The equilibrium dynamics and nonlinear rheology of unentangled polymer blends remain inadequately understood,especially regarding the influence of short-chain matrix length N_(S) on the structure and rheological behav...The equilibrium dynamics and nonlinear rheology of unentangled polymer blends remain inadequately understood,especially regarding the influence of short-chain matrix length N_(S) on the structure and rheological behavior of dispersed long chains.Using molecular dynamics simulations based on the Kremer-Grest model,we systematically explore the N_(S)-dependence of static conformations,equilibrium dynamics,and nonlinear shear responses in unentangled long-chain/short-chain polymer blends.Our results demonstrate a decoupling between the static and dynamic sensitivity to N_(S):while the static chain size,R_g,follows Flory theory with slight swelling at small N_(S) due to incomplete excluded volume screening,the diffusion coefficient,D,and the relaxation time,τ_(0),exhibit a strong,non-monotonic N_(S)-dependence,transitioning from monomeric friction dominance at small N_(S) to collective segmental rearrangement at large N_(S).Additionally,we observe partial decoupling between the viscous and normal stress responses:while the zero-shear viscosity,η,is strongly N_(S)-dependent,the first and second normal stress coefficients,Ψ_(1) and Ψ_(2),collapse onto universal curves when scaled by the dimensionless shear rate,γτ_(0),suggesting a common mechanism of orientation and stretching.Under shear,long chains compress in the vorticity direction λ_(z)~Wi^(-0.2),which reduces collision frequency and contributes to shear thinning,while the scaling of weaker orientation resistance m_(G)~Wi^(0.35)reflects hydrodynamic screening by the short-chain matrix.These findings highlight the limitations of single-chain models and emphasize the necessity of considering N_(S)-dependent matrix dynamics and flow-induced structural changes in understanding the rheology of unentangled polymer blends.展开更多
It is a challenge to identify each phase in a multi-component polymer system and uniquely determine the interfacial properties between the different phases.Using atomic force microscopy nanomechanical mapping(AFM-NM)a...It is a challenge to identify each phase in a multi-component polymer system and uniquely determine the interfacial properties between the different phases.Using atomic force microscopy nanomechanical mapping(AFM-NM)and AFM-based infrared spectroscopy(AFM-IR),we identify each phase,visualize structural developments,and determine the interfacial properties in a blend of three polymers:high-density polyethylene(HDPE),polyamide(PA6)and poly(styrene-b-ethylene-co-butylene-b-styrene)(SEBS).Each phase can be identified from the Young’s modulus,along with the structural development within the phases before and after compatibilization.The interfacial widths between HDPE/PA6,HDPE/SEBS and SEBS/PA6 were determined independently in one measurement from a Young’s modulus map.The structural,mechanical property development and identity of the phases were determined by AFM-NM,while AFM-IR,providing complementary chemical information,identified interfacial reactions,showed the chemical affinity of a compatibilizer with the component phases,and mapped the distribution of the compatibilizer in the ternary polymer blends.The chemical,structural and interfacial information obtained by these measurements provide information that is essential for producing mechanically robust materials from incompatible mixtures of polymers.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
X-ray imaging functionalization of biodegradable polyesters is a great demand and challenge in biomedical applications.In this work,a strategy of in-chain functionalization through the combination of ring opening copo...X-ray imaging functionalization of biodegradable polyesters is a great demand and challenge in biomedical applications.In this work,a strategy of in-chain functionalization through the combination of ring opening copolymerization and oxime "Click" postfunctionalization was developed towards X-ray opaque polylactide copolymers.A functionalized cyclic carbonate was first synthesized and used as comonomer of polylactide copolymers,which were subjected to postfunctionalization of oxime "Click" reaction towards iodinated polylactide copolymers.The chemical structure and physical properties of the target products were traced and confirmed.In vitro cytotoxicity evaluation with 3T3-Swiss albino by Alamar blue demonstrated a low cytotoxicity.The X-ray radiopacity was analyzed by Micro-CT and quantified by Hounsfield Units value,which could be tailorable by the feedstock.It is a promising X-ray visible implantable biomaterial in biomedical applications.展开更多
