Hydrophobic nanochannel self-assembled by amphipathic Janus particles confined in aqueous nano-space

Hydrophobic nanochannel plays a significant role in many physical, biological, and geological phenomena and ex- hibits impressive applications due to both its ubiquitous distribution and great ability to transport hydrophobic molecules, including various oils and gases. Based on theoretical modeling, we herein reveal that the amphipathic Janus nanoparticles have a large probability to self-assemble into uninterrupted hydrophobic nanochannels inside the aqueous nano-space, al- though there are large portions of the Janus nanoparticles to be hydrophilic. The key to this observation is the attractions between the hydrophobic regimes on neighboring amphipathic Janus particles through hydrophobic interaction in aqueous nano-space. More surprisingly, the permeation efficiency of hydrophobic molecules through the uninterrupted hydrophobic channel in Janus particles aggregate is even higher than that in the aggregate of hydrophobic particles. We note that the proposed amphipathic Janus particles can be transported to the appropriate positions by the water since the hydrophilic regimes still remain a strong particle-water interaction. We also note that most natural subsurface rocks are not completely hydrophobic or hydrophilic but have complex surfaces with inhomogeneous wetting property. Our work therefore provides a detailed molecular level understanding of the formation of underground strata as well as the new insight for constructing the artificial hydrophobic channels for various applications, such as the design of proppants to enhance the recovery of the unconventional oil/gas.

Photonic lenses with whispering gallery waves at Janus particles

We show that electric field on the plane surface of truncated sphere or cylinders(so called Janus particles)have sharp resonances versus the depth of removed segment of a sphere or cylinder.These resonances are related to the excited whispering gallery waves caused by truncation.It is a new mechanism of the field localization.Optimization of this effect for cylinders permits to reach a super resolution in the line thickness,which can be used for contact optical lithography.

Interfacial Engineering of Polymer Blend with Janus Particle as Compatibilizer

Mixing two or more polymers to produce the“polymer alloy”is one of the most versatile and economical strategies for developing new polymeric materials.The compatibility between polymer components largely determines the comprehensive performance of polymer blend.More recently,a type of unique surface partitioned materials,Janus particles,has been proposed to act as a novel interfacial compatibilizer for polymer blends.Such Janus particles integrates the amphipathicity of diblock copolymer and interfacial stabilization of nanoparticles,displaying a significant superiority in comparison with molecular compatibilizers for a wide range of polymer blends.In this review,we mainly focus on the compatibilizing effects of Janus nanofillers of various morphologies,including spherical,snowman-like,and two-dimensional nanosheets,on polymer blends.We shed light on the impacts of compatibilization of Janus particles on phase morphologies,mechanical properties,and functionalities of polymer blends.This review could provide a guidance for designing an effective Janus particle compatibilizer to develop high-performance polymer blends.

Numerical study on heat and mass transfer mechanisms of Janus particle sedimentation considering corrosion

Janus particle is a research hotspot due to its novelty and settlement in acid liquid during wastewater treatment.Heat and mass transfer mechanisms of Janus particle sedimentation considering corrosion are numerically investigated based on immersed boundary lattice Boltzmann method.Chemical reaction heat ratio,Damkohler number,Peclet number,and particle number effects on temperature field,concentration field,Janus particle mass reduction,position,and velocity are investigated.The uniform particle has an equilibrium position of about 1/4 times the channel width for two corroded uniform particle settlement processes.The Janus particle horizontal position deviates from the uniform particle equilibrium position due to the force caused by nonuniform buoyancy and particle rotation.When the chemical reaction heat ratio is more than 1,the Janus particle horizontal position is closer to the channel centerline and has a positive deviation.However,the converse trend happens when the chemical reaction heat ratio is less than 1,and the Janus particle horizontal position has a negative deviation.The Janus particle horizontal position deviation magnitude increases with increasing Damkohler number and decreasing Peclet number.The horizontal position deviation phenomenon exists for the single corroded Janus particle and two corroded Janus particle settlement processes.

