Langmuir, Vol.33, No.2, 537-542, 2017
Diving into the Finestructure of Macroporous Polymer Foams Synthesized via Emulsion Templating: A Phase Diagram Study
During our studies on emulsion-terriplated monodisperse polymer foams we found significant differences in, the' finestructure if the locus of initiation is changed. This, motivated sus to study the phase behavior of the liquid template. Our studies indicate that the template consists of droplets of three different length scales: The water droplets generated via microfluidics (similar to 70 iim) are surrounded by a continuous phase in which w/o emulsion (<= 100 nm) coexists with a w/o microemulsion (similar to 5 nm). We speculate that the w/o= emulsion droplets act as seeds for the porous finestructure observed in AIBN-initiated polymer foams. We have experimental evidence that the w/o emulsion inverts to an o/w emulsion with progressing polymerization. This explains the granular texture observed in KPS-initiated polymer foams. The control of the finestructure is important in the preparation of tailor-made polymer foams because it directly impacts the material's density and thus, in turn, its mechanical stability.