Partial Analytical Solution of a Model Used for Measuring Oxygen Diffusion Coefficients of Polymer Films by Luminescence Quenching

A recently developed spectroscopic technique was used to determine oxygen diffusion coefficients as a function of temperature for polystyrene and polycarbonate films. Data were recorded at total pressures <300 Torr over the temperature range 5–45 °C under conditions in which argon, helium, and nitrogen, respectively, were copenetrants. In all cases, the presence of the additional gas caused an increase in the oxygen diffusion coefficient. Arrhenius plots of the data yield (a) a diffusion activation barrier, Eact, and (b) a diffusion coefficient, D0, that represents the condition of "barrier-free" gas transport for the temperature domain over which the Arrhenius plot is linear. For all cases examined in both polystyrene and polycarbonate, D0 increased with an increase in the partial pressure of added gas. In polystyrene, the presence of an additional gas did not change Eact. In polycarbonate, Eact obtained in the presence of helium and argon likewise did not differ from that obtained in the absence of the copenetrant. When nitrogen was the added gas, however, a larger value of Eact was obtained. This latter observation is interpreted to reflect the plasticization of polycarbonate by nitrogen. Eact and D0 data are discussed within the context of a model that distinguishes between dynamic and static elements of free volume in the polymer matrix. Keywords: oxygen diffusion, polystyrene, polycarbonate, activation barrier.

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Oxygen diffusion in amorphous and partially crystalline gallium oxide

Physical Chemistry Chemical Physics ◽

10.1039/c8cp06439c ◽

2019 ◽

Vol 21 (8) ◽

pp. 4268-4275 ◽

Cited By ~ 2

Author(s):

Alexandra von der Heiden ◽

Manuel Bornhöfft ◽

Joachim Mayer ◽

Manfred Martin

Keyword(s):

Activation Energy ◽

Diffusion Coefficients ◽

Low Temperatures ◽

Oxygen Diffusion ◽

Gallium Oxide ◽

Tracer Diffusion ◽

Tof Sims ◽

Tracer Diffusion Coefficients ◽

Oxygen Tracer

We established a TTT diagram of crystallisation of gallium oxide. Determination of oxygen tracer diffusion coefficients by IEDP/ToF-SIMS allowed us to access the activation energy for amorphous GaO1.5 at low temperatures.

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Thin Polymer Films: Simple Optical Determination of Molecular Diffusion Coefficients

ACS Applied Polymer Materials ◽

10.1021/acsapm.9b00964 ◽

2019 ◽

Vol 2 (2) ◽

pp. 563-568 ◽

Cited By ~ 5

Author(s):

Paola Lova ◽

Heba Megahd ◽

Davide Comoretto

Keyword(s):

Polymer Films ◽

Diffusion Coefficients ◽

Molecular Diffusion ◽

Thin Polymer Films ◽

Thin Polymer ◽

Optical Determination

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An analytical solution of multi-dimensional space fractional diffusion equations with variable coefficients

International Journal of Modeling Simulation and Scientific Computing ◽

10.1142/s1793962321500069 ◽

2020 ◽

pp. 2150006

Author(s):

Pratibha Verma ◽

Manoj Kumar

Keyword(s):

Analytical Solution ◽

Diffusion Coefficients ◽

High Efficiency ◽

Dimensional Space ◽

Adomian Decomposition Method ◽

Fractional Diffusion ◽

Variable Coefficients ◽

Diffusion Equations ◽

Fractional Diffusion Equations ◽

Adomian Decomposition

In this paper, we have considered the multi-dimensional space fractional diffusion equations with variable coefficients. The fractional operators (derivative/integral) are used based on the Caputo definition. This study provides an analytical approach to determine the analytical solution of the considered problems with the help of the two-step Adomian decomposition method (TSADM). Moreover, new results have been obtained for the existence and uniqueness of a solution by using the Banach contraction principle and a fixed point theorem. We have extended the dimension of the space fractional diffusion equations with variable coefficients into multi-dimensions. Finally, the generalized problems with two different types of the forcing term have been included demonstrating the applicability and high efficiency of the TSADM in comparison to other existing numerical methods. The diffusion coefficients do not require to satisfy any certain conditions/restrictions for using the TSADM. There are no restrictions imposed on the problems for diffusion coefficients, and a similar procedures of the TSADM has followed to the obtained analytical solution for the multi-dimensional space fractional diffusion equations with variable coefficients.

