Platinum Tetrakis(pentafluorophenyl)porphyrin Research Articles

Dual-luminophore fast-responding pressure-sensitive paint for the simultaneous elimination of motion- and temperature-induced errors

Abstract Motion- and temperature-induced errors are the major sources of error in pressure-sensitive paint (PSP) measurement. In this study, we developed a novel dual-luminophore fast-responding PSP with reference and pressure-sensitive channels that have similar temperature sensitivities, enabling motion- and temperature-induced errors to be simultaneously eliminated by taking the intensity ratio of the two channels. Rhodamine B (RhB), which was loaded on the Mobil Composition of Matter No. 41 (MCM-41) molecular sieve, and platinum tetrakis(pentafluorophenyl) porphyrin (PtTFPP) were chosen as the reference and pressure-sensitive luminophores, respectively. These luminophores were mixed with mesoporous SiO2 particles and a small amount of polymer to form a sprayable motion–temperature cancellation (MTC) PSP. By controlling the concentration of RhB, the temperature sensitivity of the reference channel was adjusted to match that of PtTFPP. To minimize temperature-induced errors, the effect of spectral ranges was also investigated. The lowest temperature sensitivity achieved for the MTC-PSP was 0.025%/℃, yielding an extremely low temperature-induced error of 55 Pa/℃. Its pressure sensitivity and response time were 0.46%/kPa and 145 μs, respectively. In addition, a theoretical model for the MTC-PSP that considers the effect of spectral overlap was proposed. The model accurately predicted the nonlinear relationship between the intensity ratio and pressure. The capability of the MTC-PSP was confirmed in a fast-rotating-disk experiment, and the pressure results agreed well with the theoretical pressure distribution on the disk.

Development of fast response bi-luminophore pressure-sensitive paint by means of an inkjet printing technique

A novel fast response bi-luminophore pressure-sensitive paint (PSP) by inkjet printing of sensor-dot arrays on an anodized aluminum (AA) substrate has been developed for unsteady flow measurements. A bi-luminophore AA-PSP, which is a combination of PSP and temperature-sensitive paint (TSP), is essential for precise pressure measurements, because the PSP result needs the temperature correction. However, a conventional bi-luminophore AA-PSP prepared by a dipping method does not work well due to the interference between the PSP and TSP luminophores. To overcome this problem, we have developed isolated dot arrays of PSP and TSP formed on an anodized aluminum substrate by an inkjet printing method. In this study, platinum tetrakis (pentafluorophenyl) porphyrin (PtTFPP) and ZnS-AgInS2 (ZAIS) were employed as pressure- and temperature-sensitive dyes, respectively. A suitable solvent was chosen for each dye to form the dots with uniform, high luminescence intensity, and high sensitivity. The developed bi-luminophore AA-PSP could simultaneously measure pressure and temperature and could reduce the temperature effect of the PSP from −0.97%/K (without temperature correction) to −0.01%/K (with temperature correction). It showed a pressure response time of 17.8 ± 0.8 μs at 90% pressure rise to a step change of pressure, which is in the same range as a conventional AA-PSP.

Poly(norbornene)s as matrix materials for platinum tetrakis(pentafluorophenyl)porphyrin based optical oxygen sensors

A set of poly(norbornenes) was prepared using ring opening metathesis polymerization (ROMP) and used as matrix material for the preparation of optical oxygen sensor layers based on platinum tetrakis(pentafluorophenyl)porphyrin (PtTFPP) as the sensitive dye. Different polymers were prepared and investigated in order to retrieve information on the influence of the anchor group and the side chain attached to the polymer backbone on their performance as matrix material for the dye. Bulky side groups increased the oxygen permeability through ROM polymer layers, especially when the bulky group was directly attached via an anchor group to the polymer backbone without any aliphatic spacer in between. Sensor layers made of poly( endo, exo[2.2.1]bicyclo-5-heptene-2,3-dicarboxyclic acid di- tert-butylester) and PtTFPP exhibited the highest τ 0/ τ ratio and responded strongly to small amounts of oxygen.

