Search

The polymer/inorganic composite trilayered Janus mesoporous nanodiscs are synthesized by coassembly of gelable poly(ethylene oxide)-block-poly(3-triethoxysilylpropyl methacrylate)-block-polystyrene (PEO-b-PTEPM-b-PS) and PEO-b-PS via a sol–gel process at an emulsion interface. Bimodal phase separations are responsible for the formation of isolated nanodiscs and mesopores within the discs. The Janus mesoporous nanodiscs are amphiphilic to form superstructures in dispersions. They can serve as a solid surfactant to stabilize emulsions.

We describe a simple method to prepare magnetic responsive polydivinylbenzene (PDVB) nanofiber composites by precipitated cationic living polymerization in the present of oleic acid capped Fe3O4 nanoparticles (NPs). The Fe3O4 NPs are encapsulated with the PDVB forming dendrites, from which thin nanofibers are grown in the tip-growth mode. The thin nanofibers are interwoven with the thick nanofibers forming robust composite network. The composites are magnetic responsive and highly efficient to gel almost all chemicals. Separation of the gelled chemicals from water becomes easier with a magnet. The performance is promising for magnetic collection of chemical spills.

A bottlebrush-colloid Janus nanoparticle (JNP) with a ball-and-stick structure is reported. A single poly(4-vinyl benzyl chloride) (PVBC) polymer chain was grafted onto the amine-capped Fe3O4@NH2 n...

In this work, we developed a continuous non-aqueous flow Pickering emulsion interface catalysis (FPIC) system for heterogeneous acylation. Poly (1-vinyl-3-ethylimidazolium bromide) (PILs) functionalized silica@PS/PDVB Janus particles (JPs) were synthesized. The catalyst H3PW12O40 (PA) was then immobilized on PIL-modified JPs by anion-exchanging. The PIL grafted on the silica side and the inherent oleophilic phenyl groups on the other side endow the Janus particle with excellent amphipathy for the immiscible ionic liquid (IL) [BMIM]BF4 and toluene. Therefore, emulsification and catalytic capability were realized simultaneously on the PA-PILs-JPs. The FPIC column system for acylation reaction was accomplished by packing the IL-in-oil Pickering emulsion into a column reactor, and exhibited excellent catalytic performance, high stability during the reaction process as well as remarkable recyclability.

Strength is usually compromised with toughness of polymer blends. We report a new way to synchronously strengthen and toughen a typical blend of epoxy resin/nitrile-butadiene rubber (EP/LNBR) with ...

Hairy composite particles with polymer nanoscale hairs are grown by precipitated cationic living polymerization onto a particle surface. Composition and length of the hairs are tuneable. The hair growth is general following the tip-growth mode. By step polymerization of varied monomers, multiple segmental hairs are achieved onto a particle surface. As an example, the PEG-conjugated PVBC-PDVB@Fe3O4 hairy particle is derived. It is highly effective to capture oil from the aqueous surroundings and easily recycled with a magnet.

A Janus silica cage was synthesized by selectively grafting an ionic liquid (IL) and poly-N-isopropylacrylamide (PNIPAM) (lower critical solution temperature (LCST)≈32 °C) onto the exterior and interior sides of the mesoporous SiO2 shell. The paramagnetic core inside the cavity is responsible for magnetic collection. The PW12 O40 3- anion is further conjugated onto the IL side by anion exchange. The Janus cage acts as a thermal-responsive reactor for catalytic oxidization of dibenzothiophene (DBT) in the presence of H2 O2 . The sulfide in the model oil can be completely decomposed at 25 °C, whilst the oxidative products are more dissoluble in water and preferentially captured inside the Janus cage. The Janus cage reactor could be regenerated at high temperature above 32 °C after releasing the products.

