Gore, SonaliSonaliGoreRane, KaustubhKaustubhRane2025-08-312025-08-312023-05-1010.1021/acs.iecr.3c003622-s2.0-85156214490https://repository.iitgn.ac.in/handle/IITG2025/26802Calcium ions in hard water deteriorate the cleaning performance of detergents by interacting with the anionic surfactants and inducing their precipitation. Polystyrene sulfonate is a common component of cation-exchange resins that adsorb hard ions such as Ca⁺² and Mg⁺², which adhere to the sulfonate groups. Therefore, understanding the calcium-binding ability of polystyrene sulfonate in the presence of dodecyl sulfate can help in designing novel water-softening agents for applications related to detergency. Studying the association between polystyrene sulfonate and dodecyl sulfate via calcium ion bridges is also important. Since resins contain cross-linked polystyrene sulfonate, degrees of cross-linking and sulfonation are two important parameters. We use molecular dynamics simulations to study the effect of the above parameters on the calcium-binding ability of isotactic polystyrene sulfonate in the presence of dodecyl sulfate. We observe negligible dependence of calcium-ion binding of polystyrene sulfonate on the degrees of cross-linking and sulfonation. The formation of calcium ion bridges between cross-linked polystyrene sulfonate and dodecyl sulfate is strongly affected by the degree of sulfonation. Such bridges are observed more for the intermediate degrees of sulfonation. This is because, at a very low degree of sulfonation, dodecyl sulfate ions align closer to the cross-linking aromatic groups than the sulfonated ones. On the other hand, at high degrees of sulfonation, stronger electrostatic repulsion disfavors the proximity between dodecyl sulfate and polystyrene sulfonate.en-USfalseArticle152050457017-703010 May 202367WOS:000980925600001