One of the most widely used and well-established atomic oxygen(AO)protection solutions for low Earth orbit(LEO)satellites is the deposition of protective coatings on polymeric materials.However,manufacturing extensive...One of the most widely used and well-established atomic oxygen(AO)protection solutions for low Earth orbit(LEO)satellites is the deposition of protective coatings on polymeric materials.However,manufacturing extensive expanses of these coating materials with good transparency,flexibility,smoothness,ultra-thinness,and exceptional AO resistance remains a critical issue.Herein,we successfully deposited a 400 nm thick polyorgansiloxane(SiO_(x)C_(y)H_(z))coating with high optical transparency and uniform good adherence on to a 1.2 m wide polyimide surface,by optimizing the distribution of hexamethyldisiloxane and oxygen as precursors in the roll-to-roll compatible plasmaenhanced chemical vapor deposition process.After AO irradiation with the fluence of 7.9×10^(20)atoms·cm^(–2),the erosion yield of the SiO_(x)C_(y)H_(z)-coated Kapton was less than 2.30×10^(–26)cm^3·atom^(–1),which was less than 0.77%of that of the Kapton.It indicates that the SiO_(x)C_(y)H_(z)coating can well prevent the erosion of Kapton by AO.In addition,it was also clarified that a SiO_(2) passivation layer was formed on the surface of the SiO_(x)C_(y)H_(z)coating during AO irradiation,which exhibited a‘self-reinforcing’defense mechanism.The entire preparation process of the SiO_(x)C_(y)H_(z)coating was highly efficient and low-cost,and it has shown great potential for applications in LEO.展开更多
Lithium-sulfur(Li-S)batteries with lithium sulfide(Li2S)as cathode have attracted great attention recently,because of high specific capacity(1166 mA h g^-1)of Li2S and potential safety of using Li metal-free anode.Li2...Lithium-sulfur(Li-S)batteries with lithium sulfide(Li2S)as cathode have attracted great attention recently,because of high specific capacity(1166 mA h g^-1)of Li2S and potential safety of using Li metal-free anode.Li2S cathode has lower volume expansion and higher thermal stability than the traditional sulfur cathode.However,the problems of"shuttle effect"and poor electrical conductivity of the cathode material still need to be overcome.In this work,multi-layered Ti3C2/Li2S(ML-Ti3C2/Li2S)composite has been prepared and applied as a cathode in advanced Li-S batteries.The unique multi-layer sheet structure of Ti3 C2 provides space for the storage of Li2S,and its good conductivity greatly enhances the usage ratio of Li2 S and improves the conductivity of the whole Li2S cathode.Compared with commonly used graphene,ML-Ti3C2 can trap polysulfides effectively by chemical adsorption and also activate the reaction of Li2S to polysulfides by forming Ti-S bond.As a result,during the cycling of the batteries with ML-Ti3C2/Li2S cathodes,the activation voltage barrier of the first cycle has decreased to 2.8 V,and the"shuttle effect"has been suppressed effectively.The cycling and rate performances of the ML-Ti3C2/Li2S cathodes have been significantly improved compared to that of graphene/Li2 S cathodes.They maintain a capacity of 450 mAh g^-1 at 0.2 C after 100 cycles,and deliver attractive rate performances of 750,630,540,470 and 360 mAh g^-1 at 0.1 C,0.2 C,0.5 C,1 C,and 2 C,respectively.展开更多
In traditional in situ polymerization preparation for solid-state electrolytes,initiators are directly added to the liquid precursor.In this article,a novel cellulose paper-based composite separator is fabricated,whic...In traditional in situ polymerization preparation for solid-state electrolytes,initiators are directly added to the liquid precursor.In this article,a novel cellulose paper-based composite separator is fabricated,which employs alumina as the inorganic reinforcing material and is loaded with polymerization initiator aluminum trifluoromethanesulfonate.Based upon this,a separator-induced in situ directional polymerization technique is demonstrated,and the extra addition of initiators into liquid precursors is no longer required.The polymerization starts from the surface and interior of the separator and extends outward with the gradually dissolving of initiators into the precursor.Compared with its traditional counterpart,the separator-induced poly(1,3-dioxolane)electrolyte shows improved interfacial contact as well as appropriately mitigated polymerization rate,which are conducive to practical applications.Electrochemical measurement results show that the prepared poly(1,3-dioxolane)solid electrolyte possesses an oxidation potential up to 4.4 V and a high Li+transference number of 0.72.After 1000 cycles at 2 C rate(340 mA g^(−1)),the assembled Li||LiFePO_(4)solid battery possesses a 106.8 mAh g^(−1)discharge capacity retention and 83.5%capacity retention ratio,with high average Coulombic efficiency of 99.5%achieved.Our work may provide new ideas for the design and application of in situ polymerization technique for solid electrolytes and solid batteries.展开更多
