Friday Materials Science Colloquia (#8)


Friday, May 5th  2023, 12 p.m., Seminar room, U5 Building – via Roberto Cozzi 55, Milano.

Lecturer: Dott. Jacopo Perego

Title:  Nanoporous Architectures: porous organic polymers and metal-organic frameworks designed for fast dynamics, gas sorption and detection

Abstract. The assembly by design of suitable molecular building blocks produces Porous Organic Polymers (POPs) and Metal-Organic Frameworks (MOFs) architectures endowed with large free volume and accessible surface area. The rich and versatile chemistry of the building blocks and the strict control over framework topology and pore geometry boost the development of tailored materials for selective gas sorption and release, separation of gas mixtures and photonic applications. Nanoporous materials with molecular-sized pores are promising candidates for the development of sorbent materials for low-energy-demanding gas selective capture and separation processes and high pressure adsorbed gas storage. High surface area functionalized POPs and MOFs with high thermal and chemical stability were explored as selective sorbent for CO2 molecules using adsorption isotherms measurements, direct evaluation of CO2 adsorption enthalpy by in-situ adsorption-coupled microcalorimetry and gas mixture separation under continuous flow conditions (breakthrough experiments) coupled with modeling of CO2-host interactions to provide useful insights towards the development of highly porous sorbent for effective CO2 separation with low energy regeneration process. Nanoporous materials provide a stable platform for the development of smart materials endowed with fast dynamics and stimuli-responsive properties. Isolated bicyclo[1.1.1] pentane (BCP) molecular rotors were assembled in a Zn-based MOF with cubic crystal structure. The rotors experience fast molecular reorientation even at temperature below 2 K, with a negligible activation barrier as low as 6 cal mol-1 resulting from the symmetry mismatch between the tri-fold geometry of the rotor and the four-fold symmetry imposed by the frameworks.[1] Moreover, the integration of molecular motors with active dynamical behavior allowed the generation of POPs with on command responsive properties. Indeed, light-responsive nanosponges with BET surface area as high as 3950 m2 g-1 were engineered by copolymerization of an overcrowded alkene photoswitch and a rigid tetrahedral building block.[2] Upon light irradiation, the quantitative molecular photoisomerization induces modulation of the total adsorption capacity of about 20%, generating light-responsive materials suitable for on-command switching devices. The modular approach to MOF materials allowed the precise assembly of inorganic and organic building blocks at nanometric distances promoting the formation of mixed-ligand innovative photonic materials which display fast scintillation and large Stokes shift emission.[3] The high gas uptake and efficient scintillation properties of hafnium MOF, based on highly luminescent diphenyl anthracene (DPA) ligand, stimulate the development of an innovative solid-state radioactive gas detector.[4] Hf-DPA MOF displays high porosity (SBET = 2550 m2 g-1), fast and reversible adsorption of noble gases and high photoluminescence and scintillating properties. After exposure to radioactive gases, Hf-DPA displays fast and bright scintillation emission sensitized by the decay of the radioactive nuclei that allows for their effective detection at ultra-low concentrations. Indeed, 85Kr isotope was detected even at activity as low as 0.3 kBq⋅m3, below the minimum value declared for commercial devices, strongly supporting the development of MOF-based scintillators for radioactive gas detection.



[1] J. Perego, et al., Nature Chemistry, 12, 845 - 851 (2020).

[2] F. Castiglioni, et al., Nature Chemistry, 12, 595 - 602 (2020).

[3] J. Perego, et al., Nature Communications, 13, 3504 (2022).

[4] M. Orfano, J. Perego et al., Nature Photonics, in press



Lecturer: Dott.ssa Irene Villa

Title: Luminescent and scintillating nanomaterials for imaging, diagnostic, and therapy

Abstract. Luminescent and scintillating nanomaterials offers the great advantage of the tunability of their physico-chemical properties and of their emission features through the control of their structure, morphology, and doping. The scientific community is continuously drawing up novel surface engineering/doping and materials design approaches to obtain the best nanomaterial to satisfy the more and more demanding requirements of most advanced applications in photonics, in detection of ionizing radiation, and in theranostics. In this context, I propose an excursus on the results obtained from diverse luminescent and scintillating nanomaterials. Starting from rare earth ions doped and undoped inorganic scintillating nanoparticles (HfO2) [1] to the development of brand-new hybrid and composite nanoscintillators [2], I will show a systematic approach to adapt the nanomaterials qualities according to the targeted application. Especially, I will present the exploitation of luminescent and scintillating nanomaterials with ad-hoc features for in vitro/in vivo imaging and for radiotherapeutic protocols [3]. Lastly, I will show how the use of hybrid and composite nanoscintillators with fast timing qualities represents a potential breakthrough in medical diagnostics for the requirements for early-stage cancer diagnostic [4-5].



[1] I. Villa, et al., Nanoscale 10, 7933–7940 (2018)

[2] M. Gandini et al. Nat. Nanotechnol. 15, 462–468 (2020).

[3] I. Villa, et al., ACS Appl. Mater. Interfaces 13, 11, 12997–13008 (2021)

[4] J. Perego, et al., Nat. Photonics 15, 393–400 (2021).

[5] J. Perego, et al., Nature communications 13.1, 3504 (2022)