3D Printing of Mesoporous Polymer Composites Enabled by Flash-Freezing

Shaping mesoporous polymers into complex 3D geometries remains a challenge due to limitations in traditional molding and templating techniques. Here, we report a facile and generalizable strategy that integrates direct ink writing (DIW) with flash-freezing to produce 3D-printed mesoporous polymer composites. Using polystyrene (PS) as a model polymer and tuning the rheological properties of the polymer solution with fumed silica (FS), we achieved 3D printable inks that generate nanoscale porosity via flash-freezing and preserve the structure through solvent exchange and freeze-drying. Nitrogen adsorption/desorption analysis and scanning electron microscopy analysis confirmed the formation of mesoporous networks with tunable pore size and surface area. The addition of FS also significantly toughens the mesoporous composites. This method is further extended to polyacrylonitrile (PAN)-based composites, demonstrating compatibility with diverse polymer–solvent formulations. This approach enables the fabrication of structurally robust, hierarchically porous polymer composites with design flexibility, offering additional possibilities for separation, insulation, and other functional applications.