Solvent‐Free Self‐Assembly for Scalable Preparation of Highly Crystalline Mesoporous Metal Oxides

Mesoporous metal oxides (MMOs) have been demonstrated great potential in various applications. Up to now, the direct synthesis of MMOs is still limited to the solvent induced inorganic‐organic self‐assembly process. Here, we develop a facile, general, and high throughput solvent‐free self‐assembly strategy to synthesize a series of MMOs including single‐component MMOs and multi‐component MMOs (e.g., doped MMOs, composite MMOs, and polymetallic oxide) with high crystallinity and remarkable porous properties by grinding and heating raw materials. Compared with the traditional solution self‐assembly process, the avoidance of solvents in this method not only greatly increases the yield of target products and synthesis efficiency, but also reduces the environmental pollution and the consumption of cost and energy. We believe the presented approach will pave a new avenue for scalable production of advanced mesoporous materials for various applications.     

A Stable Extra‐Large‐Pore Zeolite with Intersecting 14‐ and 10‐Membered‐Ring Channels

The development of inorganic frameworks with extra‐large pores (larger than 12‐membered rings) has attracted considerable attention because of their potential applications in catalysis, the separation of large molecules, and so forth. We herein report the synthesis of the new extra‐large‐pore zeolite NUD‐2 by using the supramolecular self‐assembly of simple aromatic organic cations as structure‐directing agents (SDAs). NUD‐2 is a high‐silicon‐content germanosilicate with interconnecting 14×10‐membered‐ring channels. The SDAs in NUD‐2 can be removed by calcination in air at 550 °C to yield permanent pores with a BET surface area of 500 m²g^?1. Both germanium and organic cations in NUD‐2 can also be removed by treatment with acid at lower temperature, thus not only affording recycling of germanium and SDAs, but also providing a highly stable siliceous zeolite. In addition, aluminum ions can be incorporated into the framework of NUD‐2. The NUD‐2 structure is yet another extra‐large‐pore zeolite synthesized by using the supramolecular self‐assembling templating approach, thus demonstrating that this approach is a general and applicable strategy for synthesis of new large‐ and extra‐large‐pore zeolites.     

Real‐Time Probing of Nanowire Assembly Kinetics at the Air–Water Interface by In Situ Synchrotron X‐Ray Scattering

Although many assembly strategies have been used to successfully construct well‐aligned nanowire (NW) assemblies, the understanding of their assembly kinetics has remained elusive, which restricts the development of NW‐based device and circuit fabrication. Now a versatile strategy that combines interfacial assembly and synchrotron‐based grazing‐incidence small‐angle X‐ray scattering (GISAXS) is presented to track the assembly evolution of the NWs in real time. During the interface assembly process, the randomly dispersed NWs gradually aggregate to form small ordered NW‐blocks and finally are constructed into well‐defined NW monolayer driven by the conformation entropy. The NW assembly mechanism can be well revealed by the thermodynamic analysis and large‐scale molecular dynamics theoretical evaluation. These findings point to new opportunities for understanding NW assembly kinetics and manipulating NW assembled structures by bottom‐up strategy.     

A Self‐Growing Strategy for Large‐Scale Crystal Assembly Tubes

Assembled tubular materials have attracted widespread attention due to their potential applications in catalysis, bionics, and optic‐electronics. Many versatile methods, including template assistance and self‐assembly, have been developed for fabrication of tubular materials. Here we demonstrate a self‐growing strategy to prepare large‐scale crystal assembly tubes. Addition of the template and the need for the sophisticated equipment are avoided with this method. The sidewall of the tubes is composed of a layer of polyhedral crystals that are connected together through grain coalescence. We demonstrate that the assembled tubular structure is obtained by the synergetic effect of the passivation layer and the dissolution‐recrystallization process. This facile one‐step strategy and the formation mechanism will offer guidance for fabrication of new superstructures.     

