The self-healing properties of dual-component epoxy microcapsules are evaluated when incorporated into an epoxy coating.The performance of the coating was assessed under immersion in a saline solution,simulating seawa...The self-healing properties of dual-component epoxy microcapsules are evaluated when incorporated into an epoxy coating.The performance of the coating was assessed under immersion in a saline solution,simulating seawater conditions.Initially,synthesized microcapsules are incorporated into the epoxy coating.Then,the self-healing capabilities of the coating are studied under immersion using scanning vibrating electrode technique(SVET),open circuit potential(OCP),electrochemical impedance spectroscopy(EIS)and immersion corrosion test on coated samples with intentionally created artificial defects.The last three tests were conducted in a 3.5%NaCl solution.The adhesion of the coating is also studied by pull-off adhesion test.SVET analyses reveal lower ionic current densities in coated samples containing microcapsules during 24 h of immersion.EIS results demonstrate self-healing at the defect site for up to 12 h of immersion.After this time,the corrosion protection diminishes with prolonged immersion in the saline solution.Despite this,the coating with the microcapsules exhibits decrease in the corrosion process compared to the coating without the microcapsules.These results are consistent and complement the outcomes of the immersion tests conducted over 360 and 1056 h,which indicate that coated samples without microcapsules exhibit double the corroded areas around the scribes compared to coated samples containing the microcapsules.These findings offer a promising outlook for applying this coating on offshore carbon steel structures under immersion aiming for a longer lifetime with less maintenance intervention.展开更多
The research,fabrication and development of piezoelectric nanofibrous materials offer effective solutions to the challenges related to energy consumption and non-renewable resources.However,enhancing their electrical ...The research,fabrication and development of piezoelectric nanofibrous materials offer effective solutions to the challenges related to energy consumption and non-renewable resources.However,enhancing their electrical output still remains a significant challenge.Here,a strategy of inducing constrained phase separation on single nanofibers via shear force was proposed.Employing electrospinning technology,a polyacrylonitrile/polyvinylidene difluoride(PAN/PVDF)nanofibrous membrane was fabricated in one step,which enabled simultaneous piezoelectric and triboelectric conversion within a single-layer membrane.Each nanofiber contained independent components of PAN and PVDF and exhibited a rough surface.The abundant frictional contact points formed between these heterogeneous components contributed to an enhanced endogenous triboelectric output,showcasing an excellent synergistic effect of piezoelectric and triboelectric response in the nanofibrous membrane.Additionally,the component mass ratio influenced the microstructure,piezoelectric conformation and piezoelectric performance of the PAN/PVDF nanofibrous membranes.Through comprehensive performance comparison,the optimal mass ratio of PAN to PVDF was determined to be 9∶1.The piezoelectric devices made of the optimal PAN/PVDF nanofibrous membranes with rough nanofiber surfaces generated an output voltage of 20 V,which was about 1.8 times that of the smooth one at the same component mass ratio.The strategy of constrained phase separation on the surface of individual nanofibers provides a new approach to enhance the output performance of single-layer piezoelectric nanofibrous materials.展开更多
基金supported by CAPES scholarship-Brazil Coordination for the Improvement of Higher Education Personnel(No.88887.507764/2020-00)]by CNPq-Brazil National Council of Technological and Scientific Development(No.308564/2023-5).
文摘The self-healing properties of dual-component epoxy microcapsules are evaluated when incorporated into an epoxy coating.The performance of the coating was assessed under immersion in a saline solution,simulating seawater conditions.Initially,synthesized microcapsules are incorporated into the epoxy coating.Then,the self-healing capabilities of the coating are studied under immersion using scanning vibrating electrode technique(SVET),open circuit potential(OCP),electrochemical impedance spectroscopy(EIS)and immersion corrosion test on coated samples with intentionally created artificial defects.The last three tests were conducted in a 3.5%NaCl solution.The adhesion of the coating is also studied by pull-off adhesion test.SVET analyses reveal lower ionic current densities in coated samples containing microcapsules during 24 h of immersion.EIS results demonstrate self-healing at the defect site for up to 12 h of immersion.After this time,the corrosion protection diminishes with prolonged immersion in the saline solution.Despite this,the coating with the microcapsules exhibits decrease in the corrosion process compared to the coating without the microcapsules.These results are consistent and complement the outcomes of the immersion tests conducted over 360 and 1056 h,which indicate that coated samples without microcapsules exhibit double the corroded areas around the scribes compared to coated samples containing the microcapsules.These findings offer a promising outlook for applying this coating on offshore carbon steel structures under immersion aiming for a longer lifetime with less maintenance intervention.
基金National Natural Science Foundation of China(No.52373281)National Energy-Saving and Low-Carbon Materials Production and Application Demonstration Platform Program,China(No.TC220H06N)。
文摘The research,fabrication and development of piezoelectric nanofibrous materials offer effective solutions to the challenges related to energy consumption and non-renewable resources.However,enhancing their electrical output still remains a significant challenge.Here,a strategy of inducing constrained phase separation on single nanofibers via shear force was proposed.Employing electrospinning technology,a polyacrylonitrile/polyvinylidene difluoride(PAN/PVDF)nanofibrous membrane was fabricated in one step,which enabled simultaneous piezoelectric and triboelectric conversion within a single-layer membrane.Each nanofiber contained independent components of PAN and PVDF and exhibited a rough surface.The abundant frictional contact points formed between these heterogeneous components contributed to an enhanced endogenous triboelectric output,showcasing an excellent synergistic effect of piezoelectric and triboelectric response in the nanofibrous membrane.Additionally,the component mass ratio influenced the microstructure,piezoelectric conformation and piezoelectric performance of the PAN/PVDF nanofibrous membranes.Through comprehensive performance comparison,the optimal mass ratio of PAN to PVDF was determined to be 9∶1.The piezoelectric devices made of the optimal PAN/PVDF nanofibrous membranes with rough nanofiber surfaces generated an output voltage of 20 V,which was about 1.8 times that of the smooth one at the same component mass ratio.The strategy of constrained phase separation on the surface of individual nanofibers provides a new approach to enhance the output performance of single-layer piezoelectric nanofibrous materials.
