Carbon fiber in situ grown ZIF‐67 nanocrystals with excellent electrochemical and interfacial property

Abstract

Carbon fiber(CF) reinforced flexible composites had a wide range of applications. However, the interfacial adhesion of composites was weak as a result of the smooth and chemically inert CF surface. To settle this issue, this paper described a method to enhance the specific surface area, roughness and wettability of the CF surface by in situ growing Cobalt‐based zeolitic imidazolate framework (ZIF‐67) nanocrystals and CF reinforced waterborne polyurethane (WPU) composites were prepared by a simple casting method. Scanning electron microscopy clearly revealed uniformly grown ZIF‐67 nanoarrays with distinct morphology on the CF surface. As a result, the CF@ZIF‐3 electrode exhibited excellent electrochemical property, with specific capacitance reaching 368.2 mF/cm2. The reinforcing effect of ZIF‐67 with different morphology was further verified through transverse fiber bundle tension test and shear bonding strength measurements, showing improvements of 51.9 and 72.1% respectively, in comparison to the CF/WPU composites due to the unique structure of the ZIF‐67 nanocrystals acted as buffer area, effectively relieving stress concentration and altering the direction of crack propagation. As a result, the interfacial properties of the composites were enhanced. Moreover, tensile and tear strengths of CF@ZIF/WPU composites showed remarkable improvement compared to CF/WPU composites. This study presented a potential reinforcement strategy for achieving high‐performance CF/WPU composites.Highlights ZIF‐67 with different morphologies were grown in situ on the CF surface. CF@ZIF electrode exhibited excellent electrochemical property. ZIF‐67 interface layer improved interfacial properties of composites. The tensile strength of the composites improved after ZIF‐67 modification. Introduction of ZIF‐67 enhanced the tear strength of composites.