Gold‐Nanoparticle‐Mediated Jigsaw‐Puzzle‐like Assembly of Supersized Plasmonic DNA Origami

DNA origami has rapidly emerged as a powerful and programmable method to construct functional nanostructures. However, the size limitation of approximately 100 nm in classic DNA origami hampers its plasmonic applications. Herein, we report a jigsaw‐puzzle‐like assembly strategy mediated by gold nanoparticles (AuNPs) to break the size limitation of DNA origami. We demonstrated that oligonucleotide‐functionalized AuNPs function as universal joint units for the one‐pot assembly of parent DNA origami of triangular shape to form sub‐microscale super‐origami nanostructures. AuNPs anchored at predefined positions of the super‐origami exhibited strong interparticle plasmonic coupling. This AuNP‐mediated strategy offers new opportunities to drive macroscopic self‐assembly and to fabricate well‐defined nanophotonic materials and devices.     

Controlling the Structure and Length of Self‐Synthesizing Supramolecular Polymers through Nucleated Growth and Disassembly

Directing self‐assembly processes out‐of‐equilibrium to yield kinetically trapped materials with well‐defined dimensions remains a considerable challenge. Kinetically controlled assembly of self‐synthesizing peptide‐functionalized macrocycles through a nucleation–growth mechanism is reported. Spontaneous fiber formation in this system is effectively shut down as most of the material is diverted into metastable non‐assembling trimeric and tetrameric macrocycles. However, upon adding seeds to this mixture, well‐defined fibers with controllable lengths and narrow polydispersities are obtained. This seeded growth strategy also allows access to supramolecular triblock copolymers. The resulting noncovalent assemblies can be further stabilized through covalent capture. Taken together, these results show that self‐synthesizing materials, through their interplay between dynamic covalent bonds and noncovalent interactions, are uniquely suited for out‐of‐equilibrium self‐assembly.     

Colloidal Rings by Site‐Selective Growth on Patchy Colloidal Disc Templates

Anisotropic colloidal building blocks are quite attractive as they enable the self‐assembly towards new materials with designated hierarchical structures. Although many advances have been achieved in colloidal synthetic methodology, synthesis of colloidal rings with low polydispersity and on a large scale remains a challenge. To address this issue we introduce a new site‐selective growth strategy, which relies on using patchy particles. For example, by using patchy discs as templates, silica can selectively be grown on only side surfaces, resulting in formation of silica rings. We demonstrate that shape parameters are tunable and find that these silica rings can be used as secondary template to synthesize other types of rings. This method for synthesizing ring‐like colloids provides possibilities for studying their self‐assembly and associated phase transitions, and this patchy particles template strategy paves a new route for fabricating other new colloidal particles.     

Porphyrin/Ionic‐Liquid Co‐assembly Polymorphism Controlled by Liquid–Liquid Phase Separation

Understanding and controlling multicomponent co‐assembly is of primary importance in different fields, such as materials fabrication, pharmaceutical polymorphism, and supramolecular polymerization, but these aspects have been a long‐standing challenge. Herein, we discover that liquid–liquid phase separation (LLPS) into ion‐cluster‐rich and ion‐cluster‐poor liquid phases is the first step prior to co‐assembly nucleation based on a model system of water‐soluble porphyrin and ionic liquids. The LLPS‐formed droplets serve as the nucleation precursors, which determine the resulting structures and properties of co‐assemblies. Co‐assembly polymorphism and tunable supramolecular phase transition behaviors can be achieved by regulating the intermolecular interactions at the LLPS stage. These findings elucidate the key role of LLPS in multicomponent co‐assembly evolution and enable it to be an effective strategy to control co‐assembly polymorphism as well as supramolecular phase transitions.     