A facile and environment friendly approach to synthesis of unique hierarchical BiOCl flowery microspheres(FMs)using a biodegradable surfactant polyvinyl alcohol(PVA)was reported herein for the first time.Compared to t...A facile and environment friendly approach to synthesis of unique hierarchical BiOCl flowery microspheres(FMs)using a biodegradable surfactant polyvinyl alcohol(PVA)was reported herein for the first time.Compared to the BiOCl nanosheets synthesized in the absence of PVA,hierarchical BiOCl FMs consist of large amounts of interwoven polycrystalline nanosheets that assemble into a porous flowery structure.The formation mechanism of the hierarchical BiOCl FMs was also proposed,whereby PVA was believed to play a key role in the crystal growth and the formation of the final microstructures.Compared with TiO2-P25 and BiOCl nanosheets,hierarchical BiOCl FMs displayed remarkably enhanced photocatalytic activity,and20 mg of BiOCl FMs could completely degrade 50 mL of methyl orange solution(20 mg/L)within 30 min under UVlight irradiation.According to the comprehensive analysis,it can be concluded that the larger specific surface area,porosity,suitable band gap,and the enhanced light absorption capacity may contribute to the remarkably enhanced photocatalytic activity.This facile and green approach to fabricating hierarchical BiOCl FMs would give vital clues to develop new route for synthesizing other hierarchical structured materials.展开更多
Lightweight microcellular polyurethane(TPU)/carbon nanotubes(CNTs)/nickel-coated CNTs(Ni@CNTs)/polymerizable ionic liquid copolymer(PIL)composite foams are prepared by non-solvent induced phase separation(NIPS).CNTs a...Lightweight microcellular polyurethane(TPU)/carbon nanotubes(CNTs)/nickel-coated CNTs(Ni@CNTs)/polymerizable ionic liquid copolymer(PIL)composite foams are prepared by non-solvent induced phase separation(NIPS).CNTs and Ni@CNTs modified by PIL provide more heterogeneous nucleation sites and inhibit the aggregation and combination of microcellular structure.Compared with TPU/CNTs,the TPU/CNTs/PIL and TPU/CNTs/Ni@CNTs/PIL composite foams with smaller microcellular structures have a high electromagnetic interference shielding effectiveness(EMI SE).The evaporate time regulates the microcellular structure,improves the conductive network of composite foams and reduces the microcellular size,which strengthens the multiple reflections of electromagnetic wave.The TPU/10CNTs/10Ni@CNTs/PIL foam exhibits slightly higher SE values(69.9 dB)compared with TPU/20CNTs/PIL foam(53.3 dB).The highest specific EMI SE of TPU/20CNTs/PIL and TPU/10CNTs/10Ni@CNTs/PIL reaches up to 187.2 and 211.5 dB/(g cm^(−3)),respectively.The polarization losses caused by interfacial polarization between TPU substrates and conductive fillers,conduction loss caused by conductive network of fillers and magnetic loss caused by Ni@CNT synergistically attenuate the microwave energy.展开更多
A high-performance quasi-solid polymer electrolyte for sodium metal batteries(SMBs)based on in-situ polymerized poly(1,3-dioxolane)(DOL)with 20%volume ratio of fluoroethylene carbonate(FEC),termed"PDFE-20",i...A high-performance quasi-solid polymer electrolyte for sodium metal batteries(SMBs)based on in-situ polymerized poly(1,3-dioxolane)(DOL)with 20%volume ratio of fluoroethylene carbonate(FEC),termed"PDFE-20",is proposed in this work.It is demonstrated PDFE-20 possesses a room-temperature ionic conductivity of 3.31×10^(-3) S cm^(-1),an ionic diffusion activation energy of 0.10 eV,and an oxidation potential of 4.4 V.SMBs based on PDFE-20 and Na_(3)V_(2)(PO_(4))_(3)(NVP)cathodes were evaluated with an active material mass loading of 6.8 mg cm^(-2).The cell displayed an initial discharge specific capacity of 104 mA h g^(-1),and97.1%capacity retention after 100 cycles at 0.5 C.In-situ polymerization conformally coats the anode/-cathode interfaces,avoiding geometrical gaps and high charge transfer resistance with ex-situ polymerization of the same chemistry.FEC acts as a plasticizer during polymerization to suppress crystallization and significantly improves ionic transport.During battery cycling FEC promotes mechanical congruence of electrolyte-electrode interfaces while forming a stable NaF-rich solid electrolyte interphase(SEI)at the anode.Density functional theory(DFT)calculations were also performed to further understand the role FEC in the poly(DOL)-FEC electrolytes.This work broadens the application of in-situ prepared poly(DOL)electrolytes to sodium storage and demonstrates the crucial role of FEC in improving the electrochemical performance.展开更多
