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

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 ...

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.