Controlled thermally-driven mass transport in carbon nanotubes using carbon hoops

Controlling mass transportation using intrinsic mechanisms is a challenging topic in nanotechnology.Herein,we employ molecular dynamics simulations to investigate the mass transport inside carbon nanotubes(CNT)with temperature gradients,specifically the effects of adding a static carbon hoop to the outside of a CNT on the transport of a nanomotor inside the CNT.We reveal that the underlying mechanism is the uneven potential energy created by the hoops,i.e.,the hoop outside the CNT forms potential energy barriers or wells that affect mass transport inside the CNT.This fundamental control of directional mass transportation may lead to promising routes for nanoscale actuation and energy conversion.

Enhancing the Interaction of Carbon Nanotubes by Metal-Organic Decomposition with Improved Mechanical Strength and Ultra-Broadband EMI Shielding Performance

The remarkable properties of carbon nanotubes(CNTs)have led to promising applications in the field of electromagnetic inter-ference(EMI)shielding.However,for macroscopic CNT assemblies,such as CNT film,achieving high electrical and mechanical properties remains challenging,which heavily depends on the tube-tube interac-tions of CNTs.Herein,we develop a novel strategy based on metal-organic decomposition(MOD)to fabricate a flexible silver-carbon nanotube(Ag-CNT)film.The Ag particles are introduced in situ into the CNT film through annealing of MOD,leading to enhanced tube-tube interactions.As a result,the electrical conductivity of Ag-CNT film is up to 6.82×10^(5) S m^(-1),and the EMI shielding effectiveness of Ag-CNT film with a thickness of~7.8μm exceeds 66 dB in the ultra-broad frequency range(3-40 GHz).The tensile strength and Young’s modulus of Ag-CNT film increase from 30.09±3.14 to 76.06±6.20 MPa(~253%)and from 1.12±0.33 to 8.90±0.97 GPa(~795%),respectively.Moreover,the Ag-CNT film exhibits excellent near-field shield-ing performance,which can effectively block wireless transmission.This innovative approach provides an effective route to further apply macroscopic CNT assemblies to future portable and wearable electronic devices.

Self-templating synthesis of biomass-based porous carbon nanotubes for energy storage and catalytic degradation applications

Dwindling energy sources and a worsening environment are huge global problems,and biomass wastes are an under-exploited source of material for both energy and material generation.Herein,self-template decoction dregs of Ganoderma lucidum-derived porous carbon nanotubes(ST-DDLGCs)were synthesized via a facile and scalable strategy in response to these challenges.ST-DDLGCs exhibited a large surface area(1731.51 m^(2)g^(-1))and high pore volume(0.76 cm^(3)g^(-1)),due to the interlacing tubular structures of precursors and extra-hierarchical porous structures on tube walls.In the ST-DDLGC/PMS system,the degradation efficiency of capecitabine(CAP)reached~97.3%within 120 min.Moreover,ST-DDLGCs displayed high catalytic activity over a wide pH range of 3–9,and strong anti-interference to these typical and ubiquitous anions in wastewater and natural water bodies(i.e.,H_(2)PO_(4)^(-),NO_(3)^(-),Cl^(-) and HCO_(3)^(-)),in which a ^(1)O_(2)-dominated oxidation was identified and non-radical mechanisms were deduced.Additionally,ST-DDLGC-based coin-type symmetrical supercapacitors exhibited outstanding electrochemical performance,with specific capacitances of up to 328.1 F g^(-1)at 0.5 A g^(-1),and cycling stability of up to 98.6%after 10,000 cycles at a current density of 2 A g^(-1).The superior properties of ST-DDLGCs could be attributed to the unique porous tubular structure,which facilitated mass transfer and presented numerous active sites.The results highlight ST-DDLGCs as a potential candidate for constructing inexpensive and advanced environmentally functional materials and energy storage devices.

