Pentanary cross-diffusion in water-in-oil microemulsions loaded with two components of the belousov-zhabotinsky reaction

We measure cross-diffusion coefficients in a five-component system, an aerosol OT (AOT) water-in-oil microemulsion loaded with two constituents of the Belousov-Zhabotinsky (BZ) reaction (H2O/AOT/BZ1/BZ2/octane). The species BZ1 is either NaBr, an inhibitor of the BZ reaction, or ferroin, a catalyst for the reaction. As species BZ2, we choose Br2, an intermediate in the reaction. The cross-diffusion coefficients between BZ1 and BZ2 are found to be negative, which can be understood in terms of complexation between these species. Using a four-variable model for the BZ reaction, we find that the cross-diffusion coefficients measured here can lead to a noticeable shift in the onset of Turing instability in the BZ-AOT system

Quaternary cross-diffusion in water-in-oil microemulsions loaded with a component of the belousov-zhabotinsky reaction

We obtain the diffusion matrix, D, consisting of the main and cross-diffusion coefficients for a loaded AOT microemulsion, a quaternary system containing water (1)/AOT (2)/species (3)/octane (4). Here “species” is a component of the Belousov−Zhabotinsky reaction: NaBr, NaBrO3, bathoferroin, ferroin, or Br2. The main and cross-diffusion coefficients of each species depend crucially on its solubility. For water-soluble species (the salts), D13 and D23 are large (much larger than the main diffusion coefficients) and positive. For species located mainly in the surfactant shell (bathoferroin or ferroin), D13 and D23 are large and negative. For oil-soluble Br2, D13 and D23 are larger and more negative, whereas D33 ≫ D11, D22. The coefficients D31 and D32 are small for all species studied

Cross-Diffusion in a Water-in-Oil Microemulsion Loaded with Malonic Acid or Ferroin. Taylor Dispersion Method for Four-Component Systems

Abstract: We describe an improved Taylor dispersion method for four-component systems, which we apply to measure the main- and cross-diffusion coefficients in an Aerosol {OT} water-in-oil microemulsion loaded with one of the reactants of the {BelousovZhabotinsky} {(BZ)} reaction, {water(1)/AOT(2)/R(3)/octane(4)} system, where R is malonic acid or ferroin. With {[H2O]/[AOT]} = 11.8 and volume droplet fraction �d = 0.18, when the microemulsion is below the percolation transition, the cross-diffusion coefficients D13 and D23 are large and positive {(D13/D33} @ 14, {D23/D33} @ 3) for malonic acid and large and negative for ferroin {(D13/D33} @ 112, {D23/D33} @ 30) while coefficients D31 and D32 are small and negative for malonic acid {(D31/D33} @ 0.01, {D32/D33} @ 0.14) and small and positive for ferroin {(D31/D33} @ 5 � 104, {D32/D33} @ 8 � 103). These data represent the first direct determination of cross-diffusion effects in a pattern-forming system and of the full matrix of diffusion coefficients for a four-component system. The results should provide a basis for modeling pattern formation in the {BZAOT} system

Quaternary cross-diffusion in water-in-oil microemulsions loaded with a component of the belousov-zhabotinsky reaction

We obtain the diffusion matrix, D, consisting of the main and cross-diffusion coefficients for a loaded AOT microemulsion, a quaternary system containing water (1)/AOT (2)/species (3)/octane (4). Here “species” is a component of the Belousov−Zhabotinsky reaction: NaBr, NaBrO3, bathoferroin, ferroin, or Br2. The main and cross-diffusion coefficients of each species depend crucially on its solubility. For water-soluble species (the salts), D13 and D23 are large (much larger than the main diffusion coefficients) and positive. For species located mainly in the surfactant shell (bathoferroin or ferroin), D13 and D23 are large and negative. For oil-soluble Br2, D13 and D23 are larger and more negative, whereas D33 ≫ D11, D22. The coefficients D31 and D32 are small for all species studied