Photophysical analysis of dual fluorescence and phosphorescence emissions observed for semi-aliphatic polyimides at lower temperatures.

The photoluminescence (PL) properties of four types of blue fluorescent semi-aliphatic polyimides (PIs) derived from aromatic dianhydrides (ODPA, BPDA, HQDEA, and BPADA) and an alicyclic diamine (DCHM) were investigated at temperatures ranging from room temperature (RT, 298 K) to 30 K to analyse the origins of their non-radiative relaxation (NR) processes. These PIs exhibited significant increases in fluorescence (FL) intensity and lifetimes when lowering the temperature, stabilising below 100 K. The PIs containing ether (-O-) linkages showed a shoulder peak at around 500 nm below 150 K, which is attributable to phosphorescence (PH). These results show that the NR deactivation at RT includes three processes: intersystem crossing (ISC) from the excited singlet (S1) to the triplet (T1) state, temperature-dependent NR from the S1 state, which becomes suppressed below around 100 K, and temperature-independent NR. Based on the analyses of the temperature dependences, polymer structures, and quantum chemical analysis of molecular orbitals, we contemplate that the temperature-dependent NR is attributable to the excitation quenching by defect states mediated by excitation migration, and the temperature-independent NR may be caused by the deactivation of the excited state induced by molecular vibrations.

Hybrid transileocecal portal vein embolization associated with staging laparoscopy for planned major hepatectomy in advanced hepatobiliary cancers.

BACKGROUND: Portal vein embolization (PVE) is widely used to promote the hypertrophy of a future liver remnant (FLR) and reduce posthepatectomy liver failure. The aim of this study was to evaluate the efficacy of transileocecal portal embolization (TIPE) associated with staging laparoscopy (hybrid lap-TIPE) for a planned hepatectomy in advanced hepatobiliary cancers. METHODS: The hybrid lap-TIPE procedure consisted of staging laparoscopy for complete screening of the abdominal cavity with cytoreductive surgery and subsequent TIPE. Data on hybrid lap-TIPE, performed between March 2013 and February 2020, were collected retrospectively. RESULTS: Hybrid lap-TIPE was conducted for 52 patients, and a subsequent TIPE was accomplished in 42 patients (80.8%), since staging laparoscopy detected latent or unresectable factors in 13 patients (25.0%), among which 2 patients with hepatocellular carcinoma and 1 with colorectal liver metastasis received laparoscopic cytoreductive surgery for latent lesions in the FLR. Finally, radical hepatectomy was completed in 36 patients (69.2%), including 3 patients who underwent cytoreductive surgery. The most common operation was an extended right hepatectomy (50.0%), followed by right hepatectomy (30.6%), including 3 hepatopancreatoduodenectomies. The overall morbidity associated with hybrid lap-TIPE and hepatectomy was 7.1% and 41.7%, respectively. The mortality associated with hybrid lap-TIPE and hepatectomy was 0% and 5.6%, respectively. The rates of 2-year survival and 2-year disease-free survival were 64.8% and 61.9%, respectively, after hepatectomy. CONCLUSIONS: Hybrid lap-TIPE is safe and could be a useful treatment option for patients with advanced hepatobiliary cancer because it can help to identify optimal candidates for PVE followed by a planned hepatectomy.

Laparoscopic portal branch ligation of the right caudate lobe concomitant with portal vein embolization for planned right hemihepatectomy in advanced hepatobiliary cancers.

BACKGROUND: The role of ligation of the portal venous branches to the caudate lobe (cPVL) as preparation for planned major hepatectomy is unclear. The aim of this study was to evaluate the efficacy of laparoscopic cPVL (Lap-cPVL) concomitant with transileocolic portal vein embolization of the right portal venous system (rTIPE), namely, Lap-cPVL/rTIPE, for planned right hemihepatectomy (rHx) in advanced hepatobiliary cancer patients. METHODS: Thirty-one patients who underwent rHx after rTIPE with/without Lap-cPVL between March 2013 and March 2020 were enrolled in this study. The Lap-cPVL was performed for the portal branches of the right caudate lobe. RESULTS: Eight of the 31 patients underwent Lap-cPVL/rTIPE. The degree of hypertrophy was significantly increased in Lap-cPVL/rTIPE (19.3%, range 6.5-25.6%) as compared to rTIPE (7.2%, range - 1.1 to 21.2%) (p=0.027). The functional kinetic growth rate was also significantly increased in Lap-cPVL/rTIPE (5.40%, range 2.17-5.97) than that in rTIPE (1.85%, range - 0.22 to 6.45%) (p=0.046). Postoperative liver failure ≧ grade B occurred in 21.7% of patients in rTIPE, while there was no postoperative liver failure ≧ grade B in Lap-cPVL/rTIPE. Mortality rates were zero after rHx in this study. CONCLUSIONS: Lap-cPVL/rTIPE is safe and provides an additional effect on liver hypertrophy in advanced hepatobiliary cancers.

