The effective conductivity of graphene-based nanocomposites is suggested by the characteristics of polymer-filler interfacial areas as well as the contact resistance between the neighboring nanosheets.The interfacial ...The effective conductivity of graphene-based nanocomposites is suggested by the characteristics of polymer-filler interfacial areas as well as the contact resistance between the neighboring nanosheets.The interfacial properties are expressed by the effective levels of the inverse aspect ratio and the filler volume fraction.Moreover,the resistances of components in the contact regions are used to define the contact resistance,which inversely affects the effective conductivity.The obtained model is utilized to predict the effective conductivity for some examples.The discrepancy of the effective conductivity at various ranks of all factors is clarified.The interfacial conductivity directly controls the effective conductivity,while the filler conductivity plays a dissimilar role in the effective conductivity,due to the incomplete interfacial adhesion.A high operative conductivity is also achieved by small contact distances and high interfacial properties.Additionally,big contact diameters and little tunnel resistivity decrease the contact resistance,thus enhancing the effective conductivity.展开更多
We report chemical vapor phase polymerization(VPP) deposition of poly(3,4-ethylenedioxythiophene)(PEDOT) and PEDOT/graphene on porous dielectric tantalum pentoxide(Ta_2O_5) surface as cathode films for solid tantalum ...We report chemical vapor phase polymerization(VPP) deposition of poly(3,4-ethylenedioxythiophene)(PEDOT) and PEDOT/graphene on porous dielectric tantalum pentoxide(Ta_2O_5) surface as cathode films for solid tantalum electrolyte capacitors. The modified oxidant/oxidant-graphene films were first deposited on Ta_2O_5 by dip-coating, and VPP process was subsequently utilized to transfer oxidant/oxidant-graphene into PEDOT/PEDOT-graphene films. The SEM images showed PEDOT/PEDOT-graphene films was successfully constructed on porous Ta_2O_5 surface through VPP deposition, and a solid tantalum electrolyte capacitor with conducting polymer-graphene nano-composites as cathode films was constructed. The high conductivity nature of PEDOT-graphene leads to resistance decrease of cathode films and lower contact resistance between PEDOT/graphene and carbon paste. This nano-composite cathode films based capacitor showed ultralow equivalent series resistance(ESR) ca. 12 m? and exhibited excellent capacitance-frequency performance, which can keep 82% of initial capacitance at 500 KHz. The investigation on leakage current revealed that the device encapsulation process has no influence on capacitor leakage current, indicating the excellent mechanical strength of PEDOT/PEDOT-gaphene films. This high conductivity and mechanical strength of graphene-based polymer films shows promising future for electrode materials such as capacitors, organic solar cells and electrochemical energy storage devices.展开更多
Acrylonitrile-sodium styrene sulfonate copolymer/layered double hydroxides nanocomposites were prepared by in situ aqueous precipitation copolymerization of acrylonitrile (AN) and sodium styrene sulfonate (SSS) in...Acrylonitrile-sodium styrene sulfonate copolymer/layered double hydroxides nanocomposites were prepared by in situ aqueous precipitation copolymerization of acrylonitrile (AN) and sodium styrene sulfonate (SSS) in the presence of 4-vinylbenzene sulfonate intercalated layered double hydroxides (MgA1-VBS LDHs) and transferred to acrylonitrile-styrene sulfonic acid (AN-SSA) copolymer/LDHs nanocomposites as a proton-conducting polymer electrolyte. MgA1-VBS LDHs were prepared by a coprecipitation method, and the structure and composition of MgAl-VBS LDHs were determined by X-ray diffraction (XRD), infrared spectroscopy, and elemental analysis. X-ray diffraction result of AN-SSS copolymer/LDHs nanocomposites indicated that the LDHs layers were well dispersed in the AN-SSS copolymer matrix. All the AN-SSS copolymer/LDHs nanocomposites showed significant enhancement of the decomposition temperatures compared with the pristine AN-SSS copolymer, as identified by the thermogravimetric analysis. The methanol crossover was decreased and the proton conductivity was highly enhanced for the AN-SSA copolymer/LDHs nanocomposite electrolyte systems. In the case of the nanocomposite electrolyte containing 2% (by mass) LDHs, the proton conductivity of 2.60×10^- 3 S·m^-1 was achieved for the polymer electrolyte.展开更多
