The synthesis of nanoparticles at CIMaINa dates back to the studies on carbon fullerenes in the 90s at the Molecular Beam and Nanocrystalline Materials Laboratory (LGM) of the University of Milan. At present CIMAINA uses different PVD techniques. In particular, a patented cluster source (Pulsed Microplasma Cluster Source – PMCS) was developed and used in Supersonic Cluster Beam Deposition (SCBD) apparata, for fundamental studies on free clusters, and for the fabrication of cluster-assembled films. Other techniques such as evaporation, ion beam or magnetron sputtering, are used to integrate PMCS depositions. A flame pyrolysis facility is used for the production of nano-powders. A large variety of elements and composites has been investigated, for different applications, spanning from bio-medical to microfluidic, friction reduction, energy storage etc. Two spin-off companies (i.e. Tethis and Wise) were created in the years developing ideas generated in CIMaINa experimental activity.

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Referent: Paolo Piseri

Last publications show all

Patterning of gold-polydimethylsiloxane (Au-PDMS) nanocomposites by supersonic cluster beam implantation

Ghisleri, C.; Borghi, F.; Ravagnan, L.; Podesta, A.; Melis, C.; Colombo, L.; Milani, P.: J. Phys. D-Appl. Phys. 47 (2014) 015301 [DOI: 10.1088/0022-3727/47/015301]

Related grants:

CATSENSE – Design of novel high performance catalysts and biosensors based on deposited mass-selected clusters assisted by computational theoretical screening

European Community (EU FP7 Marie Curie ITN) (from 2014-01-01 to 2018-01-31)

Supersonic Cluster Beam Deposition

PMCS-SCBD technique consists in the fabrication of cluster molecules in the source supported by an inert carrier gas that, expanding through a series of vacuum chambers, form a supersonic cluster-seeded beam. Thin films can be assembled starting from cluster molecules with a bottom-up approach, simply intercepting the beam with a substrate. Substrate controlled movement (rastering) is used to get a uniform coverage over typical areas of few square centimeters.The main characteristics of this technique are:

  • large presence of molecular clusters in the film – SCBD is a low kinetic energy process so that the cluster particles keep their original structure once they impinge on the substrate
  • complete freedom of choice of the support substrate – clusters deposition is a room temperature, neutrally charged process thus imposing no limitations to the substrate nature
  • large variety of cluster species – in principle PMCS can work with any solid conductive or semi-conductive material and composites or mixtures of them; also non-conductive species can be introduced in the source in solid or liquid phase through the carrier gas
  • high purity films – the separation of cluster formation and cluster deposition steps allows the use of differential pumping to take off the process all unreacted species
  • micro/nano patterning – through aerodynamic manipulation the supersonic cluster beam can be collimated to replicate stencil mask patterns down to the nano-scale

The materials produced are in general extremely porous (high surface to volume ratio), have medium/low density and are quite soft. The average size of the clusters can be tuned in order to design the film morphology. The resulting films are particularly adapt to applications where the interface properties at the micro/nano scale are crucial.

Referent: Claudio Piazzoni

Participants: Paolo Piseri, Paolo Milani

Impact of nanoscale morphology on the IsoElectric Point of nanostructured surfaces

We study how surface nanoscale roughness and morphology affect the charging behaviour of nanostructured surfaces (titania, zirconia) in aqueous electrolytes. The charging behavior of surfaces has important consequences for nanoparticle adsorption processes, as in the case of cell or protein-surface interactions, as well as for the behaviour of photo-electrochemical and catalytic devices.

We use AFM in force spectroscopy mode, equipped with colloidal probes, to characterise the IsoElectric Point (IEP) of surfaces. The use of a colloidal probe provides well-defined interaction geometry, and allows effectively probing the overall effect of nanoscale morphology.

By using supersonic cluster beam deposition (SCBD) to fabricate nanostructured films, we achieve a quantitative control over the surface morphological parameters, which is mandatory in order to perform a systematical exploration of the electrical double layer properties in different interaction regimes, characterized by different ratios of characteristic nanometric lengths of the system: the surface rms roughness, the correlation length, and the Debye length.

Our main result is the observation of a remarkable reduction by several pH units of the IEP on rough nanostructured surfaces, with respect to flat samples.

