In recent years, polymer mechanochemistry has evolved as a methodology to provide insights into the action‐reaction relationships of polymers and polymer‐based materials and composites in terms of macroscopic force application (stress) and subsequent deformation (strain) through a mechanophore‐assisted coupling of mechanical and chemical phenomena. The perplexity of the process, however, from the viewpoint of mechanophore activation via a molecular‐scaled disruption of the structure that yields a macroscopically detectable optical signal, renders this otherwise rapidly evolving field challenging. Motivated by this, we highlight here recent advancements of polymer mechanochemistry with particular focus on the establishment of methodologies for the efficient activation and quantification of mechanophores and anticipate to aptly pinpoint unresolved matters and limitations of the respective approaches, thus highlighting possible developments.

Employing mechanofluorophores in polymer fractography to obtain new information on force-induced events when analyzed by confocal laser scanning microscopy.

The fracture of polymer materials is am ultiscale process starting with the scission of as ingle molecular bond advancing to as ite of failure within the bulk. Quantifying the bonds broken during this process remains ab ig challenge yet would help to understand the distribution and dissipation of macroscopic mechanical energy.W ehere showthe design and synthesis of fluorogenic molecular optical force probes (mechanofluorophores) covering the entire visible spectrum in both absorption and emission. Their dual fluorescent character allows to tracknon-broken and broken bonds in dissolved and bulk polymers by fluorescence spectroscopya nd microscopy. Importantly,wedevelop an approach to determine the absolute number and relative fraction of intact and cleaved bonds with high local resolution. We anticipate that our mechanofluorophores in combination with our quantification methodology will allowt oq uantitatively describe fracture processes in materials ranging from soft hydrogels to high-performance polymers.

The correlation of mechanical properties of polymer materials with those of their molecular constituents is the foundation for their holistic comprehension and eventually for improved material designs and syntheses. Over the last decade, optical force probes (OFPs) were developed, shedding light on various unique mechanical behaviors of materials. The properties of polymers are diverse, ranging from soft hydrogels to ultra-tough composites, from purely elastic rubbers to viscous colloidal solutions, and from transparent glasses to super black dyed coatings. Only very recently, researchers started to develop tailored OFP solutions that account for such material requirements in energy (both light and force), in time, and in their spatially detectable resolution. We here highlight notable recent examples and identify future challenges in this emergent field.