Implementation of advanced Atomic Force Microscopy (AFM) techniques for the mechanical characterization of biological samples
Thesis type EXPERIMENTAL/MODELLING
Description We are looking for candidates for master theses within the European FET OPEN Project “BOHEME” = Bio-Inspired Hierarchical MetaMaterials.
BOHEME starts from an innovative assumption, increasingly supported by experimental evidence, that the working principle behind metamaterials (a class of materials exhibiting exotic vibrational properties) is already exploited in Nature, and that through evolution, this has given rise to optimized designs for impact damping. The “fundamental science” part of the project aims to explore biological structural materials for evidence of this, to investigate novel optimized bioinspired designs (e.g., porous hierarchical structures spanning various length scales) using state-of-the-art analytical and numerical approaches, to design and manufacture vibrationally effective structures, and to experimentally verify their performance over wide frequency ranges.
Proposal: experimental thesis (with the possibility of performing also finite-elements simulations).
The candidate will implement an advanced Scanning Probe Technique on the departmental Atomic Force Microscopy (AFM) Innova, by Bruker, namely the Contact Resonance AFM (CR-AFM) technique. CR-AFM allows to characterize the mechanical properties of the samples at the nanoscale, including viscoelastic properties, by means of suitable models. The technique will be validated on some test samples by acquiring maps i) of the resonance frequency and ii) of the resonance amplitude of the tip-sample mechanical contact, iii) of the storage modulus and iv) of the loss modulus. Subsequently, it will be applied to biological samples like the woodpecker beak and some seashells, already available in our lab.
The main task of this thesis will be i) to control, by means of LabVIEW or Matlab, the electronic instruments outside the AFM (waveform generator, lock-in amplifier, oscilloscope) and perform the frequency sweeps by using a piezoelectric transducer mounted below the sample, ii) to obtain, from the acquired signals, the resonance frequency peaks (frequency and amplitude) and iii) to synchronize the obtained information with that coming from the inside the electronic controller of the AFM (related to the surface topography), in order to produce maps of the extracted quantities. Additionally, finite-elements simulations can be done to quantitatively determine the above-mentioned quantities.
Deadline 25/01/2023 PROPONI LA TUA CANDIDATURA