title: Dispersion and surface functionalization of oxide nanoparticles for transparent photocatalytic and UV-protecting coatings and sunscreens.
abstract: This review describes recent efforts on the synthesis, dispersion and surface functionalization of the three dominating oxide nanoparticles used for photocatalytic, UV-blocking and sunscreen applications: titania, zinc oxide, and ceria. The gas phase and liquid phase synthesis is described briefly and examples are given of how weakly aggregated photocatalytic or UV-absorbing oxide nanoparticles with different composition, morphology and size can be generated. The principles of deagglomeration are reviewed and the specific challenges for nanoparticles highlighted. The stabilization of oxide nanoparticles in both aqueous and non-aqueous media requires a good understanding of the magnitude of the interparticle forces and the surface chemistry of the materials. Quantitative estimates of the Hamaker constants in various media and measurements of the isoelectric points for the different oxide nanoparticles are presented together with an overview of different additives used to prepare stable dispersions. The structural and chemical requirements and the various routes to produce transparent photocatalytic and nanoparticle-based UV-protecting coatings, and UV-blocking sunscreens are described and discussed.
authors.affiliation: Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden.
authors.forename: Bertrand
authors.initials: B
authors.lastname: Faure
authors.affiliation: Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden.
authors.forename: German
authors.initials: G
authors.lastname: Salazar-Alvarez
authors.affiliation: YKI, Ytkemiska Institutet, Institute for Surface Chemistry, Drottning Kristinas Väg 45, SE-114 86 Stockholm, Sweden.
authors.forename: Anwar
authors.initials: A
authors.lastname: Ahniyaz
authors.affiliation: Sustainable Construction Division, TECNALIA, Parque Tecnológico de Bizkaia, C/Geldo, Edificio 700, E-48160 Derio-Bizkaia, Spain.
authors.forename: Irune
authors.initials: I
authors.lastname: Villaluenga
authors.affiliation: Sustainable Construction Division, TECNALIA, Parque Tecnológico de Bizkaia, C/Geldo, Edificio 700, E-48160 Derio-Bizkaia, Spain.
authors.forename: Gemma
authors.initials: G
authors.lastname: Berriozabal
authors.affiliation: Sustainable Construction Division, TECNALIA, Parque Tecnológico de Bizkaia, C/Geldo, Edificio 700, E-48160 Derio-Bizkaia, Spain.
authors.forename: Yolanda R
authors.initials: YR
authors.lastname: De Miguel
authors.affiliation: Department of Materials and Environmental Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden.
authors.forename: Lennart
authors.initials: L
authors.lastname: Bergström
keywords: cerium dioxide; coatings; dispersion; functionalization; nanoparticles; photocatalysis; sunscreens; synthesis; titanium dioxide; transparency; zinc oxide