The organic/inorganic nanocomposites polymer electrolytes were designed and synthesized. The organic/inorganic nanocomposites membrane materials and their lithium salt complexes have been found thermally stable below ...The organic/inorganic nanocomposites polymer electrolytes were designed and synthesized. The organic/inorganic nanocomposites membrane materials and their lithium salt complexes have been found thermally stable below 200 °C. The conductivity of the organic/inorganic nanocomposites polymer electrolytes prepared at room temperature was at magnitude range of 10(?6) S/cm.展开更多
PVC/CdS nanocomposites have been prepared by solution casting method taking 2, 4, 6 and 8 wt% of CdS nanoparticles. PVC/CdS nanocomposites were characterized through TEM measurement. The measurement of effective therm...PVC/CdS nanocomposites have been prepared by solution casting method taking 2, 4, 6 and 8 wt% of CdS nanoparticles. PVC/CdS nanocomposites were characterized through TEM measurement. The measurement of effective thermal conductivity of PVC/CdS nanocomposites has also been done using transient plane source (TPS) method. The effects of concentration of CdS nanoparticles and temperature on the effective thermal conductivity of polymer PVC/CdS nanocomposites have been studied. The variation of effective thermal conductivity with the concentration of filler particles and temperature has also been discussed in terms of dispersion of filler particles into polymer matrix and phonon scattering mechanism, respectively.展开更多
PANI (polyaniline) as a promising conducting polymer and photosensitizer has been used to prepare PANI/TiO2 (polyaniline/TiO2) nanocomposite as photocatalyst. TiO2 nanoparticles with size of 5-100 nm were encapsul...PANI (polyaniline) as a promising conducting polymer and photosensitizer has been used to prepare PANI/TiO2 (polyaniline/TiO2) nanocomposite as photocatalyst. TiO2 nanoparticles with size of 5-100 nm were encapsulated by PANI via the "in situ" polymerization of aniline on the surface of TiO2 nanoparticles. IR, SEM, EPR techniques were used to characterize the mechanism of electron interaction in PANI/TiO2 nanocomposite. The resulting PANI-modified TiO2 composites exhibit significantly higher photocatalytic activity than that of neat PANI on degradation of MB (methylen blue) aqueous solution under UV irradiation.展开更多
We have investigated the electrical properties of carbon black (CB) loaded in ethylene butylacrylate copolymer composite (EBA) in the frequency range between 102 and 104 Hz and temperature range between 153 and 353 K....We have investigated the electrical properties of carbon black (CB) loaded in ethylene butylacrylate copolymer composite (EBA) in the frequency range between 102 and 104 Hz and temperature range between 153 and 353 K. The frequency dependence of electrical data that have been analyzed in two frameworks: the electrical modulus formalism with the Kohlrausch-Williams-Watts stretched exponential function (KWW) and the electrical conductivity by using the Jonscher’s power law in the frequency domain. The stretching exponent βKWW and n are found to be temperature independent for all CB fractions and to be decreased when the CB volume concentrations loaded in copolymer matrix increases. It is found that the activation energy obtained by the modulus method is in good agreement with that obtained by the DC conductivity in the power law which is independent on the CB contents that exist in the copolymer matrix, suggesting that these particles do not interact significantly with the chain segments of the macromolecules in the EBA copolymer.展开更多
