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Université de Fribourg

Mechanoresponsive Luminescent Molecular Assemblies : An Emerging Class of Materials

Sagara, Yoshimitsu ; Yamane, Shogo ; Mitani, Masato ; Weder, Christoph ; Kato, Takashi

In: Advanced Materials, 2015, vol. 28, no. 6, p. 1073-1095

The possibility to change the molecular assembled structures of organic and organometallic materials through mechanical stimulation is emerging as a general and powerful concept for the design of functional materials. In particular, the photophysical properties such as photoluminescence color, quantum yield, and emission lifetime of organic and organometallic fluorophores can significantly...

Université de Fribourg

Mechanochemistry in polymers with supramolecular mechanophores

Haehnel, Alexander P. ; Sagara, Yoshimitsu ; Simon, Yoan C. ; Weder, Christoph

In: Topics in current chemistry, 2015, vol. 369, p. 345-375

Mechanochemistry is a burgeoning field of materials science. Inspired by nature, many scientists have looked at different ways to introduce weak bonds into polymeric materials to impart them with function and in particular mechano-responsiveness. In the following sections, the incorporation of some of the weakest bonds, i.e. non- covalent bonds, into polymeric solids is being surveyed. This...

Université de Fribourg

Healable Supramolecular Polymer Solids

Montero de Espinosa, Lucas ; Fiore, Gina L. ; Weder, Christoph ; Foster, E. Johan ; Simon, Yoan C.

In: Progress in Polymer Science, 2015, vol. 49-50, p. 60-78

The reversible nature of non-covalent interactions between constituting building blocks permits one to temporarily disassemble supramolecular polymers through the application of an appropriate external stimulus “on command”. This framework has recently emerged as a general design strategy for the development of healable polymer systems. The approach exploits that the temporary disassembly...

Université de Fribourg

Synthesis of poly(sulfonate ester)s by ADMET polymerization

Parkhurst, Rebecca R. ; Balog, Sandor ; Weder, Christoph ; Simon, Yoan C.

In: RSC Advances, 2014, vol. 4, p. 53967-53974

Many hydrocarbon polymers containing heteroatom defects in the main chain have been investigated as degradable polyethylene-like materials, including aliphatic polyesters. Here, acyclic diene metathesis (ADMET) polymerization was used for the synthesis of aliphatic poly(sulfonate ester)s. The requisite sulfonate ester containing α,ω-diene monomers with varying numbers of methylene groups...

Université de Fribourg

Mechanochemistry with Metallosupramolecular Polymers

Balkenende, Diederik W. R. ; Coulibaly, Souleymane ; Balog, Sandor ; Simon, Yoan C. ; Fiore, Gina L. ; Weder, Christoph

In: Journal of the American Chemical Society, 2014, vol. 136, no. 29, p. 10493-10498

The transduction of mechanical force into useful chemical reactions is an emerging design approach to impart soft materials with new functions. Here, we report that mechanochemical transductions can be achieved in metallo-supramolecular polymers. We show that both reversible and irreversible reactions are possible and useful to create me-chanically responsive materials that display new...

Université de Fribourg

The role of mass and length in the sonochemistry of polymers

Schaefer, Mark ; Icli, Burcak ; Weder, Christoph ; Lattuada, Marco ; Kilbinger, Andreas F. M. ; Simon, Yoan C.

In: Macromolecules, 2016, vol. 49, no. 5, p. 1630–1636

The ultrasound-induced cleavage of macromolecules has become a routine experiment in the emerging field of polymer mechanochemistry. To date, it has not been conclusively proven whether the molecular weight of a polymer or its contour length is the determining factor for chain scission upon ultrasonication. Here we report comparative experiments that confirm unequivocally that the contour length...

Université de Fribourg

A Thermo‐ and mechanoresponsive cyano‐substituted oligo(p‐phenylene vinylene) derivative with five emissive states

Sagara, Yoshimitsu ; Lavrenova, Anna ; Crochet, Aurélien ; Simon, Yoan C. ; Fromm, Katharina M. ; Weder, Christoph

In: Chemistry - A European Journal, 2016, vol. 22, no. 13, p. 4374–4378

Multiresponsive materials that display predefined photoluminescence color changes upon exposure to different stimuli are attractive candidates for advanced sensing schemes. Herein, we report a cyano-substituted oligo(p-phenylene vinylene) (cyano-OPV) derivative that forms five different solvent-free solid-state molecular assemblies, luminescence properties of which change upon thermal and...

Université de Fribourg

Visualization of polymer deformation using microcapsules filled with charge-transfer complex precursors

Lavrenova, Anna ; Farkas, Jacob ; Weder, Christoph ; Simon, Yoan C.

In: ACS Appl. Mater. Interfaces, 2015, vol. 7, no. 39, p. 21828–21834

The visualization of polymer deformation using microcapsules filled with charge- transfer complex precursors is reported. Poly(urea-formaldehyde) microcapsules filled with toluene and either hexamethylbenzene as donor or chloranil as acceptor were prepared by in situ polymerization of an oil-in-water emulsion. The resulting microcapsules were incorporated in a poly(dimethylsiloxane) matrix by...