TY - JOUR
T1 - Interfacial Tension in Phase Separated Gelatin/Dextran Aqueous Mixtures
AU - Ding, Ping
AU - Wolf, B
AU - Frith, WJ
AU - Clark, AH
AU - Norton, Ian
AU - Pacek, Andrzej
PY - 2002/9/15
Y1 - 2002/9/15
N2 - The effect of solute concentrations on interfacial tension was investigated in phase-separated mixtures of dextran and gelatin over a range of concentrations that covered different tie-lines and different positions on one tie-line. The investigations were carried out using equilibrated gelatin-rich and dextran-rich phases in a computer-controlled Couette device at 40 degrees C (above the gelation point of gelatin) and interfacial tensions were measured using the retracting drop method. The results show that the interfacial tension can be related to the length of the tie-line or to the difference in the concentration of dextran (or gelatin) in the separated phases. Interfacial tension increases as either of these parameters increases. For concentrations lying on any single tie-line, the interfacial tension is constant and independent of the concentration of biopolymers. Also, the addition of small amounts of low molecular weight dextran to a dextran-rich phase does not significantly affect the interfacial tension between the gelatine-rich and dextran-rich phases. Experimental results were also compared with theoretical predictions of the interfacial tension using a Flory-Huggins based analysis of the measured tie-line data. Reasonable agreement was found between predicted and measured values, indicating that this approach captures the basic physics of the system.
AB - The effect of solute concentrations on interfacial tension was investigated in phase-separated mixtures of dextran and gelatin over a range of concentrations that covered different tie-lines and different positions on one tie-line. The investigations were carried out using equilibrated gelatin-rich and dextran-rich phases in a computer-controlled Couette device at 40 degrees C (above the gelation point of gelatin) and interfacial tensions were measured using the retracting drop method. The results show that the interfacial tension can be related to the length of the tie-line or to the difference in the concentration of dextran (or gelatin) in the separated phases. Interfacial tension increases as either of these parameters increases. For concentrations lying on any single tie-line, the interfacial tension is constant and independent of the concentration of biopolymers. Also, the addition of small amounts of low molecular weight dextran to a dextran-rich phase does not significantly affect the interfacial tension between the gelatine-rich and dextran-rich phases. Experimental results were also compared with theoretical predictions of the interfacial tension using a Flory-Huggins based analysis of the measured tie-line data. Reasonable agreement was found between predicted and measured values, indicating that this approach captures the basic physics of the system.
KW - aqueous/aqueous two-phase systems
KW - tie-lines
KW - retracting drop method
KW - interfacial tension
UR - http://www.scopus.com/inward/record.url?scp=0036435515&partnerID=8YFLogxK
U2 - 10.1006/jcis.2002.8572
DO - 10.1006/jcis.2002.8572
M3 - Article
C2 - 16290867
SN - 1095-7103
VL - 253
SP - 367
EP - 376
JO - Journal of Colloid and Interface Science
JF - Journal of Colloid and Interface Science
IS - 2
ER -