The metal-mediated self-assembly process allows the well-directed and controlled construction of supramolecular architectures, and the assembled metal−ligand complexes display diverse functionalities depending on the composition of the complex template. Through the deliberate introduction of a metal-binding nucleobase, cytosine, to the macrocyclic diacetylene (MCDA), a macrocyclic ligand, CytMCDA, was synthesized. On account of the metal affinity of cytosine and the π−π interaction of the diacetylene template, a Hg-coordinated unidirectional columnar self-assembly of CytMCDA was generated that formed into organic nanotubes. The monomeric CytMCDA-Hg is covalently cross-linked to the blue-phase macrocyclic polydiacetylene nanotubes (CytMCPDA-Hg) via UV-induced topochemical polymerization. CytMCPDA-Hg displayed a naked-eye-detectable sensing response toward heat and solvents with a brilliant blue−red chromatic transition. Moreover, owing to the high affinity of the mercury complex toward sulfur, CytMCPDA-Hg displayed a high sensitivity against thiols.

High-resolution structures are crucial for understanding the functional properties of nanomaterials. We applied single-particle cryo-electron microscopy (cryo-EM), a method traditionally used for structure determination of biological macromolecules, to obtain high-resolution structures of synthetic non-biological filaments formed by photopolymerization of macrocyclic diacetylene (MDA) amphiphilic monomers. Tomographic analysis showed that the MDA monomers self-assemble into hollow nanotubes upon dispersion in water. Single-particle analysis revealed tubes consisting of six pairs of covalently bonded filaments held together by hydrophobic interactions, where each filament is composed of macrocyclic rings stacked in parallel “chair” conformations. The hollow MDA nanotube structures we found may account for the efficient scavenging of amphiphilic pollutants in water and subsequent photodegradation of the guest species.

We deposited amorphous silicon (a-Si) films below 150 C with a custom-designed catalytic chemical vapor deposition (Cat-CVD) system. The hydrogen content of the films was controlled at less than 1.5 at. %. Excimer laser crystallization was performed without the preliminary dehydrogenation process. Crystallization occurred at a laser energy density above 70 mJ/ cm 2. Thin-film transistors (TFTs) were fabricated while the entire process temperatures were maintained at below 200 C. We obtained a field-effect mobility of higher than 100 cm 2 /(V s) and a sub-threshold slope of 116 mV/dec. The a-Si film prepared by a low temperature Cat-CVD is a promising candidate for polycrystalline silicon TFTs of the active matrix display.

Self‐assembly process represents one of the most powerful and efficient methods for designing functional nanomaterials. For generating optimal functional materials, understanding the pathway complexity during self‐assembly is essential, which involves the aggregation of molecules into thermodynamically or kinetically favored pathways. Herein, a functional perylene diimide (PDI) derivative by introducing diacetylene (DA) chains (PDI‐DA) is designed. Temperature control pathway complexity with the evolution of distinct morphology for the kinetic and thermodynamic product of PDI‐DA is investigated in detail. A facile strategy of UV‐induced polymerization is adopted to trap and capture metastable kinetic intermediates to understand the self‐assembly mechanism. PDI‐DA showed two kinetic intermediates having the morphology of nanosheets and nanoparticles before transforming into the thermodynamic product having fibrous morphology. Spectroscopic studies revealed the existence of distinct H‐ and J‐aggregates for kinetic and thermodynamic products respectively. The polymerized fibrous PDI‐DA displayed reversible switching between J‐aggregate and H‐aggregate.

Despite their great utility in synthetic and materials chemistry, Diels-Alder (DA) and retro Diels-Alder (rDA) reactions have been vastly unexplored in promoting self-assembly processes. Herein we describe the first example of a retro Diels-Alder (rDA) reaction-triggered self-assembly method. Release of the steric bulkiness associated with the bridged bicyclic DA adduct by the rDA reaction allowed generation of two building blocks that spontaneously self-assembled to form a supramolecular polymer. By employing photopolymerizable lipid building blocks, we demonstrated the efficiency of the rDA-based self-assembly strategy. Generation of reactive functional groups (maleimide and furan) that can be used for further modification of the supramolecular polymer is an additional meritorious feature of the rDA-based approach. Advantage was taken of reactive functional groups to fabricate stimulus-responsive selective and tunable colorimetric sensors. The strategy developed in this study could open new avenues to the design of systems that participate in triggered molecular assembly.