Showing papers by "Giancarlo Canavese published in 2018"

Unexpected behaviors in molecular transport through size-controlled nanochannels down to the ultra-nanoscale

Abstract: Ionic transport through nanofluidic systems is a problem of fundamental interest in transport physics and has broad relevance in desalination, fuel cells, batteries, filtration, and drug delivery. When the dimension of the fluidic system approaches the size of molecules in solution, fluid properties are not homogeneous and a departure in behavior is observed with respect to continuum-based theories. Here we present a systematic study of the transport of charged and neutral small molecules in an ideal nanofluidic platform with precise channels from the sub-microscale to the ultra-nanoscale (<5 nm). Surprisingly, we find that diffusive transport of nano-confined neutral molecules matches that of charged molecules, as though the former carry an effective charge. Further, approaching the ultra-nanoscale molecular diffusivities suddenly drop by up to an order of magnitude for all molecules, irrespective of their electric charge. New theoretical investigations will be required to shed light onto these intriguing results.

Zinc Oxide Nanostructures in Biomedicine

Abstract: In this chapter, we give an overview about the use of zinc oxide (ZnO) nanomaterials in the biomedical field, looking at the ongoing research and identifying the needs and improvements for future perspectives. We start describing the properties of ZnO at the nanoscale and considering the requirements to have a nanomaterial interfacing with different biological environments. We then report how synthetic approaches allow the obtainment of biocompatible ZnO nanostructures detailing the strategies to pursue their biostability and dispersibility in biological fluids. In a further step, we consider the requirements and tests used to evaluate nanomaterial hemocompatibility, focusing on the strategies for obtaining hemocompatible, yet injectable, ZnO nanoparticles. An evaluation on the mechanisms underlying the intrinsic cytotoxicity of ZnO nanomaterials is also presented taking chance of these features for the engineerization of efficient therapeutics against cancer, of antibacterial agents, and for tissue engineering solutions.

Investigation of Fatigue Behavior of ABS and PC-ABS Polymers at Different Temperatures.

Abstract: Plastics are widely used in structural components where cyclic loads may cause fatigue failure. In particular, in some applications such as in vehicles, the working temperature may change and therefore the strength of the polymeric materials. In this work, the fatigue behavior of two thermoplastic materials (ABS and PC-ABS) at different temperatures has been investigated. In particular, three temperatures have been considered representing the working condition at room temperature, at low temperature (winter conditions), and high temperature (summer conditions and/or components close to the engine). Results show that high temperature have big impact on fatigue performance, while low temperatures may also have a slight positive effect.

Multiscale measurements of piezoelectric response of hydrothermal converted BaTiO3 1D vertical arrays

Abstract: In this work, the piezoelectric properties of BaTiO3 1D vertical nanostructures were investigated with a comparison between the macroscopic and the nanometric response. The piezoelectric nanostructured carpet was obtained by the topotactic conversion of anodic TiO2 nanotubes exploiting hydrothermal treatment in Ba-enriched water solution. The nanoscale investigation by a piezoelectric force microscope returns a detailed map of ferroelectric polarization, which is preferentially confined over the vertical nanostructure axis. The scanning probe microscopy results were then coupled to the macroscopic response of the piezo-evaluation system to compare the multiscale response of the nanostructured material. Both the local and macroscopic measurement techniques provide d33 values in the range of 5.5–7 pm/V, in agreement with the values reported in the literature for other barium titanate nanostructures. The characterization of the piezoelectric response of BaTiO3 nanostructures at the nanoscale can provide useful guidelines for the next generation of Pb-free materials to be integrated into near-future nanodevices.