Incorporating the surface-grafted cellulose nanocrystals(CNCs)with enantiomeric polylactide(PLLA or PDLA)is an effective and sustainable way to modify PLLA,but their difference in promoting matrix crystallization is s...Incorporating the surface-grafted cellulose nanocrystals(CNCs)with enantiomeric polylactide(PLLA or PDLA)is an effective and sustainable way to modify PLLA,but their difference in promoting matrix crystallization is still unrevealed.In this study,the CNCs with identical content and length of PLLA and PDLA(CNC-g-L and CNC-g-D)were prepared and blended with PLLA.The rheological properties of PLLA/CNC-gD are greatly improved,indicating that the stereocomplexation can significantly improve the interfacial strength as compared with the conventional van der Waals force in PLLA/CNC-g-L.Surprisingly,the matrix crystallizes at a higher rate in PLLA/CNC-g-L than PLLA/CNC-g-D.PLLA/CNC-g-L15 reaches its half crystallinity in 8.26 min while a longer period of 13.41 min is required for PLLA/CNC-g-D15.POM observation reveals that the superior crystallization behavior in PLLA/CNC-g-L is originated from its higher nucleation efficiency and faster growth rate.The formation of low content of sc-PLA at the interface can restrict the diffusion of PLLA but contribute less to generate crystalline nuclei,which synergistically leads to the retarded crystallization kinetics in PLLA/CNC-g-D.Revealing the mechanism of different interfacial enantiomeric grafting on the melt rheology and crystallization of PLLA is of great significance for the development of high-performance polylactide materials.展开更多
To investigate the performance of graphene(Gra) modified with ethoxycarbonyl ionic liquid(IL), chain mobility and crystallization kinetics of poly(L-lactic acid)(PLLA), a series of PLLA nanocomposites have been prepar...To investigate the performance of graphene(Gra) modified with ethoxycarbonyl ionic liquid(IL), chain mobility and crystallization kinetics of poly(L-lactic acid)(PLLA), a series of PLLA nanocomposites have been prepared using solution-cast method.IL can improve the dispersion of Gra in PLLA matrix and the samples containing IL have higher growth rate of PLLA spherulite than neat PLLA does. PLLA/IL/Gra and PLLA/2 Gra exhibit the same relaxation strength and time of αN relaxation that corresponds to the longest normal mode motion at 110-140 °C. PLLA/IL/Gra shows a faster crystallization rate than PLLA/2 Gra does, which might be attributed to the Gra-imidazolium cation interaction in IL modified Gra, the significant dispersion effect of IL at Gra surface, and the increase of nuclei density of PLLA/IL/Gra.展开更多
The synthesis of two linear terpy-based metallo-supramolecular fluorescent coordination polymers through 1 ： 1 complexation of Zn^2＋ and Cd^2＋ ions with ditopic terpyridine ligand was reported. The dispersibility o...The synthesis of two linear terpy-based metallo-supramolecular fluorescent coordination polymers through 1 ： 1 complexation of Zn^2＋ and Cd^2＋ ions with ditopic terpyridine ligand was reported. The dispersibility of P1 and P2 was significantly improved in organic solvent and water through the introduction of hydrophilic oligo-ethyoxy side chain. Two polymers displayed yellow light emission both in solution and the solid state due to the intra-ligand charge transfer （ILCT） between the d^10 metal ions and the conjugated spacer unit. These coordination polymers were explored as fluorescent chemosensors for detecting picric acid in aqueous media, displaying high sensitivity and good selectivity. In addition, test strips were prepared from these polymers and exhibited the practical potential of detecting the NACs pollutants in the outdoor water for public safety and security.展开更多
Vanadium pentoxide （V2O5.nH2O） nanoribbons are synthesized via a hydrothermal process. These ribbons are 20nm thick, 200nm to 1 μm wide and several tens of micrometers long. Free-standing binder-free films are prep...Vanadium pentoxide （V2O5.nH2O） nanoribbons are synthesized via a hydrothermal process. These ribbons are 20nm thick, 200nm to 1 μm wide and several tens of micrometers long. Free-standing binder-free films are prepared by using these nanoribbons with multi-walled carbon nanotubes （MWCNTs） and used as the cathode for rechargeable sodium batteries. The large interlayer space between the V20s5 bilayers can enhance the kinetics of sodium ion intercalation/deintercalation. In addition, the intertwining network of the V2O5. 0.34H2O film provides efficient electron conduction pathways and shortens diffusion distances of sodium ion. The electrochemical tests prove that the free- standing V2O5. 0.34H2O film cathode delivers high reversible specific capacities （190 mAh/g） and good cycling stabilities （170 mAh/g after 150 cycles） in the voltage range between 1.5V and 3.5V.展开更多