A109 流体計測のための担持型TSPの開発とPSPへの応用

In this paper, current status of the development of luminophore-pendant temperature-sensitive paint of poly[l-(trimetylsilyl)phenyl-2-phenylacetylene] (PTMST) is discussed. PTMST uses poly(l-trimethylsilyl-l-propyne) (PTMSP) based polymer, which is known as one of the highest gas permeable polymers. Because of its high gas permeability and single luminescent compound, we can expect fast response of PTMST to the change in temperature and pressure of the test gas. We can also create PTMST-based two-color PSP for temperature-compensated pressure sensor by simply mixing pressure-sensitive luminophore in PTMST. In this paper, we mix platinum tetrakis (pentafluorophenyl) porphyrin (PtTFPP) as a pressure-sensitive luminophore to create PTMST-based two-color PSP (PtTFPP-PTMST). Spectral analysis shows that PtTFPP-PTMST provides temperature sensitive peak of PTMST (around 540 nm) and pressure sensitive peak of PtTFPP (around 650 nm), which can be separated by band-pass filters. We have calibrated PTMST from 100 K to 373 K as well as PtTFPP-PTMST from 120 K to 333 K to study the static characteristics of these sensors. PTMST provides the temperature sensitivity over the calibrated range, giving the maximum value of 2.72%/K at 100 K. PTMST itself is almost pressure independent. Pressure sensitivity of PtTFPP-PTMST is 0.26%/kPa at 293 K. PtTFPP-PTMST shows pressure sensitivity of 0.66%/kPa even at cryogenic temperature of 120 K. The unsteady characteristic of PtTFPP-PTMST is determined using a step response to a pressure change caused by a shock tube. The response time of PtTFPP-PTMST is on the order of milliseconds. A demonstration of PTMST at cryogenic measurement is shown by transition detection of PTMST-coated NACA64A012 model in JAXA 0.1m Transonic Cryogenic Wind Tunnel. PTMST detects a natural transition as well as a forced transition induced by a roughness at the leading edge at Mach 0.4, total temperature 200 K, and total pressure 120 kPa.

Application of Pressure-Sensitive Paints to Low-Pressure Range

The pressure-sensitive paint (PSP) technique has potential as a powerful diagnostic tool for measurements in the high Knudsen number regime because it is based on luminescence of molecules. Three types of PSP [two composed of organic dye and polymer (luminophore/binder), platinum octaethylporphyrin (PtOEP)/silicone polymer (GP197) and platinumtetrakis (pentafluorophenyl) porphyrin (PtTFPP)/poly[1-(trimethylsilyl)-propyne] [poly(TMSP)], and the other ruthenium II tris (4,7-diphenyl-1, 10-phenanthrolin chloride (Bath-Ru) adsorbed on anodized aluminum] are applied to the rarefied gas flow mainly lower than 150 Pa (about 1 torr) to examine fundamental properties, such as pressure/temperature sensitivity, time response of luminescence, and so on

Characterizing the Quenching Process for Phosphorescent Dyes in Poly[((n-butylamino)thionyl)phosphazene] Films

