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 relate...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.展开更多
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 hyd...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.展开更多
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 part...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.展开更多
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 ...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.展开更多
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 polym...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.展开更多
Compatibilization is crucial for the blending of immiscible polymers to develop high-performance composites;however,traditional compatibilization by copolymers(pre-made or in-situ generation)suffers from weak interfac...Compatibilization is crucial for the blending of immiscible polymers to develop high-performance composites;however,traditional compatibilization by copolymers(pre-made or in-situ generation)suffers from weak interface anchoring,and inorganic particles have gained extensive attention recently owing to their large interfacial desorption energy,while their low affinity to bulk components is a drawback.In this study,an interfacial atom transfer radical polymerization(ATRP)technique was employed to grow polystyrene(PS)and poly(2-hydroxyethyl methacrylate)(PHEMA)simultaneously on different hemispheres of Br-functionalized SiO_(2) nanoparticles to stabilize a Pickering emulsion,whereby a brush-type Janus nanoparticle(SiO_(2)@JNP)was developed.The polymer brushes were well-characterized,and the Janus feature was validated by transmission electron microscope(TEM)observation of the sole hemisphere grafting of SiO_(2)-PS as a control sample.SiO_(2)@JNP was demonstrated to be an efficient compatibilizer for a PS/poly(methyl methacrylate)(PMMA)immiscible blend,and the droplet-matrix morphology was significantly refined.The mechanical strength and toughness of the blend were synchronously enhanced at a low content SiO_(2)@JNP optimized~0.9 wt%,with the tensile strength,elongation at break and impact strength increased by 17.7%,26.6%and 19.6%,respectively.This enhancement may be attributed to the entanglements between the grafted polymer brushes and individual components that improve the particle-bulk phase affinity and enforce interfacial adhesion.展开更多
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 st...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.展开更多
Biocompatible amphiphilic nanoparticles(NPs)with tunable particle morphology and surface property are important for their applications as functional materials.However,previously developed methods to prepare amphiphili...Biocompatible amphiphilic nanoparticles(NPs)with tunable particle morphology and surface property are important for their applications as functional materials.However,previously developed methods to prepare amphiphilic NPs generally involve several steps,especially an additional step for surface modification,greatly hindering their largescale production and widespread applications.Here,a versatile one-step strategy is developed to prepare biocompatible amphiphilic dimer NPs with tunable particle morphology and surface property.The amphiphilic dimer NPs,which consist of a hydrophobic shellac bulb and a hydrophilic poly(lactic acid)(PLA)bulb with PLA-poly(ethylene glycol)(PEG)on the bulb surface,are prepared in a single step by controlled co-precipitation and self-assembly.Amphiphilic PLA-PEG/shellac dimer NPs demonstrate excellent tunability in particle morphology,thus showing good performances in controlling the interfacial curvature and emulsion type.In addition,temperatureresponsive PLA-poly(N-isopropyl acrylamide)(PNIPAM)/shellac dimer NPs are prepared following the same method and emulsions stabilized by them show temperature-triggered response.The applications of PLA-PEG-folic acid(FA)/shellac dimer NPs for drug delivery have also been demonstrated,which show a very good performance.The strategy of preparing the dimer NPs is green,scalable,facile and versatile,which provides a good platform for the design of dimer NPs with tunable particle morphology and surface property for diverse applications.展开更多
Sizing treatment is a suitable technique to modify the fiber-matrix interfaces without damage of inherent performance of fibers.In this work,sizing agents based on Janus particles(JPs)were utilized to enhance the inte...Sizing treatment is a suitable technique to modify the fiber-matrix interfaces without damage of inherent performance of fibers.In this work,sizing agents based on Janus particles(JPs)were utilized to enhance the interface of basalt fiber(BF)/poly(vinyl chloride)(PVC)composites.polystyrene/poly(butyl acrylate)(PS/PBA)@silica JPs were synthesized by seed emulsion polymerization and three different sizing agents were prepared for BF sizing treatment.JPs with organic soft sphere and inorganic hard hemisphere enhanced the interfaces through their amphiphilicity,chemical bonding and mechanical interlock.The mechanical properties of composite with JPs sizing treated BFs performed better when there was one JPs layer modified on the interface.According to the intermitting bonding and gradient modulus theory,JPs patterned interfaces are ideal transition layers between high modulus BF and low modulus PVC.展开更多
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 ...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.展开更多
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...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.展开更多
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 devi...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.展开更多
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...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.展开更多