Hollow ZIF-67-derived Co@N-doped carbon nanotubes boosting the hydrogenation of phenolic compounds to alcohols

The selective hydrogenation of highly toxic phenolic compounds to generate alcohols with thermal stability,environmental friendliness,and non-toxicity is of great importance.Herein,a series of Co-based catalysts,named Co@NCNTs,were designed and constructed by direct pyrolysis of hollow ZIF-67(HZIF-67)under H_(2)/Ar atmosphere.The evolution of the catalyst surface from the shell layer assembled by ZIF-67-derived particles to the in situ-grown hollow nitrogen-doped carbon nanotubes(NCNTs)with certain length and density is achieved by adjusting the pyrolysis atmosphere and temperature.Due to the synergistic effects of in situ-formed hollow NCNTs,well-dispersed Co nanoparticles,and intact carbon matrix,the as-prepared Co@NCNTs-0.10-450 catalyst exhibits superior catalytic performance in the hydrogenation of phenolic compounds to alcohols.The turnover frequency value of Co@NCNTs-0.10-450is 3.52 h^(-1),5.9 times higher than that of Co@NCNTs-0.40-450 and 4.5 times higher than that of Co@NCNTs-0.10-550,exceeding most previously reported non-noble metal catalysts.Our findings provide new insights into the development of non-precious metal,efficient,and cost-effective metal-organic framework-derived catalysts for the hydrogenation of phenolic compounds to alcohols.

Nonlinear phenomena in vibrations of embedded carbon nanotubes conveying viscous fluid

Various nonlinear phenomena such as bifurcations and chaos in the responses of carbon nanotubes(CNTs)are recognized as being major contributors to the inaccuracy and instability of nanoscale mechanical systems.Therefore,the main purpose of this paper is to predict the nonlinear dynamic behavior of a CNT conveying viscousfluid and supported on a nonlinear elastic foundation.The proposed model is based on nonlocal Euler–Bernoulli beam theory.The Galerkin method and perturbation analysis are used to discretize the partial differential equation of motion and obtain the frequency-response equation,respectively.A detailed parametric study is reported into how the nonlocal parameter,foundation coefficients,fluid viscosity,and amplitude and frequency of the external force influence the nonlinear dynamics of the system.Subharmonic,quasi-periodic,and chaotic behaviors and hardening nonlinearity are revealed by means of the vibration time histories,frequency-response curves,bifurcation diagrams,phase portraits,power spectra,and Poincarémaps.Also,the results show that it is possible to eliminate irregular motion in the whole range of external force amplitude by selecting appropriate parameters.

Heat transfer enhanced inorganic phase change material compositing carbon nanotubes for battery thermal management and thermal runaway propagation mitigation

Developing technologies that can be applied simultaneously in battery thermal management(BTM)and thermal runaway(TR)mitigation is significant to improving the safety of lithium-ion battery systems.Inorganic phase change material(PCM)with nonflammability has the potential to achieve this dual function.This study proposed an encapsulated inorganic phase change material(EPCM)with a heat transfer enhancement for battery systems,where Na_(2)HPO_(4)·12H_(2)O was used as the core PCM encapsulated by silica and the additive of carbon nanotube(CNT)was applied to enhance the thermal conductivity.The microstructure and thermal properties of the EPCM/CNT were analyzed by a series of characterization tests.Two different incorporating methods of CNT were compared and the proper CNT adding amount was also studied.After preparation,the battery thermal management performance and TR propagation mitigation effects of EPCM/CNT were further investigated on the battery modules.The experimental results of thermal management tests showed that EPCM/CNT not only slowed down the temperature rising of the module but also improved the temperature uniformity during normal operation.The peak battery temperature decreased from 76℃to 61.2℃at 2 C discharge rate and the temperature difference was controlled below 3℃.Moreover,the results of TR propagation tests demonstrated that nonflammable EPCM/CNT with good heat absorption could work as a TR barrier,which exhibited effective mitigation on TR and TR propagation.The trigger time of three cells was successfully delayed by 129,474 and 551 s,respectively and the propagation intervals were greatly extended as well.

