Highly Porous Polymer Structures Fabricated via Rapid Precipitation from Ternary Systems

In this study, we present a versatile fabrication route for producing polymeric foams which is different from common phase inversion processes. Highly porous (up to ∼86%) polylactic acid (PLA) structures are produced via a rapid precipitation process wherein nonsolvent hexane is directly incorporated into PLA–dichloromethane solutions. Despite many advantages, this method is underutilized due to a complex correlation between thermodynamics and kinetics during solidification making it challenging to control and understand. We describe the phase separation of these systems as a three-state process which contributes to the current knowledge and understanding of the nonsolvent induced solid–liquid phase separation process. Also, we show that the shish-kebab morphologies formed in certain foams may result in an increase in their compressive modulus. The flexibility of this fabrication route allows for producing highly porous PLA structures for various applications such as acoustic and tissue engineering.