A deterministic approach was taken to predict membrane morphologies resulting from the matrix solidification step that occurs in the formation of microporous membranes via liquid-liquid thermally induced phase separation (L-L TIPS). Many studies have examined the growth rate of droplets in the isothermal coarsening stage of membrane formation, but few have attempted to extend this information into the subsequent processing steps of matrix solidification, diluent extraction/exchange, and drying. This research is the first to take into account the compositional change of the matrix phase during non-isothermal quenching of an L-L TIPS system that has gone through droplet coarsening. In the research presented here on matrix solidification, the approach taken utilized Monte-Carlo routines to provide quantitative information on cell size and cell size distribution for a representative L-L TIPS system, isotactic poly(propylene)-diphenyl ether. The model accounts for diluent expulsion from the polymer-rich phase, continued droplet growth during the solidification process, and shrinkage due to crystallization of the polymer-rich phase. The predicted structures were compared to experimentally formed membranes. (C) 2007 Elsevier B.V. All rights reserved.