Structural Design,Preparation And Performance Characterization Of Superhydrophobic Carbon Fibers

In recent years,the superhydrophobic materials developed by the"Lotus Effect"have been obtained in aerospace,fluid drag reduction,desert water harvesting,metal anti-corrosion,anti-icing,anti-fog,microfluidic systems and biomedical compatibility.Extensive research,its potential practical value has aroused widespread concern in academia and business.However,the superhydrophobic materials reported so far can achieve superhydrophobic properties under relatively mild conditions,but they lose superhydrophobic properties under complex working conditions such as strong acid,strong alkali,high concentration salt,high temperature and organic solvent,Superhydrophobic materials cannot achieve large-scale applications.In order to realize the long-term stable superhydrophobic performance of superhydrophobic materials in complex environments,the following research work has been carried out:1.Taking Xinjiang coal as raw material,using the strong oxidative breaking ability of H₂SO₄-HNO₃ mixed acid,the raw coal is oxidized to obtain oxidized coal（OC）,which can be dissolved in N,N-dimethylformamide（DMF）.Further,a fiber nonwoven fabric precursor was prepared by an electrospinning method.In the process of fiber carbonization,the superhydrophobic carbon fiber with core-shell structure was prepared by chemical vapor deposition using petroleum asphalt as carbon source,and the effect of asphalt dosage on the morphology,structure and superhydrophobic properties of carbon fiber was investigated.The oil-water separation,self-cleaning,high temperature resistance and corrosion resistance of carbon fiber were tested.The experimental results show that the superhydrophobic properties of the obtained carbon fiber have not changed significantly after being immersed in various corrosive environments for more than 120 days.2.Inspired by the"papillary"structure of the lotus leaf,superhydrophobic carbon fiber with a"leaf-like"structure was prepared by electrospinning.The relationship between the microstructure and hydrophobic properties of carbon fiber and the concentration of spinning solution was systematically studied.When V_8%:V_4%=1:2,the water contact angle of the obtained carbon fiber LSCF_1:2 was as high as 156.5°,and Excellent oil/water separation performance,the separation flux of carbon fiber to dichloromethane/water mixture reached 3268 L/m²*h under gravity driving.After 30cycles of testing,the separation efficiency is still higher than 98.0%.In addition,after the carbon fiber obtained is immersed in a harsh environment such as strong acid or alkali,the carbon fiber still has good hydrophobicity,indicating that the carbon fiber has good stability in a corrosive environment.3.A flexible superhydrophobic carbon fiber prepared by one-step electrospinning using a spinning solution modified with Zn（NO₃）₂.Different kinds of Zn（NO₃）₂ were added into the spinning solution.With the increase of Zn（NO₃）₂,the hydrophobic properties of carbon fiber increased first and then decreased.The water contact angle of sample FSCF-0.4 reached 152.5°.The effect of adding Zn（NO₃）₂ on the hydrophobic properties of the obtained carbon fiber was studied.On the one hand,due to the addition of metal ions,the conductivity of the spinning solution increased,and the electric field force received by the droplet during the electrospinning process also increased.The increase in fiber diameter further increases the roughness of the fiber.On the other hand,after carbonization at a high temperature,the surface of the carbon fiber contains almost no reactive functional groups,which lowers the surface energy of the carbon fiber,which is advantageous for improving the superhydrophobic property of the carbon fiber.The oil/water separation performance and environmental stability of the carbon fiber were tested.The carbon fiber was bent at random and heated at 160℃for more than 24 h,and the superhydrophobic property of the carbon fiber remained substantially unchanged.In this thesis,superhydrophobic materials without any modification of low surface energy materials were successfully prepared by electrospinning.The superhydrophobic carbon fibers prepared can be used in a variety of harsh conditions such as strong acid,strong alkali,saturated salt solution,organic solvent and high temperature.It maintains superhydrophobic properties for a long time and is expected to be used in various complex environments in the future.