We report a method to prepare polymer/inorganic Janus particles by transferring self-assembled membranes of copolymers such as PS- b-PAA at an emulsion interface when the amine-capped particles such as paramagnetic Fe3O4@SiO2 core/shell particles are preferentially adsorbed by specific interactions. While the particles are protected, the exposed side can be further modified to conjugate aldehyde-capped polyethylene oxide (PEO). Both connections become robust by covalent bonds. The hydrophilic PEO and hydrophobic PS chains are distinctly compartmentalized onto the opposite sides of the Fe3O4@SiO2 particles. As a magnetic responsive solid surfactant, the stabilized emulsions can be driven with a magnet for directional movement and coalescence with increasing magnetic strength. This method can be extended to other Janus particles with tunable organic materials and solid particles.

Triblock Janus particles are prepared by two-step seeded emulsion polymerization against eccentric polymer hollow particles. Two silica bulges are sequentially grown at the eccentric zone transiting from the thick shell to the thin shell. The angle between the two silica bulge axes is tunable within 0–180°, determined by the eccentricity degree of the PS/PDVB hollow seed particles. The two silica bulges and the PS/PDVB domain of the triblock Janus particles can be selectively modified to enrich composition and functionality. As an example, the paramagnetic PS/PEO modified triblock Janus composite particle can serve as a functional solid surfactant to manipulate emulsion droplets with a magnet and deliver desired materials toward the interface.

A superhydrophobic surface was achieved using a monolayer of the perpendicularly oriented epoxy-silica@polydivinylbenzene (PDVB) Janus particles (JPs) on an epoxy resin substrate. The epoxy-silica@PDVB JPs were synthesized from the silica@PDVB/polystyrene (PS) JPs through selective etching of the PDVB/PS belly and the surface modification of the silica part. The modified silica parts can be covalently bonded with the epoxy resin to make the perpendicular orientation spontaneous as well as the coating more robust. The outward PDVB bellies can constitute the micro-/nanoscale hierarchical structures for the superhydrophobic property. The superhydrophobic coating exhibits water repellence and self-cleaning properties. Moreover, the coating exhibits good chemical durability that it can keep the superhydrophobic property after long-time immersion in various aqueous solutions and organic solvents. The coating is still superhydrophobic after water flushing and mechanical wearing, showing the perfect mechanical durability.

When superhydrophobic meshes are used for oil/water separation, high flux and high intrusion pressure are usually compromised. Herein, a high-performance superhydrophobic stainless steel mesh membrane with a hairy-like poly(divinylbenzene) (PDVB) coating is fabricated by precipitated cationic polymerization. The synthesis is facile, which is completed in one step at ambient temperature within a short time, i.e., less than 90 s. The unique hair-like microstructure of PDVB is responsible for the superhydrophobic performance with less blockage for the pores. A higher flux for oil is achieved while keeping a high intrusion pressure. Especially, the ellipsoidal pore texture with two sharp tips can give additional high intrusion pressure. In the case of 2800 mesh, the superhydrophobic mesh displays an unprecedentedly high value of up to 22 kPa while maintaining a high flux of 2.0 × 104 L·m-2·h-1. The high intrusion pressure enables further increment of flux to 4.2 × 104 L·m-2·h-1 under a reduced pressure at a higher loading. The current high-performance superhydrophobic mesh realizes higher efficiency in separating oil/water mixtures, which is promising for practical applications, for example, in industrial extraction.

A strategy is proposed to stabilize the polymeric interface by using the irregular Janus nanosheet (JNS). The poly(vinylidene fluoride) (PVDF)/poly(l-lactic acid) (PLLA) at 60/40 (wt/wt) with a bi-continuous structure is selected as the model melt blend, and the PMMA/epoxy JNS is synthesized and used as the compatibilizer. The JNS is preferentially located at the interface. The interfacial coverage by the JNS reaches a saturated state forming the interconnected jamming structure at 0.5 wt% of the JNS. The interface is thus stabilized which is well preserved after annealing at high temperature. After selectively etching PLLA, the robust PVDF porous material is derived with the JNS armored at the pore skeleton surface. The porous material provides a universal scaffold to achieve stable functional materials after filling the pores.