Optical tweezers are precise tools for translating and rotating micrometer-sized particles and are used widely in biology and physics.In a linearly polarized optical trap,Janus particles comprising two hemispheres wit...Optical tweezers are precise tools for translating and rotating micrometer-sized particles and are used widely in biology and physics.In a linearly polarized optical trap,Janus particles comprising two hemispheres with different refractive indexes can be rotated about the beam axis following the polarization direction.In previous research,the position and orientation of a Janus particle relative to the polarization direction were simulated using the T-matrix method,whereas this paper is focused on accurate experimental measurements.The position and orientation of a Janus particle are extracted by image processing,and the polarization direction is controlled by a motor-driven half-wave plate(HWP).The particle’s orientation and the polarization direction are related via the HWP’s rotation angle.However,rotating the HWP not only rotates the polarization direction but also causes the trap center to fluctuate positionally because of the inevitable misalignment between the HWP’s rotation axis and the optical axis.Both the trap center and the polarization direction affect the particle’s position,but the influence of the former is removed with the aid of a homogeneous microsphere.The experimental results show that the Janus particle rotates following the polarization direction to keep the interface between its two hemispheres always parallel to the polarization direction.Also,the particle’s centroid moves in a circular orbit around the trap center to hold the trap center in the hemisphere with the higher refractive index.The experimental results agree with the previous simulation results and are of use for future applications.展开更多
Active matter encompasses all systems in which each individual constituent independently dissipates energy in its environment.This definition brings together biological systems such as cellular tissues,bacterial colon...Active matter encompasses all systems in which each individual constituent independently dissipates energy in its environment.This definition brings together biological systems such as cellular tissues,bacterial colonies,cytoskeletal filaments driven by molecular motors and animal groups,as well as collections of inert self-propelled particles such as Janus particles,[1]colloidal rollers[2]or vibrated grains.[3]Because of the local persistent drive,these systems are far from thermal equilibrium and cannot be described in terms of thermodynamic potentials.This leads to surprising physics that defies some of the basic intuitions that we have from passive systems,including longrange order in two dimensions[4]and phase-separation in absence of attractive interactions.展开更多
Janus particles,in which two distinct compositions are integrated,have attracted considerable interest for their potential multi-functionalities and synergistic effects.Although seed-mediated growth appears to be a su...Janus particles,in which two distinct compositions are integrated,have attracted considerable interest for their potential multi-functionalities and synergistic effects.Although seed-mediated growth appears to be a suitable strategy that meets the stringent specifications for obtaining Janus particles,it is inapplicable to guide the growth of two crystalline components with different crystal structures.Herein,the formation of Janus particles via phase segregation is proposed.As proof-of-concept,promising photon conversion materials,ScF_(3)and lanthanide(Ln)fluorides,with great differences in structure,were chosen to build a series of Janus particles.Interestingly,using heavy(Lu,Yb,Dy and Tb)and light(Pr,Nd,Sm,Eu and Gd)lanthanides,ScF_(3)-LiLnF_(4)and ScF_(3)-LnF_(3)were formed,respectively.Time-dependent reaction studies indicate that phase segregation paves the way for the formation of these Janus nanoparticles(NPs),and this speculation is further confirmed by in situ transmission electron microscopy observations.These investigations provide new insights for the synthesis of heterostructured materials.展开更多
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...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.展开更多
基金This work was also supported by the Ministry of Science and Higher Education of the Russian Federation(project no.14.W03.31.0008)in part by the Russian Science Foundation(project no.20-12-00389)+1 种基金in part by the Russian Foundation for Basic Research(projects no.20-02-00715,no.21-58-10005,no.21-57-10001).Z.B.Wang acknowledges European ERDF grants(CPE 81400 and SPARCII c81133)through WEFO,and Royal society grants(IEC\NSFC\181378 and IEC\R2\202178).
文摘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.
基金Project supported by the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB10040304)the National Natural Science Foundation of China(Grant Nos.51490654,11290164,and U1262109)the Key Research Program of Chinese Academy of Sciences(Grant No.KJZDEW-M03)
文摘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.
基金supported by the Yunnan Fundamental Research Projects (Grant No. 2019FI002, 202101AS070018 and 202101AV070015)Xingdian Talents Support Program, Yunnan Province Ten Thousand Talents Plan Young & Elite Talents Project+1 种基金Yunnan Province Computational Physics and Applied Science and Technology Innovation Teamsupport of the National Natural Science Foundation of China with Grant Nos. 12075017 & 12265017。
文摘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.
基金partial financial support from the Department of Science and Technology,Government of India
文摘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.
基金financially supported by the National Natural Science Foundation of China(Nos.21274102 and 21304063)the Priority Academic Program Development(PAPD)of Jiangsu Higher Education Institutions
文摘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.
