Antonella Esposito

Amorphous glasses are formed by rapid cooling of the melt to avoid crystallization. The vitrification temperature increases with increasing the cooling rate. The viscosity of the supercooled melt and the vitrification are related to the atomic or molecular mobility, which in turn is linked to the dynamic heterogeneities and the size of cooperative rearrangement regions (CRR). The temperature dependence of the average correlation length of the CRR, ξ, for organic compounds, polymers, chalcogenide glass formers and metallic glass formers with a fragility index m ≥ 40 was investigated. The results show an almost material-independent variation of ξ as a function of the reduced reciprocal temperature T_g/T, where T_g is the glass transition temperature. This suggests that ξ(T_g/T) is a universal function for all the investigated glass formers. It was also found that ξ and the activation energy of the α-relaxation are proportional to each other. Furthermore, relations between the macroscopic parameters of the glass-forming kinetics were identified.

Tissue regeneration can be achieved by providing endogenous cells with a biomaterial scaffold that supports their adhesion and proliferation, as well as the synthesis and deposition of an extracellular matrix (ECM). In this work, silk fibroin protein foams were formed by lyophilization to generate tissue engineering scaffolds. Three types of medically relevant nanoparticles (NPs) (iron oxide, gold and silver) were added to this biomaterial to assess the ability of silk foams to be functionalized with these NPs. The structural and mechanical properties of the foams with and without the NPs were suitable for tissue support. The in vitro cytocompatibility of the scaffolds was confirmed according to the ISO 10993 guidelines. The biocompatibility of the scaffolds was investigated by assessing inflammation and endogenous cell colonization in a mouse subcutaneous model These in vivo experiments demonstrated a loss of acute inflammation and the absence of chronic inflammation in the grafted animals. The obtained results show that silk foams are good candidates for supporting soft tissue regeneration with the additional possibility of functionalization with NPs.

This review represents an overview of the status quo of the furan-based monomers and related bio-based polymers, highlighting key challenges for scaling from lab to pre-industrial levels.

The kinetics of the glass transition and the characteristic size of the fluctuating spatio-temporal domains in supercooled glass-forming liquids, i.e., the Cooperatively Rearranging Regions (CRR), were measured upon cooling over a broad range of cooling rates using Differential Scanning Calorimetry (DSC) and chip-based Fast Scanning Calorimetry (FSC). The investigations were conducted on a selection of fragile glass formers (fragility indices between 80 and 140), with a large variance in the atomic or molecular structure but comparable thermal glass transition temperatures T_g, with the aim of evaluating the influence of chemical composition and structure on the CRR size and the associated temperature fluctuation. The selected materials are two polymers (poly(vinyl acetate) (PVAc), poly(lactic acid) (PLA)) as well as the simplest chalcogenide glass-former (selenium). It turned out that the CRR size plotted against the reduced temperature T/T_g follows the same trend, irrespective of the considered glass-former.