Refractive Index Of Poly Research Articles

Refractive Indices of Poly[(2,5-didecyloxy-1,4-phenylene)-alt-(2,5-thienylene)] Polymer

Conjugated polymers have attracted an increasing amount of attention in recent years for various organic electronic devices due to their potential advantages over inorganic and small-molecule organic semiconductors [1]. Optical and sensing characteristics of poly[(2,5-didecyloxy-1,4-phenylene)-alt-(2,5-thienylene)] (PODT) polymer were studied by using solution method. The refractive indices of the PODT polymer for different relations were obtained and the refractive index dispersion of the PODT polymer was analyzed in detail. Fig. 1 indicates the chemical structure of the PODT polymer. Also, the reflectance spectrum of the PODT polymer is shown in Fig. 2.

Characterization of Chromatic Dispersion and Refractive Index of Polymer Optical Fibers.

The chromatic dispersion and the refractive index of poly(methyl methacrylate) polymer optical fibers (POFs) have been characterized in this work by using a tunable femtosecond laser and a Streak Camera. The characterization technique is based on the measurement of the time delays of light pulses propagating along POFs at different wavelengths. Polymer fibers of three different lengths made by two manufacturers have been employed for that purpose, and discrepancies lower than 3% have been obtained in all cases.

Synthesis of poly(norbornene ester)s by using (η 3-substituted allyl) palladium (NHC) complex as catalyst and investigation of their chemical structure - Glass transition temperature - Refractive index relationships

The synthesis of poly(norbornene ester)s by using a (η 3-substituted allyl) palladium (N-heterocyclic carbene (NHC)) complex as catalyst was performed and the relationship between chemical structure and glass transition temperature or refractive index of poly(norbornene ester)s was investigated. Norbornene ester monomers were synthesized via esterification of 5-norbornene-2-methyl alcohol and aromatic carboxylic acids. The polymerization catalyst, (η 3-substituted allyl) palladium (NHC) complex, was synthesized according to a published procedure. 1H-NMR spectroscopy was performed to determine chemical structure of monomers and polymers. The molecular weight of the polymers was measured via gel permeation chromatography and the thermal properties were analyzed via thermogravimetric analysis and dynamic mechanical analysis. Refractive indices of polymer films were measured using a prism coupler. Polymers with the highest M n (between 100 kg/mol and 300 kg/mol) were synthesized when the ratio of monomer to catalyst was 2000:1. The glass transition temperature of synthesized polymers was about 100 °C lower than that of conventional norbornene polymers. Among the six polymers of different chemical structures, four polymers exhibited a refractive index of 1.6 or more at a wavelength in the visible light region.

Tunable thermal degradation and refractive index of poly(norbornene sulfone)s via two different polymerization methods

ABSTRACTA novel polysulfone was easily synthesized by alternating copolymerization of norbornene with sulfur dioxide (SO2) via free radical copolymerization and coordination copolymerization. Compared with other olefin derivatives, norbornene is a cyclic olefin having a larger steric hindrance, which is easily copolymerized with SO2, and the obtained poly(norbornene sulfone)s have excellent thermomechanical and optical properties. The effect of the different polymerization methods on the copolymerization reaction was analyzed in detail. The results suggested that different polymerization mechanisms exist in the different polymerization methods and affect the thermal stability and optical properties of the polysulfone. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44534.

Monodispersepoly[BMA-co-(COPS-I)] Particles by Soap-Free Emulsion Copolymerization and Its Optical Properties as Photonic Crystals.