Study of the Diffusion Behavior of Seawater Absorption in Multi-Walled Carbon Nanotubes/Halloysite Nanotubes Hybrid Nanofillers Modified Epoxy-Based Glass/Carbon Fiber Composites

In the maritime industry, cost-effective and lightweight Fiber Reinforced Polymer (FRP) composites offer excellent mechanical properties, design flexibility, and corrosion resistance. However, their reliability in harsh seawater conditions is a concern. Researchers address this by exploring three approaches: coating fiber surfaces, hybridizing fibers and matrices with or without nanofillers, and interply rearrangement. This study focuses on evaluating the synergistic effects of interply rearrangement of glass/carbon fibers and hybrid nanofillers, specifically Multi-walled carbon nanotubes (MWCNT) and Halloysite nanotubes (HNT). The aim is to enhance impact properties by minimizing moisture absorption. Hybrid nanocomposites with equal-weight proportions of two nanofillers: 0 wt.%, 1 wt.%, and 2 wt.% were exposed to seawater for 90 days. Experimental data was subjected to modelling through the application of Predictive Fick’s Law. The study found that the hybrid composite containing 2 wt.% hybrid nanofillers exhibited a 22.10% increase in impact performance compared to non-modified counterparts. After 90 days of seawater aging, the material exhibited enhanced resistance to moisture absorption (15.74%) and minimal reduction in impact strength (8.52%) compared to its dry strength, with lower diffusion coefficients.

In situ formation of multiple catalysts for enhancing the hydrogen storage of MgH_(2) by adding porous Ni_(3)ZnC_(0.7)/Ni loaded carbon nanotubes microspheres

MgH_(2) is considered one of the most promising hydrogen storage materials because of its safety,high efficiency,high hydrogen storage quantity and low cost characteristics.But some shortcomings are still existed:high operating temperature and poor hydrogen absorption dynamics,which limit its application.Porous Ni_(3)ZnC_(0.7)/Ni loaded carbon nanotubes microspheres(NZC/Ni@CNT)is prepared by facile filtration and calcination method.Then the different amount of NZC/Ni@CNT(2.5,5.0 and 7.5 wt%)is added to the MgH_(2) by ball milling.Among the three samples with different amount of NZC/Ni@CNT(2.5,5.0 and 7.5 wt%),the MgH_(2)-5 wt%NZC/Ni@CNT composite exhibits the best hydrogen storage performances.After testing,the MgH_(2)-5 wt%NZC/Ni@CNT begins to release hydrogen at around 110℃ and hydrogen absorption capacity reaches 2.34 wt%H_(2) at 80℃ within 60 min.Moreover,the composite can release about 5.36 wt%H_(2) at 300℃.In addition,hydrogen absorption and desorption activation energies of the MgH_(2)-5 wt%NZC/Ni@CNT composite are reduced to 37.28 and 84.22 KJ/mol H_(2),respectively.The in situ generated Mg_(2)NiH_(4)/Mg_(2)Ni can serve as a"hydrogen pump"that plays the main role in providing more activation sites and hydrogen diffusion channels which promotes H_(2) dissociation during hydrogen absorption process.In addition,the evenly dispersed Zn and MgZn2 in Mg and MgH_(2) could provide sites for Mg/MgH_(2) nucleation and hydrogen diffusion channel.This attempt clearly proved that the bimetallic carbide Ni_(3)ZnC_(0.7) is a effective additive for the hydrogen storage performances modification of MgH_(2),and the facile synthesis of the Ni_(3)ZnC_(0.7)/Ni@CNT can provide directions of better designing high performance carbide catalysts for improving MgH_(2).

Reactive template-derived interfacial engineering of CoP/CoO heterostructured porous nanotubes towards superior electrocatalytic hydrogen evolution

The development of economical,efficient,and robust electrocatalysts toward the hydrogen evolution reaction(HER)is highly imperative for the rapid advancement of renewable H2 energy-associated technologies.Extensive utilization of the heterointerface effect can endow the catalysts with remarkably boosted electrocatalytic performance due to the modified electronic state of active sites.Herein,we demonstrate deliberate crafting of CoP/CoO heterojunction porous nanotubes(abbreviated as CoP/CoO PNTs hereafter)using a self-sacrificial template-engaged strategy.Precise control over the Kirkendall diffusion process of the presynthesized cobalt–aspartic acid complex nanowires is indispensable for the formation of CoP/CoO heterostructures.The topochemical transformation strategy of the reactive templates enables uniform and maximized construction of CoP/CoO heterojunctions throughout all the porous nanotubes.The establishment of CoP/CoO heterojunctions could considerably modify the electronic configuration of the active sites and also improve the electric conductivity,which endows the resultant CoP/CoO PNTs with enhanced intrinsic activity.Simultaneously,the hollow and porous nanotube architectures allow sufficient accessibility of exterior/interior surfaces and molecular permeability,drastically promoting the reaction kinetics.Consequently,when used as HER electrocatalysts,the well-designed CoP/CoO PNTs show Pt-like activity,with an overpotential of only 61 mV at 10mA cm^(−2) and excellent stability in 1.0M KOH medium,exceeding those of the vast majority of the previously reported nonprecious candidates.Density functional theory calculations further substantiate that the construction of CoP/CoO heterojunctions enables optimization of the Gibbs free energies for water adsorption and H adsorption,resulting in boosted HER intrinsic activity.The present study may provide in-depth insights into the fundamental mechanisms of heterojunction-induced electronic regulation,which may pave the way for the rational design of advanced Earth-abundant electrocatalysts in the future.

