Spatial heterogeneity in alignment and ordering in 3D printed elastomeric block copolymers

We have previously demonstrated the ability to induce nearly two orders of magnitude in locally tailored mechanical anisotropy by 3D printing a single elastomeric SEBS block copolymer. This functional anisotropy results from the flow-induced alignment of polystyrene cylinders within an elastomeric matrix. Our preliminary study evaluated the extent of alignment, nanostructure ordering, and domain connectivity as a function of 3D printing conditions and post-processing at the filament scale using benchtop x-ray characterization and mechanical testing. However, regions of block copolymer near the center versus the edge of extruded filaments experience distinct flow histories, which are dependent upon both nozzle geometry and flow rate. Here we leverage the micro-focused x-ray beam capabilities at beamline 12-ID at NSLS-II to probe spatial heterogeneity within individual 3D printed filaments to gain insight into how nanostructure alignment and ordering is impacted by local flow history.