In order to study the surfactant-free emulsion copolymerization of benzyl methacrylate (BMA) with sodium 1-allyloxy-2-hydroxypropane sulfonate (COPS-I) and the resulting optical properties, a series of experiments was carried out at various reaction conditions such as the changes of BMA concentration, COPS-I concentration, BMA concentration under a fixed COPS-I amount, initiator and divinyl benzene (DVB) concentration. All the latices showed highly monodispersed spherical particles in the size range of 144~435 nm and the respective shiny structural colors from their colloidal photonic crystals. It is found that the changes in such polymerization factors greatly affect the number of particles and particle diameter, polymerization rate, molecular weight, zeta-potential, and refractive indices. The increase of number of particles led to the increased rate of polymerization and zeta-potential of the latices, on the other hand, to the decreased molecular weight. Refractive indices and the reflectivity increased with COPS-I concentration, on the other hand, and decreased with DVB concentration. Especially, refractive indices of the resulting poly[BMA-co-(COPS-I)] colloidal photonic crystals showed much higher values of 1.65~2.21 than that of polystyrene, due to the formation of core-shell shaped morphology. Monodisperse and high refractive index of poly[BMA-co-(COPS-I)] particles prepared in this work could be used for the study in photonic crystals and electrophoretic display.

Preparation of poly(BMA-co-MMA) particles by soap-free emulsion polymerization and its optical properties as photonic crystals.

Narrowly dispersed poly(BMA-co-MMA) and PBMA latices with particle diameters ranging within 216-435 nm were synthesized successfully by surfactant-free emulsion polymerization with KPS and AIBA. The average particle diameter and particle size distribution, average molecular weight and its distribution, glass transition temperature, reflectance spectra in visible wavelength, and refractive indices for the respective poly(BMA-co-MMA) latices and their photonic crystals were systematically investigated in terms of BMA/MMA ratio, BMA content, polymerization temperature, and DVB effect. The rate of polymerization increased with increasing MMA concentration in BMA/MMA ratio. The particle diameter increased with BMA concentration in BMA/MMA ratio. The molecular weight increased with BMA concentration in BMA/MMA ratio and monomer concentration. The drying of the latices offered self-assembled shiny colloidal crystal films showing the characteristic structural colors in visible wavelength. All the poly(BMA-co-MMA) latices prepared in the study were fallen within the range of photonic grade microspheres. The reflectance measurement on the colloidal photonic crystals having different particle diameters clearly exhibited narrow stopbands. The reflection maxima (λ(max)) measured in this study were well close to the λ(max) calculated, derived from the Bragg's equation. The refractive indices of poly(BMA-co-MMA) photonic crystals were found to be almost same as the theoretical values and increased proportionally from 1.50 to 1.57 with BMA content in BMA/MMA ratios. It was, thus, found that the optical reflectance properties of the poly(BMA-co-MMA) colloidal photonic crystals can be controlled easily by adjusting the reaction conditions and BMA/MMA ratio in soap-free emulsion copolymerization of BMA and MMA.

Thermal and optical properties of highly fluorinated copolymers of methacrylates

Copolymers of pentafluorophenylhexafluoroisopropyl methacrylate (FPPMA) with trifluoroethyl methacrylate (TFEMA) were prepared in THF solution and in bulk using azobisisobutyronitrile as a free radical initiator. The monomer reactivity ratios of TFEMA (M1) and FPPMA (M2) were calculated as r1 = 0.55 and r2 = 0.07. The refractive indices of poly(TFEMA) and poly(FPPMA) are very similar as 1.435 and 1.430, respectively, at 532 nm, and the copolymer films were transparent. The glass transition temperatures (Tg) of the copolymers were in the range of 80–90°C and showed a negative deviation from the Gordon–Taylor equation. The thermal decomposition temperature (Td) was increased with the content of FPPMA in copolymers. Low water absorption for 1:1 FPPMA/TFEMA copolymer was detected. Copolymers of FPPMA with hexafluoroisopropyl methacrylate (HFPMA) were also prepared. The monomer reactivity ratios of HFPMA (M1) and FPPMA (M2) were calculated as r1 = 0.43 and r2 = 0.10. The Tgs of the copolymers were in the range of 88–95°C and showed also a negative deviation from the Gordon–Taylor equation. Tg and Td of the copolymers were increased with the content of FPPMA. The refractive index of poly(HFPMA) (1.384 at 532 nm) is much lower than that of FPPMA homopolymer, but copolymer films obtained were clear and transparent. Copyright © 2013 John Wiley & Sons, Ltd.