The use of proteins as therapeutics in nanomedicine is an emerging research field and has developed rapidly.However,proteins are always vulnerable to renal excretion or digestion by the proteolytic system in vivo,whic...The use of proteins as therapeutics in nanomedicine is an emerging research field and has developed rapidly.However,proteins are always vulnerable to renal excretion or digestion by the proteolytic system in vivo,which limits their usage to a large extent.Although biocompatible polymers have been covalently linked to proteins to protect them from recognition by the immune system and prolong their circulation time,the biological activity of them is sometimes decreased.To fill this gap,physical isolation,wrapping,or encapsulation techniques are employed.Up to now,various mature examples were reported,but the whole time scales for vip molecules loading and releasing,especially the initial rapid loading process,were rarely mentioned.Herein,a series of dual-responsive poly（N-isopropylacrylamide-co-methacrylic acid）（P（NIPAM-co-MAA）） microgels were synthesized and employed to investigate the kinetics of in situ complexation and release of lysozyme under external stimuli modulation upon a stopped-flow apparatus,which was suitable for rapid dynamic monitoring.Close inspection of the adsorption kinetics during the early stages（〈 50 s） revealed that the initial microgel collapse occurred within ~1 s,with more rapid transitions being observed when higher lysozyme concentrations were targeted.All the dynamic traces could be well fitted with a double exponential function,suggesting a fast（τ1） and a slow（τ2） relaxation time,respectively.Then,the kinetics of releasing bound lysozyme from microgels was carried on by utilizing the p H-responsive property,and the evaluation of the activity of released lysozyme was synchronously measured in a Micrococcus lysodeikticus（M.lysodeikticus） cell suspension.The corresponding relaxation time（τ） was also calculated by fitting the recorded dynamic traces.We speculate that this work can provide basic dynamics data and theoretical basis for microgels based nanocarriers to be used for protein delivery,controlled release,and possible chemical separation.展开更多
Polyisocyanides and their block copolymers have widespread applications in many fields due to their unique helix and self-assembly properties.At first,the latest progress in the preparation of helical polyisocyanide-b...Polyisocyanides and their block copolymers have widespread applications in many fields due to their unique helix and self-assembly properties.At first,the latest progress in the preparation of helical polyisocyanide-based block copolymers via the method of one-pot sequential controlled synthesis and stepwise polymerization was highlighted in this minireview.Various categories of helical polyisocyanide-based copolymers including amphiphilic block copolymers,UV-response block copolymers,π-conjugated block copolymers,etc.,have been prepared successfully.Moreover,recent advances in the self-assembly and circularly polarized luminescence performance of amphiphilic andπ-conjugated helical polyisocyanide-based copolymers have been introduced,respectively.We hope this minireview will not only inspire more interest in developing helical polyisocyanide-based copolymers,but also encourage further progress in the field of building artificial functional materials.展开更多
P2-type layered oxide Na_(0.67)Fe_(0.5)Mn_(0.5)O_(2)is recognized as a very promising cathode material for sodium-ion batteries due to the merits of high capacity,high voltage,low cost,and easy preparation.However,its...P2-type layered oxide Na_(0.67)Fe_(0.5)Mn_(0.5)O_(2)is recognized as a very promising cathode material for sodium-ion batteries due to the merits of high capacity,high voltage,low cost,and easy preparation.However,its unsatisfactory cycle and rate performances remain huge obstacles for practical applications.Here,we report a strategy of SnO_(2)modification on P2-type Na_(0.67)Fe_(0.5)Mn_(0.5)O_(2)to improve the cycle and rate performance.展开更多
We present an ultrasensitive ultraviolet （UV） detector based on a p-type ZnS nanoribbon （NR）/indium tin oxide （ITO） Schottky barrier diode （SBD）. The device exhibits a pseudo-photovoltaic behavior which can al...We present an ultrasensitive ultraviolet （UV） detector based on a p-type ZnS nanoribbon （NR）/indium tin oxide （ITO） Schottky barrier diode （SBD）. The device exhibits a pseudo-photovoltaic behavior which can allow the SBD to detect UV light irradiation with incident power of 6 × 10^-17 W （-85 photons/s on the NR） at room temperature, with excellent reproducibility and stability. The corresponding detectivity and photoconductive gain are calculated to be 3.1 × 10^20 cm.Hz1/2.W^-1 and 6.6 × 10^5, respectively. It is found that the presence of the trapping states at the p-ZnS NWITO interface plays a crucial role in determining the ultrahigh sensitivity of this nanoSBDs. Based on our theoretical calculation, even ultra-low photon fluxes on the order of several tens of photons could induce a significant change in interface potential and consequently cause a large photocurrent variation. The present study provides new opportunities for developiphigh-performance optoelectronic devices in the future.展开更多
基金financially supported by National Natural Science Foundation of China (No.U1937601)the Industrial Technology Development Program of China(No.JCKY 2020203B019).