Ring polymers are ubiquitous in various fields including biomaterials,drug release and gene therapy.All of these applications involve the dynamics and diffusion process of ring polymers in a confined environment.By us...Ring polymers are ubiquitous in various fields including biomaterials,drug release and gene therapy.All of these applications involve the dynamics and diffusion process of ring polymers in a confined environment.By using dynamic light scattering(DLS),we discovered a dynamical transition for charged ring polymers with increasing ring concentration in the gel matrix from a diffusive state to a non-diffusive topological frustrated state with a more compact conformation.When the ring polymer size is smaller than the mesh size of the gel matrix,the rings are diffusive at low concentration of 5 g/L.The ring diffusion coefficient in the gel matrix is an order of magnitude smaller than that of rings in solution,obeying the Ogston's model.At high ring concentration of 40 g/L,the collective dynamical behavior of the charged rings exhibits a topologically frustrated non-diffusive state,which may originate from the inter-ring threading with the external confinement from the gel matrix.Based on our previous theoretical work,we also conjectured that in such a non-diffusive state,the ring polymers might adopt a more compact conformation with the overall size exponentν=1/3.展开更多
With an excellent power conversion efficiency of 25.7%,closer to the Shockley–Queisser limit,perovskite solar cells(PSCs)have become a strong candidate for a next-generation energy harvester.However,the lack of stabi...With an excellent power conversion efficiency of 25.7%,closer to the Shockley–Queisser limit,perovskite solar cells(PSCs)have become a strong candidate for a next-generation energy harvester.However,the lack of stability and reliability in PSCs remained challenging for commercialization.Strategies,such as interfacial and structural engineering,have a more critical influence on enhanced performance.MXenes,two-dimensional materials,have emerged as promising materials in solar cell applications due to their metallic electrical conductivity,high carrier mobility,excellent optical transparency,wide tunable work function,and superior mechanical properties.Owing to different choices of transition elements and surface-terminating functional groups,MXenes possess the feature of tuning the work function,which is an essential metric for band energy alignment between the absorber layer and the charge transport layers for charge carrier extraction and collection in PSCs.Furthermore,adopting MXenes to their respective components helps reduce the interfacial recombination resistance and provides smooth charge transfer paths,leading to enhanced conductivity and operational stability of PSCs.This review paper aims to provide an overview of the applications of MXenes as components,classified according to their roles as additives(into the perovskite absorber layer,charge transport layers,and electrodes)and themselves alone or as interfacial layers,and their significant importance in PSCs in terms of device performance and stability.Lastly,we discuss the present research status and future directions toward its use in PSCs.展开更多
The paper describes a kind of truly full-color photoluminescence(PL)CDs.The CDs were prepared by using one-pot hydrothermally heating citric acid and formamide at 200℃ for 2 h.The CDs have three fluorescent centers a...The paper describes a kind of truly full-color photoluminescence(PL)CDs.The CDs were prepared by using one-pot hydrothermally heating citric acid and formamide at 200℃ for 2 h.The CDs have three fluorescent centers at blue,green,and red light region.Their color was regulated through two means,including changing excitation wavelengths or CDs concentrations.The emission maxima changed from blue to red with the increase of excitation wavelengths or CDs concentrations.The full-color PL behavior of the CDs was inherited and conserved in the solid polymer matrix,giving multicolor CDs/polymer films and light emitting diodes(LEDs).White-light LED(WLED)with the CIE coordinate approaching to(0.31,0.32)were also achieved.展开更多
