| 1. |
- Bassani, Carlos L., et al.
(författare)
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Nanocrystal Assemblies : Current Advances and Open Problems
- 2024
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Ingår i: ACS Nano. - 1936-0851. ; 18:23, s. 14791-14840
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Forskningsöversikt (refereegranskat)abstract
- We explore the potential of nanocrystals (a term used equivalently to nanoparticles) as building blocks for nanomaterials, and the current advances and open challenges for fundamental science developments and applications. Nanocrystal assemblies are inherently multiscale, and the generation of revolutionary material properties requires a precise understanding of the relationship between structure and function, the former being determined by classical effects and the latter often by quantum effects. With an emphasis on theory and computation, we discuss challenges that hamper current assembly strategies and to what extent nanocrystal assemblies represent thermodynamic equilibrium or kinetically trapped metastable states. We also examine dynamic effects and optimization of assembly protocols. Finally, we discuss promising material functions and examples of their realization with nanocrystal assemblies.
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| 2. |
- Palacios-Rivera, Rogger, et al.
(författare)
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Enantiopure Supramolecular Motifs of Self-Assembled Diamine-Based Chiral Molecules on Cu(100)
- 2018
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Ingår i: The Journal of Physical Chemistry C. - : AMER CHEMICAL SOC. - 1932-7447 .- 1932-7455. ; 122:42, s. 24129-24136
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Tidskriftsartikel (refereegranskat)abstract
- The assembly of two diphenylethylenediamine enantiomers, separately deposited on Cu(100), is investigated from the first stages of two-dimensional crystallization to the nucleation and growth of the second layer. By means of scanning tunneling microscopy, we show that the chirality of enantiomers is expressed at different levels of molecular organization. Below the monolayer completion, a disordered phase coexists with domains of a square lattice aligned with the principal crystallographic directions of the substrate. The intrinsic chirality of the molecules is only manifested through specific features contained within the corresponding unit cell. For increasing coverage, this arrangement is accompanied by a second square structure, which appears to be clockwise or counterclockwise rotated with respect to the Cu(100) directions depending on the enantiomer. The nucleation of molecular chains on top of the aligned square structure gives rise to a second layer exhibiting a stripelike configuration with remarkable left- or right-handed helicity that mirrors that of the particular enantiomer. The nearly flat configuration of the first-layer molecules is confirmed by angular-dependent X-ray absorption experiments and supported by molecular dynamics simulations.
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| 3. |
- Roig-Sanchez, Soledad, et al.
(författare)
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Nanocellulose films with multiple functional nanoparticles in confined spatial distribution
- 2019
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Ingår i: Nanoscale Horizons. - : ROYAL SOC CHEMISTRY. - 2055-6764 .- 2055-6756. ; 4:3, s. 634-641
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Tidskriftsartikel (refereegranskat)abstract
- Industries, governments and consumers increasingly request sustainable resources and greener routes for the integration of advanced functional nanocomposites in products and devices. Among renewable biopolymers, cellulose deserves special consideration since it is the most abundant one. While inorganic nanoparticles add functional properties to a nanocomposite, a flexible and porous cellulosic support will facilitate the interaction of the nanoparticles with the surroundings, their handling and recycling. A significant challenge is to develop high strength, flexible nanobiocomposites controlling the nanoparticle properties, their volume fraction and their topographic distribution within the scaffold. A new concept is presented here for multifunctional laminates where layers consist of bacterial cellulose fibrils decorated by inorganic nanoparticles. Each layer can provide a specific function using a different nanoparticle. As model systems, we have selected two metals (Au, Ag) and two semiconductors (TiO2 and Fe2O3). Energy-efficient microwave-assisted synthetic routes have been used to in situ nucleate and grow the inorganic nanocrystals on the cellulose fibrils. Then, functionalized bacterial cellulose films can be arranged as laminates in a millefeuille construct simply by layering and drying the wet films at 60 degrees C. After drying, they perform as a single integrated and thicker film. Structural, functional and mechanical integrity of the laminates have been investigated. Molecular dynamics simulations were used to compute the surface adhesion energy between two cellulose fibrils and the results are discussed in light of the experimental peel-off data for the separation of the layers in the laminate.
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