The Two‐Step Assemblies of Basic‐Amino‐Acid‐Rich Peptide with a Highly Charged Polyoxometalate

Two‐step assembly of a peptide from HPV16 L1 with a highly charged europium‐substituted polyoxometalate (POM) cluster, accompanying a great luminescence enhancement of the inorganic polyanions, is reported. The mechanism is discussed in detail by analyzing the thermodynamic parameters from isothermal titration calorimetry (ITC), time‐resolved fluorescent and NMR spectra. By comparing the actions of the peptide analogues, a binding process and model are proposed accordingly. The driving forces in each binding step are clarified, and the initial POM aggregation, basic‐sequence and hydrophobic C termini of peptide are revealed to contribute essentially to the two‐step assembly. The present study demonstrates both a meaningful preparation for bioinorganic materials and a strategy using POMs to modulate the assembly of peptides and even proteins, which could be extended to other proteins and/or viruses by using peptides and POMs with similar properties.     

Enrichment of large‐diameter semiconducting single‐walled carbon nanotubes by a mixed‐extractor strategy

In this work, we report a new mixed‐extractor strategy to improve the sorting yield of large‐diameter semiconducting single‐walled carbon nanotubes (s‐SWCNTs) with high purity. In the new mixed‐extractor strategy, two kinds of conjugated polymers with different rigidity, poly(9,9‐n‐dihexyl‐2,7‐fluorene‐alt‐9‐phenyl‐3,6‐carbazole) (PDFP) and poly(9,9‐dioctylfluorene‐alt‐benzothiadiazole) (P8BT), are used to sort large‐diameter s‐SWCNTs through two simple sonication processes. To our surprise, although PDFP itself shows no selectivity toward s‐SWCNTs, it can greatly enhance the sorting yield of P8BT. Using the PDFP/P8BT mixed‐extractor method, the yield of sorted s‐SWCNTs has been enhanced by 5 times with a purity above 99 % in comparison to that using P8BT single‐extractor method. In addition, the photoluminescence (PL) excitation maps shows that the PDFP/P8BT mixed‐extractor system not only enhances the sorting yield substantially, but also tends to be enrichment of (15,4) SWCNTs with the diameter of 1.36 nm.     

Microfluidics as A Tool to Understand the Build‐Up Mechanism of Exponential‐Like Growing Films

Microfluidics is used here for the first time to efficiently tune the growth conditions for understanding the build‐up mechanism of exponentially growing polyelectrolyte (PE) films. The velocity of PE supply and time of interaction can be successfully altered during the layer‐by‐layer assembly. Another advantage of this method is that the deposition of poly‐L ‐lysine/hyaluronic acid (PLL/HA) films in microchannels can be monitored online by fluorescence microscopy. The study demonstrates that PE mass transport to the film surface and diffusion in the film are key parameters affecting PLL/HA film build‐up. Increase of PE supply rate results in a change in the “transition” (exponential‐to‐linear growth) towards higher number of deposition steps, thus indicating a mass transport‐mediated growth mechanism.     

Synthesis of Low‐Dimensional Polyion Complex Nanomaterials via Polymerization‐Induced Electrostatic Self‐Assembly

Nanostructured polyion complexes (PICs) are appealing in biomaterials applications. Yet, conventional assembly suffers from the weakness in scale‐up and reproducibility. Only a few low‐dimensional PICs are available to date. Herein we report an efficient and scalable strategy to prepare libraries of low‐dimensional PICs. It involves a visible‐light‐mediated RAFT polymerization of ionic monomer in the presence of a polyion of the opposite charge at 5–50 % w/w total solids concentration in water at 25 °C, namely, polymerization‐induced electrostatic self‐assembly (PIESA). A Vesicle, multi‐compartmental vesicle, and large‐area unilamellar nanofilm can be achieved in water. A long nanowire and porous nanofilm can be prepared in methanol/water. An unusual unimolecular polyion complex (uPIC)‐sphere‐branch/network‐film transition is reported. This green chemistry offers a general platform to prepare various low‐dimensional PICs with high reproducibility on a commercially viable scale under eco‐friendly conditions.     