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Observation of Diffusion Behavior in Al-Implanted ZnO Single Crystal

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.421-422.197 ◽

2009 ◽

Vol 421-422 ◽

pp. 197-200 ◽

Cited By ~ 2

Author(s):

Tsubasa Nakagawa ◽

Isao Sakaguchi ◽

Kenji Matsumoto ◽

Masashi Uematsu ◽

Hajime Haneda ◽

...

Keyword(s):

Diffusion Coefficients ◽

Oxygen Diffusion ◽

Depth Profiling ◽

Implantation Technique ◽

Constant Concentration ◽

Concentration Region ◽

Diffusion Behavior ◽

Oxygen Interstitial ◽

Zno Single Crystal ◽

Diffusion Behaviors

Diffusion behaviors of aluminum (Al) in zinc-oxide (ZnO) single crystals were measured by means of ion implantation technique and SIMS depth profiling. It was found that Al concentration profile had a peculiar shape with a constant-concentration region and a steep tail, which was also found in profiles of other donors such as Ga and In. Detailed analysis of the profiles revealed that the diffusivity of Al was proportional to the square of Al concentration and its intrinsic diffusivity was much smaller than previously reported values. Oxygen diffusion experiments were also performed and the implantation of Al ions enhanced the oxygen diffusion coefficients by about 20 times. This result indicates that oxygen interstitial diffusion occurs in n-type ZnO.

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A simple device for quality control of polymer films, using measurements of permeation and diffusion coefficients

Desalination ◽

10.1016/0011-9164(84)85057-2 ◽

1984 ◽

Vol 51 (1) ◽

pp. 113-122 ◽

Cited By ~ 10

Author(s):

B. Marcandalli ◽

E. Selli ◽

R. Tacchi ◽

I.R. Bellobono ◽

G. Leidi

Keyword(s):

Quality Control ◽

Polymer Films ◽

Diffusion Coefficients ◽

Simple Device ◽

And Diffusion

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Oxygen diffusion studies. I. A preliminary ion microprobe investigation of oxygen diffusion in some rock-forming minerals

Mineralogical Magazine ◽

10.1180/minmag.1982.045.337.21 ◽

1982 ◽

Vol 45 (337) ◽

pp. 179-192 ◽

Cited By ~ 48

Author(s):

R. Freer ◽

P. F. Dennis

Keyword(s):

Diffusion Coefficients ◽

Oxygen Diffusion ◽

Isotope Exchange ◽

Water Pressure ◽

Ion Microprobe ◽

Oxygen Isotope Exchange ◽

Self Diffusion ◽

Diffusion Studies ◽

Diffusion Rates ◽

Grossular Garnet

AbstractThe self diffusion of oxygen has been studied in prepared natural crystals of albite, grossular garnet, quartz, and ruffle by isotope exchange with hydrothermal water enriched in 18O, and subsequent analysis by ion microprobe. Measured oxygen diffusion coefficients (D) in quartz (‖c) may be described by D = 1.08 × 10−11 exp(−31.5 kcal/RT) cm2s−1 at 600−750°C and 1 kbar water pressure. For grossular, D = 2.5 × 10−16 cm2s−1 at 1050°C and 8 kbar, and D = 4.8 × 10−17 cm2s−1 at 850 °C and 2 kbar. All ruffle crystals exhibited variable amounts of corrosion, and an approximate diffusion coefficient of D(‖c) = 3.16 × 10−15 cm2s−1 cm2s−1 was obtained at 1050 °C and 1 kbar. Oxygen diffusion coefficients in albite, perpendicular to (001) faces, have been determined as a function of pressure at 600 °C Between 0.5 and 8.0 kbar pressure no systematic variation in the results was observed and most of the data may be described by D = 4.1 (±0.5) × 10−15 cm2s−1. Slow oxygen diffusion rates in quartz and garnet suggest that these minerals should have high ‘closure temperatures’ for oxygen exchange, and may provide reliable oxygen isotope exchange geothermometers.

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