Nature regulates complex structures in space and time via feedback loops, kinetically controlled transformations, and under energy dissipation to allow non-equilibrium processes. Although man-made static self-assemblies realize excellent control over hierarchical structures via molecular programming, managing their temporal destiny by self-regulation is a largely unsolved challenge. Herein, we introduce a generic concept to control the time domain by programming the lifetimes of switchable self-assemblies in closed systems. We conceive dormant deactivators that, in combination with fast promoters, enable a unique kinetic balance to establish an autonomously self-regulating, transient pH-state, whose duration can be programmed over orders of magnitude-from minutes to days. Coupling this non-equilibrium state to pH-switchable self-assemblies allows predicting their assembly/disassembly fate in time, similar to a precise self-destruction mechanism. We demonstrate a platform approach by programming self-assembly lifetimes of block copolymers, nanoparticles, and peptides, enabling dynamic materials with a self-regulation functionality.

We synthesize heterofluorene monomers with Si, Ge, N, As, Se, and Te occupying the 9-position of the fluorene motif, which are then polymerized by Suzuki coupling. The optical properties of the obtained polymers are investigated in their solid state. We compare and elucidate effects in the materials absorption, emission, quantum yield (Φ), and fluorescence lifetime. Moreover, we determine the refractive indices n and absorption coefficient k by variable angle spectroscopic ellipsometry (VASE). We show that in addition to already known C, Si, and N containing polyfluorenes also Ge and As containing polymers exhibit amplified spontaneous emission.

Photoresponsive polymers can be conveniently used to fabricate anti‐counterfeiting materials through photopatterning. However, an unsolved problem is that ambient light and heat can damage anti‐counterfeiting patterns on photoresponsive polymers. Herein, photo‐ and thermostable anti‐counterfeiting materials are developed by photopatterning and thermal annealing of a photoresponsive conjugated polymer (MC‐Azo). MC‐Azo contains alternating azobenzene and fluorene units in the polymer backbone. To prepare an anti‐counterfeiting material, an MC‐Azo film is irradiated with polarized blue light through a photomask, and then thermally annealed under the pressure of a photonic stamp. This strategy generates a highly secure anti‐counterfeiting material with dual patterns, which is stable to sunlight and heat over 200 °C. A key for the stability is that thermal annealing promotes interchain stacking, which converts photoresponsive MC‐Azo to a photostable material. Another key for the stability is that the conjugated structure endows MC‐Azo with desirable thermal properties. This study shows that the design of photopatternable conjugated polymers with thermal‐annealing‐promoted interchain stacking provides a new strategy for the development of highly stable and secure anti‐counterfeiting materials.

Tuning the resonator quality is a long established technique for inorganic lasers giving access to extremely short or temporally precise laser pulses. However, this so-called q-switching, where the resonator can be "on" and sustain lasing or be switched "off" and inhibit lasing is widely unknown for conjugated polymer lasers. Here, we admix thermally stable photochromic dithienylethenes with conjugated polymer laser gain materials on 1D and 2D diffractive feedback gratings, which are generated by two-photon laser writing. By irradiation with differently colored light, the thermally bistable dithienylethenes reversibly modulate the refractive index of and exhibit competing absorption with the gain medium, effectively suppressing laser emission in the one state and allowing low threshold (2.15 mJ/cm 2 ) laser emission in the other state.