title: Formation of gold branched plates in diluted solutions of poly(vinylpyrrolidone) and their use for the fabrication of near-infrared-absorbing films and coatings.
abstract: Ribbon-like and branched gold nano- and microstructures were produced by simple heating of diluted aqueous solutions of poly(vinylpyrrolidone) (PVP) and HAuCl4. The reaction was carried out in a one-pot, one-step process at mild temperatures. Modification of the synthesis variables allowed the obtaining of structures with different sizes and branching degrees which formed stable hydrosols with characteristic colors. A mechanism for the growth of the crystals was proposed, based on the aggregation of metal units followed by reorientation and attachment processes facilitated by the presence of low concentrations of the polymer. These anisotropic structures were used to obtain large-area porous coatings on metallic, plastic, and glass substrates and to synthesize homogeneous polymer composites. The resulting gold-modified materials showed an important increase of absorption in the near-infrared (NIR) region of the electromagnetic spectrum, which could find interesting applications in the development of NIR-absorbing filters and coatings.
authors.affiliation: Laboratory of Magnetism and Nanotechnology, Institute of Technological Investigations, Department of Physical Chemistry, University of Santiago de Compostela, Santiago de Compostela, Spain.
authors.forename: Iván
authors.initials: I
authors.lastname: Pardiñas-Blanco
authors.forename: Cristina E
authors.initials: CE
authors.lastname: Hoppe
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Piñeiro-Redondo
authors.forename: M Arturo
authors.initials: MA
authors.lastname: López-Quintela
authors.forename: José
authors.initials: J
authors.lastname: Rivas