A Size‐Reducible Nanodrug with an Aggregation‐Enhanced Photodynamic Effect for Deep Chemo‐Photodynamic Therapy

Fluorescent dyes with multi‐functionality are of great interest for photo‐based cancer theranostics. However, their low singlet oxygen quantum yield impedes their potential applications for photodynamic therapy (PDT). Now, a molecular self‐assembly strategy is presented for a nanodrug with a remarkably enhanced photodynamic effect based on a dye‐chemodrug conjugate. The self‐assembled nanodrug possesses an increased intersystem crossing rate owing to the aggregation of dye, leading to a distinct singlet oxygen quantum yield (Φ(¹O₂)). Subsequently, upon red light irradiation, the generated singlet oxygen reduces the size of the nanodrug from 90 to 10 nm, which facilitates deep tumor penetration of the nanodrug and release of chemodrug. The nanodrug achieved in situ tumor imaging and potent tumor inhibition by deep chemo‐PDT. Our work verifies a facile and effective self‐assembly strategy to construct nanodrugs with enhanced performance for cancer theranostics.     

Visible‐Light‐Excited Room‐Temperature Phosphorescence in Water by Cucurbit[8]uril‐Mediated Supramolecular Assembly

Solid‐state materials with efficient room‐temperature phosphorescence (RTP) emissions have found widespread applications in materials science, while liquid or solution‐phase pure organic RTP emission systems has been rarely reported, because of the nonradiative decay and quenchers from the liquid medium. Reported here is the first example of visible‐light‐excited pure organic RTP in aqueous solution by using a supramolecular host‐guest assembly strategy. The unique cucurbit[8]uril‐mediated quaternary stacking structure allows tunable photoluminescence and visible‐light excitation, enabling the fabrication of multicolor hydrogels and cell imaging. The present assembly‐induced emission approach, as a proof of concept, contributes to the construction of novel metal‐free RTP systems with tunable photoluminescence in aqueous solution, providing broad opportunities for further applications in biological imaging, detection, optical sensors, and so forth.     

Miniaturization of Metal–Biomolecule Frameworks Based on Stereoselective Self‐Assembly and Potential Application in Water Treatment and as Antibacterial Agents

Miniaturization of metal–biomolecule frameworks (MBioFs) to the nanometer scale represents a novel strategy for fabricating materials with tunable physical and chemical properties. Herein, we demonstrate a simple, low‐cost, and completely organic solvent‐free strategy for constructing a dl ‐glutamic acid–copper ion‐based three‐dimensional nanofibrous network structure. The building blocks used are available in large quantities and do not require any laborious synthesis or modification. Importantly, we demonstrate with an intriguing example, that the self‐assembly ability of supramolecular nanofibers could be finely tuned with the ligands’ chirality. This offers opportunities for obtaining one‐dimensional hierarchical nanostructures and expands the investigation scope of stereoselective self‐assembly. Furthermore, the material displays good ability in removing anionic dyes from water and inhibits the growth of both Gram positive and Gram negative bacteria, possibly through the contact‐killing mechanism; this indicates potential applications in environmental issues and antimicrobial nanotherapeutics.     

A Surfactant‐Encapsulating Polyoxometalate Nanowire Assembly as a New Carrier for Nanoscale Noble‐Metal Catalysts

The loading of noble‐metal nanoparticles (NMNPs) onto various carriers to obtain stable and highly efficient catalysts is currently an important strategy in the development of noble metal (NM)‐based catalytic reactions and their applications. We herein report a nanowire supramolecular assembly constructed from the surfactant‐encapsulating polyoxometalates (SEPs) CTAB‐PW₁₂, which can act as new carriers for NMNPs. In this case, the Ag NPs are loaded onto the SEP nanowire assembly with a narrow size distribution from 5 to 20 nm in diameter; the average size is approximately 10 nm. The Ag NPs on the nanowire assemblies are well stabilized and the over agglomeration of Ag NPs is avoided owing to the existence of well‐arranged polyoxometalate (POM) units in the SEP assembly and the hydrophobic surfactant on the surface of the nanowire assembly. Furthermore, the loading amount of the Ag NPs can be adjusted by controlling the concentration of the AgNO₃ aqueous solution. The resultant Ag/CTAB‐PW₁₂ composite materials exhibit high activity and good stability for the catalytic reduction of 4‐nitrophenol (4‐NP) with NaBH₄ in isopropanol/H₂O solution. The NMNPs‐loaded SEP nanoassembly may represent a new composite catalyst system for application in NM‐based catalysis.     