Electrically conductive and flame-retardant maleic anhydride grafted high-density polyethylene(MA-HDPE) nanocomposites with satisfactory mechanical properties are fabricated by melt compounding MA-HDPE with polyethyle...Electrically conductive and flame-retardant maleic anhydride grafted high-density polyethylene(MA-HDPE) nanocomposites with satisfactory mechanical properties are fabricated by melt compounding MA-HDPE with polyethyleneimine(PEI)-modified reduced graphene oxide(PEI@RGO) as the conductive nanofiller and brominated polystyrene(BPS) as the flame retardant. The modification with PEI significantly improves the interfacial compatibility and dispersion of the RGO sheets in the MA-HDPE matrix, leading to electrically conductive nanocomposites with enhanced mechanical properties. Furthermore, the addition of 25 wt% of BPS makes the nanocomposite flame-retardant with a UL-94 V-0 rating. Thus, the multifunctional RGO/MA-HDPE nanocomposites with good electrical, flameretardant, and mechanical properties would have potential applications in construction and pipeline fields.展开更多
Carbon nanotubes(CNTs) have long been recognized as the stiffest and strongest man-made material known to date. In addition, their high electrical conductivity has roused interest in the areas of electrical applianc...Carbon nanotubes(CNTs) have long been recognized as the stiffest and strongest man-made material known to date. In addition, their high electrical conductivity has roused interest in the areas of electrical appliances and communication related applications. However, due to their miniature size, the excellent properties of these nanostructures can only be exploited if they are homogeneously embedded into light-weight matrices as those offered by a whole series of engineering polymers. In order to enhance their chemical affinity to engineering polymer matrices, chemical modification of the graphitic sidewalls and tips is necessary. The mechanical and electrical properties to date of a whole range of nanocomposites of various carbon nanotube contents are also reviewed in this attempt to facilitate progress in this emerging area. Recently, carbonaceous nano-fillers such as graphene and carbon nanotubes(CNTs) play a promising role due to their better structural and functional properties and broad range of applications in every field. Since CNTs usually form stabilized bundles due to van der Waals interactions, they are extremely difficult to disperse and align in a polymer matrix. The biggest issues in the preparation of CNTs reinforced composites reside in efficient dispersion of CNTs into a polymer matrix, the assessment of the dispersion, and the alignment and control of the CNTs in the matrix. An overview of various CNT functionalization methods is given. In particular, CNT functionalization using click chemistry and the preparation of CNT composites employing hyperbranched polymers are stressed as potential techniques to achieve good CNT dispersion. In addition, discussions on mechanical, thermal, electrical, electrochemical and applications of polymer/CNT composites are also included.展开更多
This paper used a new approach of preparing poly-composites by covalent linkage between the MWCNT’s by imine group. The Poly (Imine)/MWCNT Composite was synthesized by the solution blending method from reacted amino ...This paper used a new approach of preparing poly-composites by covalent linkage between the MWCNT’s by imine group. The Poly (Imine)/MWCNT Composite was synthesized by the solution blending method from reacted amino multi-walled carbon nanotubes (MWCNT-NH2) with Terephthalaldehyde (TPAL). The obtained poly-composite was characterized by FT-IR, UV-Vis, XRD, TEM, SEM, TGA, DSC and DC electrical conductivity. The formation of Poly (Imine)/MWCNT composite was confirmed. The DC electrical conductivity of poly-composites was within the range 2.3 × 10–4 - 5.3 × 10–4 S/cm due to the interaction between the nanotubes.展开更多
The polyaniline(PANI)/CoFe_(2)O_(4)nanocomposites were prepared by an in situ polymerization of aniline in an aqueous solution.The composites were characterized by X-ray diffraction(XRD),Fourier transform infrared(FTI...The polyaniline(PANI)/CoFe_(2)O_(4)nanocomposites were prepared by an in situ polymerization of aniline in an aqueous solution.The composites were characterized by X-ray diffraction(XRD),Fourier transform infrared(FTIR)spectrum,thermogravimetric analysis(TGA)and scanning electron micrograph(SEM).The AC conductivity and dielectric properties of these composites were investigated in the frequency range 1 kHz10 MHz at room temperature.The AC conductivity was found to be constant up to 1 MHz and thereafter it increases steeply and it was observed maximum for the PANI with 60 wt%of CoFe_(2)O_(4)nanocomposite.At lower frequencies the values of dielectric constant is maximum for pure CoFe_(2)O_(4)nanoparticles.展开更多
