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Diffusion and solubility of some azo dyes in swollen gelatin matrices: The effects of dye size, matrix swell, and dye–matrix interactions
Author(s) -
Chen S. P.,
Osterhoudt H. W.
Publication year - 1985
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1985.070300524
Subject(s) - gelatin , solubility , polymer chemistry , membrane , diffusion , polyvinylpyrrolidone , matrix (chemical analysis) , desorption , chemical engineering , solvent , chemistry , polymer , vinyl alcohol , materials science , chromatography , organic chemistry , biochemistry , physics , adsorption , engineering , thermodynamics
The diffusion coefficient ( D ) and the solubility coefficient ( K ) of three sulfonated azo dyes were measured in swollen gelatin membranes at pH 12 by two techniques (time lag and desorption rate), with good agreement between the two. A strong correlation was established between log D and the reciprocal of the free volume of the matrix. Hence, as free volume of the matrix increased (due to increasing solvent imbibition), dye mobility increased. As dye size increased, however, mobility decreased. Dye affinity for gelatin, as measured in dilute solutions by dynamic dialysis, was small and could be related to the dye solubility in more concentrated gelatin matrices. Increasing ionic strength or decreasing alcohol content increased K without affecting the dye mobility. On the other hand, the presence of polymers with strong affinity for the dye anions, e.g., polyvinylpyrrolidone, immobilized a large fraction of the dye ions and greatly slowed the overall dye transport.