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Influence of surfactant properties on thermal behavior and sol–gel transitions in surfactant‐HPMC mixtures
Author(s) -
Joshi Sunil C.,
Chen Bin
Publication year - 2009
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.30317
Subject(s) - pulmonary surfactant , sodium dodecyl sulfate , differential scanning calorimetry , polymer , aqueous solution , methyl cellulose , chemistry , chemical engineering , hydroxypropyl cellulose , ionic bonding , salt (chemistry) , sodium , materials science , polymer chemistry , chromatography , cellulose , organic chemistry , ion , thermodynamics , biochemistry , physics , engineering
Four surfactants, namely, sodium n ‐decyl sulfate (SDeS), sodium n ‐hexadecyl sulfate (SHS), sodium n ‐dodecyl sulfate (SDS), and Triton X‐100, were used as additives to study thermal behavior and sol–gel transformations in dilute aqueous hydroxypropyl methyl cellulose (HPMC)/surfactant mixtures using micro‐differential scanning calorimetry. The influence of anionic surfactant, SDS on the gelation varied with SDS concentration where the sol–gel transition started at a higher temperature. Shape of the thermograms changed from single mode to dual mode at the SDS concentration of 6 m M and higher. SDeS and SHS, however, resulted in “salt‐in” effect of a different magnitude during gelation. Triton X‐100, being a non‐ionic surfactant, showed a minor “salt‐out” effect on the thermo‐gelation process. On the basis of different thermal behavior of anionic and non‐ionic surfactant/HPMC systems, a mechanism is proposed explaining how the chemical structure and electro‐charge of the surfactants affect the polymer/surfactant binding and polymer/polymer aggregation because of hydrophobic interaction during the sol–gel transition. © 2009 Wiley Periodicals, Inc. Journal of Applied Polymer Science, 2009