One-Step Synthesis of Calcium Sulfate Hemihydrate Nanofibers from Calcite at Room Temperature

In recent years, researchers have made significant progress in the development of inorganic nanofibers (including nanowires). Typically, inorganic nanofibers are synthesized via crystal growth in solution; however, a limited number of studies have focused on their preparation directly from solid raw materials (with no examples of synthesis conducted at room temperature and atmospheric pressure). In this work, we successfully synthesized nanofibers of calcium sulfate hemihydrate (bassanite, CaSO₄·0.5H₂O) at 20 °C and 1 atm by mixing calcite and dilute sulfuric acid in methanol. The bassanite nanofibers are concluded to be synthesized by the formation of calcium sulfate on the calcite surface and its simultaneous reaction with the generated H₂O. Because bassanite exhibits useful physical properties that include high mechanical strength, high thermal stability, and excellent chemical stability, its nanofibers can be widely applied to rubber, plastics, antifriction materials, and paper as a strengthening agent, for heat-resistance, or as a flame retardant, or for creep resistance.