Preparation Of Superhydrophobic Polyaniline Micro/nano Structure And Its Corrosion Resistance

In this thesis,a series of superhydrophobic polyanilines were prepared by combining superhydrophobicity with the anticorrosive property of polyaniline itself.Fourier transform infrared spectrometer?FT-IR?,UV-visible spectrophotometer?UV-Vis?,X-ray diffractometer?XRD?,field emission scanning electron microscopy?SEM?,atomic force microscopy?AFM?,energy dispersive spectrometer?EDS?and static water contact angle measuring instrument were used to investigate the structure,morphology,elemental composition and infiltrate of samples.The relationship between hydrophobicity and anti-corrosion property of the product was studied by an electrochemical workstation.Salt spray machine was further used to test the salt spray resistance of the film samples.The main research contents are as follows:?1?Camphor sulfonic acid-doped polyaniline?PANI-CSA?was synthesized by chemical oxidation polymerization in 0.1 mol/L camphorsulfonic acid?CSA?solution using ammonium persulfate?APS?as the initiator.Then,the intrinsic polyaniline?PANI-EB?was prepared by de-doping with ammonia water.The SEM results showed that the PANI-CSA exhibited a rough surface morphology with some agglomeration phenomena.The static water contact angle?CA?was 73.4°,showing hydrophilicity.The surface of PANI-EB was relatively smooth and the structure was denser block agglomeration,CA was 125.8°,showing hydrophobic.The electrochemical workstation and salt spray machine test results showed that the corrosion resistance performance of hydrophobic PANI-EB was better,the corresponding working electrode corrosion potential(E_corr)was-0.509 V,the impedance value was 3.44×10⁶?·cm².The anticorrosive efficiency up to88.93%compared with the blank electrode and exhibited better ability to delay the metal corrosion.?2?Superhydrophobic polyaniline was prepared by one-step chemical oxidative polymerization,using sodium dodecyl sulfate?SDS?and cetyltrimethylammonium bromide?CTAB?surfactants with different hydrophobic segments as dopants,APS as the initiator.FT-IR,UV-Vis,XRD and EDS results showed that the two surfactants were successfully doped on the polyaniline molecular chain,the regularity of molecular chain increased and the crystallization ability was improved.The static water contact angle of the obtained product PANI-SDS-3?dosage of SDS was 0.009 mol?and PANI-CTAB-3?dosage of CTAB was 0.003 mol?were the bigest,which were 153.7°and 158.3°,respectively,showing superhydrophobicity.The results of SEM showed that PANI-SDS-3 and PANI-CTAB-3 exhibited a relatively uniform rod-like structure with small nano-scale protrusions on the surface compared with non-surfactant-modified polyaniline?PANI?.The results of electrochemical tests showed that the E_corr of PANI-SDS-3 and PANI-CTAB-3 were all positively shifted to a greater degree than that of PANI,the E_corr of the PANI-CTAB-3 which exhibit best hydrophobicity was-0.349 V,the impedance value was 1.51×10⁷?·cm²,capacitance arc radius of the largest,the preservation efficiency of up to 96.89%.Salt spray test results also proved that corrosion resistance of polyaniline after surfactant doping was improved,and the preservative effect of PANI-CTAB-3 slightly stronger than PANI-SDS-3.However,with the passage of time,PANI-CTAB-3 corrosion resistance decreased.?3?A copolymer surfactant?CPS?with strong hydrophobic segments was prepared by classical free radical emulsion polymerization,using2-acrylamide-2-methylpropanesulfonic acid?AMPS?and hexafluorobutyl acrylate?F₆BA?as the hydrophilic monomer and the hydrophobic monomer,respectively.It was then used as a dopant in the process of prepared polyaniline by one-step chemical oxidative polymerization.The control variable method was used to study the doping effect of polyaniline on the ratio of hydrophilic monomers to hydrophobic monomers and the amount of dopants when synthesizing CPS.FT-IR results showed that CPS was successfully synthesized and further doped on polyaniline.The results of SEM,AFM and water contact angle showed that the surface of PANI-3?same as PANI-CPS3?was rough when the mole ratio of AMPS to F₆BA was1:1.0 and the amount of CPS was 2.8 g.The average degree of surface roughness R_a was 11.19 nm,showing a uniform rod-like structure and relatively loose,almost no agglomeration,the corresponding hydrophobic performance best,CA up to 162.7°,it showed superhydrophobicity.The results of electrochemical tests showed that the corrosion potential of PANI-3 was the highest,up to-0.196 V,the impedance was 2.03×10⁸?·cm²,and the radius of capacitive arc was the largest and the anticorrosion efficiency reached 99.34%.In the water absorption test of the coating film,the film corresponding to PANI-3 had the best water resistance and the water absorption rate was only 5.63%.In addition,the salt spray test from the macro also proved its best corrosion resistance.With the passage of time,the corrosion resistance of the working electrode corresponding to PANI-3 was still decreased,but the reduction was smaller than that of the small molecule dopant.