One-dimensional nanomaterials have widely applied in the fields of energy conversion and storage due to their exceptional performance because of the nano-size effect. Herein, we synthesized bamboo-like polymer nanotubes based on cationic polymerization using immiscible initiator nanodroplets that results in a hollow structure. The suspended microelectrode is fabricated to measure the axial thermal conductivity of a single polymer nanotube, which demonstrates that this hollow structure can reduce its effective thermal conductivity. The experimental results show that its effective thermal conductivity is close to 0.03 W m-1 K-1, and decreases to 0.02 W m-1 K-1 with increasing temperature of the heating microelectrode, which may be due to the increasing lattice vibration and inelastic scattering between phonons. Its effective thermal conductivity is smaller than that of air, indicating that the synthetic method is an effective way to fabricate thermal insulating polymer nanotubes by significantly lowering the effective thermal conductivity. Hence, the method offers a new strategy in the fields of thermal insulation and protection.

In addition to intravenous injections (i.v.), topical dosing of doxorubicin hydrochloride (DOX) has also been the focus of cancer treatment recently, although it normally requires well-designed drug carriers. In this work, we found that DOX could form fibril-shaped DOX aggregates via self-assembly in phosphate buffer (PB) and then co-assemble with poly(L-glutamic acid) (PGA) at a proper polymer–drug ratio, giving a unique nano-rod-shaped microstructure. The release rate of DOX from the PGA/DOX nano-rods was thus easily controlled at a slower release rate without being encapsulated by any classic carrier. In vitro cell culture demonstrated that the PGA/DOX nano-rods were not favorably taken up by cancer cells, which can be attributed to the negatively charged nature and the non-spherical shape of the aggregates. These features suggest great potential for the PGA/DOX assemblies for a sustained delivery through the intratumoral pathway (i.t.) as a carrier-free formulation. In the mouse model it diminished organ damage at a dose level of 30 mg kg−1via i.t. injections compared to the serious cardiotoxicity and renal toxicity via typical multiple i.v. dosage of free drug solution at 5 mg kg−1. As a result, the PGA/DOX formulation showed efficient anti-tumor activity. The survival rate of tumor bearing mice was significantly increased by over 35% compared to the i.v. injections of DOX solutions. Therefore, PGA/DOX nano-rods may provide a new and safe delivery route of the common anti-tumor drug.

Cable-like Au@SiO 2 Janus composite nanorods with PS and PEG grafting on both ends respectively are fabricated by skiving in combination of a post favorable modification. The cable-like Au@SiO 2 composite nanofibers are synthesized in the channel of porous anodic aluminium oxide (AAO) membrane. After skiving, the corresponding composite nanorods are obtained. Following, PEG-SH and PS-SH are conjugated onto the two ends of the nanorods by a selective partial modification, respectively. Length and diameter of the Au@SiO 2 Janus composite nanorods can be tuned controllably. It can be extended to fabricate a variety of different Janus nanorods with different compositions and microstructures.

A new method is proposed to fabricate high-performance phase change material capsules with high thermal storage capacity and increased thermal conductivity . The capsules are achieved by free radical polymerization against the example paraffin/water emulsions stabilized with Janus particles (JPs). It is key that the highly conductive Ag-contained JP adopt parallel lying at the emulsion interface, which is responsible for increasing the interfacial thermal conductivity. Thermal storage capacity can be retained over 90% with no paraffin leakage, which is stable after many cycles of heating and cooling. The high-performance phase change material capsules are promising in effective thermal management in the form of either powder or slurry.