The concept of artificial enzymes has been proposed for a long time and a large variety of materials have been exploited in enzyme-like catalytic field for decades. The emergence of nanotechnology provides increasing ...The concept of artificial enzymes has been proposed for a long time and a large variety of materials have been exploited in enzyme-like catalytic field for decades. The emergence of nanotechnology provides increasing opportu- nities for the development of artificial enzymes. Conducting polymer-based nanocomposites are a new type of burgeoning functional materials as enzyme mimics owing to their nu- merous functional groups, excellent electrical conductivity and redox properties. This review summarizes the recent progress of the synthesis of conducting polymers and their nanocomposites, as well as their applications as efficient peroxidase mimics. After a brief description of the develop- ment of conducting polymers, we specifically introduce the fabrication of conducting polymers and their nanocomposites via diverse approaches and show the enhanced peroxidase-like catalytic properties. In addition, the mechanism of the en- hanced catalytic efficiency of the conducting polymer-based nanocomposites has been proposed. Finally, we highlight the applications of such conducting polymer-based nanocompo- sites in the sensitive detection of different types of substances. It is anticipated that this review will pave the way for devel- oping more intriguing functional nanomaterials as enzyme mimics, which shows promising applications in a great many technological fields.展开更多
The key challenge for the use of polymer electrolytes is to realize a high ionic conductivity without scarifying their mechanical performance.Herein,we report a facile strategy to prepare a nanostructured polymer elec...The key challenge for the use of polymer electrolytes is to realize a high ionic conductivity without scarifying their mechanical performance.Herein,we report a facile strategy to prepare a nanostructured polymer electrolyte with both high proton conductivity and high modulus,based on the electrostatic self-assembly of polyoxometalate cluster H_(3)PW_(12)O_(40)(PW)and comb copolymer poly(ether-etherketone)-grafted-poly(vinyl pyrrolidone)(PEEK-gPVP).The incorporation of protonic acid PW can enable the PEEK-g-PVP to be highly proton conductive and create flexible composite electrolyte membranes.Moreover,nanoscale phase separation between PEEK domains and PVP/PW domains spontaneously occurs in these membranes,forming a bicontinuous structure with three-dimensional(3D)-connected PW networks.Due to the dual role of PW networks as both proton transport pathways and mechanical enhancers,these membranes exhibit proton conductivities higher than 30 mS cm^(−1) and modulus over 4 GPa.Notably,the direct methanol fuel cells equipped with these membranes show good cell performance.Given the wide tunability of comb copolymers and polyoxometalates,this system can be extended to develop a variety of functional electrolyte materials,for example,the lithium-ion conductive electrolytes by using polyoxometalatebased lithium salts,which provides a promising platform to explore versatile electrolyte materials for energy and electronic applications.展开更多
Expanded graphite,prepared from the rapid heating of graphite intercalated compound,was blended with polystyrene via the intercalation and the in situ polymerization of styrene.SEM,STM and etc were used to characteriz...Expanded graphite,prepared from the rapid heating of graphite intercalated compound,was blended with polystyrene via the intercalation and the in situ polymerization of styrene.SEM,STM and etc were used to characterize the nanostructure of the expanded graphite the composite of polymer/expanded graphite,and the changes of the nanostructure during the rolling process.The graphite formed the nanostructure during the expanding process of the GIC.The nanosheets were confirmed to have been dispersed in polystyrene matrix with the thickness of 10~30 nm.The conductivity of PS/expanded graphite composite was sensitive to the rolling process.The intensive rolling caused great decrease in its conductivity,due to the destruction of conducting network.展开更多