Poly （ glycidyl methacrylate ） / silica （PGMA/silica） composite nanoparticles , containing epoxy functional groups on the surface, were synthesized via emulsion polymerization. With batch process, high yield and b...Poly （ glycidyl methacrylate ） / silica （PGMA/silica） composite nanoparticles , containing epoxy functional groups on the surface, were synthesized via emulsion polymerization. With batch process, high yield and binding efficiency （ both around 90% ） were achieved. The amount of crosslinked GMA was approximately 8wt%- 14wt% to the polymerized monomer. It was found that both the encapsulating ratio and the number of the original silica beads per composite particles altered with the amount of silica added. The obtained particles, with their average particle size of about 60- 70 nm, had a spherical shape and a clear core- shell structure.展开更多
Biopolymer chitosan was used to modify the mechanical properties of soluble eggshell membrane protein (SEP) films. The SEP/chitosan blend films were prepared by solution casting from 10% aqueous acetic acid. Tensile s...Biopolymer chitosan was used to modify the mechanical properties of soluble eggshell membrane protein (SEP) films. The SEP/chitosan blend films were prepared by solution casting from 10% aqueous acetic acid. Tensile strength and elongation at break of the blend films increased with increasing amount of chitosan. Microphase separation was observed by field emission scanning electron microscopy, although interaction between the two components was revealed by FTIR. The biocompatibility of SEP/chitosan blend films containing 10%-50% of chitosan, as demonstrated by cell culture of NIH3T3, was much better than that of pure chitosan.展开更多
Polypropylene (PP)/multi-walled carbon nanotube (MWCNT)/calcium carbonate (CaCO(3)) composites are prepared by melt mixing using two types of CaCO(3) of different sizes. The electrical resistivities of the composites ...Polypropylene (PP)/multi-walled carbon nanotube (MWCNT)/calcium carbonate (CaCO(3)) composites are prepared by melt mixing using two types of CaCO(3) of different sizes. The electrical resistivities of the composites with the two types of CaCO(3) are all lower than those of the corresponding PP/MWCNT composites at various MWCNT loadings (1 wt%-5 wt%). The morphology of the composites is investigated by field emission scanning electron microscopy (FESEM). The crystallization behavior of PP in the composites is characterized by differential scanning calorimetry (DSC). The storage modulus, as measured by dynamic mechanical analysis (DMA), increases significantly by the presence of CaCO(3).展开更多
Two master-batches,polyamide 66 (PA66)/organo-montmorillonite (OMMT) and polyamide 6 (PA6)/OMMT, prepared by melt compounding with methyl methacrylate (MMA) as co-intercalation agent,have been used to prepare nearly e...Two master-batches,polyamide 66 (PA66)/organo-montmorillonite (OMMT) and polyamide 6 (PA6)/OMMT, prepared by melt compounding with methyl methacrylate (MMA) as co-intercalation agent,have been used to prepare nearly exfoliated PA661montmorillonite (MMT) nanocomposites.The resulting nanocomposites are compared in view of their morphology and properties.Nano-scale dispersion of OMMT is realized in both types of nanocomposites,as revealed by XRD,TEM and Molau tests.PA66/MMT nanocomposites having superior mecha...展开更多
The antibacterial property and biodegradability of soluble eggshell membrane protein （SEP） are reported. Unlike the natural eggshell membrane （ESM）, SEP does not possess antibacterial property against E. coli. The...The antibacterial property and biodegradability of soluble eggshell membrane protein （SEP） are reported. Unlike the natural eggshell membrane （ESM）, SEP does not possess antibacterial property against E. coli. The biodegradation tests with trypsin show that both ESM and SEP are biodegradable.展开更多
