High refractive index of transparent acrylate polymers functionalized with alkyl sulfur groups

Abstract

Several sulfur-containing acrylate polymers were developed for a high refractive index with high transparency and good processing performance for thin films. A series of poly(methacrylate)s were synthesized by radical polymerization, in which thin films are coated on a quartz substrate for optical characterization. One, two and three sulfur atoms were bound into acrylate monomers and thermally copolymerized with methyl methacrylate. An alicyclic structure was used to achieve a dense molecular volume of the sulfur-containing monomer. Refractive index was measured under visible light. The index linearly increased with the sulfur-containing monomer content of the copolymer. Each homopolymer was predicted by an extrapolation method, resulting in a high refractive index of 1.624-1.725 at 589 nm. An Abbe's number of B30 was recorded for most sulfur polymers, indicating low wavelength dispersion of the index. A polymer with dipolar functionality displayed an Abbe's number of 40.9. High optical transparency of films was observed at the wavelengths of the index measurement. All polymers were thermally stable up to B250 1C and exhibited glass transition around 100 1C.

Realizing High Refractive Index Thiol-X Materials: A General and Scalable Synthetic Approach

“…While significant progress has been made in the pursuit of high refractive index polymers, − a majority of these strategies involve a thermally driven polymerization, such as polycondensation or inverse vulcanization, to produce the high refractive index polymer. − However, since thermal polymerizations do not afford good spatial control, these high refractive index values are typically only realized in the spatially uniform case. Furthermore, additional considerations such as color, , processability, or synthetic accessibility/scalability − ,,, further preclude these approaches from their use in many photopolymerization-based applications. Significantly, among the body of work for high refractive index polymers, only a small subset are applicable toward photopolymerizations. , However, emerging high-value applications such as additive manufacturing, GRIN optics, and HOEs each require spatial variations in refractive index, with preference for large refractive index modulations.…”

“…Furthermore, additional considerations such as color, , processability, or synthetic accessibility/scalability − ,,, further preclude these approaches from their use in many photopolymerization-based applications. Significantly, among the body of work for high refractive index polymers, only a small subset are applicable toward photopolymerizations. , However, emerging high-value applications such as additive manufacturing, GRIN optics, and HOEs each require spatial variations in refractive index, with preference for large refractive index modulations. In this respect, there has been limited work on the rational design of customizable monomers capable of achieving high refractive index photopolymers. , …”

Surfaces modification of methylcellulose: Cobalt nitrate polymer electrolyte by sulfurated hydrogen gas treatment

“…The formation of CoS nanoparticles on the surface of electrolyte films caused the decrease in interatomic spacing and the samples are more packed, that is, samples with higher density . High refractive index polymeric materials attracted much attention in recent year due to their potential applications in advanced optoelectronic devices …”

High-refractive index acrylate polymers for applications in nanoimprint lithography

“…Most of the existing acrylate polymers exhibit low refractive index (~1.50), which considerably prevents their prospective application in advanced optical devices [47]. Few reports can be found with acrylic polymers having a higher refractive index (over 1.60) including poly(pentabromophenyl methacrylate), poly(2,4,6tribromophenyl methacrylate) and poly(2-((1,3-dithiolan-2-yl)methylthio)ethylmethacrylate derivative) [48][49][50][51][52][53][54]. However, the halogen presence in their chemical structures restricts their use due to the known adverse effect to the environment [55].…”