Artificial light-switchable polymers are raising a wide interest in the soft material market for their tunable properties upon light-irradiation. This particular feature makes them very suitable and versatile frameworks spanning applications from organic electronics towards in cell imaging devices. Atomistic simulations combined with free-energy predictions have successfully achieved a quantitative structural and energetic level of theory, allowing an improved and bespoke design of self-assembling polymers with tunable properties and functions. In these regards, enhanced sampling free-energy simulations based on well-tempered metadynamics disclosed the mechanism of the screw-sense switching in racemic fluorene-based polymers. Those polymers acquire a dichroic signal through circularly polarized light irradiation owing to a stepwise rotation of the fluorene-fluorene dihedrals. The simulations predicted before the experiments were carried out that the polymer can cycle from chiral to racemic states only when deposited on amorphous silica surface. The UV and ECD spectra calculated at the TD-DFT level reproduce the experimental spectra and indicate that the polymers switch the screw-sense forming 51 helixes. Solid substrate surface may facilitate the achiral-to-chiral transition as an inert supramolecular scaffold.

Free-energy predictions of self-assembling polymers through nanoscale simulations

256th National Meeting (2018)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.