Strong near-field scattering enhancement (NFSE) of polyhedral oligomeric silsesquioxanes(POSS) nanoparticles (NPs) aggregates is found through physical simulation. An aggregation of N,N′-di-[3-(isobutyl polyhedral ol...Strong near-field scattering enhancement (NFSE) of polyhedral oligomeric silsesquioxanes(POSS) nanoparticles (NPs) aggregates is found through physical simulation. An aggregation of N,N′-di-[3-(isobutyl polyhedral oligomeric silsesquioxanes) propyl] perylene diimide(DPP) which possesses POSS as scatteres experimentally performs strong NFSE, which confirms the physical simulation results. Moreover, coherent random laser is triggered from the DPP aggregates in carbon disulfide. It is the NFSE of POSS NPs connected to both ends of DPP through covalent bonds and the NFSE of their aggregation thanks to DPP’s aggregation that is responsible for the coherent random laser. So, this work develops a method to improve weak scattering of system through construction of molecules, and opens a road to a variety of novel interdisciplinary investigations, involving molecular designing for disordered photonics.展开更多
The grafting of polystyrene onto a nanometer silica surface by microemulsion polymerization is described. Silica was functionalized with 3-methacryloxypropyltrimethoxysilane coupling agent before polymerization. A mix...The grafting of polystyrene onto a nanometer silica surface by microemulsion polymerization is described. Silica was functionalized with 3-methacryloxypropyltrimethoxysilane coupling agent before polymerization. A mixture of ionic and non-ionic surfactants as well as water-soluble and oil-soluble initiators were used. The effect of the amount of silica and ionic surfactant on the graft polymerization was studied. The graft polymerization procedure for styrene was also applied to methyl methacrylate, Composite particles with a core-shell structure were obtained and the yield and grafting efficiency of monomer were high.展开更多
A series of thermotropic liquid crystalline polyesteramides with differ-ent sequence structure based on dimethylbenzidine (DMBD), bisphenol-A(BPA) and p-terephthalyl chloride (TPC) was synthesized by changing the feed...A series of thermotropic liquid crystalline polyesteramides with differ-ent sequence structure based on dimethylbenzidine (DMBD), bisphenol-A(BPA) and p-terephthalyl chloride (TPC) was synthesized by changing the feeding order of monomers inlow temperature solution polycondensation system. By means of NMR and a computer pro-gram the sequence structure parameters were measured. The effect of sequence structureon liquid crystalline phase transition temperature of PEAs obtained was investigated.展开更多
Functionalized PS/SiO_2 composite nanoparticles bearing sulfonic groups on the surface were successfully synthesized via emulsion copolymerization using a polymerizable emulsifierαolefin solfonate(AOS).As demonstrate...Functionalized PS/SiO_2 composite nanoparticles bearing sulfonic groups on the surface were successfully synthesized via emulsion copolymerization using a polymerizable emulsifierαolefin solfonate(AOS).As demonstrated by transmission electron microscopy and atomic force microscopy,well-defined core-shell PS/SiO_2 composite nanoparticles with a diameter of 50 nm were obtained.Sulfonic groups introduced onto the surface of the composite nanoparticles were quantified by FTIR,and can be controlled to some exten...展开更多
A general procedure for surface modification of nano-alumina using N, N＇-dicyclohexyl- carbodiimide （DCC） mediated amidation is reported. Aliphatic and aromatic carboxylic acids reacted smoothly with nano-alumina p...A general procedure for surface modification of nano-alumina using N, N＇-dicyclohexyl- carbodiimide （DCC） mediated amidation is reported. Aliphatic and aromatic carboxylic acids reacted smoothly with nano-alumina pretreated with 3-aminopropyltriethoxysilane in the presence of DCC, giving modified aluminas having organic surfaces. The grafted aluminas have been characterized qualitatively by FT-IR or ^13C CPMAS NMR spectroscopy, and quantitatively by thermogravimetric analysis and elemental analysis. The procedure was applied to polyether dendrons bearing carboxyl groups at the focal points, giving successful grafting of dendrimers onto nano-alumina.展开更多
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 F...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.展开更多
