title: Interfacial Activity and Contact Angle of Homogeneous, Functionalized, and Janus Nanoparticles at the Water/Decane Interface.
abstract: Surface heterogeneity affects the behavior of nanoparticles at liquid interfaces. To gain a deeper understanding on the details of these phenomena, we have measured the interfacial activity and contact angle at water/decane interfaces for three different types of nanoparticles: homogeneous poly(methyl methacrylate) (PMMA), silica functionalized with a capping ligand containing a methacrylate terminal group, and Ag-based Janus colloids with two capping ligands of different hydrophobicity. The interfacial activity was analyzed by pendant drop tensiometry, and the contact angle was measured directly by freeze-fracture shadow-casting cryo-scanning electron microscopy. The silver Janus nanoparticles presented the highest interfacial activity, compared to the silica nanoparticles and the homogeneous PMMA nanoparticles. Additionally, increasing the bulk concentration of the PMMA and silica nanoparticles up to 100-fold compared to the Janus nanoparticles led to silica particles forming fractal-like structures at the interface, contrary to the PMMA particles that did not show any spontaneous adsorption.
authors.affiliation: †Biocolloid and Fluid Physics Group, Applied Physics Department, Faculty of Sciences, University of Granada, 18071 Granada, Spain.
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: Fernandez-Rodriguez
authors.affiliation: ‡POLYMAT, Bionanoparticles Group, Applied Chemistry Department, UFI 11/56, Faculty of Chemical Sciences, University of País Vasco UPV/EHU, 20018 Donostia-San Sebastián, Spain.|§Department of Materials, Department of Bioengineering, and the Institute for Biomedical Engineering, Imperial College London, London SW7 2AZ, United Kingdom.
authors.forename: Jose
authors.initials: J
authors.lastname: Ramos
authors.affiliation: ∥Laboratory for Interfaces, Soft Matter and Assembly, ETH Zürich, Vladimir-Prelog-Weg 5, 8093 Zürich, Switzerland.
authors.forename: Lucio
authors.initials: L
authors.lastname: Isa
authors.affiliation: †Biocolloid and Fluid Physics Group, Applied Physics Department, Faculty of Sciences, University of Granada, 18071 Granada, Spain.
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: Rodriguez-Valverde
authors.affiliation: †Biocolloid and Fluid Physics Group, Applied Physics Department, Faculty of Sciences, University of Granada, 18071 Granada, Spain.
authors.forename: Miguel Angel
authors.initials: MA
authors.lastname: Cabrerizo-Vilchez
authors.affiliation: †Biocolloid and Fluid Physics Group, Applied Physics Department, Faculty of Sciences, University of Granada, 18071 Granada, Spain.
authors.forename: Roque
authors.initials: R
authors.lastname: Hidalgo-Alvarez
mesh_terms: D000473:Alkanes / Q000737:chemistry*; D008024:Ligands; D053768:Metal Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
chemical_list: D000473:Alkanes; D008024:Ligands; D014867:Water; D012834:Silver; D019904:Polymethyl Methacrylate; C012867:decane