A preparation process of PMMA/graphite nanocomposites was developed via in situ polymerization of monomers in the presence of sonicated expanded graphite with the aid of sonication.Expanded graphite was sonicated in a...A preparation process of PMMA/graphite nanocomposites was developed via in situ polymerization of monomers in the presence of sonicated expanded graphite with the aid of sonication.Expanded graphite was sonicated in a 70% aqueous alcohol solution to get graphite platelets (NanoG) with thickness of 30~80 nm and diameter of 0.5~20 μm.The NanoG were dispersed in MMA monomers with BPO initiator.In situ polymerization was taken place when the mixture was heated under sonication.The TEM studies showed that the graphite nano-platelets were well dispersed in the PMMA matrix.Solution cast films of the nanocomposite were used for electrical conductivity measurements.The percolation threshold of polymer/NanoG nanocomposite films at room temperature was lower than 1.0 wt%,which was much lower than that of the composites with conventional graphite filler which was 5.5 wt%.The electrical conductivity reached 10 -3 S/cm at a graphite content of about 4.0 wt%.The special structure of graphite nano- platelets with high aspect ratio of as high as 100~500 (width-to-thickness) played an important role in forming a conducting network within the PMMA matrix.展开更多
基金Project supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education,Science and Technology(No.2022R1A2C1004437)。
文摘The effective conductivity of graphene-based nanocomposites is suggested by the characteristics of polymer-filler interfacial areas as well as the contact resistance between the neighboring nanosheets.The interfacial properties are expressed by the effective levels of the inverse aspect ratio and the filler volume fraction.Moreover,the resistances of components in the contact regions are used to define the contact resistance,which inversely affects the effective conductivity.The obtained model is utilized to predict the effective conductivity for some examples.The discrepancy of the effective conductivity at various ranks of all factors is clarified.The interfacial conductivity directly controls the effective conductivity,while the filler conductivity plays a dissimilar role in the effective conductivity,due to the incomplete interfacial adhesion.A high operative conductivity is also achieved by small contact distances and high interfacial properties.Additionally,big contact diameters and little tunnel resistivity decrease the contact resistance,thus enhancing the effective conductivity.
基金supported by the National Science Foundation of China(NSFC)(No.61101029)the Fundamental Research Funds for the Central Universities(No.ZYGX2010J057)+1 种基金the national defense pre-research foundation(No.9140A23070111DZ02042)A Plan for Supporting the New Century Talents(No.NCET-12-0091)
文摘We report chemical vapor phase polymerization(VPP) deposition of poly(3,4-ethylenedioxythiophene)(PEDOT) and PEDOT/graphene on porous dielectric tantalum pentoxide(Ta_2O_5) surface as cathode films for solid tantalum electrolyte capacitors. The modified oxidant/oxidant-graphene films were first deposited on Ta_2O_5 by dip-coating, and VPP process was subsequently utilized to transfer oxidant/oxidant-graphene into PEDOT/PEDOT-graphene films. The SEM images showed PEDOT/PEDOT-graphene films was successfully constructed on porous Ta_2O_5 surface through VPP deposition, and a solid tantalum electrolyte capacitor with conducting polymer-graphene nano-composites as cathode films was constructed. The high conductivity nature of PEDOT-graphene leads to resistance decrease of cathode films and lower contact resistance between PEDOT/graphene and carbon paste. This nano-composite cathode films based capacitor showed ultralow equivalent series resistance(ESR) ca. 12 m? and exhibited excellent capacitance-frequency performance, which can keep 82% of initial capacitance at 500 KHz. The investigation on leakage current revealed that the device encapsulation process has no influence on capacitor leakage current, indicating the excellent mechanical strength of PEDOT/PEDOT-gaphene films. This high conductivity and mechanical strength of graphene-based polymer films shows promising future for electrode materials such as capacitors, organic solar cells and electrochemical energy storage devices.
