Phase inversion mechanism

A few empirical and theoretical studies to postulate a general set of rules for the fabrication of asymmetric membranes by phase inversion mechanism (in which the polymer solution is coagulated within a nonsolvent bath) have been attempted. Thus, for example, from the literature which described the formation of asymmetric membranes, Klein and Smith (5) compiled working rules in the early 1970s regarding the requirements of a casting solution ... 

Akay, G. Flow induced phase inversion mechanism and applications. In Recent Advances in Transport Phenomena] Dincer, I., Yardim, F., Eds. Elsevier Paris, 2000 11-17. 

The formation of a porous structure results from phase separation (or phase inversion) mechanisms that are not limited to electrospraying. It is the process that controls membrane formation, as the solvent exchanges with a nonsolvent, polymer solution solidifies and polymeric device forms. The phase separation is fully investigated in fabrication of flat or hollow fiber membranes or in situ forming drug delivery systems. - Usually, quick evaporation of the solvent produces particles with porous or golf ball-shaped surfaces (Figure 22.26). 

Figure 7.34 Phase inversion mechanism in injection-molded sheet...

A considerable amount of work has been done in the past in the development of blends with CC morphology and coarsening of the minority phase. However, most of the earlier work was intended towards understanding the coarsening and phase inversion mechanism in polymer blends [1-19]. To date, the fabrication of porous polymer fibers with CC morphology and subsequent coarsening of the minority phase with annealing has not been reported. 

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