基金financially supported by the National Natural Science Foundation of China(Nos.22172028,21903015,and 22403017)Natural Science Foundation of Fujian Province of China(No.2022J05041)。
文摘Compatibilization is crucial for the blending of immiscible polymers to develop high-performance composites;however,traditional compatibilization by copolymers(pre-made or in-situ generation)suffers from weak interface anchoring,and inorganic particles have gained extensive attention recently owing to their large interfacial desorption energy,while their low affinity to bulk components is a drawback.In this study,an interfacial atom transfer radical polymerization(ATRP)technique was employed to grow polystyrene(PS)and poly(2-hydroxyethyl methacrylate)(PHEMA)simultaneously on different hemispheres of Br-functionalized SiO_(2) nanoparticles to stabilize a Pickering emulsion,whereby a brush-type Janus nanoparticle(SiO_(2)@JNP)was developed.The polymer brushes were well-characterized,and the Janus feature was validated by transmission electron microscope(TEM)observation of the sole hemisphere grafting of SiO_(2)-PS as a control sample.SiO_(2)@JNP was demonstrated to be an efficient compatibilizer for a PS/poly(methyl methacrylate)(PMMA)immiscible blend,and the droplet-matrix morphology was significantly refined.The mechanical strength and toughness of the blend were synchronously enhanced at a low content SiO_(2)@JNP optimized~0.9 wt%,with the tensile strength,elongation at break and impact strength increased by 17.7%,26.6%and 19.6%,respectively.This enhancement may be attributed to the entanglements between the grafted polymer brushes and individual components that improve the particle-bulk phase affinity and enforce interfacial adhesion.
基金This work was supported by the National Natural Science Foundation of China(No.51703185,51803170,and 51803171)the Fundamental Research Funds for the Central Universities(nos.XDJK2019AC003 and XDJK2020B017).
文摘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.
基金supported by National Natural Science Foundation of China(No.22278352)National Key Research and Development Program of China(No.2021YFC3001100)+3 种基金Longyan City Science and Technology Plan Project(No.2020LYF17043)Longyan City Science and Technology Plan Project(No.2020LYF17042)ARC Discovery Project(No.DP200101238)and NHMRC Investigator Grant(No.APP2008698)supported by the Harvard Materials Research Science and Engineering Center(No.DMR2011754)。
文摘Biocompatible amphiphilic nanoparticles(NPs)with tunable particle morphology and surface property are important for their applications as functional materials.However,previously developed methods to prepare amphiphilic NPs generally involve several steps,especially an additional step for surface modification,greatly hindering their largescale production and widespread applications.Here,a versatile one-step strategy is developed to prepare biocompatible amphiphilic dimer NPs with tunable particle morphology and surface property.The amphiphilic dimer NPs,which consist of a hydrophobic shellac bulb and a hydrophilic poly(lactic acid)(PLA)bulb with PLA-poly(ethylene glycol)(PEG)on the bulb surface,are prepared in a single step by controlled co-precipitation and self-assembly.Amphiphilic PLA-PEG/shellac dimer NPs demonstrate excellent tunability in particle morphology,thus showing good performances in controlling the interfacial curvature and emulsion type.In addition,temperatureresponsive PLA-poly(N-isopropyl acrylamide)(PNIPAM)/shellac dimer NPs are prepared following the same method and emulsions stabilized by them show temperature-triggered response.The applications of PLA-PEG-folic acid(FA)/shellac dimer NPs for drug delivery have also been demonstrated,which show a very good performance.The strategy of preparing the dimer NPs is green,scalable,facile and versatile,which provides a good platform for the design of dimer NPs with tunable particle morphology and surface property for diverse applications.
基金supported by the National Natural Science Foundation of China(Nos.U22A20252 and 52173076)the Beijing Natural Science Foundation(Nos.Z240030 and L248023)the Liaoning Province Key Research and Development Project(No.2024JH2/102400046)。
文摘Sizing treatment is a suitable technique to modify the fiber-matrix interfaces without damage of inherent performance of fibers.In this work,sizing agents based on Janus particles(JPs)were utilized to enhance the interface of basalt fiber(BF)/poly(vinyl chloride)(PVC)composites.polystyrene/poly(butyl acrylate)(PS/PBA)@silica JPs were synthesized by seed emulsion polymerization and three different sizing agents were prepared for BF sizing treatment.JPs with organic soft sphere and inorganic hard hemisphere enhanced the interfaces through their amphiphilicity,chemical bonding and mechanical interlock.The mechanical properties of composite with JPs sizing treated BFs performed better when there was one JPs layer modified on the interface.According to the intermitting bonding and gradient modulus theory,JPs patterned interfaces are ideal transition layers between high modulus BF and low modulus PVC.