Janus polymer nanorods with tunable compositions and microstructures possess directionally specific interactions,enabling their self-assembly into hierarchically structured materials(e.g.,biomimetic pillared nanostruc...Janus polymer nanorods with tunable compositions and microstructures possess directionally specific interactions,enabling their self-assembly into hierarchically structured materials(e.g.,biomimetic pillared nanostructures).Traditional synthesis methods usually require highly dilute conditions(<1 mg/mL)to prevent aggregation.Herein,we report the synthesis of Janus polymer nanorods by electrostatics-mediated reversible addition-fragmentation chain transfer copolymerization of cross-linkers and monomers from polymer bottlebrushes.This method achieves an unprecedentedly high solid content over 100 mg/mL,that is,two orders of magnitude higher than that attainable by conventional approaches.The composition,microstructure(e.g.,multilayered architecture),and characteristic dimension of the nanorods are broadly tunable.As a representative example,AB-type Janus nanorods are derived by orthogonal modifications of the end blocks,introducing desired functional groups to drive directional interactions.The Janus nanorods serve as building blocks to self-assemble into diverse superstructures from nanowires to continuous networks,providing a facile platform for the in-situ construction of functional materials within suitable matrices.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.22341304,22303100 and 12205270)the National Key R&D Program of China(Nos.2023YFA1008800 and 2020YFA0713601)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDC0180303)。
文摘The equilibrium dynamics and nonlinear rheology of unentangled polymer blends remain inadequately understood,especially regarding the influence of short-chain matrix length N_(S) on the structure and rheological behavior of dispersed long chains.Using molecular dynamics simulations based on the Kremer-Grest model,we systematically explore the N_(S)-dependence of static conformations,equilibrium dynamics,and nonlinear shear responses in unentangled long-chain/short-chain polymer blends.Our results demonstrate a decoupling between the static and dynamic sensitivity to N_(S):while the static chain size,R_g,follows Flory theory with slight swelling at small N_(S) due to incomplete excluded volume screening,the diffusion coefficient,D,and the relaxation time,τ_(0),exhibit a strong,non-monotonic N_(S)-dependence,transitioning from monomeric friction dominance at small N_(S) to collective segmental rearrangement at large N_(S).Additionally,we observe partial decoupling between the viscous and normal stress responses:while the zero-shear viscosity,η,is strongly N_(S)-dependent,the first and second normal stress coefficients,Ψ_(1) and Ψ_(2),collapse onto universal curves when scaled by the dimensionless shear rate,γτ_(0),suggesting a common mechanism of orientation and stretching.Under shear,long chains compress in the vorticity direction λ_(z)~Wi^(-0.2),which reduces collision frequency and contributes to shear thinning,while the scaling of weaker orientation resistance m_(G)~Wi^(0.35)reflects hydrodynamic screening by the short-chain matrix.These findings highlight the limitations of single-chain models and emphasize the necessity of considering N_(S)-dependent matrix dynamics and flow-induced structural changes in understanding the rheology of unentangled polymer blends.
基金by the National Natural Science Foundation of China(No.51673016)the Beijing Advanced Innovation Center for Soft matter Science and Engineering.
文摘It is a challenge to identify each phase in a multi-component polymer system and uniquely determine the interfacial properties between the different phases.Using atomic force microscopy nanomechanical mapping(AFM-NM)and AFM-based infrared spectroscopy(AFM-IR),we identify each phase,visualize structural developments,and determine the interfacial properties in a blend of three polymers:high-density polyethylene(HDPE),polyamide(PA6)and poly(styrene-b-ethylene-co-butylene-b-styrene)(SEBS).Each phase can be identified from the Young’s modulus,along with the structural development within the phases before and after compatibilization.The interfacial widths between HDPE/PA6,HDPE/SEBS and SEBS/PA6 were determined independently in one measurement from a Young’s modulus map.The structural,mechanical property development and identity of the phases were determined by AFM-NM,while AFM-IR,providing complementary chemical information,identified interfacial reactions,showed the chemical affinity of a compatibilizer with the component phases,and mapped the distribution of the compatibilizer in the ternary polymer blends.The chemical,structural and interfacial information obtained by these measurements provide information that is essential for producing mechanically robust materials from incompatible mixtures of polymers.
