The mechanism of oxidizing reaction in the preparation of graphene oxide (GO) by a chemical oxidation method remains unclear. The main oxidant of graphite oxide has not been determined. Here, we show a new mechanism in which Mn 2 O 7 , the main oxidant, is heated to decompose oxygen atoms and react with graphite. The whole preparation process constitutes of four distinct independent steps, different from the three steps of literature registration, and each step has its own chemical oxidation reaction. In the first step, concentrated sulfuric acid and nitric acid are intercalated between graphite layers in the form of a molecular thermal motion to produce HNO 3 –H 2 SO 4 –GIC. In the second step, Mn 2 O 7 is intercalated between graphite layers in the molecular convection–diffusion to Mn 2 O 7 –H 2 SO 4 –GIC. In the third step, Mn 2 O 7 is decomposed by heat. Oxygen atoms are generated to oxidize the defects in the graphite layer to PGO. This discovery is the latest and most important. In the fourth step, PGO is purified with deionized water, hydrogen peroxide, and hydrochloric acid to GO. Optical microscopy, ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction spectrometry, and scanning electron microscopy analytical evidence was used for confirming Mn 2 O 7 as the main oxidant and the structure of GO. This work provides a more plausible explanation for the mechanism of oxidizing reaction in the preparation of GO by a chemical oxidation method.

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Water-based superamphiphobic coatings that are environmentally friendly have attracted tremendous attention recently, but their performances are severely limited by dispersibility and mechanical durability. Herein, a dispersion of poly­(tetrafluoroethylene)/SiO2@cetyltrimethoxysilane&sodium silicate-modified aluminum tripolyphosphate (PTFE/SiO2@CTMS&Na2SiO3-ATP) superamphiphobic coatings was formed by mechanical dispersion of poly­(tetrafluoroethylene) emulsion (PTFE), modified silica emulsion (SiO2@CTMS), sodium silicate (Na2SiO3), and modified aluminum tripolyphosphate (modified ATP). The four kinds of emulsions were mixed together to effectively solve the dispersity of waterborne superamphiphobic coatings. Robust waterborne superamphiphobic coatings were successfully obtained by one-step spraying and curing at 310 °C for 15 min, showing strong adhesive ability (grade 1 according to the GB/T9286), high hardness (6H), superior antifouling performance, excellent impact resistance, high-temperature resistance (<415 °C), anticorrosion (immersion of strong acid and alkali for 120 h), and heat insulation. Remarkably, the prepared coating surface showed superior wear resistance, which can undergo more than 140 abrasion cycles. Moreover, the composite coating with 35.53 wt % SiO2@CTMS possesses superamphiphobic properties, with contact angles of 160 and 156° toward water and glycerol, respectively. The preparation method of superamphiphobic coatings may be expected to present a strategy for the preparation of multifunctional waterborne superamphiphobic coatings with excellent properties and a simple method.

Water-based superamphiphobic coatings are environmentfriendly, which have attracted tremendous attention recently, but the performances are severely limited by the dispersibility of hydrophobic particles. To solve the poor dispersibility of modified silica powder with hydrophobicity, silica dispersion was blended with polytetrafluoroethylene (PTFE) emulsion and modified aluminum tripolyphosphate (ATP) dispersion to successfully prepare water-based coatings. Multifunctional coatings were prepared by one-step spraying. It possessed good adhesion (grade 1), excellent antifouling, impact resistance, chemical stability (acid and alkali resistance for 96 h of immersion), and corrosion resistance (3.5 wt % NaCl solutions for 20 days). More importantly, the superamphiphobic coatings had high contact angles (CAs) and low slide angles (SAs) for ethylene glycol (CAs = 154 ± 0.8°; SAs = 13 ± 0.7°) and water (CAs = 158 ± 0.7°; SAs = 4 ± 0.3°). Furthermore, the composite coating was still hydrophobic after 35 cycles of wear with high roughness sandpaper (120 mesh) under three different loads, which maintained superamphiphobicity at 425 °C. This work is expected to provide a facile idea and method for the preparation of waterborne superamphiphobic coatings.