文摘One of the most widely used and well-established atomic oxygen(AO)protection solutions for low Earth orbit(LEO)satellites is the deposition of protective coatings on polymeric materials.However,manufacturing extensive expanses of these coating materials with good transparency,flexibility,smoothness,ultra-thinness,and exceptional AO resistance remains a critical issue.Herein,we successfully deposited a 400 nm thick polyorgansiloxane(SiO_(x)C_(y)H_(z))coating with high optical transparency and uniform good adherence on to a 1.2 m wide polyimide surface,by optimizing the distribution of hexamethyldisiloxane and oxygen as precursors in the roll-to-roll compatible plasmaenhanced chemical vapor deposition process.After AO irradiation with the fluence of 7.9×10^(20)atoms·cm^(–2),the erosion yield of the SiO_(x)C_(y)H_(z)-coated Kapton was less than 2.30×10^(–26)cm^3·atom^(–1),which was less than 0.77%of that of the Kapton.It indicates that the SiO_(x)C_(y)H_(z)coating can well prevent the erosion of Kapton by AO.In addition,it was also clarified that a SiO_(2) passivation layer was formed on the surface of the SiO_(x)C_(y)H_(z)coating during AO irradiation,which exhibited a‘self-reinforcing’defense mechanism.The entire preparation process of the SiO_(x)C_(y)H_(z)coating was highly efficient and low-cost,and it has shown great potential for applications in LEO.
基金financially supported by the National Natural Science Foundation of China(21606065,51372060,and 21676067)Anhui Provincial Natural Science Foundation(1708085QE98)+1 种基金the Fundamental Research Funds for the Central Universities(JZ2017HGTB0198,JZ2018HGBZ0138)the Opening Project of CAS Key Laboratory of Materials for Energy Conversion(KF2018003)
文摘Lithium-sulfur(Li-S)batteries with lithium sulfide(Li2S)as cathode have attracted great attention recently,because of high specific capacity(1166 mA h g^-1)of Li2S and potential safety of using Li metal-free anode.Li2S cathode has lower volume expansion and higher thermal stability than the traditional sulfur cathode.However,the problems of"shuttle effect"and poor electrical conductivity of the cathode material still need to be overcome.In this work,multi-layered Ti3C2/Li2S(ML-Ti3C2/Li2S)composite has been prepared and applied as a cathode in advanced Li-S batteries.The unique multi-layer sheet structure of Ti3 C2 provides space for the storage of Li2S,and its good conductivity greatly enhances the usage ratio of Li2 S and improves the conductivity of the whole Li2S cathode.Compared with commonly used graphene,ML-Ti3C2 can trap polysulfides effectively by chemical adsorption and also activate the reaction of Li2S to polysulfides by forming Ti-S bond.As a result,during the cycling of the batteries with ML-Ti3C2/Li2S cathodes,the activation voltage barrier of the first cycle has decreased to 2.8 V,and the"shuttle effect"has been suppressed effectively.The cycling and rate performances of the ML-Ti3C2/Li2S cathodes have been significantly improved compared to that of graphene/Li2 S cathodes.They maintain a capacity of 450 mAh g^-1 at 0.2 C after 100 cycles,and deliver attractive rate performances of 750,630,540,470 and 360 mAh g^-1 at 0.1 C,0.2 C,0.5 C,1 C,and 2 C,respectively.
基金supported by the National Natural Science Foundation of China(Grant Nos.52072105,21676067)the Key R&D Program of Anhui Province(202104a05020044)+2 种基金the Anhui Provincial Natural Science Foundation(2108085J23)Science and Technology Major Project of Anhui Province(202003a05020014)the Fundamental Research Funds for the Central Universities(PA2021KCPY0028,JZ2020YYPY0109).
文摘In traditional in situ polymerization preparation for solid-state electrolytes,initiators are directly added to the liquid precursor.In this article,a novel cellulose paper-based composite separator is fabricated,which employs alumina as the inorganic reinforcing material and is loaded with polymerization initiator aluminum trifluoromethanesulfonate.Based upon this,a separator-induced in situ directional polymerization technique is demonstrated,and the extra addition of initiators into liquid precursors is no longer required.The polymerization starts from the surface and interior of the separator and extends outward with the gradually dissolving of initiators into the precursor.Compared with its traditional counterpart,the separator-induced poly(1,3-dioxolane)electrolyte shows improved interfacial contact as well as appropriately mitigated polymerization rate,which are conducive to practical applications.Electrochemical measurement results show that the prepared poly(1,3-dioxolane)solid electrolyte possesses an oxidation potential up to 4.4 V and a high Li+transference number of 0.72.After 1000 cycles at 2 C rate(340 mA g^(−1)),the assembled Li||LiFePO_(4)solid battery possesses a 106.8 mAh g^(−1)discharge capacity retention and 83.5%capacity retention ratio,with high average Coulombic efficiency of 99.5%achieved.Our work may provide new ideas for the design and application of in situ polymerization technique for solid electrolytes and solid batteries.