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financially supported by the National Natural Science Foundation of China(No.31500767)the Natural ScienceFoundation of Liaoning Province of China(No.20180510037)the Fundamental Research Funds for the Central Universities(No.DUT19LAB27)。
文摘X-ray imaging functionalization of biodegradable polyesters is a great demand and challenge in biomedical applications.In this work,a strategy of in-chain functionalization through the combination of ring opening copolymerization and oxime "Click" postfunctionalization was developed towards X-ray opaque polylactide copolymers.A functionalized cyclic carbonate was first synthesized and used as comonomer of polylactide copolymers,which were subjected to postfunctionalization of oxime "Click" reaction towards iodinated polylactide copolymers.The chemical structure and physical properties of the target products were traced and confirmed.In vitro cytotoxicity evaluation with 3T3-Swiss albino by Alamar blue demonstrated a low cytotoxicity.The X-ray radiopacity was analyzed by Micro-CT and quantified by Hounsfield Units value,which could be tailorable by the feedstock.It is a promising X-ray visible implantable biomaterial in biomedical applications.
基金supported by the National Natural Science Foundation of China(No.22273114)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0770101)+1 种基金the National Key R&D Program of China(No.2023YFE0124500),the National Key R&D Program of China(No.2023YFC2411203)International Partnership Program of the Chinese Academy of Sciences(No.027GJHZ2022061FN)。
文摘Ring polymers are ubiquitous in various fields including biomaterials,drug release and gene therapy.All of these applications involve the dynamics and diffusion process of ring polymers in a confined environment.By using dynamic light scattering(DLS),we discovered a dynamical transition for charged ring polymers with increasing ring concentration in the gel matrix from a diffusive state to a non-diffusive topological frustrated state with a more compact conformation.When the ring polymer size is smaller than the mesh size of the gel matrix,the rings are diffusive at low concentration of 5 g/L.The ring diffusion coefficient in the gel matrix is an order of magnitude smaller than that of rings in solution,obeying the Ogston's model.At high ring concentration of 40 g/L,the collective dynamical behavior of the charged rings exhibits a topologically frustrated non-diffusive state,which may originate from the inter-ring threading with the external confinement from the gel matrix.Based on our previous theoretical work,we also conjectured that in such a non-diffusive state,the ring polymers might adopt a more compact conformation with the overall size exponentν=1/3.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korean government(MSIT)(No.2022M3J7A1062940 and 2022033777)supported by Korea Electric Power Corporation(Grant Number:R21XO01-5)+2 种基金supported by the Technology Innovation Program(or Industrial Strategic Technology Development Program)(1415172732/20011410,Development of SPD smart film and service of aftermarket for energy saving in building and automobiles)the Ministry of Trade,Industry&Energy(MOTIE,Korea)supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(2018R1A6A1A03023788 and 2021R1I1A1A01055790).
文摘With an excellent power conversion efficiency of 25.7%,closer to the Shockley–Queisser limit,perovskite solar cells(PSCs)have become a strong candidate for a next-generation energy harvester.However,the lack of stability and reliability in PSCs remained challenging for commercialization.Strategies,such as interfacial and structural engineering,have a more critical influence on enhanced performance.MXenes,two-dimensional materials,have emerged as promising materials in solar cell applications due to their metallic electrical conductivity,high carrier mobility,excellent optical transparency,wide tunable work function,and superior mechanical properties.Owing to different choices of transition elements and surface-terminating functional groups,MXenes possess the feature of tuning the work function,which is an essential metric for band energy alignment between the absorber layer and the charge transport layers for charge carrier extraction and collection in PSCs.Furthermore,adopting MXenes to their respective components helps reduce the interfacial recombination resistance and provides smooth charge transfer paths,leading to enhanced conductivity and operational stability of PSCs.This review paper aims to provide an overview of the applications of MXenes as components,classified according to their roles as additives(into the perovskite absorber layer,charge transport layers,and electrodes)and themselves alone or as interfacial layers,and their significant importance in PSCs in terms of device performance and stability.Lastly,we discuss the present research status and future directions toward its use in PSCs.
基金supported by National Natural Science Foundation of China(No.51873085)Liaoning Revitalization Talents Program(No.XLYC2007056)。
文摘The paper describes a kind of truly full-color photoluminescence(PL)CDs.The CDs were prepared by using one-pot hydrothermally heating citric acid and formamide at 200℃ for 2 h.The CDs have three fluorescent centers at blue,green,and red light region.Their color was regulated through two means,including changing excitation wavelengths or CDs concentrations.The emission maxima changed from blue to red with the increase of excitation wavelengths or CDs concentrations.The full-color PL behavior of the CDs was inherited and conserved in the solid polymer matrix,giving multicolor CDs/polymer films and light emitting diodes(LEDs).White-light LED(WLED)with the CIE coordinate approaching to(0.31,0.32)were also achieved.
