Multibranched Fluorocarbon Networks for Synergistic Wetting–Agglomeration of Coal Dust: Mechanisms from Experiments and Molecular Dynamics Simulations

The prevention and control of coal mine dust is a critical challenge confronting the coal mining industry. Exhibiting exceptionally high surface activity, excellent wettability, and robust chemical stability, fluorocarbon surfactants significantly enhance the wetting and capturing efficiency of coal dust. In this study, utilizing a highly wettable single-chain fluorocarbon solution as the matrix material, a multibranched structure is constructed within the solution via chemical cross-linking. Consequently, a multibranched fluorocarbon material with superior agglomeration performance is synthesized, and its agglomeration characteristics and underlying mechanisms are systematically investigated. The results indicate that the content of hydroxyl groups and carbon–carbon double bonds in aromatic rings by the polybranched fluorocarbon solution increased significantly compared to the raw coal. After 60 h of ventilation, the T7-treated coal retained 68.3% of its initial sample mass. Furthermore, particle size analysis and liquid nitrogen adsorption experiments demonstrate that following the solution treatment, the proportion of large coal dust particles exceeding 50 μm increases to 50%. Through molecular dynamics simulations, the microscopic agglomeration mechanism of the multibranched fluorocarbon solution at the solid–liquid interface is explored, revealing that the number of hydrogen bonds in the solution remains approximately 350. Ultimately, this study elucidates the mechanisms by which the multibranched fluorocarbon solution influences the wettability and agglomeration of coal dust from both macroscopic and microscopic perspectives.