Lazzari

Our research concerns material science and technology and macromolecular chemistry, with a special attention on the fabrication of nanomaterials mainly by means of a self-assembly bottom-up approximation but also trying to force the limits of top-down strategies.

We are focusing broadly on different aspects ranging from the self-assembling of different “building units” such as block copolymers and metal nanoparticles to the study of basic aspects polymer synthesis, through a more general interest for their potential use for specific application.

Actually we are dedicated to the realization of such vision through the studies focusing on:

• material science for cultural heritage;
• block copolymers.

Block copolymers

Polymers and especially block copolymers (BCs) are an excellent tool for the preparation of nanostructured materials and more specifically for the controlled fabrication of functional nanocomposite materials. BCs may be defined as two or more chemically homogeneous polymeric fragments, i.e. homopolymeric chains, joined together by covalent bonds to form diverse and complex linear and non-linear architectures. In the frequent case of immiscibility among the constituent polymers, the competing thermodynamic effects give rise to different types of self-assembled morphologies depending on composition, segmental interaction and molecular weights, and having periodicity in the nanoscale (as those shown in the SEM or TEM images, corresponding to cylindrical morphology in thin films or micellar aggregates with different shapes).

As an example of applications, we are using low molecular weight PAN-based BCs synthesyzed by ATRP as precursors for the fabrication of hierarchically porous activated carbons with controlled N- and S-functionalities to maximize CO₂, metallic cations and organic pollutants adsorption capacity. Controlled pyrolysis of PAN provides a partially graphitic carbon with pyridinic, pyridine oxide, pyrrolic and pyridine (N-containing) species, whereas self-assembly of the BC forms the nanostructured interpenetrating network, where the sacrificial block constituent (i.e. easily degradable PMMA) leaves nanopores upon complete volatilization.

Replica moulding of sub-100 nm features such as those produced by self-assembling of BCs is the subject of another research line focused on the development of scalable nanotechnology methods for the fabrication of optical and optoelectronic devices through a cost-effective procedures.

Different elastomeric micro and nanostructures based on a UV-curable multifunctional urethane methacrylate perfluoropolyether could be generated either by UV-lithography from integrated microlenses or replica molding of different optical components, such as diffraction gratings, waveguides and photonic crystals.

The fine-tuning of such fast replication methodology without applying pressure or thermal treatments is actually in progress, aiming to demonstrate the efficiency of this polymer to reproduce not only micro and over 100 nm features with large aspect ratios, but also smaller features down to those available by BC assembling.

Material science for cultural heritage

Nanotechnology for Cultural Heritage protection

We have been recently involved in an European Commission – Horizon 2020 project, focused on “NANOmaterials for the REStoration of works of ART” (NANORESTART).

Contemporary art is a major challenge for conservators since there is a significant lack of established conservation methodologies that can safely tackle the often extremely fast degradation of materials used by contemporary artists. It may be said that many current modern and contemporary works of art will probably not be accessible to visitors/users in a hundred years due to rapid degradation, as they degrade beyond restoration.

The NANORESTART project focused on the synthesis of novel poly-functional nanomaterials and on the development of highly innovative restoration techniques to address the conservation of a wide variety of materials mainly used by modern and contemporary artists. In NANORESTART, enterprises and academic centers of excellence in the field of synthesis and characterization of nano- and advanced materials have joined forces with complementary conservation institutions and freelance restorers. This multidisciplinary approach covered the development of different materials in response to real conservation needs, the testing of such materials, the assessment of their environmental impact, and their industrial scalability.

In particular, our contribution within the Project concerns the following aspects:

• Active protection of plastics and other organic substrates is pursued using radical scavengers based on metal clusters supported by metal nanoparticles, with the purpose to protect these surfaces from radical oxidation.
• Development of Surface-Enhanced Raman Scattering spectroscopy (SERS)-active substrates with modulable surface polarity for the detection of art materials and degradation products, prepared by soft-lithography.

Durability of plastic-made artworks

Our group is also involved in the study of the durability of Contemporary Artworks. This more traditional application of material science for the safeguard of cultural heritage is related with the fact that objects partially or completely made of plastics may be found in almost all international collections devoted to science and technology, modern history, design and fine arts, and their proportion is likely to increase with time, as museums continue to collect materials which reflect modern life and contemporary cultural heritage. On the other hand, polymers, owing to their intrinsic nature, are much more prone to chemical reactions than most traditional materials and concerns about the longevity of plastics are well established. Plastic objects may often have to face serious problems of either physical or chemical ageing even in much protected indoor environments, at relatively low temperature, such as those typically found in museums during display and storage.

Although plastics either as objects in their own right or as components of composite materials are present in different types of collections, especially the durability of important pieces of modern and contemporary art is of particular interest.

In the framework of a comprehensive project aimed to develop a multi-analytical approach for evaluating the degradability of polymeric materials in contemporary works of art, we are focusing our efforts on the evaluation of the actual state of conservation and the prediction of the long term stability of contemporary artworks.