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CNF-based organic coating with different micromorphological structures was fabricated on the surface of carbon fiber (CF) by regulating the solvent ratio of binary solvents (deionized water/ethanol). The trends of their chemical components and microstructures were investigated, as well as their effects on the interfacial bonding performance of CFRP. [Display omitted] • CNF-based organic coatings with different micro-morphologies were prepared on carbon fiber surfaces by modulating the solvent ratio of binary solvents. • As the ratio of deionized water in the binary solvent increased, the CNF-based coating was gradually flattened and homogeneous, and the raised structures on the coating surfaces were gradually reduced. • The raised structures with poorer adhesion were more prone to generate stress concentration points, leading to premature fiber failure. • Crack extension in composites occurred not only in the resin phase, but also between the coating and the resin. Current research on cellulose nanofiber (CNF) in the field of mechanical properties mainly involves the direct application of CNF and simple composites with other materials. The relationship between the morphology and structure of CNF-based materials and the target functions of composites has rarely been explored. Here, as an example of carbon fiber reinforced composites (CFRP), CNF-based organic coating with different micromorphological structures was fabricated on the surface of carbon fiber (CF) by regulating the solvent ratio of binary solvents (deionized water/ethanol). The trends of their chemical components and microstructures were investigated, as well as their effects on the interfacial bonding performance of CFRP. The results indicated that an increase in the ratio of deionized water in the binary solvent led to a smaller raised structure with poor adhesion and an increase in coating uniformity on the organic coating, which would directly affect the tensile strength (TS) of the CF and the interlaminar shear strength (ILSS) of CFRP. This research presents important insights into the mechanism of composite interfaces based on the differences in the micro-morphological structures of materials. [ABSTRACT FROM AUTHOR]

[Display omitted] • Lanthanum hydroxide was firmly loaded on N -doped C layer modified ACF without binder. • LNA exhibited stable P electrosorption behavior after 5 adsorption–desorption cycles. • The Langmuir maximum electrosorption capacity of P on LNA was 70.656 mg/g. • Co-existing anions improved P removal in the order of Cl->NO 3 –>SO 4 2-> HCO 3 –>CO 3 2– • N -doped C layer promoted P electrosorption by affecting electronic structure of La. Binder-free La(OH) 3 supported activated carbon fiber (ACF) electrode with modification of N -doped C layer (named LNA) was developed for phosphate (P) electrosorption. The optimum electrosorption of P on LNA was achieved at pH = 4 and voltage = 4 V. The electrosorption capacity was 6.5 times that without voltage, and adsorption rate also increased by 9 times. The presence of 0.1 mol/L inorganic anions improved the electrosorption efficiency in the order of Cl->NO 3 –>SO 4 2->HCO 3 –>CO 3 2–. The regeneration study revealed that LNA still exhibited a high electrosorption capacity (29.91 mg/g) after 5 cycles. The mechanism of phosphate electrosorption of LNA was analyzed by kinetics, isotherms, FTIR and XPS, etc. The adsorption kinetics followed the pseudo-second-order model, and the adsorption equilibrium data were well described by the Langmuir isotherm. The Langmuir maximum electrosorption capacity of LNA was 70.66 mg/g. The electrosorption of phosphate was controlled by ion exchange, electrostatic attraction and the formation of surface complexes. N -doped C layer affected the local electronic structure of La and strengthened the interaction with lanthanum hydroxide, promoting the electrosorption of phosphate. The results demonstrated that LNA is a promising electrosorption material for efficient phosphate recovery. [ABSTRACT FROM AUTHOR]

[Display omitted] • Carbon fiber is treated by NH 3 plasma with low damage to realize electrostatic self-assembly with graphene oxide. • Graphene oxide of different sizes forms multi-layered restoration structures on fiber surfaces by electrostatic forces. • Electrostatic self-assemblies of carbon fibers with graphene oxide can optimize the mechanical properties of composites. The introduction of graphene oxide (GO) on the surface of carbon fiber (CF) is considered an effective strategy to modulate the structure and properties of the fiber/matrix interface in CF reinforced polymer composites. However, the tensile strength of fibers often decreases due to the etching effect during treatment. In this study, a new method was proposed to graft GO onto fiber surfaces by electrostatic self-assembly. The results showed that NH 2 grafted onto CF through NH 3 plasma treatment caused CF and GO to have opposite charges in deionized water; subsequently, they self-assembled to form CF@GO due to the electrostatic force. The tensile strength of CF@GO was 31.23% greater than that of pristine CF, which may be because the different sizes of GO repaired the surface defects on the CF with its multilayer restoration structure. The CF showed a noticeable improvement in surface wettability due to the GO coating. Moreover, the interfacial properties were significantly improved, with the interfacial shear strength (IFSS) of CF@GO increasing to 81.31 MPa, which was about twice that of unmodified CF. This work provides a promising strategy for nondestructive grafting nanoparticles on CF to build a strong interface in CF composites. [ABSTRACT FROM AUTHOR]