Enhanced fluorescence of phthalimide compounds induced by the incorporation of electron-donating alicyclic amino groups.

Due to their high thermal and environmental stability, polyimides (PIs) are one of the most attractive candidates for novel highly fluorescent polymers, though photophysical studies of PIs are challenging owing to their poor solubility in common solvents. To overcome these problems, we have synthesized and examined a series of low molecular weight model imide compounds: substituted N-cyclohexylphthalimides with alicyclic amino groups at the 3 or 4-positions of the benzene rings (x-NHPIs). Their photophysical properties were systematically investigated by steady-state UV/Visible absorption, fluorescence, and time-resolved fluorescence techniques. In solution, unsubstituted N-cyclohexylphthalimide (NHPI) showed almost no emission, while x-NHPIs exhibited enhanced fluorescence emission depending on the solvent polarity. Analysis of the solvatochromism of the x-NHPIs via Lippert-Mataga plots indicated the generation of large dipole moments in the excited singlet states originating from the intramolecular charge-transfer (ICT) states. The significant difference in the fluorescence quantum yields (Φ) between the 3-substituted (3Pi and 3Pyr) and 4-substituted NHPIs (4Pi and 4Pyr) strongly suggests that the former form a twisted ICT (TICT) state, whereas the latter form a planar ICT (PICT) state when excited. 4-Substituted NHPIs also show high fluorescence yields in the crystalline state. A particularly large Φ value was obtained for the 4Pi crystal, which we explain by the large intermolecular distances and the arrangement of molecules minimizing intermolecular interactions as well as the small non-radiative deactivation rate. These facts clearly demonstrate that the introduction of an alicyclic amino group into NHPI at the 4-position enhances the fluorescence quantum yields significantly, which suggests a new pathway for the development of novel, highly fluorescent PIs.

Fluorescence emissions of imide compounds and end-capped polyimides enhanced by intramolecular double hydrogen bonds.

The structure and optical properties of a newly synthesized imide compound (DHNHPI) that forms intramolecular double hydrogen bonds (intra-HBs) were investigated. This compound exhibits intense absorption at 372 nm (ε = 5091 cm(-1) M(-1)) and strong emission at 427 nm (Φ = 0.507) in CHCl3. Under basic conditions, the absorption and fluorescence peaks showed large bathochromic shifts by 70 nm and 95 nm, respectively, compared with the neutral condition due to conversion to anion form. Based on the single-crystal X-ray diffraction analysis, DHNHPI can exert intermolecular π-π interactions between adjacent molecules along the stacking direction, with resultant emission peaks exhibiting longer wavelengths (∼525 nm) in the solid state. Moreover, an end-capped polyimide having DHNHPI moieties at the termini exhibited a strong fluorescence peak at 427 nm by photo-excitation at 332 nm. The large Stokes shift of 6701 cm(-1) clearly indicates the occurrence of an effective Förster-resonance energy transfer from the main chains to the fluorescent end-groups. These facts demonstrate that the incorporation of two -OH groups, which form intra-HBs, endows imide compounds and polyimides with enhanced fluorescence properties as well as high sensitivity towards pH.

Pressure-Induced Enhancement of Room-Temperature Phosphorescence in Heavy Halogen-Containing Imide and Polyimide.