Influence of Plasma Modified Carbon Nanotubes on the Resistance Sensitiveness of Cement

The surface of carbon nanotubes(CNTs)was modified by plasma to improve the dispersion,conductivity and adsorption properties of carbon nanotubes.Cement-based composites made with plasmatreated carbon nanotubes(P-CNTs)at different perntages were tested under repeated cyclic axial compressive stress by four electrode methods to measure the electric resistance.Those made with CNTs without plasma treatment as controls were tested also.The results showed that electric resistance change values of the cement mortar with P-CNT and CNT were all monatomic corresponding to the cyclic loading.When the water-cement ratio of the mortar was fixed,increasing of the P-CNT/CNT content would increase the resistance change value of the mortars added with P-CNT/CNT,and the sensitivity performance.It has certain engineering application value.

Melatonin,tunneling nanotubes,mesenchymal cells,and tissue regeneration

Mesenchymal stem cells are multipotent stem cells that reside in many human tissues and organs.Mesenchymal stem cells are widely used in experimental and clinical regenerative medicine due to their capability to transdifferentiate into various lineages.However,when transplanted,they lose part of their multipotency and immunomodulatory properties,and most of them die after injection into the damaged tissue.In this review,we discuss the potential utility of melatonin in preserving mesenchymal stem cells’survival and function after transplantation.Melatonin is a pleiotropic molecule regulating critical cell functions including apoptosis,endoplasmic reticulum stress,and autophagy.Melatonin is also synthesized in the mitochondria where it reduces oxidative stress,the opening of the mitochondrial permeability transition pore and the downstream caspase activation,activates uncoupling proteins,and curtails the proinflammatory response.In addition,recent findings showed that melatonin also promotes the formation of tunneling nanotubes and the transfer of mitochondria between cells through the connecting tubules.As mitochondrial dysfunction is a primary cause of mesenchymal stem cells death and senescence and a critical issue for survival after transplantation,we propose that melatonin by favoring mitochondria functionality and their transfer through tunneling nanotubes from healthy to suffering cells could improve mesenchymal stem cellbased therapy in a large number of diseases for which basic and clinical trials are underway.

Effect of Surfactants on the Thermoelectric Performance of Double-Walled Carbon Nanotubes

Thermoelectrics are a promising solution to the recovery of some of the 60%of the worldwide energy wasted as heat.However,their conversion efficiency is low and the best performing materials are brittle,toxic,and made of expensive ceramics.The challenge in developing better performing materials is in disrupting the electrical vs thermal conductivity correlation,to achieve low thermal conductivity simultaneously with a high electrical conductivity.Carbon nanotubes allow for the decoupling of the electronic density of states from the phonon density of states and this paper shows that flexible,thin films of double-walled carbon nanotube(DWCNT)can form effective n-and p-doped semiconductors that can achieve a combined Seebeck coefficient of 157.6µV K^(−1),the highest reported for a single DWCNT device to date.This is achieved through selected surfactant doping,whose role is correlated with the length of the hydrocarbon chain of the hydrophobic tail group of the surfactant’s molecules.CNTs functionalized with Triton X-405 show the highest output power consisting of a single junction of p-and n-type thermoelectric elements,reaching as high as 67 nW for a 45 K temperature gradient.Thus enabling flexible,cheaper,and more efficient thermoelectric generators through the use of functionalized CNTs.

