Materials with highly ordered molecular arrangements have the capacity to display unique properties derived from their nanoscale structure. Here, the synthesis and characterization of azobenzene (AZO)‐functionalized siloxane oligomers of discrete length that form photoswitchable supramolecular materials are described. Specifically, synergy between phase segregation and azobenzene crystallization leads to the self‐assembly of an exfoliated 2D crystal that becomes isotropic upon photoisomerization with UV light. Consequently, the material undergoes a rapid athermal solid‐to‐liquid transition which can be reversed using blue light due to the unexpectedly fast 2D crystallization that is facilitated by phase segregation. In contrast, enabling telechelic supramolecular polymerization through hydrogen bonding inhibits azobenzene crystallization, and nanostructured pastes with well‐ordered morphologies are obtained based on phase segregation alone, thus demonstrating block copolymer‐like behavior. Therefore, by tailoring the balance of self‐assembly forces in the azobenzene‐functionalized siloxane oligomers, fast and reversible phase‐changing materials can be engineered with various mechanical properties for applications in photolithography or switchable adhesion to lubricant properties.

Devising energy‐efficient strategies for the depolymerization of plastics and the recovery of their structural components in high yield and purity is key to a circular plastics economy. Here, we report a case study in which we demonstrate that vinylogous urethane (VU) vitrimers synthesized from bis‐polyethylene glycol acetoacetates (aPEG) and tris(2‐aminoethyl)amine can be degraded by water at moderate temperature with almost quantitative recovery (≈98 %) of aPEG. The rate of depolymerization can be controlled by the temperature, amount of water, molecular weight of aPEG, and composition of the starting material. These last two parameters also allow one to tailor the mechanical properties of the final materials, and this was used to access soft, tough, and brittle vitrimers, respectively. The straightforward preparation and depolymerization of the aPEG‐based VU vitrimers are interesting elements for the design of polymer materials with enhanced closed‐loop recycling characteristics.

This work deals with the use of 2-cyano-2-arylpropanoic acids as chemical fuels for an acid–base operated molecular switch that consists of a Sauvage-type catenand composed of two identical macrocycles incorporating a phenanthroline unit. When used as a base promoter of the decarboxylation of propanoic acid derivatives, the switch undergoes large amplitude motion from the neutral catenand to a protonated catenate and back again to the neutral state. The rate of back proton transfer, which determines the rate of the overall process, was markedly affected by para-substituents in the order Cl > H > CH₃ > OCH₃ (ρ = +5.2). Thus, the time required to complete a full cycle was almost two days for the OCH₃ derivative and dropped to a few minutes for the Cl derivative. These results show for the first time that the rate of operation of a molecular switch can be regulated by variations in the fuel structure.

We report off-white circularly polarized luminescence (CPL) from supramolecular aggregates formed by a chiral carboxylic acid-functionalized naphthalene diimide. The self-assembly behaviour and the stability of the aggregates in solution were assessed by variable-temperature UV-Vis and electronic circular dichroism experiments. The observed 200 nm-wide emission band is unusual for a single chromophore and is a consequence of the supramolecular ordering due to a combination of π-stacking and H-bonding interactions, leading to excimer formation. High emission anisotropy factors g_lum, around |1–2| × 10⁻², were observed over the whole spectrum in chlorinated/hydrocarbon solvent mixtures, as well as in thin films. These values are one order of magnitude higher than those of most chiral self-assembled fluorophores and other common small organic emitters.