Annealing induced variation in refractive index of Rhodamine B doped Poly (vinyl) alcohol films

The present paper reports the influence of fluorescent dye doping on the optical properties, in particular on the refractive index of Poly (vinyl) alcohol (PVA) host matrix. The dye (Rhodamine B) is doped in weight percent ranging from 0 to 2wt%. It is found that at highest doping wt% (2%), dye molecules segregate to the surface breaking the bonds of the PVA matrix as well as simultaneously forming new bonds, thereby modifying the overall refractive index. Also, annealing of these samples produces a change in the refractive index. The refractive index shows a general decreasing trend with increasing wavelength but with modified values upon changing doping percentage or upon annealing. Overall results are interpreted in terms of bond modifications at the surface and interior of PVA due to the inclusion of Rhodamine B molecules.

Modulation of Polymer Refractive Indices with Diamond Nanoparticles for Metal-Free Multilayer Film Mirrors

Modulation of the refractive index of a polymer was achieved by combining it with diamond nanoparticles (NDs). The increase in the refractive index was controlled by the amount of NDs added, according to the Lorentz-Lorenz equation. The refractive index of poly(vinyl alcohol) (PVA), which was used as the base polymer, increased from 1.52 to 1.88. A multilayer film consisting of alternating layers of ND-PVA composite and poly(methyl methacrylate) exhibited ca. 80% reflectance with 10 bilayers.

Dielectric constant and refractive index of poly (siloxane–imide) block copolymer

Recent technological advances demanded polyimides of improved versatility in terms of electronic, optical and thermal properties. In this work, a series of poly(siloxane–imide) block copolymers were synthesized in order to investigate the effect on their optical and electronic properties. The polyimide unit was derived from 3,3′,4,4′-Biphenyltetracarboxylic dianhydride (BPDA) and 4-(4-{1-[4-(4-aminophenoxy) phenyl]-1-methylethyl} phenoxy) aniline (BAPP) while the siloxane unit was derived from 3-[3-(3-aminopropyl)-1,1,3,3-tetramethyldisiloxanyl] propylamine (DMS) and Poly(dimethylsiloxane), bis(3-aminopropyl)terminated (PDMS). The structure of the polyimide was characterized by fourier transformer infra red (FT-IR), nuclear magnetic resonance (NMR) spectroscopy, elemental analysis, solution viscosity and gas permeation chromatography (GPC). Scanning electron microscope (SEM) analysis suggested a microphase separation between the two components. The refractive index and dielectric properties showed a decreasing trend with increased silicone unit in the polyimide backbone. However ultra violet visible (UV–Vis) and optical transparency was not significantly affected. Electronic and optical properties of this copolymer were discussed in relation to the polysiloxane content.

Surface functionalization of titanium dioxide nanoparticles with alkanephosphonic acids for transparent nanocomposites

The surface functionalization of rutile titanium dioxide nanoparticles with 1-decylphosphonic acid and diethyl undec-10-enyl phosphonate in a two-stage process, involving a change in reaction medium, is described. Similarly, 1-decylphosphonic acid and diethyl 1-decylphosphonate were employed as surface modifiers. The nanoparticles coated in two successive steps formed stable, transparent dispersions in toluene. Surface functionalization was monitored using thermogravimetric analysis (TGA), which showed enhanced surface coverage after the second capping step. Incorporation of C=C-terminal surface coupling molecules in the second stage was directly proved using FTIR. Dynamic light scattering measurements showed that the dual-functionalized particles possessed a uniform size of around 13 nm. Particle dimensions were further analyzed using atomic force microscopy (AFM) and transmission electron microscopy (TEM). Transparent nanocomposites were formed by introducing the functionalized nanoparticles into a poly(benzyl acrylate) matrix. The refractive index of poly(benzyl acrylate) composites, measured by spectroscopic ellipsometry, increased from 1.57 for the pure polymer to 1.63 for 14.0 vol.% TiO2 at λ = 586 nm. Nanocomposite films with particle weight percentages of up to 30% (9.5 vol.%) showed a high light transmittance of around 90% at wavelengths above λ = 400 nm.

