Designing Ultrahigh-Refractive-Index Amorphous Poly(phenylene sulfide)s Based on Dense Intermolecular Hydrogen-Bond Networks

Abstract

High-refractive-index polymers (HRIPs) are currently in demand for the fabrication of state-of-the-art optical devices with high performance. However, few HRIPs that display both ultrahigh refractive index (over 1.8) and high Abbe number (over 20) have been reported owing to the typical trade-off between these two parameters. Herein, we found that poly(2hydroxy-1,4-phenylene sulfide) exhibited an unprecedented ultrahigh refractive index (n D = 1.80) with an amorphous nature, high glass-transition temperature, good transparency, and high Abbe number (ν D = 20). Spectroscopic analyses and density measurements revealed that the dense hydrogen-bond (H-bond) networks of the hydroxy-substituted poly(phenylene sulfide) in the bulk state enabled the realization of an ultrahigh refractive index without any decline in transparency.

High temperature shape memory poly(amide-imide)s with strong mechanical robustness

“…As is well-documented that, the major halo at 14.9°–16.2° is due to the main-chain segmental packing for most of the aromatic polymers, 45,48,50–53 while the shoulder peak locating at 23.8°–25.8° is probably ascribed to the presence of π–π stacking interactions of aromatic rings. 51,54–58 For XRD patterns of the polymers containing amide linkages, the diffraction peaks correlated with π–π stacking interactions are slightly stronger than that for PI-R3 where amide hydrogen bonding is absent, indicating that the amide hydrogen bonding interaction plays a positive role in enhancing the π–π stacking interactions within the PAI polymer backbone. 10,54…”

“…51,54–58 For XRD patterns of the polymers containing amide linkages, the diffraction peaks correlated with π–π stacking interactions are slightly stronger than that for PI-R3 where amide hydrogen bonding is absent, indicating that the amide hydrogen bonding interaction plays a positive role in enhancing the π–π stacking interactions within the PAI polymer backbone. 10,54…”

“…As is welldocumented that, the major halo at 14.9°-16.2°is due to the main-chain segmental packing for most of the aromatic polymers, 45,48,[50][51][52][53] while the shoulder peak locating at 23.8°-25.8°is probably ascribed to the presence of π-π stacking interactions of aromatic rings. 51,[54][55][56][57][58] For XRD patterns of the polymers containing amide linkages, the diffraction peaks correlated with π-π stacking interactions are slightly stronger than that for PI-R3 where amide hydrogen bonding is absent, indicating that the amide hydrogen bonding interaction plays a positive role in enhancing the π-π stacking interactions within the PAI polymer backbone. 10,54 The π-π interaction is a kind of non-covalent supramolecular interaction and usually generates when aromatic rings approach together, 10,34,[59][60][61][62] which would alter the chemical environment of benzene rings and result in an evident red shift of the UV absorption wavelength.…”

“…51,[54][55][56][57][58] For XRD patterns of the polymers containing amide linkages, the diffraction peaks correlated with π-π stacking interactions are slightly stronger than that for PI-R3 where amide hydrogen bonding is absent, indicating that the amide hydrogen bonding interaction plays a positive role in enhancing the π-π stacking interactions within the PAI polymer backbone. 10,54 The π-π interaction is a kind of non-covalent supramolecular interaction and usually generates when aromatic rings approach together, 10,34,[59][60][61][62] which would alter the chemical environment of benzene rings and result in an evident red shift of the UV absorption wavelength. 10,34,55,59,63,64 To further confirm the presence of π-π interactions within the resulting polymers, UV-vis absorption was performed on the resulting polymers in dilute DMAc solutions.…”

“…S37 (ESI †), the singlet peak of the amide protons displays an upfield shift as the polarity of the NMR solvent decreases (from DMSO-d 6 to acetone-d 6 ), indicating that the amide groups behave as H-bonding sites in the solution. 54 To make the amide hydrogen bonding visible, in situ variable temperature infrared spectroscopy IR (VT-IR) measurements were performed on select PAI and reference samples. As is indicated in a few spectroscopic investigations about amide-containing polymers, 55,[65][66][67][68][69] the hydrogen bonding is weakened or even disrupted at elevated temperature, consequently leading to a blue shift (moving to a larger wavenumber) of the amide carbonyl and amide N-H bond…”