<p>Poly(acrylic acid)-based xerogels synthesized by precipitation polymerization form three-dimensional hydrophilic networks that significantly enhance water absorption and viscosity. However, conventional cross-linked poly(carboxylic acid) xerogels, typically produced through homopolymerization, exhibit poor salt resistance, resulting in rapid dehydration upon salt addition. In this work, hydrophobic comonomers, namely lauryl methacrylate and stearyl methacrylate, were incorporated into the polymer backbone to improve salt tolerance by reducing the density of ionizable groups. The effects of varying comonomer concentrations on the salt resistance, rheological behavior, and structural characteristics of the hydrogels were systematically investigated. Results showed that hydrophobic modification delayed wetting time, improved flowability, and altered xerogel morphology, enhancing performance under saline conditions. Incorporation of long-chain hydrophobic comonomers also improved the viscoelastic response and low-shear flow resistance of PAA-based xerogels by promoting network structuring through hydrophobic interactions. These findings offer a straightforward strategy for tailoring the salt-resistance and thickening/rheological properties of poly(acrylic acid)-based hydrogels for industrial applications.</p> Graphical Abstract <p></p>