Janus colloids are functional particles consisting of two surfaces (or internal materials) with distinct physical or chemical properties in the same particle. Owing to their amphiphilic nature, Janus colloids composed of both hydrophilic and hydrophobic faces provide a powerful tool to generate functional surfaces and to manipulate the properties of interfaces. Amphiphilic Janus colloids have shown promising applications as particulate surfactants in oil/water separation, as interfacial compatibilizers in polymer blends, and as assembly blocks in robust coatings with unique wettability. In this Feature Article, we summarize recent advances in engineering interfaces by using Janus colloids.

We report a general method to synthesize polymeric Janus nanosheets (PJS) by sequential RAFT grafting from a template particle surface. Layer number and composition of the PJS are tunable by feeding sequence and type of monomers. The cPNIPAM–PS PJS is flexible and thermal responsive, which can form a scrolled superstructure. A dually responsive cPAA–PNIPAM PJS is derived by hydrolysis of cPtBA–PNIPAM. Accordingly, stability of the emulsion with the cPAA–PNIPAM PJS is triggered by alternation of pH or/and temperature.

A robust light-responsive coating based on Janus composite particles is achieved. First, strawberry-like silica Janus particles are synthesized by the sol-gel process at a patchy emulsion interface. One side of the silica Janus particles possesses nanoscale roughness, and the other side is flat. Then, spiropyran-containing polymer brushes are grafted onto the coarse hemispherical side of the as-synthesized Janus particles, and the other flat side is modified with imidazoline groups. The light-responsive polymer brush-terminated coarse hemispherical sides direct toward the air when the Janus composite particles self-organize into a layer on the surface of epoxy resin substrate. The imidazoline groups react with the epoxy groups in the epoxy resin to form a robust smart coating. The coating can be reversibly triggered between hydrophobic and hydrophilic by UV and visible-light irradiation, which is attributed to the isomerization of spiropyran moieties. When the hydrophobic ring-closed spiropyran form is prominent, HeLa cells can be effectively captured onto the coating. After UV light irradiation, the ring-closed spiropyran form changes to the hydrophilic ring-opened zwitterionic merocyanine form, and then the captured cells are released. This work shows promising potential for engineering advanced smart biointerfaces.

Polymer/metal composite segmental Janus nanoparticles (NPs) are synthesized by sequential growth against poly(4-vinylpyridine) (P4VP) crosslinked cP4VP-PS Janus NPs. A Janus cluster of poly(4-vinylpyridine)-block-polystyrene (P4VP-b-PS) diblock copolymer is self-organized after absorption onto a silica patchy sphere via hydrogen bonding. Selective crosslinking of P4VP leads to the formation of robust cP4VP-PS Janus NPs. Within the cP4VP domain, functional species such as metals are preferentially grown by in situ reduction. Other thiol-capped polymers, for example, thiol-capped poly(N-isopropylacrylamide) (PNIPAM-SH), can be conjugated onto the opposite side to form polymer/metal triple segmental Janus NPs. The hyperthermia effect of Au NP of PNIPAM-Au@cP4VP-PS by near infrared (NIR) irradiation can trigger a fast transition from amphiphilic to hydrophobic of the Janus NPs at low surrounding temperature. De-stabilization of the emulsion is NIR triggered although the system temperature is below LCST (~32℃).

Ultrathin Janus nanodiscs with single molecular scale thickness are fabricated by self-organized sol–gel process against a patchy magnetic microsphere. Functional groups onto the patch domains can induce a favourable absorption of an amine. The morphology of Janus nanodiscs is adjusted by controlling the patchy regions on the surface of paramagnetic Fe3O4@SiO2 core/shell microspheres. The as-used patchy C8–(Fe3O4@SiO2)–PhCHO microspheres serving as templates can be easily separated from the as-formed Janus nanodiscs and reused to fabricate other Janus nanodiscs. Functional compositions such as paramagnetic Fe3O4 nanoparticles and polymers with different wettability properties are introduced onto the different regions of Janus nanodiscs to achieve magnetic Janus nanodiscs. They are used as efficient solid surfactants to stabilize emulsion.

