Goethite (α-FeOOH, pHpzc = 8.4) , a representative hydrophilic surface with a water contact angle (WCA) = 26.8°, was synthesized by the method of Schwertmann and Cornell . The synthesized product was characterized by XRD and FTIR to verify its purity (Figure ). The goethite needles observed by transmission electron microscopy (FEI Tecnai 12 BioTwin TEM) had an average crystal length of 0.85 μm (Figure ) and a BET determined surface area of 59.1 m 2 g -1 . A monolithic diamond crystal (Figure ; GladiATR accessory, PIKE Technologies Inc., MA) was used as a representative hydrophobic surface (surface area ≈ 7.1 × 10 -6 m 2 and WCA = 105.0°). An amidated-high-methoxy pectin (Sigma-Aldrich, WI), a polysaccharide (PS), was used to represent a multifunctional model biomolecule in our study (Figure ). This PS has a MW of ≈ 71100 g mol -1 . The galacturonic acid, methoxy and amide contents are 37.1, 58.7 and 4.2%, respectively.