In situ synthesis of Ag-SiO_2 Janus particles with epoxy functionality for textile applications

A facile method for the synthesis of silver-silica （Ag-SiO2）Janus particles with functionalities suitable for textile applications is reported. Silica nanoparticles prepared by the StOber method were functionalized with epoxy, amine, and thiol groups, which were confirmed by Fourier transform infrared analysis. The functionalized silica nanoparticles were used to produce Pickering emulsions, and the exposed surface was used for the attachment of silver nanoparticles （AgNPs） via the low-temperature chemical reduction method. The morphology and structure of the Ag-SiO2 Janus particles were characterized by scanning electron microscopy, scanning transmission electron microscopy, high-resolution transmission electron microscopy, energy-dispersive X-ray analysis, and UV-vis spectroscopy. Because of their specific functionalities, these Ag-SiO2 Janus particles are proposed for applications on textile substrates, as they can overcome several drawbacks of direct application of AgNPs on textiles, such as leaching, agglomeration, and instability during storage.

Magnetic field-mediated Janus particles with sustained driving capability for severe bleeding control in perforating and inflected wounds

Severe bleeding in perforating and inflected wounds with forky cavities or fine voids encountered during prehospital treatments and surgical procedures is a complex challenge.Therefore,we present a novel hemostatic strategy based on magnetic field-mediated guidance.The biphasic Janus magnetic particle(MSS@Fe2O3-T)comprised aggregates ofα-Fe2O3 nanoparticles(Fe_(2)O_(3) NPs)as the motion actuator,negatively modified microporous starch(MSS)as the base hemostatic substrate,and thrombin as the loaded hemostatic drug.Before application,the particles were first wrapped using NaHCO_(3) and then doped with protonated tranexamic acid(TXA-NH_(3)^(+)),which ensured their high self-dispersibility in liquids.During application,the particles promptly self-diffused in blood by bubble propulsion and travelled to deep bleeding sites against reverse rushing blood flow under magnetic guidance.In vivo tests confirmed the superior hemostatic performance of the particles in perforating and inflected wounds(“V”-shaped femoral artery and“J”-shaped liver bleeding models).The present strategy,for the first time,extends the range of magnetically guided drug carriers to address the challenges in the hemorrhage control of perforating and inflected wounds.

Collective diffusion in a two-dimensional liquid composed of Janus particles

The collective diffusion of anisotropic particles in liquids plays a crucial role in many processes,such as self-assembly.The patchy particle,which is usually nearly spherical in shape,is an important anisotropic particle with different properties from other anisotropic particles like the ellipsoid liquid crystal particles.In the present study,molecular dynamics simulations are performed to study the collective diffusion of a two-dimensional anisotropic liquid system composed of Janus particles.The static structures and diffusion behaviours of anisotropic and isotropic Lennard-Jones liquids are compared.The long-time diffusion behaviour of an anisotropic liquid of nearly spherical Janus particles is found to be similar to that of an isotropic liquid because the orientation of the particles disappears over long-term averaging.The anisotropic properties of the Janus particles are mainly reflected in the spatial correlation of particle orientations and mid-time diffusion behaviour.The difference between nearly spherical anisotropic particles and rod-like particles is also discussed in this paper.

Phase behavior and percolation in an equilibrium system of symmetrically interacting Janus disks on the triangular lattice