基金Supported by Program for New Century Excellent Talents in University(NCET-07-0738)
文摘Acrylonitrile-sodium styrene sulfonate copolymer/layered double hydroxides nanocomposites were prepared by in situ aqueous precipitation copolymerization of acrylonitrile (AN) and sodium styrene sulfonate (SSS) in the presence of 4-vinylbenzene sulfonate intercalated layered double hydroxides (MgA1-VBS LDHs) and transferred to acrylonitrile-styrene sulfonic acid (AN-SSA) copolymer/LDHs nanocomposites as a proton-conducting polymer electrolyte. MgA1-VBS LDHs were prepared by a coprecipitation method, and the structure and composition of MgAl-VBS LDHs were determined by X-ray diffraction (XRD), infrared spectroscopy, and elemental analysis. X-ray diffraction result of AN-SSS copolymer/LDHs nanocomposites indicated that the LDHs layers were well dispersed in the AN-SSS copolymer matrix. All the AN-SSS copolymer/LDHs nanocomposites showed significant enhancement of the decomposition temperatures compared with the pristine AN-SSS copolymer, as identified by the thermogravimetric analysis. The methanol crossover was decreased and the proton conductivity was highly enhanced for the AN-SSA copolymer/LDHs nanocomposite electrolyte systems. In the case of the nanocomposite electrolyte containing 2% (by mass) LDHs, the proton conductivity of 2.60×10^- 3 S·m^-1 was achieved for the polymer electrolyte.
文摘The organic/inorganic nanocomposites polymer electrolytes were designed and synthesized. The organic/inorganic nanocomposites membrane materials and their lithium salt complexes have been found thermally stable below 200 °C. The conductivity of the organic/inorganic nanocomposites polymer electrolytes prepared at room temperature was at magnitude range of 10(?6) S/cm.
文摘PVC/CdS nanocomposites have been prepared by solution casting method taking 2, 4, 6 and 8 wt% of CdS nanoparticles. PVC/CdS nanocomposites were characterized through TEM measurement. The measurement of effective thermal conductivity of PVC/CdS nanocomposites has also been done using transient plane source (TPS) method. The effects of concentration of CdS nanoparticles and temperature on the effective thermal conductivity of polymer PVC/CdS nanocomposites have been studied. The variation of effective thermal conductivity with the concentration of filler particles and temperature has also been discussed in terms of dispersion of filler particles into polymer matrix and phonon scattering mechanism, respectively.
文摘PANI (polyaniline) as a promising conducting polymer and photosensitizer has been used to prepare PANI/TiO2 (polyaniline/TiO2) nanocomposite as photocatalyst. TiO2 nanoparticles with size of 5-100 nm were encapsulated by PANI via the "in situ" polymerization of aniline on the surface of TiO2 nanoparticles. IR, SEM, EPR techniques were used to characterize the mechanism of electron interaction in PANI/TiO2 nanocomposite. The resulting PANI-modified TiO2 composites exhibit significantly higher photocatalytic activity than that of neat PANI on degradation of MB (methylen blue) aqueous solution under UV irradiation.
基金supported by an action integrated(N°Physique/04/08/09)granted by the Portugal-Moroccan committee.
文摘We have investigated the electrical properties of carbon black (CB) loaded in ethylene butylacrylate copolymer composite (EBA) in the frequency range between 102 and 104 Hz and temperature range between 153 and 353 K. The frequency dependence of electrical data that have been analyzed in two frameworks: the electrical modulus formalism with the Kohlrausch-Williams-Watts stretched exponential function (KWW) and the electrical conductivity by using the Jonscher’s power law in the frequency domain. The stretching exponent βKWW and n are found to be temperature independent for all CB fractions and to be decreased when the CB volume concentrations loaded in copolymer matrix increases. It is found that the activation energy obtained by the modulus method is in good agreement with that obtained by the DC conductivity in the power law which is independent on the CB contents that exist in the copolymer matrix, suggesting that these particles do not interact significantly with the chain segments of the macromolecules in the EBA copolymer.