Referent: Alessandro Podestà

Participants: Francesca Borghi

Last publications show all

Nanoscale Roughness and Morphology Affect the IsoElectric Point of Titania Surfaces

Borghi, Francesca; Vyas, Varun; Podesta, Alessandro; Milani, Paolo: PLoS One 8 (2013) e68655 [DOI: 10.1371/journal.pone.0068655]

Study of the interfacial properties of ionic liquids at smooth and nanostructured solid surfaces

The knowledge of the structural properties of ILs at interfaces, in particular with solid surfaces, is directly relevant for those applications where ILs are employed in form of thin films supported on solid surfaces, such as in microelectromechanical or microelectronic devices.

A better understanding of the behavior of ILs at interfaces can be achieved studying systems where the surface to volume ratio is very large, as in very thin supported films. At the time of our first publication (2009), this was a largely unexplored field, since most studies were conducted on systems where a bulk amount of IL was present right above, or below, the interface.

The results of our studies, supported in recent years by those of other groups, suggest that at the liquid/solid interface ILs are driven by surface interactions through a liquidlike-to-solidlike transition, which also leads to an electrically insulating behaviour.

We are currently exploring similar phenomena at nanostructured interfaces, produced by supersonic cluster beam deposition.

Referent: Alessandro Podestà

Participants: Francesca Borghi, Massimiliano Galluzzi, Simone Bovio

Last publications show all

Surface Confinement Induces the Formation of Solid-Like Insulating Ionic Liquid Nanostructures

Galluzzi, Massimiliano; Bovio, Simone; Milani, Paolo; Podesta, Alessandro: J. Phys. Chem. C 122 (2018) 7934-7944 [DOI: 10.1021/acs.jpcc.7b12600]

Nano-indentation of a room-temperature ionic liquid film on silica: a computational experiment

Ballone, P.; Del Popolo, M. G.; Bovio, S.; Podesta, A.; Milani, P.; Manini, N.: Phys. Chem. Chem. Phys. 14 (2012) 2475-2482 [DOI: 10.1039/c2cp23459a]

Nanometric ionic-liquid films on silica: a joint experimental and computational study

Bovio, S.; Podesta, A.; Milani, P.; Ballone, P.; Del Popolo, M. G.: J. Phys.-Condes. Matter 21 (2009) 424118 [DOI: 10.1088/0953-8984/21/42/424118]

Related grants:

Study of the interactions of ionic liquids with surfaces of cluster-assembled nanostructured materials (Materials Science #2007.5758)

Fondazione Cariplo (from 2008-05-01 to 2011-01-31)

Study of the interfacial properties of nanostructured systems

The peculiar nanoscale morphology of cluster-assembled nanostructured materials strongly affects the interfacial properties of thin films, which typically possess high surface area.

We study the evolution of the surface morphology of cluster-assembled nanostructured materials, identifying the morphological parameters (roughness, correlation length, aspect ratio, asperity pattern,..) that most likely affect the interfacial properties of the thin films.  Simple scaling laws, such as those of the ballistic deposition regime, govern this evolution, which makes SCBD very suitable for the preparation of rough interfaces with controlled morphology.

We investigate the dependance of surface wettability, electric, mechanical (including friction and adhesion), and other interfacial properties of thin nanostructured films on nanoscale morphological parameters.

Referent: Alessandro Podestà

Participants: Francesca Borghi

Last publications show all

Cluster-assembled cubic zirconia films with tunable and stable nanoscale morphology against thermal annealing

Borghi, F.; Sogne, E.; Lenardi, C.; Podesta, A.; Merlini, M.; Ducati, C.; Milani, P.: J. Appl. Phys. 120 (2016) 055302 [DOI: 10.1063/1.4960441]

Nanomanufacturing of titania interfaces with controlled structural and functional properties by supersonic cluster beam deposition

Podesta, Alessandro; Borghi, Francesca; Indrieri, Marco; Bovio, Simone; Piazzoni, Claudio; Milani, Paolo: J. Appl. Phys. 118 (2015) 234309 [DOI: 10.1063/1.4937549]

Stretchable nanocomposite electrodes with tunable mechanical properties by supersonic cluster beam implantation in elastomers

Borghi, F.; Melis, C.; Ghisleri, C.; Podesta, A.; Ravagnan, L.; Colombo, L.; Milani, P.: Appl. Phys. Lett. 106 (2015) 121902 [DOI: 10.1063/1.4916350]