Impact of Radiation and Slip on Newtonian Liquid Flow Past a Porous Stretching/Shrinking Sheet in the Presence of Carbon Nanotubes

The impacts of radiation,mass transpiration,and volume fraction of carbon nanotubes on the flow of a Newtonian fluid past a porous stretching/shrinking sheet are investigated.For this purpose,three types of base liquids are considered,namely,water,ethylene glycol and engine oil.Moreover,single and multi-wall carbon nanotubes are examined in the analysis.The overall physical problem is modeled using a system of highly nonlinear partial differential equations,which are then converted into highly nonlinear third order ordinary differential equations via a suitable similarity transformation.These equations are solved analytically along with the corresponding boundary conditions.It is found that the carbon nanotubes can significantly improve the heat transfer process.Their potential application in cutting-edge areas is also discussed to a certain extent.

Ultralight pyrolytic carbon foam reinforced with amorphous carbon nanotubes for broadband electromagnetic absorption

For electromagnetic wave-absorbing materials,maximizing absorption at a specific frequency has been constantly achieved,but enhancing the absorption properties in the entire band remains a challenge.In this work,a 3D porous pyrolytic carbon(PyC)foam matrix was synthesized by a template method.Amorphous carbon nanotubes(CNTs)were then in-situ grown on the matrix surface to obtain ultralight CNTs/Py C foam.These in-situ grown amorphous CNTs were distributed uniformly and controlled by the catalytic growth time and can enhance the interface polarization and conduction loss of composites.When the electromagnetic wave enters the internal holes,the electromagnetic energy can be completely attenuated under the combined action of polarization,conductivity loss,and multiple reflections.The ultralight CNTs/Py C foam had a density of 22.0 mg·cm^(-3)and a reflection coefficient lower than-13.3 d B in the whole X-band(8.2-12.4 GHz),which is better than the conventional standard of effective absorption bandwidth(≤-10 dB).The results provide ideas for researching ultralight and strong electromagnetic wave absorbing materials in the X-band.

Multiscale Theories and Applications:From Microstructure Design to Macroscopic Assessment for Carbon Nanotubes Networks

Carbon nanotube(CNT)networks enable CNTs to be used as building blocks for synthesizing novel advanced materials,thus taking full advantage of the superior properties of individual CNTs.Multiscale analyses have to be adopted to study the load transfer mechanisms of CNT networks from the atomic scale to the macroscopic scale due to the huge computational cost.Among them,fully resolved structural features include the graphitic honeycomb lattice(atomic),inter-tube stacking(nano)and assembly(meso)of CNTs.On an atomic scale,the elastic properties,ultimate stresses,and failure strains of individual CNTs with distinct chiralities and radii are obtained under various loading conditions by molecular mechanics.The dependence of the cohesive energies on spacing distances,crossing angles,size and edge effects between two CNTs is analyzed through continuum modeling in nanoscale.The mesoscale models,which neglect the atomic structures of individual CNTs but retain geometrical information about the shape of CNTs and their assembly into a network,have been developed to study the multi-level mechanism of material deformation and microstructural evolution in CNT networks under stretching,from elastic elongation,strengthening to damage and failure.This paper summarizes the multiscale theories mentioned above,which should provide insight into the optimal assembling of CNT network materials for elevated mechanical performance.

Interface Engineering of Fe_(7)S_(8)/FeS_(2) Heterostructure in situ Encapsulated into Nitrogen‑Doped Carbon Nanotubes for High Power Sodium‑Ion Batteries

Heterostructure engineering combined with carbonaceous materials shows great promise toward promoting sluggish kinetics,improving electronic conductivity,and mitigating the huge expansion of transition metal sulfide electrodes for high-performance sodium storage.Herein,the iron sulfide-based heterostructures in situ hybridized with nitrogen-doped carbon nanotubes(Fe_(7)S_(8)/FeS_(2)/NCNT)have been prepared through a successive pyrolysis and sulfidation approach.The Fe_(7)S_(8)/FeS_(2)/NCNT heterostructure delivered a high reversible capacity of 403.2 mAh g^(−1) up to 100 cycles at 1.0 A g^(−1) and superior rate capability(273.4 mAh g^(−1) at 20.0 A g^(−1))in ester-based electrolyte.Meanwhile,the electrodes also demonstrated long-term cycling stability(466.7 mAh g^(−1) after 1,000 cycles at 5.0 A g^(−1))and outstanding rate capability(536.5 mAh g^(−1) at 20.0 A g^(−1))in ether-based electrolyte.This outstanding performance could be mainly attributed to the fast sodium-ion diffusion kinetics,high capacitive contribution,and convenient interfacial dynamics in ether-based electrolyte.

