Hierarchical Polyimide-Covalent Organic Frameworks Carbon Fiber Structures Enhancing Physical and Electrochemical Properties

The multifunctionality of carbon fiber (CF) is being extensively explored. Herein, polyimide covalent organic frameworks (PI-COFs) are grafted bound to CF to enhance their mechanical and electrochemical properties. Here, a range of COF scaffolds are grafted to the surface of CFs via a two-step functionalization. First, melamine is tethered to the fiber surface to provide an anchoring point for the COFs followed by a “graft from” approach to grow three different sized PI-COFs utilizing three differently sized dianhydride, PMDA to form MA-PMDA, NTCDA to form MA-NTCDA, and PTCDA to form MA-PTCDA COFs. These COFs increase the capacitance of CF by a maximum of 2.9 F g⁻¹ (480% increase) for the MA-PTCDA, this coincides with an increase in interfacial shear strength by 67.5% and 52% for MA-NTCDA and MA-PTCDA, respectively. This data represents that the first-time CF has been modified with PI-COFs and allows access to COF properties including their porosity and CO₂ capture ability while being attached to a substrate. This may lead to additional high-value recyclability and second-life applications for CFs.