Synthesis and characterization of alkaline‐soluble triazine‐based poly(phenylene sulfide)s with high refractive index and low birefringence

Abstract

High‐refractive‐index (high‐n) polymers (HRIPs) with a high optical transparency are highly needed in advanced optoelectronic devices. In this work, we report the synthesis and characterization of a series of high‐n, transparent, totally colorless, and high‐sulfur‐containing poly(phenylene sulfide)s (PPSs) bearing a triazine unit. Two new triazine monomers T1 and T2 with hydroxyl and tert‐butyl acetate side chains, respectively, were designed and synthesized to develop PPSs with high‐n and high alkaline solubility. These PPSs were prepared by the single‐phase polycondensation from T1/T2 and commercial aromatic dithiols such as 4,4′‐thiobisbenzenethiol (TBT) and benzene‐1,3‐dithiol (BDT), achieving very high‐n up to 1.7530 at 633 nm, a high optical transparency (T% > 90% @400 nm) and low birefringence (Δn = 0.0014–0.0080), and exhibiting high potential on the application of high‐n photoresists. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 724–731

Transparent, Ultrahigh-Refractive Index Polymer Film (n ∼1.97) with Minimal Birefringence (Δn <0.0010)

“… a Entries 1–2 are polymers from inverse vulcanization, , 3–5 are HRIPs prepared without the direct utilization of elemental sulfur, − and 6 is our initial report on sCVD …”

Development of Novel Triazine-Based Poly(phenylene sulfide)s with High Refractive Index and Low Birefringence

“…To achieve higher n values, heteroaromatic rings possessing −CN– units are introduced by replacing with the phenyl rings because the −C–NC– units possess a higher molar refraction of 4.10 than the −C–CC– units (molar refraction = 1.73). , Based on these considerations, we focused on triazine dichlorides with various pendant thioether or ether units as monomers and reported the realization of a series of high- n and transparent triazine-based poly­(phenylene thioether)­s (PPTs) also called as PPSs, which were prepared by polycondensation from different aromatic dithiols. Indeed, they exhibit high- n values ( n av = 1.6486–1.7530 at 633 nm), high transparency in the visible region ( T > 80% @ 400 nm), and low Δ n values (Δ n = 0.001–0.008). − In addition, the Oishi group has reported a series of poly­(guanamine)­s derived from 2-substituted-4,6-dichloro-1,3,5-triazine, which showed quite high- n values ( n av = 1.677–1.800 at 589 nm) and excellent transparency in the visible region ( T > 90% @ 400 nm). These results also prove that the triazine structure shows promising high- n values and high transparency in the visible region.…”

Highly Transparent Benzothiazole-Based Block and Random Copolymers with High Refractive Indices by RAFT Polymerization

“…In general, conjugated aromatic rings, sulfur atoms, and metal species lead to unfavorable colorization and a decrease in transparency. Other candidates for improving the refractive index include heteroaromatic rings involving −CN–C– bonds because their molar refractions (4.10) are higher than that of a −CC–C– bond (1.73), , and several main-chain-type polymers with triazines, − pyrimidines, − and pyridazines have been developed. Other examples include the synthesis of highly refractive polyimides, polyamides, , and poly­(amide-imide)­s , with heteroaromatic thiazole units.…”