To investigate the correlation between the aggregated state and photoluminescence (PL) mechanism of dual fluorescent (FL) and phosphorescent (PH) polyimides (PIs), the photophysical processes of FL-type BP-PI, PH-type DBrBP-PI, and their corresponding imide model compounds (BP-MC and DBrBP-MC) dispersed in poly(methyl methacrylate) (PMMA) films were analyzed at elevated pressures up to 8 GPa using a diamond anvil cell. Dibromo-substituted DBrBP-MC demonstrated a shorter wavelength absorption than BP-MC owing to the larger dihedral angle in the biphenyl moiety. Both MCs exhibited red-shifts in their absorption spectra with increasing pressure, indicating planarization occurred at the biphenyl moieties associated with the compression of the free volume in PMMA. The PL intensity of BP-MC increased with increasing pressure, while its quantum yield (ΦPL) decreased sharply due to the enhanced energy transfer via the Förster mechanism. In contrast, the PH quantum yield (ΦPH) of DBrBP-MC monotonically increased at lower pressures, while it showed excitation wavelength-dependent behaviors at higher pressures: ΦPH remained unchanged under excitation at 340 nm but gradually increased under excitation at 365 nm. This fact suggests that, at higher pressures, 365 nm excitation promoted intersystem crossing (ISC) from excited singlet states at higher energy levels. Using this phenomenon, a significant pressure-induced PH enhancement (PIPE) was observed for DBrBP-PI up to 0.9 GPa upon excitation at 365 nm, which is a rare phenomenon for organic polymers. This study indicates that even in colorless and optically transparent amorphous polymers, an enhancement of PH due to restricted molecular motion and intensified ISC outweighs the deactivation due to intermolecular energy transfer under certain pressures, leading to an increase in ΦPH.

Acute abdomen by red degeneration of a parasitic leiomyoma: A case report and literature review.

A 43-year-old woman, with a history of uterine fibroids and multiple myomectomy, presented with acute lower abdominal pain. Computed tomography revealed multiple tumors, including a high-density mass in the left lower abdomen indicative of a parasitic leiomyoma undergoing red degeneration. This uncommon condition is due to acute occlusion, often caused by peripheral venous thrombosis at the fibroid edge. The diagnosis was corroborated by distinctive findings on magnetic resonance imaging and computed tomography. Notably, high signal intensity on T1-weighted images (T1WI) suggested methemoglobin presence due to hemorrhagic infarction, whereas low signal intensity on T2-weighted images (T2WI) indicated deoxyhemoglobin. Symptom improvement followed treatment with analgesics. This case underscores the significance of considering parasitic myomas in the differential diagnosis of intraperitoneal tumors after myomectomy and proposes that vascular torsion from mechanical stress on the mobile mesentery may contribute to red degeneration in such tumors. In this report, we detail the imaging characteristics and clinical progression of red degeneration in a parasitic leiomyoma, emphasizing the importance of this diagnosis in patients with a history of uterine surgery.

Evaluation of Local Vascular Perfusion in the Lower Extremities on Intravoxel Incoherent Motion Imaging before and after Endovascular Therapy.

PURPOSE: To evaluate improvement in local vascular perfusion of the lower limbs on intravoxel incoherent motion (IVIM) imaging after endovascular therapy (EVT). MATERIALS AND METHODS: IVIM imaging was performed on 20 lower limbs of 16 patients with lower extremity arterial diseases before and after EVT. To estimate IVIM, diffusion-weighted lower-limb axial images (number of slices = 25 and slice thickness = 3.5 mm) were acquired using different b values (0, 300, and 1000 s/mm2). IVIM imaging with the simplified IVIM techniques was performed. The perfusion-related coefficient (D* [10-3 mm2/s]), perfusion fraction (f [%]), and D*f product (10-3 mm2/s %) were calculated before and 2-3 days after EVT. The ankle brachial index (ABI), mean D* (10-3 mm2/s), mean f (%), and mean D*f product (10-3 mm2/s %) before and after EVT were compared. RESULTS: Successful revascularization was achieved in all cases. After EVT, the mean ABI significantly increased from 0.59 ± 0.19 to 0.87 ± 0.15 (p < 0.001, paired t test). The mean D* (10-3 mm2/s) (22.08 ± 3.26 versus 24.87 ± 2.65, p = 0.005, paired t test), and D*f product (10-3 mm2/s%) (551.03 ± 79.02 versus 634.55 ± 76.96, p = 0.002, paired t-test) of the lower limbs significantly increased after EVT, whereas f (%) (25.00 ± 1.28 versus 25.52 ± 1.61, p = 0.261, paired t-test) did not significantly increased after EVT. CONCLUSION: D* (10-3 mm2/s) and D*f product (10-3 mm2/s %) on IVIM imaging could evaluate improvement in local vascular perfusion of the lower limbs after EVT. LEVEL OF EVIDENCE: Level 4, Case Series.

