Liquid Crystal Films as Active Substrates for Nanoparticle Control
| Autor: | Habib Ayeb, Randall D. Kamien, Dominique Demaille, Viviana Palacio-Betancur, Emmanuelle Lacaze, Ines Gharbi, Juan J. de Pablo |
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| Přispěvatelé: | Institut des Nanosciences de Paris (INSP), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique de la Matiere Molle et de la Modélisation Electromagnétique [Tunis] (LP3ME), Faculté des Sciences Mathématiques, Physiques et Naturelles de Tunis (FST), Université de Tunis El Manar (UTM)-Université de Tunis El Manar (UTM), University of Chicago, Argonne National Laboratory [Lemont] (ANL), University of Pennsylvania [Philadelphia] |
| Rok vydání: | 2021 |
| Předmět: |
Materials science
Scanning electron microscope Nanoparticle nanoparticle control 02 engineering and technology 010402 general chemistry 01 natural sciences law.invention Optical microscope Liquid crystal law Electric field Spectrophotometry Monolayer medicine spectrophotometry Molecule General Materials Science liquid crystal medicine.diagnostic_test plasmon extinction [CHIM.MATE]Chemical Sciences/Material chemistry 021001 nanoscience & nanotechnology 0104 chemical sciences Chemical physics SEM AFM 0210 nano-technology gold nanoparticle |
| Zdroj: | ACS Applied Nano Materials ACS Applied Nano Materials, American Chemical Society, 2021, 4 (7), pp.6700-6708. ⟨10.1021/acsanm.1c00680⟩ |
| ISSN: | 2574-0970 |
| Popis: | International audience; Organizing nanoparticles in a controlled way allows us to monitor their optical properties. It is particularly interesting to organize them on top of liquid crystal films to take advantage, in a second step, of the easy actuation of liquid crystals with external parameters such as temperature, electric fields, and so forth. We show that despite their fluidity, nematic and smectic films allow the formation of well-ordered hexagonal domains of gold spherical nanoparticles (AuNPs) at their surface, but we also show that both nematic films and AuNP domains impact each other. Using optical microscopy, atomic force microscopy (AFM), scanning electron microscopy (SEM), and spectrophotometry, we compare nematic, polymer-stabilized nematic, and smectic films with AuNP domains made of NPs of diameter 6 nm. On the liquid crystal films, depressions are revealed below the AuNP domains, whereas the AuNP domains appear well-organized but with a hexagonal period shortened with respect to AuNP monolayers formed on hard substrates. We interpret these features by the anchoring tilt imposed by the AuNP domains on the liquid crystal molecules. The smectic-A layers characteristic of the nematic surface transform into smectic-C layers, which induce the formation of depression. The energy penalty associated with the local smectic-A/smectic-C transition induces the shortening of the AuNP domain period in order to decrease the AuNP domain surface. The observed large depth of the polymer-stabilized nematic depressions below AuNP domains may be explained either by an increased size of the polymer-stabilized smectic layers close to the surface or by an increased number of polymer-stabilized smectic liquid crystal smectic layers close to the surface with respect to pure nematic films. |
| Databáze: | OpenAIRE |
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