AMORHE – Amorphous Rheology
Responsible: Marco Zanatta (Principal Investigator)
Units: University of Trento & Sapienza University of Roma
Project: PRIN 2022 PNRR
Decarbonization is one of the most complex challenges that Mankind has to face in the near future. The main complexity arises from the variety of CO2 sources that are integral parts of our society and cannot be easily replaced. A possible solution is thus the optimisation of industrial processes to reduce their ecological footprint as well as to increase the efficiency of the so-obtained goods. When applied to materials science, this approach leaves behind the trial-and-error view and requires a deep knowledge of the physical and chemical properties of the systems of interest. As a reward, it allows the developing of tailored and specific protocols and materials, possibly disclosing new applications.
Amorphous flow is one of the many fundamental problems that should be addressed from this perspective. Glass, toothpaste, mayonnaise, foam, clay and cement are just a few examples of amorphous materials that populate everyday life. When at rest, these systems macroscopically behave like a solid, but they can flow under sufficient stress. Such complex rheological and mechanical properties have triggered an increasing number of industrial applications, but a complete, fundamental understanding of their microscopic origin is still missing. The first hurdle stems from the huge variety of possible amorphous materials. Indeed, different systems seem to have little in common but a similar liquid-like disordered structure made of different basic constituents, from atoms to micrometric particles.
Unifying factors exist, and recent works have pointed out the existence of universal features of flow and microscopic dynamics for a broad group of amorphous materials, thus promoting the idea of a universal theory of plastic deformation in amorphous solids. One of the most intriguing points is the presence of non-local rearrangements that lead to an avalanche-based description of the flow. As in catastrophic snow avalanches, small local events (avalanche seeds) couple together throughout the material and result in highly correlated collective rearrangements. Despite this suggestive analogy, conclusive pieces of evidence are lacking and the problem is still open.
A step forward to solve the problem of the amorphous flow may come from joint and coordinated use of state-of-the-art experiments and numerical simulations using machine learning methods to capture hidden structural and dynamical properties. This strategy is the basis of our proposal to tackle the amorphous rheology problem (then the acronym AMORHE). Our approach aims at pinpointing the structural and dynamical precursors that control plastic events. This might be a fundamental piece to solve this puzzling topic and, once engineered, could help to fine-tune and control the countless production processes involving amorphous materials.
LANTERN – Efficient Light Harvesting with Self-assembled Peptide Nanostructures
Responsible: Marco Zanatta (Unit coordinator)
Units: Sapienza University of Roma, University of Parma, Consiglio Nazionale delle Ricerche, University of Trento
Project: PRIN 2022
Natural organisms use protein complexes to precisely arrange the positions and orientations of highly specialised chromophores capable of harvesting light energy with very high efficiency. In this project, we plan to take a page from Nature’s book to design, optimise and realise bio-inspired materials that can be used to build sustainable light-harvesting devices for the next generation. Such an ambitious research project has fundamental and applicative objectives that can only be achieved through the combination of experiments, theory and simulations.
The starting engineered material will exploit the self-assembly propensity of the short peptide diphenylalanine (FF), conjugated with the highly efficient chromophore boron-dipyrromethane (BODIPY), with the final aim to strongly enhance the coupling and energy transfer by optimising the BODIPYs orientation through the control of the FF scaffold morphology.
During the 2-year project, we will prepare self-aggregated structures of FF-BODIPY conjugates to provide the directional organisation of BODIPY from the molecular to the mesoscopic length scale, generating a series of FF-BODIPY aggregated structures where the disposition of BODIPYs on the scaffold can be quickly verified through linear spectroscopies. The increase of BODIPYs fluorescence quantum yield on the self-assembled structure compared to the monomeric forms guarantees their optimal orientation. The promising structures will be promptly selected and characterised by X-rays and light scattering techniques for a multi-lengthscale approach, and the role of the aggregate’s morphology on the extension of energy delocalization and electronic coupling among BODIPYs will be investigated with 1D and 2D non-linear spectroscopies. The experimental data will be related to a multiscale coarse-grained numerical model which will be developed to describe the self-assembly of up to tens of thousands of molecules accessing tens of nanometer length scales and microseconds time scales.
This collaborative project will be tackled by four research units (Sapienza, UNITN, UNIPR, CNR) having specific and complementary expertise on biomolecules self-assembly and ultrafast processes, and the research will be carried out in a highly integrated and synergistic manner, involving multiple experimental and numerical methodologies.
Providing control over self-assembly on a wide range of length scales for the fabrication of light-harvesting systems will directly impact the realisation of high-quality solar photon conversion devices. Furthermore, obtaining a new kind of bio-organic multi-function system capable of efficient light-harvesting and energy transport, which is the final goal of this project, will improve the efficiency and quality of next-generation solar cells, thus lowering their cost and make it possible to scale up their global application.