A Janus particle has two distinct areas on its surface.Denoting the two areas as P(patch)and N(nonpatch),when two particles come close to each other,the strength of the PP interaction is usually different from that of the NN interaction.Recently the interplay between a rotational-symmetry-breaking continuous phase transition and percolation has been explored for an equilibrium system of asymmetrically interacting(i.e.,attractive PP interaction,zero NN and PN interactions)Janus disks on the triangular lattice.By Monte Carlo simulation and finite-size scaling analysis,in this work we study an equilibrium system of symmetrically interacting(i.e.,attractive PP and NN interactions with the same strength,zero PN interaction)Janus disks on the same lattice.By definition,the phase diagram in the T-θplane is symmetric for systems with patch sizesθbelow and above 90°.We determine the phase diagram and compare it with that of the asymmetric system.Similar to the latter system,for 60°<θ<90°,a rotational-symmetry-breaking continuous phase transition and an anisotropic percolation transition are found in the symmetric system,though the transition points in the two systems are quite different.Phase crossover curves are found to be different,e.g.,a continuous varying crossover line extends betweenθ=0°and 90°for the symmetric model;and in the range 0°<θ≤30°,along the crossover lines of the two models,the trends of 1/T vs.θare opposite in the two systems.We understand the latter by analytically solving the models with two particles in 0°<θ≤30°.These results are helpful for understanding close-packed systems of Janus disks with more complex interactions.

Mitochondria-targeted Janus mesoporous nanoplatform for tumor photodynamic therapy

Photodynamic therapy(PDT)is an effective treatment method for tumors.But the specifically accumulated of photosensitizer was very difficult in the tumor site,which greatly limited the efficacy of PDT.Here,mitochondria-targeted Janus mesoporous nanoplatform(JPMO-Pt-CTPP-ZnPc)for PDT was prepared,the nanoplatform has uniform size(275 nm)and good dispersion and biocompatibility.The confocal laser scanning microscopy(CLSM)revealed the signal of ZnPc of JPMO-Pt-CTPP-ZnPc were higher than JPMO-Pt-ZnPc in tumor cells,and flow cytometry results showed the cell uptake efficiency of JPMO-Pt-CTPP-ZnPc was 2.5-fold higher than that of JPMO-Pt-ZnPc.This revealed the modification of CTPP significantly improves the targeting ability of the nanoplatform.In vitro anti-tumor experiment showed the JPMO-Pt-CTPP-ZnPc significantly inhibited the growth of tumor cells upon the irradiation of low-power laser,and the survival rate of cells incubated with 60μg/mL JPMO-Pt-CTPP-ZnPc was only 3%.Simultaneously,compared with JPMO-Pt-ZnPc(not modified with mitochondria targeting molecules CTPP),the PDT efficacy of JPMO-Pt-CTPP-ZnPc was significantly better,as it has targeted mitochondria in cells.

Single Emulsion Microfluidic Production of Janus and Core-Shell Particles via Off-chip Polymerization

In this work, we describe a straightforward approach to produce monodisperse Janus and core-shell particles by using organic solvent free single emulsion droplet-based microfluidic device combining with off-chip polymerization. To accomplish this, methyl methacrylate（MMA） was used as both the oil phase and solvent to dissolve a polymerizable PEGbased macromolecular surfactant, instead of traditional surfactant, and the photo-initiator. Janus particles can be easily obtained by off-chip UV polymerization due to polymerization induced phase separation between PEG and the formed poly（methyl methacrylate）. At the same time, core-shell particles can also be easily attained by inverting the original collecting tube several times and then exposing to UV light. These results may extend the scope of microfluidic technology and the studies on polymerization induced self-assembly/phase-separation into easy fabrication of various new functional materials.

Flow-pattern-altered syntheses of core–shell and hole–shell microparticles in an axisymmetric microfluidic device

Droplet-based microfluidics offers unique advantages to create platforms that fabricate functionalized particles with increased accessibility,robustness,and simplicity.Herein we present a three-phase microfluidic device that can control the flow pattern to directly generate either core–shell or hole–shell microparticles.The major benefits of this device are the ease of controlling the morphology of the compound droplets by the flow rates and thus the microstructure of the synthesized microparticles.The transition between flow patterns enables the generation of either core–shell particles or Janus particles in a single device.We further show the versatility of the proposed device in fabrication of functionalized particles:the hole size of the hole–shell microparticle can be fine-tuned while its outer diameter is kept constant,and by adding Fe_(3)O_(4) nanoparticles into the photocurable phase,the obtained magnetoresponsive microparticle can move rotationally or translationally under an external magnetic field.We anticipate that the present method could facilitate the fabrication of the functional microparticles for diverse applications.