Viscosity, Density, and Refractive Index of Poly(vinylpyrrolidone) + 1-Propanol and + 2-Propanol at 298.15 K

The density, viscosity, and refractive index for the poly(vinylpyrrolidone) (PVP) + 1-propanol and poly(vinylpyrrolidone) + 2-propanol binary systems have been measured at 298.15 K. From the density data, the apparent specific volume of polymer and the partial specific volume of polymer and solvents have been calculated. The experimental viscosity and refractive index data have been successfully fit to a polynomial-type equation.

The change in refractive index of poly(9,9-dioctylfluorene) due to the adoption of theβ-phase chain conformation

The focus of this work is to study the refractive index in thin films of bluelight-emitting poly(9,9-dioctylfluorene) (PFO) that contain extended rigid chains(β-phase). Using a post-deposition exposure to toluene vapour,β-phase chains were induced in glassy PFO films that had been spin coated from a range ofsolution concentrations to provide thicknesses from 50–200 nm. With the aid of absorptionspectroscopy, a semi-empirical calculation of the change in refractive index due to the presence ofβ-phase chains is undertaken. Over the spectral region where optical gain occurs, the refractive indexof β-phase PFO is found to be appreciably larger than for as-spin-coated glassy PFO.Further development and explicit evaluation of the Kramers–Kronig relationslead to analytic and closed form expressions describing the change in indexΔn which are used to highlight the key contributions to index change. We find that the spectral responseof Δn is largely governed by the emergence of a characteristic absorption band associated with the presenceof β-phase chains. The changes in refractive index are experimentally studied by tracking thespectral shifts of optical resonances observed from films spin coated directly onto sub-wavelength1D grating structures. These measurements are supported and compared with rigorouscalculations of the spectra, which incorporate the full optical descriptions for glassy PFO andβ-phase PFO. The excellent agreement confirms the accuracy of our semi-empirical extractionapproach. Similar polymer-coated grating structures are examined under lasing conditionsand can also be used to support the expected spectral response and the decline ofΔn for longer wavelengths.

Molar Heat Capacities, Densities, Viscosities, and Refractive Indices of Poly(ethylene glycols) + 2-Methyltetrahydrofuran at (293.15, 303.15, and 313.15) K

Molar heat capacities, Cp, densities, ρ, dynamic viscosities, η, and refractive indices, nD, for the binary mixtures poly(ethylene glycol) 200 and poly(ethylene glycol) 400 + 2-methyltetrahydrofuran (MTHF) were determined at (293.15, 303.15, and 313.15) K using a Perkin-Elmer differential scanning calorimeter, an Anton Paar density meter, a Schott-Geräte AVS unit, and an Abbe refractometer, respectively. Excess molar volumes, , deviations of the dynamic viscosities, Δη, and deviations of the refractive indices, ΔR, were calculated at these temperatures. These properties were fitted to the Redlich−Kister equation.

Physical Aging and Refractive Index of Poly(methyl methacrylate) Glass

Physical aging of poly(methyl methacrylate) (PMMA) glass was studied by refractive index measurement. We measured change of refractive index of PMMA glass with annealing at temperatures below the glass transition temperature (Tg) by optical prism coupling, and determined volume relaxation by physical aging using the Lorentz-Lorenz equation. In this paper, the effect of aging temperature on volume relaxation of PMMA glass was investigated. Maximum volume relaxation for PMMA glass was determined at 18 °C below the Tg.

Evaluation of photoinduced change in refractive index of a polymer film doped with an azobenzene liquid crystal by means of a prism-coupling method

The photoinduced change in refractive index of poly(methyl methacrylate) films doped with an azobenzene liquid crystal was measured by the prism-coupling method. Upon irradiation of the film with a high-pressure mercury lamp at 366nm, the coupling angles shifted and then recovered to the initial position by turning off the light. The change in refractive index was found to be 2×10−3, which is attributed to the reversible photoisomerization of the azobenzene moieties.

