Increased surface coverage and length of the organic molecule resulted in greater WCA values. Furthermore, organic coatings block the surface electrical charges and distorts the interlinked and overlapping arrangement of the clay platelets. Using molecular dynamic simulations, Underwood et al. explored the interactions between various organic molecules (nonpolar, polar, ionic) and kaolinite's hydrated siloxane and hydroxyl surfaces. Their findings predict the relative affinity of these molecules to kaolinite surfaces can shift between the hydroxylated and silicate domains depending on the pH and the functional group of the organic molecule. Decane, with minimal electrostatic charge, adsorbs primarily via van der Waals interactions on the silicate surface. In contrast, decanoate anions adhere to the hydroxyl surface through an anion exchange mechanism. Decanamine, capable of adsorbing to both the silicate and hydroxyl surfaces, forms hydrogen bonds (N-H•••O) with the hydroxyl groups, facilitated by waterbridging interactions. In laboratory experiments, Yang et al. demonstrated a peptide derived from Pseudomonas aeruginosa has a higher affinity for hydrophobic than for hydrophilic surfaces, where peptide adsorption on the hydrophobic surface is enthalpically favored while entropic contributions are more significant on the hydrophilic surface. Investigations of protein (BSA) adsorption and desorption dynamics reported saturation at 50% surface coverage on a hydrophobic (polystyrene) surface, while adsorption reached 95% saturation on the hydrophilic (GeOH) surface. Additionally, the BSA molecules exhibited different conformations and interaction strengths, with stronger binding on the hydrophilic surface via multiple H-bonds with GeOH. Polysaccharides in soil and in fresh and marine waters, contribute significantly to the composition of DOM, with major inputs from plants, microbes, algae, and phytoplankton. Branching and a variety of functional groups due to anionic, cationic and non-polar substitutions on natural polysaccharide chains can result in derivatives exhibiting diverse hydrophobic, hydrophilic and amphiphilic characteristics. Several studies have shown that iron oxyhydroxides, commonly found in soils and sediments (e.g., goethite, α-FeOOH), can selectively adsorb and preserve polysaccharides with binding mechanisms that include hydrogen bonding, and electrostatic and hydrophobic interactions, thereby promoting organic-organic interactions at the mineral surface. Only a few studies have however investigated potential conformational changes to polysaccharide molecules upon adsorption at mineral interfaces, and these have mostly used EPS (extracellular polymeric substances), which is a blend of protein, DNA/RNA, lipid and polysaccharide components. To the best of our knowledge, this is the first study that shows how polysaccharide adsorption-desorption dynamics and interfacial assembly alter the wettability of hydrophilic (i.e., goethite) and hydrophobic (i.e., diamond) surfaces. We study these phenomena over various polysaccharide surface loadings using in-situ ATR-FTIR spectroscopy, concentration-dependent 2D-COS analyses, and water contact angle measurements. The combination of molecular-and macro-scale measurements yielded novel results, as reported herein, that reveal new insights about polysaccharide conformational changes upon adsorption and desorption, and about the contribution of the polysaccharide's multifunctionality to hydrophobic and hydrophilic interactions at water/solid interfaces, and to decreased wettability.