Robust Co-continuous Nanostructures by Microphase Separation of Randomly Cross-linked Polystyrene and Poly(2-vinylpyridine) Networks*

 Co-continuous polymeric nanostructures have drawn considerable attention due to their synergistic effect, for example, each constituting polymer maintains its properties without significant loss in all three dimensions due to percolation, in contrast to non-percolated morphologies where the characteristics of the dispersed morphologies may be largely lost. Randomly end-linked copolymer networks (RECNs) have been shown to facilitate the formation of co-continuous nanostructures in a robust way. However, the requirement of using telechelic polymers often necessitates complicated synthetic routes. Alternatively, randomly cross-linked copolymer networks (RCCNs) are composed of polymers with crosslinkable pendants that are easily synthesized by copolymerization, promoting more general copolymer network paths for percolating structures. RCCNs provide a high degree of tunability of polymer chain- and crosslinker functionalities, both of which have been investigated in this study. Wide co-continuous windows have been defined by a selective extraction of one polymer coupled with a variety of characterization methods (gravimetry analysis, small-angle X-ray scattering, and electron microscopic images). Potential applications of the resulting porous monolith and re-collection of the washed polymer will be further studied. This RCCN platform is expected to facilitate processing of co-continuous polymer nanostructures.