Synthesis and Characterization of an Amorphous Perfluoropolymer: Poly(perfluoro-2-methylene-4-methyl-1,3-dioxolane)

A perfluorinated monomer, perfluoro-2-methylene-4-methyl-1,3-dioxolane (PFMMD), was synthesized by various methods. The monomer was polymerized in bulk and/or in the solution by a free radical mechanism using perfluorodibenzoyl peroxide and/or perfluorodi-tert-butyl peroxide as an initiators. The polymers obtained (poly(PFMMD)) were colorless and transparent. However, a polymer rod exposed to the atmosphere turned hazy. When the polymers were purified by precipitating the polymer solution into chloroform, they did not turn hazy when exposed to air for a long period of time and remained clear with a high UV−vis light transmittance. The glass transition temperature of the purified polymer was 130−134 °C. NMR measurements indicate that the purified polymers have mostly vinyl addition polymer structure. Nevertheless, we suppose that the pristine polymers contain structural units formed by ring-opening polymerization. The molecular weight of poly(PFMMD) samples can be regulated using carbon tetrachloride, carbon tetrabromide, and sulfuryl chloride as chain transfer agents. Polymerization in the presence of these regulators is characterized by nondegradative chain transfer. The intrinsic viscosity of poly(PFMMD) samples was determined in hexafluorobenzene. Hexafluorobenzene is a thermodynamically good solvent for poly(PFMMD). The molecular weights of poly(PFMMD)s were characterized by the intrinsic viscosity and dynamic light scattering (DLS). The refractive index of poly(PFMMD) between 400 and 1550 nm was between 1.3360 and 1.3270. The material dispersion of poly(PFMMD) is superior to that of a commercial poly(1,1,2,4,4,5,5,6,7,7-decafluoro-3-oxa-1,6-heptadiene) (Cytop).

Temperature dependence of the optical band gap and refractive index of poly(ethylene terepthalate) oligomer–DDQ complex thin film

The temperature dependence of the optical band gap and refractive index dispersion of thin film of poly(ethylene terepthalate) oligomer–DDQ charge transfer complex has been investigated. The absorption edge shifts to the lower energy as consequence of the thermal annealing on film and the fundamental absorption edge corresponds to a direct energy gap. The temperature coefficient of the optical band gap for the film was found as d E g/d T = − 3.15 × 10 −3 eV/K. The temperature dependence of the refractive index has also been investigated and it is observed that the refractive index changes by annealing temperatures.

Photorefractive lithography with synchrotron light in poly(methyl methacrylate)

Synchrotron light changes the refractive index of poly(methyl methacrylate) (PMMA). Refractive-index enhancements as well as reductions depending on dose and energy of the radiation used can be observed. This effect allows the manufacturing of, for example integrated-optical components, as is demonstrated by realization of waveguides in PMMA.

Densities, Viscosities, and Refractive Indices of Poly(ethylene glycol) 200 and 400 + Cyclic Ethers at 303.15 K

Densities, ρ, kinematic viscosities, ν, and refractive indices, nD, were determined for poly(ethylene glycol) 200 and 400 + 1,3-dioxolane, + 1,4-dioxane, + oxolane (tetrahydrofuran, THF), and + oxane (tetrahydropyran, THP) binary mixtures over the entire range of composition at 303.15 K and at atmospheric pressure. The excess molar volumes, , deviations in viscosities, Δη, and deviations in molar refractions, ΔR, calculated from experimental measurements, are always negative. The results were correlated with the Redlich−Kister polynomial. The McAllister multibody interaction model was used to correlate the kinematic viscosities of liquid mixtures with mole fractions. The viscosity dependence on temperature was investigated between 297.15 and 309.15 K for some solutions in a restricted composition range.