Three-dimensional velocity vector image obtained via 4-dimensional flow magnetic resonance imaging for in-stent flow visualization in the superficial femoral artery.

The assessment of stent lumen patency via non-contrast-enhanced 2-dimensional time-of-flight magnetic resonance angiography (2D TOF MRA) is complex due to stent-related artifacts. However, an imaging technique using the phase-contrast method, which can reduce susceptibility to artifact, is available. Herein, we report the use of 3-dimensional velocity vector image obtained via 4-dimensional flow magnetic resonance imaging (4D flow MRI) for in-stent flow visualization after stent development in the right superficial femoral artery. Hence, instead of 2D TOF MRA, 4D flow MRI using the phase-contrast method can be performed to assess stent lumen patency as it reduces stent-related artifacts.

Steerable-wire technique using high-flow steerable microcatheter and 0.025-inch guidewire.

A high-flow steerable microcatheter has been reported to be useful as a triaxial system. Moreover, the benefits of steerable microcatheters in acute-angle bifurcation vessel insertions and a compact coil-packing technique using intentional folding with a bendable catheter tip have been reported. However, research on the usefulness of a high-flow steerable catheter and 0.025-inch guidewire combination (steerable-wire) technique is lacking. Herein, we report a case of balloon-occluded retrograde transvenous obliteration (BRTO) via the femoral venous approach to illustrate the usefulness of the steerable-wire technique. The steerable-wire technique facilitates the selection of the wire into the target vessel. The steerable-wire can be used instead of the 0.035-inch guidewire, which is versatile as other devices can follow the steerable wire.

Massive spontaneous nontraumatic subcapsular hepatic hematoma treated using arterial embolization: A case report and review of the literature.

A nontraumatic and idiopathic spontaneous subcapsular hepatic hematoma is a rare but often fatal condition. Herein, we report a case of nontraumatic progressive massive subcapsular hepatic hematoma that straddled both liver lobes and was successfully treated by repeated arterial embolization. Following treatment, the hematoma did not progress.

Remarkable effects of terminal groups and solvents on helical folding of o-phenylene oligomers.

Although o-phenylene oligomers (OP(n)R) made of dimethoxyphenylene units are thought to be intrinsically dynamic due to π-electronic repulsion, we show that they fold into a regular helical geometry in CH(3)CN when they carry terminal groups such as CH(3), CH(2)OH, Br, CO(2)Bn, and NO(2). We evaluated their helical inversion kinetics via optical resolution of long-chain oligomers (e.g. 16- and 24-mers) by chiral HPLC. OP(24)Br at 298 K shows a half-life for the optical activity of 5.5 h in CH(3)OH/water (7/3 v/v) and requires 34 h for complete racemization. The perfectly folded helical conformers of OP(n)R, unlike their imperfectly folded ones, are devoid of extended π-conjugation and show a cyclic voltammogram featuring reversible multistep oxidation waves.

Improvement in local vascular perfusion of the lower extremities on intravoxel incoherent motion imaging: A case report.

Intravoxel incoherent motion imaging has its improvement-evaluating ability in lower limb perfusion after endovascular therapy in individuals with lower extremity arterial disease. Here, we present a 70-year-old man with intermittent claudication of the left lower limb, whose microperfusion on intravoxel incoherent motion imaging improved after endovascular therapy. The patient underwent intravoxel incoherent motion imaging of the lower extremities pre- and postendovascular therapy. After endovascular therapy, the left ankle brachial index increased from 0.46 to 1.06. The mean perfusion-related coefficient (10-3 mm2/s) of the left lower limb increased from 19.70 ± 3.17 to 24.81 ± 3.41, and mean perfusion fraction (%) of the left lower limb slightly increased from 24.41 ± 0.96% to 25.20 ± 1.89% after endovascular therapy. Therefore, successful revascularization can improve microperfusion on intravoxel incoherent motion imaging in a patient with lower extremity arterial disease.

Inverted intercostal hernia of elastofibroma dorsi mimicking well-differentiated liposarcoma in the chest wall.