We compare the results of oxygen quenching experiments for four phosphorescent dyes [platinum octaethylporphyrin (PtOEP), platinum octaethylporphyrin ketone (PtOEPK), platinum tetrakis(pentafluorophenyl)porphyrin (PtTFPP), and Ru(dpp)3Cl2 (dpp = 4,7-diphenyl-1,10-phenanthroline)] in a low-glass-transition-temperature polymer matrix [poly[((n-butylamino)thionyl)phosphazene] (C4PATP).] The Pt dyes have exponential unquenched decays, but nonexponential decays in the presence of O2. These data fit well to a two-site model in which the dyes in the short lifetime environment are more readily quenched by oxygen. Ru(dpp)3Cl2 in C4PATP has a nonexponential decay under all conditions and is much better described by a Gaussian distribution of decay rates with a common mean quenching rate. Time-scan experiments with PtOEP, PtTFPP, and Ru(dpp)3Cl2 gave very similar values for the diffusion coefficient for oxygen in the polymer (DO2 = (3.7−4.0) × 10-6 cm2 s-1). For each of these three dyes, lifetimes and intensities gave identical Stern−Volmer plots. From the slopes of these plots one can calculate the permeability PO2 and solubility SO2 = PO2/DO2 of oxygen in the matrix. In this calculation, one must assume a value (commonly taken to be 1.0 nm) for αReff, the probability of quenching per encounter times the effective quenching radius of the dye. We find differences in calculated PO2 values that can only be explained in terms different sensitivities of the dyes to quenching by oxygen.

Platinum tetrakis(pentafluorophenyl)porphyrin immobilized in polytrifluoroethylmethacrylate film as a photostable optical oxygen detection material

An optical oxygen detection material based on platinum tetrakis(pentafluorophenyl)porphyrin (PtTFPP) immobilized in fluoropolymer, polytrifluoroethylmethacrylate (poly-TFEM) film has been developed and characterized. The luminescence intensity of PtTFPP in poly-TFEM film decreased with increase of oxygen concentration. The ratio I 0/ I 100 is used as a sensitivity of the film, where I 0 and I 100 represent the detected luminescence intensities from a film exposed to 100% argon and 100% oxygen, respectively. I 0/ I 100 value of PtTFPP in poly-TFEM film is estimated to be 15.4 and large Stern–Volmer constant is obtained compared with PtTFPP in polystyrene film. The response times of PtTFPP immobilized in poly-TFEM film are 5.6 s on going from argon to oxygen and 32 s from oxygen to argon, respectively. The fast response time is obtained using PtTFPP immobilized in poly-TFEM film. PtTFPP in poly-TFEM film exhibits minimal deterioration decrease of initial intensity after continuous irradiation for 24 h (ca. 0.5%). These results indicate that PtTFPP immobilized in poly-TFEM film is photostable and highly sensitive device for oxygen.

Oxygen sensing based on lifetime of photoexcited triplet state of platinum porphyrin-polystyrene film using time-resolved spectroscopy

Optical oxygen-sensing systems based on the quenching of the photoexcited triplet state of platinum porphyrins—platinum octaethylporphyrin (PtOEP) and platinum tetrakis(pentafluorophenyl)porphyrin (PtTFPP)—in polystyrene (PS) using two different time-resolved spectroscopies (luminescence lifetime measurement and diffuse reflectance laser flash photolysis) have been developed. Using both spectroscopies, the same values of Stern-Volmer constant KSV and quenching rate constant kq (KSV = kqτ0) are obtained. The decays of the luminescence and triplet-triplet reflectance of the platinum porphyrins in PS consisted of two components (faster and slower lifetimes) in the absence and presence of oxygen. For both faster and slower components the lifetime decreases with increasing oxygen concentration. For both components a Stern-Volmer plot of the platinum porphyrin-PS films exhibits linearity. However, kq of the faster component is larger than that of the slower component (for PtOEP, three times larger; for PtTFPP, 40 times larger), indicating that two different oxygen-accessible sites exist in the platinum porphyrin-PS films. The faster and slower components are related to oxygen-accessible sites on the surface and in the bulk of the platinum porphyrin films respectively. Concerning the fractional contributions of each lifetime component, the contribution of the faster component is greater than that of the slower component, indicating that the sensing site on the surface is important for optical sensing. The contribution of different oxygen-accessible sites in platinum porphyrin-PS films for oxygen sensing is clarified by these techniques.

Photostable Optical Oxygen Sensing Material: Platinum Tetrakis(pentafluorophenyl)porphyrin Immobilized in Polystyrene

S. Lee and I. Okura, Anal. Commun., 1997, 34, 185 DOI: 10.1039/A701130J