基金supported by the National Natural Science Foundation of China(91023030,51072044,51102071 and 51128201)the International Scientific and Technological Cooperation Project of Anhui Province(10080703017)
文摘A facile and environment friendly approach to synthesis of unique hierarchical BiOCl flowery microspheres(FMs)using a biodegradable surfactant polyvinyl alcohol(PVA)was reported herein for the first time.Compared to the BiOCl nanosheets synthesized in the absence of PVA,hierarchical BiOCl FMs consist of large amounts of interwoven polycrystalline nanosheets that assemble into a porous flowery structure.The formation mechanism of the hierarchical BiOCl FMs was also proposed,whereby PVA was believed to play a key role in the crystal growth and the formation of the final microstructures.Compared with TiO2-P25 and BiOCl nanosheets,hierarchical BiOCl FMs displayed remarkably enhanced photocatalytic activity,and20 mg of BiOCl FMs could completely degrade 50 mL of methyl orange solution(20 mg/L)within 30 min under UVlight irradiation.According to the comprehensive analysis,it can be concluded that the larger specific surface area,porosity,suitable band gap,and the enhanced light absorption capacity may contribute to the remarkably enhanced photocatalytic activity.This facile and green approach to fabricating hierarchical BiOCl FMs would give vital clues to develop new route for synthesizing other hierarchical structured materials.
基金supported by the National Natural Science Foundation of China(51603060 and 51673056)the Industrial Guidance Fund Project of Bengbu City and Hefei University of Technology(JZ2020YDZJ0334)。
文摘Lightweight microcellular polyurethane(TPU)/carbon nanotubes(CNTs)/nickel-coated CNTs(Ni@CNTs)/polymerizable ionic liquid copolymer(PIL)composite foams are prepared by non-solvent induced phase separation(NIPS).CNTs and Ni@CNTs modified by PIL provide more heterogeneous nucleation sites and inhibit the aggregation and combination of microcellular structure.Compared with TPU/CNTs,the TPU/CNTs/PIL and TPU/CNTs/Ni@CNTs/PIL composite foams with smaller microcellular structures have a high electromagnetic interference shielding effectiveness(EMI SE).The evaporate time regulates the microcellular structure,improves the conductive network of composite foams and reduces the microcellular size,which strengthens the multiple reflections of electromagnetic wave.The TPU/10CNTs/10Ni@CNTs/PIL foam exhibits slightly higher SE values(69.9 dB)compared with TPU/20CNTs/PIL foam(53.3 dB).The highest specific EMI SE of TPU/20CNTs/PIL and TPU/10CNTs/10Ni@CNTs/PIL reaches up to 187.2 and 211.5 dB/(g cm^(−3)),respectively.The polarization losses caused by interfacial polarization between TPU substrates and conductive fillers,conduction loss caused by conductive network of fillers and magnetic loss caused by Ni@CNT synergistically attenuate the microwave energy.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.52072105 and 21676067)the Key R&D Program of Anhui Province(202104a05020044)+3 种基金the Anhui Provincial Natural Science Foundation(2108085J23)the Major Science and Technology Projects in Anhui Province(202003a05020014,2021e03020001)the Fundamental Research Funds for the Central Universities(PA2021KCPY0028,JZ2022HGTB0251)supported by the National Science Foundation,Division of Materials Research,Award Number 1938833。
文摘A high-performance quasi-solid polymer electrolyte for sodium metal batteries(SMBs)based on in-situ polymerized poly(1,3-dioxolane)(DOL)with 20%volume ratio of fluoroethylene carbonate(FEC),termed"PDFE-20",is proposed in this work.It is demonstrated PDFE-20 possesses a room-temperature ionic conductivity of 3.31×10^(-3) S cm^(-1),an ionic diffusion activation energy of 0.10 eV,and an oxidation potential of 4.4 V.SMBs based on PDFE-20 and Na_(3)V_(2)(PO_(4))_(3)(NVP)cathodes were evaluated with an active material mass loading of 6.8 mg cm^(-2).The cell displayed an initial discharge specific capacity of 104 mA h g^(-1),and97.1%capacity retention after 100 cycles at 0.5 C.In-situ polymerization conformally coats the anode/-cathode interfaces,avoiding geometrical gaps and high charge transfer resistance with ex-situ polymerization of the same chemistry.FEC acts as a plasticizer during polymerization to suppress crystallization and significantly improves ionic transport.During battery cycling FEC promotes mechanical congruence of electrolyte-electrode interfaces while forming a stable NaF-rich solid electrolyte interphase(SEI)at the anode.Density functional theory(DFT)calculations were also performed to further understand the role FEC in the poly(DOL)-FEC electrolytes.This work broadens the application of in-situ prepared poly(DOL)electrolytes to sodium storage and demonstrates the crucial role of FEC in improving the electrochemical performance.