We present a review of the very recent advances in the synthesis of block copolymer (BCP) Janus nanomaterials. Although Janus micelles can form by the self-assembly of BCPs in solution, patchy or core–shell structures are usually dominant. Structural transformation of the core–shell structure or disassembly of the patchy structure is further employed to achieve Janus nanomaterials. Disassembly of ABC tri-block terpolymer supramolecular structures is advantageous in tuning much more easily the shapes of the Janus nanomaterials from spherical to cylindrical and sheet/disc-like. Narrow molecular weight distributions and strict processing conditions are required. Emulsion droplet confined self-assembly of BCPs can directly achieve Janus nanomaterials in a sufficiently small droplet and/or at low polymer concentration. A neutral emulsion interface is required using proper surfactants. Alternatively, a general method has been proposed to prepare Janus nanomaterials by guided self-assembly of BCPs within a confined environment by the strong interaction and the selective crosslinking of one block. The aforementioned Janus nanomaterials are in the form of a polymer cluster. Single chain Janus nanomaterials of BCPs can be prepared by intramolecular crosslinking of one block in a very dilute solution. It remains challenging to synthesize single chain Janus nanomaterials at high solid content for example tens of percent. At the end of this review, a perspective on BCP Janus nanomaterials is provided.

In this work, an injectable composite hydrogel was synthesized via a unique way of crosslinking glycol chitosan (GC) with silica nano-particles (SiNP) through non-chemical interactions, and was then applied as a kind of wound dressing. Gelation was achieved through the incorporation of SiNPs with the GC segments in aqueous solution, therefore strictly confining the movement of the solubilized polymer chains. Rheology tests showed that the sol-gel transition and the moduli of the hydrogel were influenced by the composition of the two components, the size of the nano-particles and the conformation of the polymers. Using such a strategy, tissue adhesion properties of GC were well-preserved in the GC/SiNP hydrogel and therefore it gains gluey properties toward biological tissues as demonstrated through the adhesion of two pieces of mouse skin, obtaining a lap-shear stretching force of ca. 90 kPa. This characteristic, together with the injectability, allowed the hydrogel to be administrated directly on the wound site and to fill the wound area. Meanwhile, the hydrogel also works as a carrier of protein and cells. The in situ encapsulation of fibroblasts enabled the promising properties of the GC/SiNP hydrogel to be used for treating full-thickness skin defects in a mouse model, resulting in the favorable growth of hair follicles and microvessels, hence reducing the risk of scar formation.

Efficient control of Tetranychus cinnabarinus (B.) is in challenge worldwide. Herein we report the use of an amphiphilic block copolymer, poly(ethylene oxide)-b-poly(caprolactone) (PEO–PCL), as a micellar carrier to make formulations of ricinine, a water insoluble botanical pesticide, and the tests of their physical properties and moreover the acaricidal activity on Vigna unguiculata (L). Compared to the formulations made from small molecular surfactant, e.g. Tween-80, the polymer formulations showed differentiated spreading property on T. cinnabarinus (B.) and V. unguiculata (L.) leaf surfaces, i.e. having slightly lower contact angle on the mite's integument. This contributes a relatively easy wash-off performance of the polymer formulations from the V. unguiculata (L.) leaf and meanwhile an enhanced protection to the plant in the simulated field trial. Our work thus suggests favorable characteristic of amphiphilic polymer in the future development of insecticides.

A Fe3O4 nanoparticle (NP) based on composite Janus NP with single polymer chain is prepared by termination of the modified Fe3O4 NP with the anionic living polymer chain. The requisite that the polymer chain should be sufficiently large over the NP diameter determines the grafting of single polymer chain. From the opposite side of the NP surface, functional species can be selectively grown for example grafting responsive PNIPAM by ATRP. Besides simple combination of the thermal and magnetic responsive performances of different components, the PS–Fe3O4–PNIPAM composite Janus NP shows additional interactive performance such as NIR-triggered Janus/hydrophobic transition at low surrounding temperature below LCST ∼ 32 °C.

