Mechanochemistry in Polymeric Materials
Mechanically responsive polymeric materials.
Biological processes, such as cell-cell contacts, cell motility or even haptic perception (touch) all rely on the conversion of mechanical stimuli into chemical energy. Building on our expertise in the field of mechano-responsive polymers, we are exploring a new family of polymeric materials that translate mechanical forces into chemical reactions. These reactions, in turn, are used to bestow polymers with unusual and previously unavailable functionalities, such as mechanical morphing, mechanically induced generation of light, mechanically controlled cell growth, auto-lubricating behavior, and the ability to release small molecules such as drugs, fragrances and antiseptics.
Current research efforts include the design of new mechanically responsive motifs or “mechanophores”, the development of a predictive understanding for the relationships between the connectivity of such mechanophores with a matrix polymer, the morphology and mechanical properties of the system, and the mechanoresponse. Several mechanophores that rely on either homolytic (radical formation) or heterolytic cleavage of covalent bonds are being studied in this context. In parallel, non-covalent mechanophores based on excimer-forming dyes, cavitands, and supramolecular motifs such as metal-ligand complexes are being developed.
Selected research examples
Metal-ligand complexes are particularly promising for mechanochemical active systems as they offer a great opportunity to control the strength of the complex through the metal-ligand interaction. Recent results (J. Am. Chem. Soc. 2014, 136, 10493) showed that these metal-ligand complexes are mechanoresponsive in both solution as well as in the solid state. Currently, the details of these materials are under investigation on different length scales, ranging from the single-molecule level to macroscopic polymer films.
Hydrogen-bonding supramolecular binding motifs can be readily employed to derivatized dyes that display mechanoresponsive luminescent behavior. While hundreds of such dyes are known (Adv. Mater. 2016, 28, 1073), they generally do not display any useful mechanical properties. We have demonstrated that this can be overcome by introducing self-complementary hydrogen-bonding groups to promote the self-assembly of an excimer-forming cyano-substituted oligo(p-phenylene vinylene) derivative into a supramolecular polymer (J. Am. Chem. Soc., 2017, 139, 4302).
Novel covalent mechanophores are explored to prepare polymers that yield a tangible optical response to a mechanical stimulus. In particular, we focus on self-reporting materials that display a mechanically-triggered change of the fluorescence emission properties.
- Related publications
Mechanochemistry with Metallosupramolecular Polymers
Balkenende Diederik W. R., Coulibaly Souleymane, Balog Sandor, Simon Yoan C., Fiore Gina L., Weder Christoph
Journal of the American Chemical Society (2014)Mechanoresponsive Luminescence: Mechanoresponsive Luminescent Molecular Assemblies: An Emerging Class of Materials (Adv. Mater. 6/2016)
Sagara Yoshimitsu, Yamane Shogo, Mitani Masato, Weder Christoph, Kato Takashi
Advanced Materials (2016)Mechano- and Thermoresponsive Photoluminescent Supramolecular Polymer
Lavrenova Anna, Balkenende Diederik W. R., Sagara Yoshimitsu, Schrettl Stephen, Simon Yoan C., Weder Christoph
Journal of the American Chemical Society (2017)Self-Calibrating Mechanochromic Fluorescent Polymers Based on Encapsulated Excimer-Forming Dyes
Calvino Céline, Guha Anirvan, Weder Christoph, Schrettl Stephen
Advanced Materials (2018)Rotaxanes as Mechanochromic Fluorescent Force Transducers in Polymers
Sagara Yoshimitsu, Karman Marc, Verde-Sesto Ester, Matsuo Kazuya, Kim Yuna, Tamaoki Nobuyuki, Weder Christoph
Journal of the American Chemical Society (2018)Mechanochemical Fluorescence Switching in Polymers Containing Dithiomaleimide Moieties
Karman Marc, Verde-Sesto Ester, Weder Christoph, Simon Yoan C.
ACS Macro Letters (2018)Mechanoresponsive, Luminescent Polymer Blends Based on an Excimer-Forming Telechelic Macromolecule
Calvino Céline, Sagara Yoshimitsu, Buclin Véronique, Haehnel Alexander P., del Prado Anselmo, Aeby Christian, Simon Yoan C., Schrettl Stephen, Weder Christoph
Macromolecular Rapid Communications (2018)Rotaxane-Based Mechanophores Enable Polymers with Mechanically Switchable White Photoluminescence
Sagara Yoshimitsu, Karman Marc, Seki Atsushi, Pannipara Mehboobali, Tamaoki Nobuyuki, Weder Christoph
ACS Central Science (2019)Preparation of metallosupramolecular single-chain polymeric nanoparticles and their characterization by Taylor dispersion
Neumann Laura N., Urban Dominic A., Lemal Philipp, Ramani Sushila, Petri-Fink Alke, Balog Sandor, Weder Christoph, Schrettl Stephen
Polymer Chemistry (2020)Mechanochromic Polymers Based on Microencapsulated Solvatochromic Dyes
Calvino Céline, Henriet Emma, Muff Livius F., Schrettl Stephen, Weder Christoph
Macromolecular Rapid Communications (2020)
- Related projects
Projects of SCHRETTL Stephen
Projects of WEDER Christoph