Elastofibroma dorsi is a well-known benign chest wall tumor. Herein, we present a case in which an elastofibroma protruded into the thoracic cavity, leading to inverted intercostal hernia. Imaging revealed a soft tissue mass containing fat, typical of elastofibroma dorsi; however, precise diagnosis was difficult owing to the location of this mass that protruded into the thoracic cavity. Liposarcoma had to be ruled out because it was a growing fat-containing mass. Considering that the tumor moved while the patient was undergoing computed tomography-guided biopsy in the prone position, a diagnosis of inverted intercostal hernia of elastofibroma dorsi was made. We report this case with a review of current literature.

Synthesis and Characterization of White-Light Luminescent End-Capped Polyimides Based on FRET and Excited State Intramolecular Proton Transfer.

N-cyclohexylphthalimide-substituted trifluoroacetylamino (CF3CONH-) group (3TfAPI), which forms an intramolecular hydrogen bond, was synthesized, and it exhibited a bright yellow fluorescence owing to the excited-state intramolecular proton transfer (ESIPT) in the solution and crystalline states. In addition, CF3CONH-substituted phthalic anhydride (3TfAPA) was synthesized, which was attached to the termini of a blue-fluorescent semi-aromatic polyimide (PI) chain. Owing to the efficient Förster resonance energy transfer (FRET) occurring from the main chain to the termini and the suppression of deprotonation (anion formation) at the 3TfAPA moiety by H2SO4 doping, the resulting PI films display bright white fluorescence. Moreover, the enhancement of the chain rigidity by substituting the diamine moiety results in an increase in the quantum yield of white fluorescence (Φ) by a factor of 1.7, due to the suppression of local molecular motion. This material design strategy is promising for preparing thermally stable white-light fluorescent PIs applicable to solar spectral convertors, displays, and ICT devices.

Coil volume embolization ratio for preventing recanalization after portal vein embolization.

PURPOSE: The purpose of this study was to evaluate the optimum volume embolization ratio (VER) for the prevention of recanalization after portal vein embolization (PVE) and the influence of recanalization on future liver remnant (FLR) function using technetium-99m galactosyl human serum albumin single-photon emission computed tomography (99mTc-GSA SPECT/CT) fusion imaging. METHODS: We analyzed procedural data of 18 patients who underwent PVE from 2015 to 2018. A total of 29 portal branches were embolized (12 anterior branch, 11 posterior branch, 4 left branch, 2 right branch) with absolute ethanol and coils. Portal vein recanalization was evaluated three weeks after PVE by contrast-enhanced CT. We classified the treated portal branches as non-recanalized and recanalized. VER was compared between the groups. In addition, for each patient, we calculated and evaluated the ratio of FLR volume to total liver volume (volumetric %FLR), FLR count to total liver count on 99mTc-GSA SPECT/CT fusion imaging (functional %FLR), and functional-volumetric ratio (functional %FLR/ volumetric %FLR). RESULTS: Twenty-six portal branches showed no recanalization (non-recanalized group, n=26, 89.7%), while three portal branches showed recanalization (recanalized group, n=3, 10.3%). The median VER was 4.94% (3.12%-11.1%) in the non-recanalized group and 3.49% (2.76%-4.32%) in the recanalized group, which was significantly different between the groups (p = 0.045, Mann-Whitney U test). The median functional-volumetric ratio was 1.16 (1.03-1.50) in non-recanalized patients (n=15, 83.3%) and 1.01 (0.96-1.13) in recanalized patients (n=3, 16.7%), and it was significantly higher in the non-recanalized patients (p = 0.021, Mann-Whitney U test). CONCLUSION: The VER for preventing recanalization after PVE was approximately 5% (> 4.94%). 99mTc-GSA SPECT/CT fusion imaging revealed a decrease in FLR function due to recanalization after PVE.

CT-guided color marking of impalpable pulmonary nodules prior to video-assisted thoracoscopic surgery.