基金financially supported by the National Natural Science Foundation of China(Nos.51503055 and 51673056)the Fundamental Research Funds for the Central Universities(No.PA2020GDKC0009)。
文摘Incorporating the surface-grafted cellulose nanocrystals(CNCs)with enantiomeric polylactide(PLLA or PDLA)is an effective and sustainable way to modify PLLA,but their difference in promoting matrix crystallization is still unrevealed.In this study,the CNCs with identical content and length of PLLA and PDLA(CNC-g-L and CNC-g-D)were prepared and blended with PLLA.The rheological properties of PLLA/CNC-gD are greatly improved,indicating that the stereocomplexation can significantly improve the interfacial strength as compared with the conventional van der Waals force in PLLA/CNC-g-L.Surprisingly,the matrix crystallizes at a higher rate in PLLA/CNC-g-L than PLLA/CNC-g-D.PLLA/CNC-g-L15 reaches its half crystallinity in 8.26 min while a longer period of 13.41 min is required for PLLA/CNC-g-D15.POM observation reveals that the superior crystallization behavior in PLLA/CNC-g-L is originated from its higher nucleation efficiency and faster growth rate.The formation of low content of sc-PLA at the interface can restrict the diffusion of PLLA but contribute less to generate crystalline nuclei,which synergistically leads to the retarded crystallization kinetics in PLLA/CNC-g-D.Revealing the mechanism of different interfacial enantiomeric grafting on the melt rheology and crystallization of PLLA is of great significance for the development of high-performance polylactide materials.
基金financially supported by the National Natural Science Foundation of China(No.51603060)the Fundamental Research Funds for the Central Universities(No.JZ2017YYPY0250)
文摘To investigate the performance of graphene(Gra) modified with ethoxycarbonyl ionic liquid(IL), chain mobility and crystallization kinetics of poly(L-lactic acid)(PLLA), a series of PLLA nanocomposites have been prepared using solution-cast method.IL can improve the dispersion of Gra in PLLA matrix and the samples containing IL have higher growth rate of PLLA spherulite than neat PLLA does. PLLA/IL/Gra and PLLA/2 Gra exhibit the same relaxation strength and time of αN relaxation that corresponds to the longest normal mode motion at 110-140 °C. PLLA/IL/Gra shows a faster crystallization rate than PLLA/2 Gra does, which might be attributed to the Gra-imidazolium cation interaction in IL modified Gra, the significant dispersion effect of IL at Gra surface, and the increase of nuclei density of PLLA/IL/Gra.
文摘The synthesis of two linear terpy-based metallo-supramolecular fluorescent coordination polymers through 1 ： 1 complexation of Zn^2＋ and Cd^2＋ ions with ditopic terpyridine ligand was reported. The dispersibility of P1 and P2 was significantly improved in organic solvent and water through the introduction of hydrophilic oligo-ethyoxy side chain. Two polymers displayed yellow light emission both in solution and the solid state due to the intra-ligand charge transfer （ILCT） between the d^10 metal ions and the conjugated spacer unit. These coordination polymers were explored as fluorescent chemosensors for detecting picric acid in aqueous media, displaying high sensitivity and good selectivity. In addition, test strips were prepared from these polymers and exhibited the practical potential of detecting the NACs pollutants in the outdoor water for public safety and security.
基金supported by the National Natural Science Foundation of China (Nos.51372060,21676067 and 21606065)Anhui Provincial Natural Science Foundation of China (No.1708085QE98)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Opening Project of CAS Key Laboratory of Materials for Energy Conversion (No.KF2016005)
文摘Vanadium pentoxide （V2O5.nH2O） nanoribbons are synthesized via a hydrothermal process. These ribbons are 20nm thick, 200nm to 1 μm wide and several tens of micrometers long. Free-standing binder-free films are prepared by using these nanoribbons with multi-walled carbon nanotubes （MWCNTs） and used as the cathode for rechargeable sodium batteries. The large interlayer space between the V20s5 bilayers can enhance the kinetics of sodium ion intercalation/deintercalation. In addition, the intertwining network of the V2O5. 0.34H2O film provides efficient electron conduction pathways and shortens diffusion distances of sodium ion. The electrochemical tests prove that the free- standing V2O5. 0.34H2O film cathode delivers high reversible specific capacities （190 mAh/g） and good cycling stabilities （170 mAh/g after 150 cycles） in the voltage range between 1.5V and 3.5V.
