title: Thermal annealing as an easy tool for the controlled arrangement of gold nanoparticles in block-copolymer thin films.
abstract: Thermal annealing was used for the bottom-up fabrication of morphologically controlled gold-block-copolymer (Au-BC) nanocomposites. Three different blends formed by polystyrene (PS) homopolymer and PS-coated gold nanoparticles (PSSH@Au) were used as modifiers of asymmetric polystyrene-b-polymethylmethacrylate (PS-b-PMMA): PS26/PS26SH@Au, PS75/PS75SH@Au and PS167/PS167SH@Au (where the subscripts refer to the number of styrene monomeric units).The results indicated that all three blends used as modifiers (PSn/PSnSH@Au) were successfully located in the PS phase during thermally induced BC self-assembly for a composition range from 5 to 43 wt% without macro-phase separation. The PSnSH@Au moiety experienced molecular desorption, nanocrystal core coalescence and partial molecular re-encapsulation processes during thermal annealing, leading to sphere-like gold NPs with a larger average size (without exceeding an interdomain distance). Ligand chain length regulated the degree of coalescence and re-encapsulation, defining ultimate core size. Furthermore, proper combination of chain length and composition enabled tuning of NP partitioning and arrangement on different length scales through thermally activated cooperative assembly processes. These results have not only significant impact for establishing thermal processing as a useful tool for the precise control of NP size and distribution, but also much broader implications for many nanoparticle-based technologies.
authors.affiliation: Centre for Research in Biological Chemistry and Molecular Materials (CIQUS), c Jenaro de la Fuente-Campus Vida, University of Santiago de Compostela (USC), E-15782 Santiago de Compostela, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Ledo-Suárez
authors.forename: Cristina Elena
authors.initials: CE
authors.lastname: Hoppe
authors.forename: Massimo
authors.initials: M
authors.lastname: Lazzari
authors.forename: M Arturo
authors.initials: MA
authors.lastname: Lopez Quintela
authors.forename: Ileana Alicia
authors.initials: IA
authors.lastname: Zucchi
mesh_terms: D006046:Gold / Q000737:chemistry*; D008689:Methacrylates / Q000737:chemistry*; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000379:methods*; D011137:Polystyrenes / Q000737:chemistry*; D013696:Temperature
chemical_list: D008689:Methacrylates; D011137:Polystyrenes; C522509:polystyrene-block-poly(methyl methacrylate); D006046:Gold