OBJECTIVES: To investigate the utility and complications of computed tomography (CT)-guided color marking of impalpable pulmonary nodules for video-assisted thoracoscopic surgical resection. METHODS: This retrospective single institutional study has obtained Institutional Review Board approval. A total of 174 patients with 207 undiagnosed peripheral lesions of the lung were enrolled who had undergone preoperative computed tomography-guided color marking using colored collagen followed by video-assisted thoracoscopic surgery (VATS) from December 2015 to September 2018. RESULTS: All nodules (mean 14.0 mm, range 3.0-30.0 mm) were successfully marked by computed tomography-guided color marking, and 96.0% cases (167/174) were localized by means of intraoperative fluoroscopy as clear spots. Minor pneumothorax with a median volume of 3.8 mL (range 0.2-119.0 mL) occurred in 12 patients (6.9%) who were completely asymptomatic and were not in serious condition. No patient required a chest tube. No major bleeding complication occurred, and no air emboli were seen. No intra- or post-operative mortality of VATS was observed. CONCLUSIONS: Preoperative CT-guided color marking of impalpable pulmonary nodules is a safe and effective procedure that allows for successful surgical resection.

Ultrafast Spectroscopic Analysis of Pressure-Induced Variations of Excited-State Energy and Intramolecular Proton Transfer in Semi-Aliphatic Polyimide Films.

The relationship between the photoexcitation dynamics and the structures of semi-aliphatic polyimides (3H-PIs) was investigated using ultrafast fluorescent emission spectroscopy at atmospheric and increased pressures of up to 4 GPa. The 3H-PI films exhibited prominent fluorescence with extremely large Stokes shifts (Δν > 10 000 cm-1) through an excited-state intramolecular proton transfer (ESIPT) induced by keto-enol tautomerism at the isolated dianhydride moiety. The incorporation of bulky -CH3 and -CF3 side groups at the diamine moiety of the PIs increased the quantum yields of the ESIPT fluorescence owing to an enhanced interchain free volume. In addition, 3H-PI films emitted another fluorescence at shorter wavelengths originating from closely packed polyimide (PI) chains (in aggregated forms), which was mediated through a Förster resonance energy transfer (FRET) from an isolated enol form into aggregated forms. The FRET process became more dominant than the ESIPT process at higher pressures owing to an enhancement of the FRET efficiency caused by the increased dipole-dipole interactions associated with a densification of the PI chain packing. The efficiency of the FRET rapidly increased by applying pressure up to 1 GPa owing to an effective compression of the interchain free volume and additionally gradually increased at higher pressures owing to structural and/or conformational changes in the main chains.

White-Light Emission and Tunable Luminescence Colors of Polyimide Copolymers Based on FRET and Room-Temperature Phosphorescence.

Thermally stable copolyimide (CoPI) films exhibiting high optical transparency and room-temperature phosphorescence (RTP) were prepared by copolymerizing fluorescent dianhydride and brominated phosphorescent dianhydride with an alicyclic diamine. The CoPI films underwent a 5 wt % degradation at a temperature higher than 349 °C and exhibited dual fluorescent and phosphorescent emissions owing to their efficient Förster resonance energy transfer from the fluorescent to phosphorescent dianhydride moieties in the main chains, followed by an intersystem crossing from the singlet to triplet state of the latter moiety atoms. The CoPIs displayed bright RTP under a vacuum with various colors produced when adjusting the copolymerization ratio. CoPI with 5 mol % phosphorescent moiety (CoPI-05) emitted white light with high optical transparency owing to the suppression of the PI chain aggregation that causes a yellowish coloration. The copolymerization of fluorescent and phosphorescent PI moieties can control the photoluminescent properties of PI films and is applicable to color-tunable solid-state emitters, ratiometric oxygen sensors, and solar-spectrum converters.

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

High-refractive-index (high-n) polymers with a high optical transparency and low birefringence (Δn) have been desired in progressive optoelectronic devices. However, the trade-off between high-n and low-Δn remains a challenge at present. Here, the development of a novel array of high-n, high-sulfur-containing, highly transparent, colorless poly(phenylene sulfide) (PPS) polymers bearing triazine units in the main chains is reported. Six new triazine monomers T1-T6 with various pendant groups via different linkers (-O- and -NH-) could be prepared for developing PPSs with high-n and low Δn values. These PPSs (P1-P6) were obtained by the polycondensation of T1-T6 with commercial aromatic dithiol, 4,4'-thiobisbenzenethiol, respectively, which showed very high-n values (n av: 1.6902-1.7169 at 633 nm), high optical transparency (T % > 90% @ 400 nm), and low birefringence (Δn = 0.0015-0.0042). All the PPSs displayed high n ∞ values (1.6340-1.6654), providing valuable information for the development of high-n triazine-based PPS materials for application not only in the visible region but also in the near-infrared region.