TY - JOUR
T1 - Metastable liquid-liquid and solid-liquid phase boundaries in polymer-solvent-nonsolvent systems
AU - van de Witte, P.
AU - Dijkstra, P.J.
AU - van den Berg, J.W.A.
AU - Feijen, J.
PY - 1997
Y1 - 1997
N2 - In general liquid-liquid demixing processes are responsible for the porous morphology of membranes obtained by immersion precipitation. For rapidly crystallizing polymers, solid-liquid demixing processes also generate porous morphologies. In this study, the interference of both phase transitions has been analyzed theoretically using the Flory-Huggins theory for ternary polymer solutions. It is demonstrated that four main thermodynamic and kinetic parameters are important for the structure formation in solution: the thermodynamic driving force for crystallization, the ratio of the molar volumes of the solvent and the nonsolvent, the polymer-solvent interaction parameter, and the rate of crystallization of the polymer compared to the rate of solvent-nonsolvent exchange. An analysis of the relevance of each of these parameters for the membrane morphology is presented.
AB - In general liquid-liquid demixing processes are responsible for the porous morphology of membranes obtained by immersion precipitation. For rapidly crystallizing polymers, solid-liquid demixing processes also generate porous morphologies. In this study, the interference of both phase transitions has been analyzed theoretically using the Flory-Huggins theory for ternary polymer solutions. It is demonstrated that four main thermodynamic and kinetic parameters are important for the structure formation in solution: the thermodynamic driving force for crystallization, the ratio of the molar volumes of the solvent and the nonsolvent, the polymer-solvent interaction parameter, and the rate of crystallization of the polymer compared to the rate of solvent-nonsolvent exchange. An analysis of the relevance of each of these parameters for the membrane morphology is presented.
KW - METIS-106377
KW - IR-71366
KW - liquid-liquid demixing
KW - immersion precipitation
KW - nonequilibrium phenomena
KW - Melting transitions
KW - Membranes
U2 - 10.1002/(SICI)1099-0488(19970415)35:5<763::AID-POLB4>3.0.CO;2-N
DO - 10.1002/(SICI)1099-0488(19970415)35:5<763::AID-POLB4>3.0.CO;2-N
M3 - Article
SN - 0887-6266
VL - 35
SP - 763
EP - 770
JO - Journal of polymer science. Part B: Polymer physics
JF - Journal of polymer science. Part B: Polymer physics
IS - 5
ER -