BARC/PUB/2005/0073

 
 

Effect of added electrolytes, NaCl and LiCl, on the palisade layer water structure of Triton X-100 micelle:A fluorescence anisotropy study

 
     
 
Author(s)

Kumbhakar, M.; Mukherjee, T.; Pal, H.
(RC&CDD)

Source

Chemical Physics Letters, 2005. Vol. 413: pp. 142-146

ABSTRACT

Rotational relaxation times of coumarin 151 dye in Triton X-100 micelle gradually increase with added NaCl, and is interpreted as the increased microviscosity due to strong hydration of Na+ ions in the Palisade layer, causing the entrapped water molecules to form clusters around the ions. Contrary to this, with added LiCl, rotational relaxation times initially decrease and then show a sudden increase beyond about 1 M salt. This is attributed to the complexation of Li+ ions with surfactant oxoethylene groups at lower LiCl concentrations. At higher LiCl concentrations, the above complexation apparently gets saturated, and the excess Li+ ions in the Palisade layer cause a sudden increase in the microviscosity via the strong hydration of these ions, as it happens with Na+ ions at all the salt concentrations.

 
 
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