COLL 384 |
| Stig E. Friberg1, Robert Y. Lochhead2, and Cynthia F. Welch2. (1) The Institute for Formulation Science, The University of Southern Mississippi, Box 10076, Shelby F. Thames Building, Hattiesburg, MS 39406-0076, (2) School of Polymers and High Performance Materials, University of Southern Mississippi, Hattiesburg, MS 39406 |
| The effects of hydroxyethylcellulose(HEC) and hydrophobically modified hydroxyethyl cellulose(HMHEC) on the phase behavior of sodium octanoate/octanoic acid/water were determined. HMHEC, but not HEC, shifted both lamellar (D) phase and hexagonal phase to lower surfactant concentrations. The (D +L1) phase Helfrich layer structure (B phase) was converted from 2-phase to 1-phase by HMHEC but not by HEC. Deuterium NMR splitting revealed that both polymers narrowed the interlamellar spacing of D-phase but the HMHEC caused the spacing to increase for B phase. The rheological behavior was analyzed according to Diat and Roux. HEC and HMHEC had no effect on the transitional shear rates. B-phase did not display the well-ordered transitions but in the presence of HMHEC they were clearly evident. We conclude that HMHEC can penetrate the layers of lamellar phase if the polymer is hydrophobically anchored and the correlation length of the adsorbed polymer segments is smaller than the interlamellar spacing. |
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Symposium in Memory of Arthur W. Adamson
8:30 AM-12:10 PM, Wednesday, March 31, 2004 Marriott -- Orange County 4, Oral
Division of Colloid and Surface Chemistry |