Influence of Chemical Structure on the Refractive Index of Imide‐Type Polymers

Abstract

The influence of different substituents on the optical properties of poly(amide imide)s and polyimides is systematically investigated. All of the polymers exhibit good solubility and film‐forming ability, high thermal stability, and glass transition temperatures of 162–209 °C for poly(amide imide)s and of 209–274 °C for polyimides. The optical transmittance of the films at 450 nm is above 80% for all the studied polyimides and poly(amide imide)s containing benzonitrile units linked in the 2,6‐position. The values of refractive index for poly(amide imide)s are in the range of 1.623–1.748 and for polyimides in the domain of 1.672–1.768.

Highly refractive polyimides containing pyridine and sulfur units: synthesis and thermal, mechanical, solubility and optical properties

“…A high refractive index (high n ) is an important factor for the practical application of polymers in advanced optoelectronic fabrications. According to the Lorentz − Lorenz equation, several factors such as the molar refraction, molar volume or density affect the refractive index of polymers which is the key feature for optical applications . Thus, the refractive indices of polymers can be increased by the incorporation of substituents with high molar refractions and low free molecular volumes.…”

Accelerated Discovery of High-Refractive-Index Polyimides via First-Principles Molecular Modeling, Virtual High-Throughput Screening, and Data Mining

“…These properties are complemented by mechanical stability, flexibility, light weight, low cost, as well as flame and radiation resistance, and they thus hold much promise for a range of applications [5,6]. However, their generally low index of refraction (RI) undermines their utility for use in many optic and optoelectronic devices [7][8][9][10][11], such as (image) sensors [12,13], displays [14], and light sources (including organic lightemitting diodes) [15], in which organic materials can be deployed in situ as microlenses [16], waveguides [17], microresonators [18], interferometers [19], anti-reflective coatings [20], optical adhesives [21], and substrates [22]. Most of these applications demand large RI values, often upwards of 1.7 or 1.8.…”

Accelerated Discovery of High-Refractive-Index Polyimides via First-Principles Molecular Modeling, Virtual High-Throughput Screening, and Data Mining

“…These properties are complemented by mechanical stability, flexibility, light weight, low cost, as well as flame and radiation resistance, and they thus hold much promise for a range of applications [5,6]. However, their generally low index of refraction (RI) undermines their utility for use in many optic and optoelectronic devices [7][8][9][10][11], such as (image) sensors [12,13], displays [14], and light sources (including organic lightemitting diodes) [15], in which organic materials can be deployed in situ as microlenses [16], waveguides [17], microresonators [18], interferometers [19], anti-reflective coatings [20], optical adhesives [21], and substrates [22]. Most of these applications demand large RI values, often upwards of 1.7 or 1.8.…”