Bioinorganic Nanocomposite Hydrogels Formed by HRP–GOx‐Cascade‐Catalyzed Polymerization and Exfoliation of the Layered Composites

The mild preparation of multifunctional nanocomposite hydrogels is of great importance for practical applications. We report that bioinorganic nanocomposite hydrogels, with calcium niobate nanosheets as cross‐linkers, can be prepared by dual‐enzyme‐triggered polymerization and exfoliation of the layered composite. The layered HRP/calcium niobate composites (HRP=horseradish peroxidase) are formed by the assembly of the calcium niobate nanosheets with HRP. The dual‐enzyme‐triggered polymerization can induce the subsequent exfoliation of the layered composite and final gelation through the interaction between polymer chains and inorganic nanosheets. The self‐immobilized HRP‐GOx enzymes (GOx=glucose oxidase) within the nanocomposite hydrogel retain most of enzymatic activity. Evidently, their thermal stability and reusability can be improved. Notably, our strategy could be easily extended to other inorganic layered materials for the fabrication of other functional nanocomposite hydrogels.     

Aqueous Self‐Assembly of Purely Hydrophilic Block Copolymers into Giant Vesicles

Self‐assembly of macromolecules is fundamental to life itself, and historically, these systems have been primitively mimicked by the development of amphiphilic systems, driven by the hydrophobic effect. Herein, we demonstrate that self‐assembly of purely hydrophilic systems can be readily achieved with similar ease and success. We have synthesized double hydrophilic block copolymers from polysaccharides and poly(ethylene oxide) or poly(sarcosine) to yield high molar mass diblock copolymers through oxime chemistry. These hydrophilic materials can easily assemble into nanosized (<500 nm) and microsized (>5 μm) polymeric vesicles depending on concentration and diblock composition. Because of the solely hydrophilic nature of these materials, we expect them to be extraordinarily water permeable systems that would be well suited for use as cellular mimics.     

Thermally Triggered Frame‐Guided Assembly

We report a thermally triggered frame‐guided assembly (FGA) strategy for the preparation of vesicles. We employ thermally responsive poly(propylene oxide) (PPO) to make the leading hydrophobic groups (LHGs) thermally responsive, so that they are hydrophilic below the low critical solution temperature (LCST) and the frame forms in a homogeneous environment. When the temperature is increased above the LCST, the LHGs become hydrophobic and the assembly process is triggered, which drives DNA‐b‐PPO to assemble around the LHGs, forming vesicles. This work verified that FGA is a general strategy and can be applied to polymeric systems. The thermally triggered assembly not only provides more controllability over the FGA process but also promotes an in‐depth understanding of the FGA strategy and in a broad view, the formation mechanism and functions of cell membrane.     

Rhodium(III)‐Catalyzed ortho‐Heteroarylation of Phenols through Internal Oxidative CH Activation: Rapid Screening of Single‐Molecular White‐Light‐Emitting Materials

Reported herein is the first example of a transition‐metal‐catalyzed internal oxidative C? H/C? H cross‐coupling between two (hetero)arenes through a traceless oxidation directing strategy. Without the requirement of an external metal oxidant, a wide range of phenols, including phenol‐containing natural products, can undergo the coupling with azoles to assemble a large library of highly functionalized 2‐(2‐hydroxyphenyl)azoles. The route provides an opportunity to rapidly screen white‐light‐emitting materials. As illustrative examples, two bis(triphenylamine)‐bearing 2‐(2‐hydroxyphenyl)oxazoles, which are difficult to access otherwise, exhibit bright white‐light emission, high quantum yield, and thermal stability. Also presented is the first example of the white‐light emission, in a single excited‐state intramolecular proton transfer system, of 2‐(2‐hydroxyphenyl)azoles, thus highlighting the charm of C? H activation in the discovery of new organic optoelectronic materials.