Recent progress on highly tough and stretchable polymer networks has highlighted the potential of wearable electronic devices and structural biomaterials such as cartilage. For some given applications, a combination of desirable mechanical properties including stiffness, strength, toughness, damping, fatigue resistance, and self-healing ability is required. However, integrating such a rigorous set of requirements imposes substantial complexity and difficulty in the design and fabrication of these polymer networks, and has rarely been realized. Here, we describe the construction of supramolecular polymer networks through an in situ copolymerization of acrylamide and functional monomers, which are dynamically complexed with the host molecule cucurbit[8]uril (CB[8]). High molecular weight, thus sufficient chain entanglement, combined with a small-amount dynamic CB[8]-mediated non-covalent crosslinking (2.5 mol%), yields extremely stretchable and tough supramolecular polymer networks, exhibiting remarkable self-healing capability at room temperature. These supramolecular polymer networks can be stretched more than 100× their original length and are able to lift objects 2000× their weight. The reversible association/dissociation of the host-guest complexes bestows the networks with remarkable energy dissipation capability, but also facile complete self-healing at room temperature. In addition to their outstanding mechanical properties, the networks are ionically conductive and transparent. The CB[8]-based supramolecular networks are synthetically accessible in large scale and exhibit outstanding mechanical properties. They could readily lead to the promising use as wearable and self-healable electronic devices, sensors and structural biomaterials.

We report the facile synthesis of carbon dots with tunable fluorescence from unzipping of photonic crystals and their application in LEDs, which may provide an insight into the creation of multifunctional carbon dots adapted for various applications such as in optoelectronics, sensing, or bioimaging.

The self-assembly of colloidal particles opens novel avenues for the generation of functional materials with collective optical, elctronic, and magnetic properties.[1] Particularly, colloidal photonic crystal (CPC) materials which are created by the self-assembly of monodispersed colloidal particles often show unique optical properties beyond those of their single components, such as diffractive light abilities and photonic bandgaps.[2] Microfluidic devices have recently emerged as a powerful playform to engineer CPCs with diverse strutures, [3] high stabilities, [4] monodisperse sizes, [5] and functionalization, [6] allowing them to meet the requirments for practical applications ,such as biological analysis, [7] optical devices, [8] and chemical sensors. [9] However, it is still a great challenge to mount or shape CPCs into a desired morphology (e.g., spheres, Janus, ellipsoids, and dumbbelllike supaparticles); efficient pathways are needed to selectively endow CPCs with versatile functions whilst preserving their original optical properties.Herein, we developed a triphase microfluidic-directed self-assembly to construct CPC supraparticles with controllable and predictable shape, and selectively introduced advanced functions to them. The triphase microfluidic technique is a co-flowing system that produces continuous microdroplets comprising two immiscible phases. By adjusting the interfacial tension of each phase in the microfluidic system, CPC supraparticles with tunable shape, varying from crescent, meniscus, and ellipsoid to spherical were prepared by the self-assembly of the monodisperse colloidal particles in these microdroplet templates. Importantly, studying the interface chemistry indicated that the structure of the biphasic microdroplets and the resulting CPCs might be predicted in our strategy. The further introduction of photoinduced consolidation into the triphase microfluidic system yielded core-shell or Janus CPC superstructures. The encapsulation of magnetic nanoparticles created Janus CPC supraparticles with superparamagnetism and a photonic bandgap in two distinct hemispheres. These multifunctional Janus CPC supraparticles exhibit "Dark" and "Light" switchable behaviors under an external magnetic field, and thus can be processed into rewritable and color-tunable photonic patterns. To our knowledge, this is the first example of the utilization of the triphase microfluidic technique for the design of anisotropic CPCs. This facile strategy can be extended to build up a series of novel multidimensional colloidal structures, with the aim of collecting colloidal particles and orgnizing them into functional materials for pratical application.Figure 1 a illustrates the fabrication of shape-controllable CPC supraparticles in a triphase microfluidic flow-focusing device composed of a cylindrical polydimethylsiloxane (PDMS) capillary and a pair of inner cylindrical 25G steel needles. We chose three immiscible fluids, an aqueous solution of monodisperse polystyrene (PS) microspheres in

Biomimetic supramolecular dual networks: By mimicking the structure/function model of titin, integration of dynamic cucurbit[8]uril mediated host-guest interactions with a trace amount of covalent cross-linking leads to hierarchical dual networks with intriguing toughness, strength, elasticity, and energy dissipation properties. Dynamic host-guest interactions can be dissociated as sacrificial bonds and their facile reformation results in self-recovery of the dual network structure as well as its mechanical properties.

