulators. (D) Morphology of traveling wave electrodes of coplanar waveguides observed by optical microscopy.