title: Adsorbed Mass of Polymers on Self-Assembled Monolayers: Effect of Surface Chemistry and Polymer Charge.
abstract: The adsorbed mass of polymers on surfaces with different chemistry is presented, and the related adsorption mechanism is discussed. Strong and weak polyelectrolytes of negative and positive charge are studied, as well as an uncharged polymer. Self-assembled monolayers of alkanethiols on gold are used in reflectometry and quartz crystal microbalance (QCM-D) experiments as adsorbing substrates bearing different terminal moieties, namely, methyl, hydroxyl, carboxyl, and amine groups. The various polymer-surface combinations allow the systematic investigation of the role of surface chemistry and polymer charge on adsorbed amount. Interactions of different nature and range drive polymer adsorption: the measured adsorbed amounts reveal information about their relative contribution. When electrostatic chain-surface attraction is present, the largest adsorbed masses are observed. However, significant mass is measured even when an electrostatic barrier to adsorption is present, suggesting the importance of forces of nonelectrostatic origin, which include both hydrophobic interactions and specific forces acting at short distances. This mechanism results in large adsorbed amounts for the adsorption of weak polyelectrolytes, and it is apparent especially in the adsorption behavior of a neutral polymer.
authors.affiliation: †Department of Inorganic and Analytical Chemistry, University of Geneva, Sciences II, Quai Ernest-Ansermet 30, 1205 Geneva, Switzerland.
authors.forename: Plinio
authors.initials: P
authors.lastname: Maroni
authors.affiliation: †Department of Inorganic and Analytical Chemistry, University of Geneva, Sciences II, Quai Ernest-Ansermet 30, 1205 Geneva, Switzerland.|‡Biocolloid and Fluid Physics Group, Applied Physics Department, Faculty of Sciences, University of Granada, Fuente Nueva s/n, 18071 Granada, Spain.
authors.forename: Francisco Javier
authors.initials: FJ
authors.lastname: Montes Ruiz-Cabello
authors.affiliation: †Department of Inorganic and Analytical Chemistry, University of Geneva, Sciences II, Quai Ernest-Ansermet 30, 1205 Geneva, Switzerland.
authors.forename: Catia
authors.initials: C
authors.lastname: Cardoso
authors.affiliation: †Department of Inorganic and Analytical Chemistry, University of Geneva, Sciences II, Quai Ernest-Ansermet 30, 1205 Geneva, Switzerland.|§Department of Land, Environment and Infrastructure Engineering (DIATI), Polytechnic University of Turin, C.so Duca degli Abruzzi 24, 10129 Torino, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Tiraferri