ConspectusMicroencapsulation is a fundamental concept behind a wide range of daily applications ranging from paints, adhesives, and pesticides to targeted drug delivery, transport of vaccines, and self-healing concretes. The beauty of microfluidics to generate microcapsules arises from the capability of fabricating monodisperse and micrometer-scale droplets, which can lead to microcapsules/particles with fine-tuned control over size, shape, and hierarchical structure, as well as high reproducibility, efficient material usage, and high-throughput manipulation. The introduction of supramolecular chemistry, such as host–guest interactions, endows the resultant microcapsules with stimuli-responsiveness and self-adjusting capabilities, and facilitates hierarchical microstructures with tunable stability and porosity, leading to the maturity of current microencapsulation industry.Supramolecular architectures and materials have attracted immense attention over the past decade, as they open the possibility to obtain a large variety of aesthetically pleasing structures, with myriad applications in biomedicine, energy, sensing, catalysis, and biomimicry, on account of the inherent reversible and adaptive nature of supramolecular interactions. As a subset of supramolecular interactions, host–guest molecular recognition involves the formation of inclusion complexes between two or more moieties, with specific three-dimensional structures and spatial arrangements, in a highly controllable and cooperative manner. Such highly selective, strong yet dynamic interactions could be exploited as an alternative methodology for programmable and controllable engineering of supramolecular architectures and materials, exploiting reversible interactions between complementary components. Through the engineering of molecular structures, assemblies can be readily functionalized based on host–guest interactions, with desirable physicochemical characteristics.In this Account, we summarize the current state of development in the field of monodisperse supramolecular microcapsules, fabricated through the integration of traditional microfluidic techniques and interfacial host–guest chemistry, specifically cucurbit[n]uril (CB[n])-mediated host–guest interactions. Three different strategies, colloidal particle-driven assembly, interfacial condensation-driven assembly and electrostatic interaction-driven assembly, are classified and discussed in detail, presenting the methodology involved in each microcapsule formation process. We highlight the state-of-the-art in design and control over structural complexity with desirable functionality, as well as promising applications, such as cargo delivery stemming from the assembled microcapsules. On account of its dynamic nature, the CB[n]-mediated host–guest complexation has demonstrated efficient response toward various external stimuli such as UV light, pH change, redox chemistry, and competitive guests. Herein, we also demonstrate different microcapsule modalities, which are engineered with CB[n] host–guest ...

The first microfluidic synthesis of ionomer‐based bifunctional Janus supraballs possessing two distinct magnetic‐nanoparticle‐dropped and quantum dots–polymer hemispheres within an anisotropic structure is reported. Based on such Janus supraballs with stable fluorescence and superparamagnetism, a magnetoresponsive fluorescent switch is developed to realize free‐writing under a magnetic field. This is a promising, simple way to fabricate novel flexible bead displays.

Inspired by biological systems, we report a supramolecular polymer-colloidal hydrogel (SPCH) composed of 98 wt % water that can be readily drawn into uniform (∼6-µm thick) "supramolecular fibers" at room temperature. Functionalized polymer-grafted silica nanoparticles, a semicrystalline hydroxyethyl cellulose derivative, and cucurbit[8]uril undergo aqueous self-assembly at multiple length scales to form the SPCH facilitated by host-guest interactions at the molecular level and nanofibril formation at colloidal-length scale. The fibers exhibit a unique combination of stiffness and high damping capacity (60-70%), the latter exceeding that of even biological silks and cellulose-based viscose rayon. The remarkable damping performance of the hierarchically structured fibers is proposed to arise from the complex combination and interactions of "hard" and "soft" phases within the SPCH and its constituents. SPCH represents a class of hybrid supramolecular composites, opening a window into fiber technology through low-energy manufacturing. supramolecular fiber | hydrogel | self-assembly | damping | spider silk I n nature, spiders spin silk fibers with superb properties at ambient temperatures and pressures (1, 2). We have yet to mimic such an elegant process. Conventionally, synthetic fibers are manufactured through a variety of spinning techniques, including wet, dry, gel, and electrospinning (3). Such approaches to generate fibers are limited by high energy input, laborious procedures, and intensive use of organic solvents. Supramolecular pathways enable the formation of filamentous soft materials that are showing promise in biomedical applications (4-6), such as cell culture (7-9) and tissue engineering (10). However, such materials are constrained by the length scale (submicrometer level) (11-13), energy intake during production (9), and complex design of assembly units (14).Here, we report drawing supramolecular fibers of arbitrary length from a dynamic supramolecular polymer-colloidal hydrogel (SPCH) at room temperature (Movie S1). The components consist of methyl viologen (MV)-functionalized polymer-grafted silica nanoparticles (P1), a semicrystalline polymer in the form of a hydroxyethyl cellulose derivative (H1), and cucurbit[8]uril (CB[8]) as illustrated in Fig. 1. The macrocycle CB[8] is capable of simultaneously encapsulating two guests within its cavity, forming a stable yet dynamic ternary complex, and has been exploited as a supramolecular "handcuff" to physical cross-link functional polymers (15-18). Introducing shape-persistent nanoparticles into the supramolecular hydrogel system allows for modification of the local gel structures at the colloidal-length scale, resulting in assemblies with unique emergent properties (19). The hierarchical nature of the SPCH is presented, where the hydrogel is composed of nanoscale fibrillar structures. The self-assembled SPCH composite exhibits great elasticity at a remarkably high water content (98%), showing a low-energy manufacturing process for fibers from natural, ...

The self-assembly of nanoscale materials to form hierarchically ordered structures promises new opportunities in drug delivery, as well as magnetic materials and devices. Herein, we report a simple means to promote the self-assembly of two polymers with functional groups at a water-chloroform interface using microfluidic technology. Two polymeric layers can be assembled and disassembled at the droplet interface using the efficiency of cucurbit[8]uril (CB[8]) host-guest supramolecular chemistry. The microcapsules produced are extremely monodisperse in size and can encapsulate target molecules in a robust, well-defined manner. In addition, we exploit a dendritic copolymer architecture to trap a small hydrophilic molecule in the microcapsule skin as cargo. This demonstrates not only the ability to encapsulate small molecules but also the ability to orthogonally store both hydrophilic and hydrophobic cargos within a single microcapsule. The interfacially assembled supramolecular microcapsules can benefit from the diversity of polymeric materials, allowing for fine control over the microcapsule properties.