With low PS concentrations, relatively more carboxylate residues adsorb at the goethite surface, forming contact ion pairs (CIP, ≡FeO(H) + ⸱⸱⸱ -O(O=C)-PS) coupled with surface dehydration (Figure ). This arrangement results in increased dehydration or water exclusion, leading to the formation of a less hydrophilic surface. With increased PS surface coverage (i.e., concentration) and water exclusion, hydrophobic and inter-and intra-chain organic-organic interactions are favored through methyl ester and amide residues. Our findings align well with the observations of Petridis et al., who demonstrated that organic compounds with varying hydrophobicity form discrete zonal arrangements on a sapphire crystal (Al2O3, a hydrophilic surface), with glucose at the mineral interface and stearic acid (a saturated fatty acid) bilayers staked over it. At the highest PS concentrations, amide residues, which are amphiphilic, act as intermediates, stabilizing the interactions among PS fragments via hydrogen bonding (e.g., NH‧‧‧O interactions) and contributing to the overall adsorption network by forming water-bridges.