Solvent Mixing To Induce Molecular Motor Aggregation into Bowl-Shaped Particles: Underlying Mechanism, Particle Nature, and Application To Control Motor Behavior Linda E. Franken Yuchen Wei Jiawen Chen Egbert J. Boekema Depeng Zhao Marc C. A. Stuart Ben L. Feringa 10.1021/jacs.8b03045.s001 https://acs.figshare.com/articles/journal_contribution/Solvent_Mixing_To_Induce_Molecular_Motor_Aggregation_into_Bowl-Shaped_Particles_Underlying_Mechanism_Particle_Nature_and_Application_To_Control_Motor_Behavior/6591539 Control over dynamic functions in larger assemblies is key to many molecular systems, ranging from responsive materials to molecular machines. Here we report a molecular motor that forms bowl-shaped particles in water and how confinement of the molecular motor affects rotary motion. Studying the aggregation process in a broader context, we provide evidence that, in the case of bowl-shaped particles, the structures are not the product of self-assembly, but a direct result of the mixing a good solvent and a (partial) non-solvent and highly independent of the molecular design. Under the influence of the non-solvent, droplets are formed, of which the exterior is hardened due to the increase in the glass transition temperature by the external medium, while the interior of the droplets remains plasticized by the solvent, resulting in the formation of stable bowl-shaped particles with a fluid interior, a glass-like exterior, and a very specific shape: dense spheres with a hole in their side. Applying this to a bulky first-generation molecular motor allowed us to change its isomerization behavior. Furthermore, the motor shows <i>in situ</i> photo-switchable aggregation-induced emission. Strong confinement prohibits the thermal helix inversion step while altering the energy barriers that determine the rotary motion, such that it introduces a reverse <i>trans</i>–<i>cis</i> isomerization upon heating. These studies show a remarkable control of forward and backward rotary motion by simply changing solvent ratios and extent of confinement. 2018-06-07 00:00:00 Particle Nature non-solvent Solvent Mixing helix inversion step Strong confinement Control Motor Behavior Control isomerization behavior motor glass transition temperature Bowl-Shaped Particles studies show droplets energy barriers photo-switchable aggregation-induced emission aggregation process Induce Molecular Motor Aggregation