基金financially supported by the National Natural Science Foundation of China(Nos.51673015,51373011,51533001,51521062,and 51803200)the Fundamental Research Funds for the Central Universities(No.BHYC1707B)the National Key Research and Development Program of China(No.2016YFC0801302)
文摘Electrically conductive and flame-retardant maleic anhydride grafted high-density polyethylene(MA-HDPE) nanocomposites with satisfactory mechanical properties are fabricated by melt compounding MA-HDPE with polyethyleneimine(PEI)-modified reduced graphene oxide(PEI@RGO) as the conductive nanofiller and brominated polystyrene(BPS) as the flame retardant. The modification with PEI significantly improves the interfacial compatibility and dispersion of the RGO sheets in the MA-HDPE matrix, leading to electrically conductive nanocomposites with enhanced mechanical properties. Furthermore, the addition of 25 wt% of BPS makes the nanocomposite flame-retardant with a UL-94 V-0 rating. Thus, the multifunctional RGO/MA-HDPE nanocomposites with good electrical, flameretardant, and mechanical properties would have potential applications in construction and pipeline fields.
文摘Carbon nanotubes(CNTs) have long been recognized as the stiffest and strongest man-made material known to date. In addition, their high electrical conductivity has roused interest in the areas of electrical appliances and communication related applications. However, due to their miniature size, the excellent properties of these nanostructures can only be exploited if they are homogeneously embedded into light-weight matrices as those offered by a whole series of engineering polymers. In order to enhance their chemical affinity to engineering polymer matrices, chemical modification of the graphitic sidewalls and tips is necessary. The mechanical and electrical properties to date of a whole range of nanocomposites of various carbon nanotube contents are also reviewed in this attempt to facilitate progress in this emerging area. Recently, carbonaceous nano-fillers such as graphene and carbon nanotubes(CNTs) play a promising role due to their better structural and functional properties and broad range of applications in every field. Since CNTs usually form stabilized bundles due to van der Waals interactions, they are extremely difficult to disperse and align in a polymer matrix. The biggest issues in the preparation of CNTs reinforced composites reside in efficient dispersion of CNTs into a polymer matrix, the assessment of the dispersion, and the alignment and control of the CNTs in the matrix. An overview of various CNT functionalization methods is given. In particular, CNT functionalization using click chemistry and the preparation of CNT composites employing hyperbranched polymers are stressed as potential techniques to achieve good CNT dispersion. In addition, discussions on mechanical, thermal, electrical, electrochemical and applications of polymer/CNT composites are also included.
文摘This paper used a new approach of preparing poly-composites by covalent linkage between the MWCNT’s by imine group. The Poly (Imine)/MWCNT Composite was synthesized by the solution blending method from reacted amino multi-walled carbon nanotubes (MWCNT-NH2) with Terephthalaldehyde (TPAL). The obtained poly-composite was characterized by FT-IR, UV-Vis, XRD, TEM, SEM, TGA, DSC and DC electrical conductivity. The formation of Poly (Imine)/MWCNT composite was confirmed. The DC electrical conductivity of poly-composites was within the range 2.3 × 10–4 - 5.3 × 10–4 S/cm due to the interaction between the nanotubes.
文摘The polyaniline(PANI)/CoFe_(2)O_(4)nanocomposites were prepared by an in situ polymerization of aniline in an aqueous solution.The composites were characterized by X-ray diffraction(XRD),Fourier transform infrared(FTIR)spectrum,thermogravimetric analysis(TGA)and scanning electron micrograph(SEM).The AC conductivity and dielectric properties of these composites were investigated in the frequency range 1 kHz10 MHz at room temperature.The AC conductivity was found to be constant up to 1 MHz and thereafter it increases steeply and it was observed maximum for the PANI with 60 wt%of CoFe_(2)O_(4)nanocomposite.At lower frequencies the values of dielectric constant is maximum for pure CoFe_(2)O_(4)nanoparticles.
