Product and Process Engineering - Delft University of Technology

David Valdesueiro

David Valdesueiro

Ultrathin Coating of Nanoparticles using Atomic and Molecular Layer Deposition

Contact details

  • David Valdesueiro
  • Delft University of Technology, TNW-PPE
  • Room "Proeffabriek"
  • Julianalaan 136, Delft, The Netherlands

Research interests

  • Particle technology
  • Fluidized bed reactors
  • Atomic Layer Deposition
  • Molecular Layer Deposition


  • MSc - Chemical Engineering, University of Valladolid, Spain.
  • MSc thesis - "Supercritical Extraction of Green Coffee". University of Maribor, Slovenia.


Research description

Atomic Layer Deposition (ALD) is a coating technique that provides substrates with an ultrathin homogeneous layer of inorganic material. The ALD of particles is carried out in a fluidized bed reactor.

The ALD process consists of two subsequent self-terminating half-reactions, that are repeated a number of times. In the first half-reaction a gaseous precursor (usually organometallic compound) is adsorbed onto the surface of the particles. In the second one the adsorbed component reacts with a second gas (oxidizer) to form a monolayer. The thickness of the coating is controlled by the number of times that the cycle adsorption/reaction is repeated. The deposition can be also carried out with organic precursors; it is then called Molecular Layer Deposition (MLD).

By depositing thin layers the properties and behaviour of nanoparticles can be further improved. The coating can have two purposes. One is to inactivate the nanoparticles to prevent reactions between the core of the powder and its surroundings. The other possibility is the activation of the nanoparticle by depositing active material onto the surface.

. © Delft University of Technology - PPE group 2015