文摘Poly （ glycidyl methacrylate ） / silica （PGMA/silica） composite nanoparticles , containing epoxy functional groups on the surface, were synthesized via emulsion polymerization. With batch process, high yield and binding efficiency （ both around 90% ） were achieved. The amount of crosslinked GMA was approximately 8wt%- 14wt% to the polymerized monomer. It was found that both the encapsulating ratio and the number of the original silica beads per composite particles altered with the amount of silica added. The obtained particles, with their average particle size of about 60- 70 nm, had a spherical shape and a clear core- shell structure.
基金supported by the National Natural Science Foundation of China(No.50773035).
文摘Biopolymer chitosan was used to modify the mechanical properties of soluble eggshell membrane protein (SEP) films. The SEP/chitosan blend films were prepared by solution casting from 10% aqueous acetic acid. Tensile strength and elongation at break of the blend films increased with increasing amount of chitosan. Microphase separation was observed by field emission scanning electron microscopy, although interaction between the two components was revealed by FTIR. The biocompatibility of SEP/chitosan blend films containing 10%-50% of chitosan, as demonstrated by cell culture of NIH3T3, was much better than that of pure chitosan.
文摘Polypropylene (PP)/multi-walled carbon nanotube (MWCNT)/calcium carbonate (CaCO(3)) composites are prepared by melt mixing using two types of CaCO(3) of different sizes. The electrical resistivities of the composites with the two types of CaCO(3) are all lower than those of the corresponding PP/MWCNT composites at various MWCNT loadings (1 wt%-5 wt%). The morphology of the composites is investigated by field emission scanning electron microscopy (FESEM). The crystallization behavior of PP in the composites is characterized by differential scanning calorimetry (DSC). The storage modulus, as measured by dynamic mechanical analysis (DMA), increases significantly by the presence of CaCO(3).
文摘Two master-batches,polyamide 66 (PA66)/organo-montmorillonite (OMMT) and polyamide 6 (PA6)/OMMT, prepared by melt compounding with methyl methacrylate (MMA) as co-intercalation agent,have been used to prepare nearly exfoliated PA661montmorillonite (MMT) nanocomposites.The resulting nanocomposites are compared in view of their morphology and properties.Nano-scale dispersion of OMMT is realized in both types of nanocomposites,as revealed by XRD,TEM and Molau tests.PA66/MMT nanocomposites having superior mecha...
文摘The antibacterial property and biodegradability of soluble eggshell membrane protein （SEP） are reported. Unlike the natural eggshell membrane （ESM）, SEP does not possess antibacterial property against E. coli. The biodegradation tests with trypsin show that both ESM and SEP are biodegradable.
基金supported by the National Natural Science Foundation of China(No.51673178,No.51273186,No.21574120,No.11874012,No.11404087,and No.11574070)Basic Research Fund for the Central Universities(No.WK2060200012)+3 种基金Science and Technological Fund of Anhui Province for Outstanding Youth(No.1608085J01)Fundamental Research Funds for the Central Universities of China,Postdoctoral Science Foundation(No.2015M571918 and No.2017T100442)the European Union’s Horizon 2020 Research and Innovation Programme under the Marie Sk lodowska-Curie Grant Agreement(No.744817)the Project of State Key Laboratory of Environment-friendly Energy Materials,Southwest University of Science and Technology(No.18zxhk10)
文摘Strong near-field scattering enhancement (NFSE) of polyhedral oligomeric silsesquioxanes(POSS) nanoparticles (NPs) aggregates is found through physical simulation. An aggregation of N,N′-di-[3-(isobutyl polyhedral oligomeric silsesquioxanes) propyl] perylene diimide(DPP) which possesses POSS as scatteres experimentally performs strong NFSE, which confirms the physical simulation results. Moreover, coherent random laser is triggered from the DPP aggregates in carbon disulfide. It is the NFSE of POSS NPs connected to both ends of DPP through covalent bonds and the NFSE of their aggregation thanks to DPP’s aggregation that is responsible for the coherent random laser. So, this work develops a method to improve weak scattering of system through construction of molecules, and opens a road to a variety of novel interdisciplinary investigations, involving molecular designing for disordered photonics.
