Used as a key intermediate in the synthesis of water-soluble polymers and surfactants, particularly in electroplating and surface treatment processes. Its sulfonic acid group provides strong acidity and good thermal stability, making it effective in improving wetting and dispersing properties in industrial cleaning formulations. Also employed in the production of proton-exchange membranes for fuel cells due to its ability to conduct protons in hydrated environments. Additionally, it serves as a functional additive in dyeing processes to enhance dye solubility and fabric affinity.