On-chip purification via liquid immersion of arc-discharge synthesized multiwalled carbon nanotubes
Arc-discharge synthesized multiwalled carbon nanotubes (AD-MWNT) have been proven to be of high quality, but their use is very limited due to difficulties in obtaining them in a clean and undamaged form. Here, we present a simple method that purifies raw AD-MWNT material in laboratory scale without damage, and that in principle can be scaled up. The method consists of depositing raw AD-MWNT material on a flat substrate and immersing the substrate slowly in water, whereby the surface tension force of the liquid–substrate contact line selectively sweeps away the larger amorphous carbon debris and leaves relatively clean MWNTs on the substrate. We demonstrate the utility of the method by prepa…
Dynamic Stabilization of the Ligand-Metal Interface in Atomically Precise Gold Nanoclusters Au68 and Au144 Protected by meta-Mercaptobenzoic Acid
Ligand-stabilized, atomically precise gold nanoclusters with a metal core of a uniform size of just 1–3 nm constitute an interesting class of nanomaterials with versatile possibilities for applications due to their size-dependent properties and modifiable ligand layers. The key to extending the usability of the clusters in applications is to understand the chemical bonding in the ligand layer as a function of cluster size and ligand structure. Previously, it has been shown that monodispersed gold nanoclusters, stabilized by meta-mercaptobenzoic acid (m-MBA or 3-MBA) ligands and with sizes of 68–144 gold atoms, show ambient stability. Here we show that a combination of nuclear magnetic reson…
Kieliopilliset sidoskeinot kahdessa suomalaisella viittomakielellä tuotetussa asiatekstissä
Puhutuissa kielissä sidoksisuutta voidaan muodostaa erilaisin kieliopillisin ja leksikaalisin sidoskeinoin, jotka yhdistävät tekstissä esiintyvät lauseet toisiinsa. Tämän tutkimuksen tarkoituksena oli tutkia millaisia kieliopillisia sidoskeinoja suomalaisessa viittomakielessä voi esiintyä, sillä suomalaisessa viittomakielessä tekstilingvistiikan tutkimus on ollut vähäistä. Tutkimuksen teoreettisena viitekehyksenä toimi pääosin Trevor Johnstonin ja Adam Schembrin esitykset viittomakielissä esiintyvistä kieliopillisista sidoskeinoista. Tämän lisäksi muiden tutkijoiden, kuten Elizabeth Winstonin, esitykset sidosteisuudesta tukivat teorian rakentamista. Kieliopillisia sidoskeinoja ovat referent…
Elucidating the ligand shell structure and dynamics of Au683MBA32 gold nanocluster using molecular dynamics simulations
Synthesising novel gold nanoparticles and -clusters can be often easier than characterising them, and after experimental analysis many options for the possible molecular formula of the cluster may remain as equally valid options. These options may be investigated by quantum computational means, such as density functional theory, but since DFT includes the electronic interactions, this might take time and excessive effort if the amount of options is large. In this thesis a new way of easing the computational task is introduced by a novel method, that combines a guessing algorithm and molecular dynamics simulations. The algorithm produces possible structures by utilising existing structures o…
Experimental studies on the detachment of multi-walled carbon nanotubes by a mobile liquid interface
International audience; Retention and detachment of colloidal particles from surfaces is often considered only in terms of spontaneous chemical dispersion when the surface is already fully submerged. Nevertheless, interfacial processes, where the particles are caught on a mobile liquid contact line by capillary effects are ubiquitous. Theoretical description of such interfacial processes exist for spherical microcolloids, while for anisotropic shapes the literature is limited. Arc-discharge synthesized multiwalled carbon nanotube (MWNT) material contains besides the very anisotropic tubes also irregular amorphous carbon particles (ACP) that both are strongly hydrophobic. As a water–air–soli…
Dynamic Stabilization of the Ligand-Metal Interface in Atomically Precise Gold Nanoclusters Au68 and Au144 Protected by meta-Mercaptobenzoic Acid
Ligand-stabilized, atomically precise gold nanoclusters with a metal core of a uniform size of just 1-3 nm constitute an interesting class of nanomaterials with versatile possibilities for applications due to their size-dependent properties and modifiable ligand layers. The key to extending the usability of the clusters in applications is to understand the chemical bonding in the ligand layer as a function of cluster size and ligand structure. Previously, it has been shown that monodispersed gold nanoclusters, stabilized by meta-mercaptobenzoic acid (m-MBA or 3-MBA) ligands and with sizes of 68-144 gold atoms, show ambient stability. Here we show that a combination of nuclear magnetic reson…