Research database

The main goal of STIGMA is the development of piezochromic smart coatings, constituted by mechanoluminochromic Cu-based Hybrid Coordination Polymers (HCPs) dispersed in a polymer binder. The coatings will be able to sense both continuous compressive forces and impacts, showing a detectable change of optical properties. HCPs have never been studied as mechanochromic additives for smart polymer coatings, therefore the coatings herein developed are completely novel, and open a broad range of possibilities emerging from the chemical versatility and variety of HCPs. Indeed, depending on the types of HCP and binder, the coating responsiveness may be modulated in terms of range of forces, change of emission, stability or reversibility of the response, thus potentially opening a broad field of fundamental and applied research. Coatings are at the forefront of industrial innovation in applications ranging from civil and transportation security to health. Our smart coatings will diagnose mechanical stresses through a simple and reliable method that correlate their optical changes (i.e., light emission) with the stress. Piezochromic coatings applied on structural components will contribute to reduce materials’ maintenance costs and inspection times and to prevent catastrophic failures, with a strong improvement in infrastructure and transportation security. Moreover, piezochromic coatings represent a Key Enabling Technology to sense pressures and stresses that can assist material processing and manufacturing, thus improving efficiency in material life cycle by minimizing resource use and waste production. Piezochromic coatings may be applied also in medicine, both as diagnostic and rehabilitation tools, with a direct impact on human wellbeing. The main objective will be pursued by achieving the following sub-objectives, and the research activity is implemented in 4 Work Packages (WP), accordingly: WP1) SYNTHESIS: produce mechanoluminochromic additives with controlled crystal structure and morphology by applying a green and scalable synthetic approach; WP2) FORMULATION: prepare stable and homogeneous waterborne formulations of HCPs and polymers for functional coatings; WP3) CHARACTERIZATION: understand the interplay between microstructure of HCPs and their mechanoluminochromism in the polymer matrix, and correlate the mechanical force with the change of optical signal; WP4) MODELLING: understand the atomistic mechanisms governing the mechanoluminochromic properties via first-principles simulations. The smart piezochromic coatings will be pursued by the synergic and collective efforts of the two Research Units involved in the project: UNIBO, that merges the competences of inorganic chemistry, photochemistry and computational chemistry, and POLITO, that brings the expertise in coating formulation, fabrication and characterization.