The Fe3O4@SiO2 paramagnetic Janus particles with phenyl groups and amino groups segmented on two different sides were fabricated by the Pickering emulsion method. Then, the poly(ionic liquid)s were...

Bi-continuous emulsion stabilized with amphiphilic Janus particles was achieved. Phase inversion of the as-formed emulsion was driven by increasing water content. The orientated Janus particle monolayer at the bi-continuous emulsion interface is interconnected by interfacial polymerization to form robust materials with amphiphilic channels.

A particle mold synthesis of 2D Janus nanomaterials is proposed by crosslinking of copolymer self-assembled monolayers confined within the mold domains. Onto the silica (SiO2 ) particle surface, mold domains with functional groups such as imidazole are generated. The model copolymer of polyacrylic acid-block-polystyrene (PAA-b-PS) can be preferentially absorbed onto the domains via electrostatic interactions, forming a self-assembled monolayer. In a cosolvent such as tetrahydrofuran (THF), the crosslinking occurs within the whole of the PAA side. A Janus disc is thus achieved after detachment from the particle upon breaking the specific interaction. In a poor solvent, the crosslinking slowly occurs from the periphery, giving Janus nanorings. The rings evolve into discs with further crosslinking. The mold particles can be recycled to synthesize the same 2D Janus materials.

A Janus porous sphere with a coral-like microstructure is prepared by stepwise dealloying a metallic alloy sphere and sequential modification (for example, using silanes and polymers). Nanoscale coral-like microstructure of the internal skeleton gives remarkable capillary force, thus accelerating the mass transportation. Starting from the outer layer of the sphere, stepwise dealloying can achieve different layers inwardly, thus introducing different composition and performance. As an example, poly(ethylene glycol)-poly(N-isopropylacrylamide) (PEG-PNIPAM)- and poly(ethylene glycol)-poly(N,N-diethylamino-2-ethylmethacrylate) (PEG-PDEAEMA)-responsive Janus porous spheres can quickly capture oil by simply changing temperature or pH. Similarly, release is also triggered.

We propose a facile method to achieve paramagnetic Janus nanotubes with two compositions compartmentalized onto the interior and exterior surfaces, respectively. A sulfonated polydivinylbenzene (PDVB) nanotube is prepared by simple sulfonation of the exterior surface of a PDVB nanotube. Silica@FeOOH dual layers are sequentially grown onto the sulfonated PDVB nanotube surface. The composite nanotubes become paramagnetic after calcination and can be broken into shorter pieces under vigorous ultrasonication. After selective modification of the interior and exterior surfaces of the paramagnetic nanotubes, the nanotube shell becomes Janus in wettability. Desired hydrophobic species can be selectively captured inside the cavity. The paramagnetic Janus composite nanotubes can align into parallel chains under a magnetic field, which is self-disassembled upon removal of the magnetic field.

We present a facile approach toward straightforward synthesis of Janus nanoparticles (NPs) of poly(4-vinylpyridine)-based block copolymers by solvent evaporation induced assembly within emulsion droplets. Formation of the Janus NPs is arisen from the synergistic effect between solvent selectivity and interfacial selectivity. This method is robust without the requisites of narrow molecular weight distribution and specific range of block fraction of the copolymers. Janus NPs can also be achieved from mixtures of copolymers, whose aspect size ratio and thus Janus balance are finely tunable. The Janus NPs are capable to self-assemble into ordered superstructures either onto substrates or in dispersions, whose morphology relies on Janus balance.

Herein we report a facile route for the preparation of surface patterned dynamic hydrogel films, which are not only a matrix to encapsulate one type of cell in 3D but also a substrate to support aligned aggregates of magnetic silica rods to adhere another type of cell in 2D. This enables the composite hydrogel films to be flexible scaffolds for engineering multi-cellular tissues.

