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.
Cross-Diffusion in a Water-in-Oil Microemulsion Loaded with Malonic Acid or Ferroin. Taylor Dispersion Method for Four-Component Systems
ROSSI, FEDERICO;
2008-01-01
Abstract
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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
