Poly(4-styrenesulfonic acid-co-maleic acid) sodium salt is widely used as a dispersant in various industrial applications. It effectively stabilizes particles in suspensions, preventing aggregation and ensuring uniform distribution. This property makes it valuable in the production of paints, coatings, and inks, where it enhances the consistency and performance of the final product.

In the water treatment industry, it serves as a scale inhibitor, preventing the formation of deposits in pipelines and equipment. Its ability to chelate metal ions helps in maintaining the efficiency of water systems. Additionally, it is utilized in the formulation of detergents and cleaning agents, where it improves the removal of dirt and stains by acting as a surfactant.

In the field of biotechnology, this polymer is employed in the preparation of hydrogels and drug delivery systems. Its biocompatibility and ability to form stable matrices make it suitable for controlled release applications. Furthermore, it is used in the production of ion-exchange membranes for fuel cells and batteries, contributing to the advancement of energy storage technologies.