Overcoming the Transport Limitations of Photopolymer-Derived Architected Carbon

Photopolymer derived carbon grows in popularity, yet the range in available feature sizes is limited. Herein, the focus is on expanding the field to low surface to volume ratio (SVR) structures. A high temperature acrylic photopolymerizable precursor with FTIR and DSC is described and a thermal inert-gas treatment is developed for producing architected carbon in the mm scale with SVR of 1.38×10⁻³ µm⁻¹. Based on thermogravimetric analysis and mass spectrometry, two thermal regimes with activation energies of ≈79 and 169 kJ mol⁻¹ are distinguished, which is reasoned with mechanisms during the polymer's morphologic conversion between 300 and 500 °C. The temperature range of the major dimensional shrinkage (300–440 °C, 50%) does not match the range of the largest alteration in elemental composition (440–600 °C, O/C 0.25–0.087%). The insights lead to an optimized thermal treatment with an initial ramp (2 °C min⁻¹ to 350 °C), isothermal hold (14 h), post hold ramp (0.5 °C min⁻¹ to 440 °C) and final ramp (10 °C min⁻¹ to 1000 °C). The resulting carbon structures are dimensionally stable, non-porous at the µm scale, and comprise an unprecedented variation in feature sizes (from mm to µm scale). The findings shall advance architected carbon to industrially relevant scales.