Mechanoresponsive luminescence in polymeric materials: strategies and methods
Published:09 Dec 2022
The increasing interest for stimuli-responsive materials is transversal to a variety of application fields, ranging from medicine to automotive, from packaging to aerospace. Among the several combinations of external stimuli, materials and responses, polymeric mechanochromic materials displaying significant luminescence changes upon mechanical stimulation represent smart technological products offering stability and processability, but also sensitive, non-invasive and versatile diagnosis of mechanical stress. Yet, photophysical characterization of solid polymers – that can be optically dense matrixes, intensely coloured and highly scattering – requires special care to provide reliable and reproducible results. In this contribution we critically discuss the different aspects to consider for a successful quantification of optical properties of luminescent mechanoresponsive polymers, with an overview of the instrumental setup needed. Depending on the nature of their response, materials are classified into (i) intensity and (ii) spectrum-changing systems under mechanical stimuli, and the different approaches to obtain the luminescence variation are presented together with pros and cons of any strategy. The resulting general picture of the field gives a clear taste of the disruptive potential of these materials on a variety of applications.