基金financially supported in part by the National Natural Science Foundation of China(No.51673058)
文摘The use of proteins as therapeutics in nanomedicine is an emerging research field and has developed rapidly.However,proteins are always vulnerable to renal excretion or digestion by the proteolytic system in vivo,which limits their usage to a large extent.Although biocompatible polymers have been covalently linked to proteins to protect them from recognition by the immune system and prolong their circulation time,the biological activity of them is sometimes decreased.To fill this gap,physical isolation,wrapping,or encapsulation techniques are employed.Up to now,various mature examples were reported,but the whole time scales for vip molecules loading and releasing,especially the initial rapid loading process,were rarely mentioned.Herein,a series of dual-responsive poly（N-isopropylacrylamide-co-methacrylic acid）（P（NIPAM-co-MAA）） microgels were synthesized and employed to investigate the kinetics of in situ complexation and release of lysozyme under external stimuli modulation upon a stopped-flow apparatus,which was suitable for rapid dynamic monitoring.Close inspection of the adsorption kinetics during the early stages（〈 50 s） revealed that the initial microgel collapse occurred within ~1 s,with more rapid transitions being observed when higher lysozyme concentrations were targeted.All the dynamic traces could be well fitted with a double exponential function,suggesting a fast（τ1） and a slow（τ2） relaxation time,respectively.Then,the kinetics of releasing bound lysozyme from microgels was carried on by utilizing the p H-responsive property,and the evaluation of the activity of released lysozyme was synchronously measured in a Micrococcus lysodeikticus（M.lysodeikticus） cell suspension.The corresponding relaxation time（τ） was also calculated by fitting the recorded dynamic traces.We speculate that this work can provide basic dynamics data and theoretical basis for microgels based nanocarriers to be used for protein delivery,controlled release,and possible chemical separation.
基金This work was supported by the National Natural Science Foundation of China(Nos.52273204,52273006,22071041,21971052,51903072,21871073)the Fundamental Research Funds for the Central Universities of China(No.PA2021GDSK0064)the Natural Science Foundation of Anhui Province,China(No.2008085MB51).
文摘Polyisocyanides and their block copolymers have widespread applications in many fields due to their unique helix and self-assembly properties.At first,the latest progress in the preparation of helical polyisocyanide-based block copolymers via the method of one-pot sequential controlled synthesis and stepwise polymerization was highlighted in this minireview.Various categories of helical polyisocyanide-based copolymers including amphiphilic block copolymers,UV-response block copolymers,π-conjugated block copolymers,etc.,have been prepared successfully.Moreover,recent advances in the self-assembly and circularly polarized luminescence performance of amphiphilic andπ-conjugated helical polyisocyanide-based copolymers have been introduced,respectively.We hope this minireview will not only inspire more interest in developing helical polyisocyanide-based copolymers,but also encourage further progress in the field of building artificial functional materials.
基金This work was supported by the National Natural Science Foundation of China(No.21676067)the Natural Science Foundation of Anhui Province,China(No.1908085QE178)and the Fundamental Research Funds for the Central Universities,China.
文摘P2-type layered oxide Na_(0.67)Fe_(0.5)Mn_(0.5)O_(2)is recognized as a very promising cathode material for sodium-ion batteries due to the merits of high capacity,high voltage,low cost,and easy preparation.However,its unsatisfactory cycle and rate performances remain huge obstacles for practical applications.Here,we report a strategy of SnO_(2)modification on P2-type Na_(0.67)Fe_(0.5)Mn_(0.5)O_(2)to improve the cycle and rate performance.
文摘We present an ultrasensitive ultraviolet （UV） detector based on a p-type ZnS nanoribbon （NR）/indium tin oxide （ITO） Schottky barrier diode （SBD）. The device exhibits a pseudo-photovoltaic behavior which can allow the SBD to detect UV light irradiation with incident power of 6 × 10^-17 W （-85 photons/s on the NR） at room temperature, with excellent reproducibility and stability. The corresponding detectivity and photoconductive gain are calculated to be 3.1 × 10^20 cm.Hz1/2.W^-1 and 6.6 × 10^5, respectively. It is found that the presence of the trapping states at the p-ZnS NWITO interface plays a crucial role in determining the ultrahigh sensitivity of this nanoSBDs. Based on our theoretical calculation, even ultra-low photon fluxes on the order of several tens of photons could induce a significant change in interface potential and consequently cause a large photocurrent variation. The present study provides new opportunities for developiphigh-performance optoelectronic devices in the future.