A series of nanocomposite elastomers are prepared by dispersing surface-modified silica Janus nanoparticles into semi-interpenetrating network (Semi-IPN) of polyurethane/polyethyl methacrylate. Benefiting from the hierarchically crosslinked structures that consist of physical interlocking mediated by hydrogen-bond-rich silica Janus nanoparticles and permanent crosslinking by Semi-IPN, these elastomers exhibit excellent mechanical properties. Moreover, the Janus nanosheet is found more effective in strengthening and toughening the Semi-IPN, in comparison to Janus hollow sphere. Since 1,2-dioxetane is covalently embedded in these elastomers as a mechanoluminescent stress probe, stress transfer between the polymer and Janus nanoparticles and the toughening mechanism can be illuminated, which offer exciting opportunities to study the failure process of complex polymer nanocomposites with high spatial and temporal resolution.

Liquid crystal (LC) ordering and phase transition behavior under confined conditions have attracted extensive attention and enabled many applications. However, the ordering and phase transition behavior of LCs in submicrometer capsules have seldom been studied, primarily due to the lack of proper capsulizing and visualization approaches to such small LC microcapsules. Herein, we achieve submicrometer LC capsules with the sizes down to 100 nm by using emulsion-based interfacial sol-gel reaction. The behavior of LCs under the submicrometer confinement conditions is investigated while the sizes and chemical composition of the microcapsule shell surface are tuned in a controllable way. The phase transition temperatures of LCs in the submicrometer capsules shift from those of bulk LCs due to the surface-induced ordering of LCs under the strong confinement conditions, which causes formation of topological defects and alters the order parameter. Using nonlinear optical imaging technology, we explore the structures of director field of LCs that arise as a result of the competition between the surface boundary conditions and LC elasticity. The results show that the nanoscale encapsulation can significantly influence the structural configurations of the director and phase transitions of LCs under various confinement conditions.

Metal hydrides have attracted great intentions as anodes for lithium-ion batteries (LIBs) due to their extraordinary theoretical capacity. It is an unsolved challenge, however, to achieve high capacity with stable cyclability, owing to their insulating property and large volume expansion upon lithium storage. Here, we introduce self-initiated polymerization to realize molecular-scale functionality of metal hydrides with conductive polymer, that is, polythiophene (PTh), on graphene, leading to the formation of MgH2@PTh core-shell nanoparticles on graphene. The nanoscale characteristics of MgH2 not only relieve the induced stress upon volume changes but also allow fast diffusivity and high reactivity for Li-ion transport. More importantly, the conformal coating of ultrathin PTh membrane can effectively suppress the detrimental reactions between MgH2 and electrolyte, provide enhanced performance with facile electron and Li+ transport, and preserve its structural integrity, attributed to the strong molecular interaction between PTh and MgH2 as well as its various products during electrochemical reactions. With this structure, a high reversible specific capacity of 1311 mAh g-1 at 100 mA g-1, excellent rate performance of 1025 mAh g-1 at 2000 mA g-1, and a capacity retention of 84.5% at 2000 mA g-1 after 500 cycles are observed for MgH2@PTh nanoparticles as anode for LIBs.

The asymmetric ABC-type Janus polymer composite nanorods are synthesized by the in situ preferential growth of functional materials against the molecular bottlebrush containing a triblock copolymer of poly(ethylene oxide)-b-poly(2-methacryloyloxyethyl pentynoate-g-poly(acrylic acid))-b-polystyrene. PEO and PS single chains are terminated onto the opposite ends of the composite nanorods. The two polymer chains are responsible for amphiphilic performance, while the composite nanorod is responsible for the functionality. The Janus nanorods can stand vertically at an emulsion interface, making the interfaces easily functionalized and manipulated. Protection of the PAA molecular bottlebrush via electrostatic interaction is important to obtaining individual nanorods at high solid contents. A huge family of Janus composite nanorods is expected by changing the compositions of the two polymer chains and the nanorod.