基金supported by the National Natural Science Foundation of China (51473065, 51773075 and 21474043)
文摘The concept of artificial enzymes has been proposed for a long time and a large variety of materials have been exploited in enzyme-like catalytic field for decades. The emergence of nanotechnology provides increasing opportu- nities for the development of artificial enzymes. Conducting polymer-based nanocomposites are a new type of burgeoning functional materials as enzyme mimics owing to their nu- merous functional groups, excellent electrical conductivity and redox properties. This review summarizes the recent progress of the synthesis of conducting polymers and their nanocomposites, as well as their applications as efficient peroxidase mimics. After a brief description of the develop- ment of conducting polymers, we specifically introduce the fabrication of conducting polymers and their nanocomposites via diverse approaches and show the enhanced peroxidase-like catalytic properties. In addition, the mechanism of the en- hanced catalytic efficiency of the conducting polymer-based nanocomposites has been proposed. Finally, we highlight the applications of such conducting polymer-based nanocompo- sites in the sensitive detection of different types of substances. It is anticipated that this review will pave the way for devel- oping more intriguing functional nanomaterials as enzyme mimics, which shows promising applications in a great many technological fields.
基金The authors acknowledge financial support from the National Natural Science Foundation of China(no.22075097)the Program for JLU Science and Technology Innovative Research Team(no.2017TD-10)the Open Research Fund of State Key Laboratory of Polymer Physics and Chemistry,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences(2020-09).
文摘The key challenge for the use of polymer electrolytes is to realize a high ionic conductivity without scarifying their mechanical performance.Herein,we report a facile strategy to prepare a nanostructured polymer electrolyte with both high proton conductivity and high modulus,based on the electrostatic self-assembly of polyoxometalate cluster H_(3)PW_(12)O_(40)(PW)and comb copolymer poly(ether-etherketone)-grafted-poly(vinyl pyrrolidone)(PEEK-gPVP).The incorporation of protonic acid PW can enable the PEEK-g-PVP to be highly proton conductive and create flexible composite electrolyte membranes.Moreover,nanoscale phase separation between PEEK domains and PVP/PW domains spontaneously occurs in these membranes,forming a bicontinuous structure with three-dimensional(3D)-connected PW networks.Due to the dual role of PW networks as both proton transport pathways and mechanical enhancers,these membranes exhibit proton conductivities higher than 30 mS cm^(−1) and modulus over 4 GPa.Notably,the direct methanol fuel cells equipped with these membranes show good cell performance.Given the wide tunability of comb copolymers and polyoxometalates,this system can be extended to develop a variety of functional electrolyte materials,for example,the lithium-ion conductive electrolytes by using polyoxometalatebased lithium salts,which provides a promising platform to explore versatile electrolyte materials for energy and electronic applications.
文摘Expanded graphite,prepared from the rapid heating of graphite intercalated compound,was blended with polystyrene via the intercalation and the in situ polymerization of styrene.SEM,STM and etc were used to characterize the nanostructure of the expanded graphite the composite of polymer/expanded graphite,and the changes of the nanostructure during the rolling process.The graphite formed the nanostructure during the expanding process of the GIC.The nanosheets were confirmed to have been dispersed in polystyrene matrix with the thickness of 10~30 nm.The conductivity of PS/expanded graphite composite was sensitive to the rolling process.The intensive rolling caused great decrease in its conductivity,due to the destruction of conducting network.
文摘A preparation process of PMMA/graphite nanocomposites was developed via in situ polymerization of monomers in the presence of sonicated expanded graphite with the aid of sonication.Expanded graphite was sonicated in a 70% aqueous alcohol solution to get graphite platelets (NanoG) with thickness of 30~80 nm and diameter of 0.5~20 μm.The NanoG were dispersed in MMA monomers with BPO initiator.In situ polymerization was taken place when the mixture was heated under sonication.The TEM studies showed that the graphite nano-platelets were well dispersed in the PMMA matrix.Solution cast films of the nanocomposite were used for electrical conductivity measurements.The percolation threshold of polymer/NanoG nanocomposite films at room temperature was lower than 1.0 wt%,which was much lower than that of the composites with conventional graphite filler which was 5.5 wt%.The electrical conductivity reached 10 -3 S/cm at a graphite content of about 4.0 wt%.The special structure of graphite nano- platelets with high aspect ratio of as high as 100~500 (width-to-thickness) played an important role in forming a conducting network within the PMMA matrix.