文摘The grafting of polystyrene onto a nanometer silica surface by microemulsion polymerization is described. Silica was functionalized with 3-methacryloxypropyltrimethoxysilane coupling agent before polymerization. A mixture of ionic and non-ionic surfactants as well as water-soluble and oil-soluble initiators were used. The effect of the amount of silica and ionic surfactant on the graft polymerization was studied. The graft polymerization procedure for styrene was also applied to methyl methacrylate, Composite particles with a core-shell structure were obtained and the yield and grafting efficiency of monomer were high.
基金This work was supported by Special Foundation of State Education Committee for Doctoral Program
文摘A series of thermotropic liquid crystalline polyesteramides with differ-ent sequence structure based on dimethylbenzidine (DMBD), bisphenol-A(BPA) and p-terephthalyl chloride (TPC) was synthesized by changing the feeding order of monomers inlow temperature solution polycondensation system. By means of NMR and a computer pro-gram the sequence structure parameters were measured. The effect of sequence structureon liquid crystalline phase transition temperature of PEAs obtained was investigated.
基金supported by the Hi-Tech Research and Development Program of China(863,No2006AA03Z562)
文摘Functionalized PS/SiO_2 composite nanoparticles bearing sulfonic groups on the surface were successfully synthesized via emulsion copolymerization using a polymerizable emulsifierαolefin solfonate(AOS).As demonstrated by transmission electron microscopy and atomic force microscopy,well-defined core-shell PS/SiO_2 composite nanoparticles with a diameter of 50 nm were obtained.Sulfonic groups introduced onto the surface of the composite nanoparticles were quantified by FTIR,and can be controlled to some exten...
文摘A general procedure for surface modification of nano-alumina using N, N＇-dicyclohexyl- carbodiimide （DCC） mediated amidation is reported. Aliphatic and aromatic carboxylic acids reacted smoothly with nano-alumina pretreated with 3-aminopropyltriethoxysilane in the presence of DCC, giving modified aluminas having organic surfaces. The grafted aluminas have been characterized qualitatively by FT-IR or ^13C CPMAS NMR spectroscopy, and quantitatively by thermogravimetric analysis and elemental analysis. The procedure was applied to polyether dendrons bearing carboxyl groups at the focal points, giving successful grafting of dendrimers onto nano-alumina.
文摘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.
基金supported by the National Natural Science Foundation of China(grant nos.52293472 and 51833005)the National Key Research and Development Program of China(grant no.2021YFC2102800)start-up funding by Tsinghua University(grant no.53330100120).
文摘Janus polymer nanorods with tunable compositions and microstructures possess directionally specific interactions,enabling their self-assembly into hierarchically structured materials(e.g.,biomimetic pillared nanostructures).Traditional synthesis methods usually require highly dilute conditions(<1 mg/mL)to prevent aggregation.Herein,we report the synthesis of Janus polymer nanorods by electrostatics-mediated reversible addition-fragmentation chain transfer copolymerization of cross-linkers and monomers from polymer bottlebrushes.This method achieves an unprecedentedly high solid content over 100 mg/mL,that is,two orders of magnitude higher than that attainable by conventional approaches.The composition,microstructure(e.g.,multilayered architecture),and characteristic dimension of the nanorods are broadly tunable.As a representative example,AB-type Janus nanorods are derived by orthogonal modifications of the end blocks,introducing desired functional groups to drive directional interactions.The Janus nanorods serve as building blocks to self-assemble into diverse superstructures from nanowires to continuous networks,providing a facile platform for the in-situ construction of functional materials within suitable matrices.