Herein we present a unique method of using dynamic cross-links, which are dynamic covalent bonding and ionic interaction, for the construction of injectable double-network (DN) hydrogels, with the objective of cell delivery for cartilage repair. Glycol chitosan and dibenzaldhyde capped poly(ethylene oxide) formed the first network, while calcium alginate formed the second one, and in the resultant DN hydrogel, either of the networks could be selectively removed. The moduli of the DN hydrogel were significantly improved compared to that of the parent single-network hydrogels and were tunable by changing the chemical components. In situ 3D cell encapsulation could be easily performed by mixing cell suspension to the polymer solutions and transferred through a syringe needle before sol–gel transition. Cell proliferation and mediated differentiation of mouse chondrogenic cells were achieved in the DN hydrogel extracellular matrix.

Two Janus-type catalysts were synthesized by selective modification and further functionalization with metal nanoparticles on one or both beads of snowman-like Janus particles. The catalytic performance of Janus-type catalysts both in homogeneous and interfacial reaction systems was systematically investigated using the reduction of nitro-compound as model reaction. The results showed that Janus-type catalysts have excellent catalytic activity in homogeneous reaction system and they are easy to recycle. Further, the Janus-type catalysts exhibited more efficient catalytic activity at emulsion interface than that of oil-water biphasic interface due to the exposed Au nanoparticles on snowman-like Janus particles offer high accessibility to reactants.

The platelet-shaped Janus nanocages with a mesoporous silica shell are prepared. PEG moiety onto the exterior surface is responsible for good dispersity in water. The graphene sheet inside the cavity is responsible for hydrophobic performance to selectively capture hydrophobic species, and photothermal effect by NIR irradiation. As a biocompatible DOX-loaded Janus platelet delivery, HeLa cell cytotoxicity is greatly enhanced under NIR irradiation. There exists a synergetic effect between the chemotherapy and photothermal therapy.

Multitarget tracking in video surveillance is challenging because the appearance features of the target are often unreliable in complicated scenes. To solve the problem, we propose a multitarget tracking method using multifeature model with acceleration feature. First, an acceleration feature descriptor is derived from the histograms of the optical flow features according to the background difference. Our approach filters and normalizes the descriptors of consecutive frames to establish acceleration feature models. Then, the multifeature models of target templates are initialized by combining acceleration and multiple spatial feature models. Second, we implement data association based on the tracklet confidence by integrating the acceleration and multiple spatial feature affinities. As a result, the optimal associated pairs between target tracklets and detections are solved by the Hungarian algorithm. Finally, our tracking system updates the multifeature models of target templates online depending on the reliability of the tracklets, and the trajectories of multiple targets are output. Experiments conducted on the challenging multiple object tracking benchmark confirm the effectiveness and superiority of the proposed method.

Emulsions of two immiscible liquids can slowly coalesce over time when stabilized by surfactant molecules. Pickering emulsions stabilized by colloidal particles can be much more stable. Here, we fabricate biocompatible amphiphilic dimer particles using a hydrogel, a strongly hydrophilic material, and achieve large contrast in the wetting properties of the two bulbs, resulting in enhanced stabilization of emulsions. We generate monodisperse single emulsions of alginate and shellac solution in oil using a flow-focusing microfluidics device. Shellac precipitates from water and forms a solid bulb at the periphery of the droplet when the emulsion is exposed to acid. Molecular interactions result in amphiphilic dimer particles that consist of two joined bulbs: one hydrogel bulb of alginate in water and the other hydrophobic bulb of shellac. Alginate in the hydrogel compartment can be cross-linked using calcium cations to obtain stable particles. Analogous to surfactant molecules at the interface, the resultant amphiphilic particles stand at the water/oil interface with the hydrogel bulb submerged in water and the hydrophobic bulb in oil and are thus able to stabilize both water-in-oil and oil-in-water emulsions, making these amphiphilic hydrogel-solid particles ideal colloidal surfactants for various applications.