基金the National Natural Science Foundation of China (Nos. 52173076 and 52042302)China Postdoctoral Science Foundation (No. 2021M701825)+1 种基金Tsinghua-Foshan Innovation Special Fund (TFISF) (No. 2021THFS0212)Joint Agency Affiliate Projects of China Petroleum & Chemical Corporation (No. 20212930037)。
文摘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.
基金supported by the National Natural Science Foundation of China(Grant No.11905001)。
文摘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.
基金This work was supported by the National Natural Science Foundation of China(Grants 11832017,11772343,and 12072350)the Chinese Academy of Sciences Key Research Program of Frontier Sciences(Grant QYZDB-SSW-JSC036)+1 种基金the Chinese Academy of Sciences Strategic Priority Research Program(Grant XDB22040403)the Beijing Institute of Technology Research Fund Program for Young Scholars.Author information。
文摘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.
基金financial support from the National Natural Science Foundation of China(Nos.81971675,22275099)Project of State Key Laboratory of Organic Electronics and Information Displays,Nanjing University of Posts&Telecommunications(No.GDX2022010014)Natural Science Research Start up Foundation of Recruiting Talents of Nanjing University of Posts and Telecommunications(No.NY222067).
文摘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.
基金supported by the National Natural Science Foundation of China(Grant Nos.52075383 and 61927808)the National Key Research and Development Program of China(Grant No.2022YFF0605501).
文摘Optical tweezers are precise tools for translating and rotating micrometer-sized particles and are used widely in biology and physics.In a linearly polarized optical trap,Janus particles comprising two hemispheres with different refractive indexes can be rotated about the beam axis following the polarization direction.In previous research,the position and orientation of a Janus particle relative to the polarization direction were simulated using the T-matrix method,whereas this paper is focused on accurate experimental measurements.The position and orientation of a Janus particle are extracted by image processing,and the polarization direction is controlled by a motor-driven half-wave plate(HWP).The particle’s orientation and the polarization direction are related via the HWP’s rotation angle.However,rotating the HWP not only rotates the polarization direction but also causes the trap center to fluctuate positionally because of the inevitable misalignment between the HWP’s rotation axis and the optical axis.Both the trap center and the polarization direction affect the particle’s position,but the influence of the former is removed with the aid of a homogeneous microsphere.The experimental results show that the Janus particle rotates following the polarization direction to keep the interface between its two hemispheres always parallel to the polarization direction.Also,the particle’s centroid moves in a circular orbit around the trap center to hold the trap center in the hemisphere with the higher refractive index.The experimental results agree with the previous simulation results and are of use for future applications.
文摘Active matter encompasses all systems in which each individual constituent independently dissipates energy in its environment.This definition brings together biological systems such as cellular tissues,bacterial colonies,cytoskeletal filaments driven by molecular motors and animal groups,as well as collections of inert self-propelled particles such as Janus particles,[1]colloidal rollers[2]or vibrated grains.[3]Because of the local persistent drive,these systems are far from thermal equilibrium and cannot be described in terms of thermodynamic potentials.This leads to surprising physics that defies some of the basic intuitions that we have from passive systems,including longrange order in two dimensions[4]and phase-separation in absence of attractive interactions.
基金supported by NSFC(No.21425101,21371011,21331001,21590791)MOST of China(2014CB643800,2017YFA0205101).
文摘Janus particles,in which two distinct compositions are integrated,have attracted considerable interest for their potential multi-functionalities and synergistic effects.Although seed-mediated growth appears to be a suitable strategy that meets the stringent specifications for obtaining Janus particles,it is inapplicable to guide the growth of two crystalline components with different crystal structures.Herein,the formation of Janus particles via phase segregation is proposed.As proof-of-concept,promising photon conversion materials,ScF_(3)and lanthanide(Ln)fluorides,with great differences in structure,were chosen to build a series of Janus particles.Interestingly,using heavy(Lu,Yb,Dy and Tb)and light(Pr,Nd,Sm,Eu and Gd)lanthanides,ScF_(3)-LiLnF_(4)and ScF_(3)-LnF_(3)were formed,respectively.Time-dependent reaction studies indicate that phase segregation paves the way for the formation of these Janus nanoparticles(NPs),and this speculation is further confirmed by in situ transmission electron microscopy observations.These investigations provide new insights for the synthesis of heterostructured materials.
基金This work was supported by the National Natural Science Foundation of China(grant No.52276075).
文摘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.