Three-dimensional structural Cu^(6)Sn_(5)/carbon nanotubes alloy thin-film electrodes fabricated by in situ electrodeposition from the leaching solution of waste-printed circuit boards

Tin-based materials are very attractive anodes because of their high theoretical capacity,but their rapid capacity fading from volume expansions limits their practical applications during alloying and dealloying processes.Herein,the improved binder-free tin-copper intermetallic/carbon nanotubes(Cu6Sn5/CNTs)alloy thin-film electrodes are directly fabricated through efficient in situ electrodeposition from the leaching solution of treated waste-printed circuit boards(WPCBs).The characterization results show that the easily agglomerated Cu6Sn5 alloy nanoparticles are uniformly dispersed across the three-dimensional network when the CNTs concentration in the electrodeposition solution is maintained at 0.2 g·L−1.Moreover,the optimal Cu6Sn5/CNTs-0.2 alloy thin-film electrode can not only provide a decent discharge specific capacity of 458.35 mAh·g^(−1)after 50 cycles at 100 mA·g^(−1)within capacity retention of 82.58%but also deliver a relatively high reversible specific capacity of 518.24,445.52,418.18,345.33,and 278.05 mAh·g^(−1)at step-increased current density of 0.1,0.2,0.5,1.0,and 2.0 A·g^(−1),respectively.Therefore,the preparation process of the Cu6Sn5/CNTs-0.2 alloy thin-film electrode with improved electrochemical performance may provide a cost-effective strategy for the resource utilization of WPCBs to fabricate anode materials for lithium-ion batteries.

Uniform nanoplating of metallic magnesium film on titanium dioxide nanotubes as a skeleton for reversible Na metal anode

To meet the low-cost concept advocated by the sodium metal anode,this paper reports the use of a pulsed electrodeposition technology with ionic liquids as electrolytes to achieve uniform nanoplating of metallic magnesium films at around 20 nm on spaced titanium dioxide(TiO_(2))nanotubes(STNA-Mg).First,the sodiophilic magnesium metal coating can effectively reduce the nucleation overpotential of sodium metal.Moreover,three-dimensional STNA can limit the volume expansion during sodium metal plating and stripping to achieve the ultrastable deposition and stripping of sodium metals with a high Coulombic efficiency of up to 99.5%and a small voltage polarization of 5 mV in symmetric Na||Na batteries.In addition,the comparative study of sodium metal deposition behavior of STNA-Mg and STNA-Cu prepared by the same route further confirmed the advantage of magnesium metal to guide sodium metal growth.Finally,the prepared STNA-Mg-Na metal anode and commercial sodium vanadium phosphate cathode were assembled into a full cell,delivering a discharge capacity of 110.2 mAh·g^(-1)with a retention rate of 95.6%after 110 cycles at 1C rate.

Construction of multi-walled carbon nanotubes/ZnSnO_(3)heterostructures for enhanced acetone sensing performance

Carbon nanotubes(CNTs)have attracted many researcher's attention in gas sensing field because of their excellent physical and chemical properties.Herein,multi-walled carbon nanotubes(MWCNTs)/ZnSnO_(3)heterostructures have been obtained by a simple hydrothermal method without additional annealing process.The structural and composition information are characterized by x-ray diffraction(XRD),field-emission scanning electron microscopy(FESEM),transmission electron microscopy(TEM)and x-ray photoelectron spectroscopy(XPS).The acetone sensing properties of pure MWCNTs,ZnSnO_(3)and MWCNTs/ZnSnO_(3)heterostructures are systematically investigated,respectively.The results show that MWCNTs/ZnSnO_(3)heterostructures have better sensing properties compared with pure MWCNTs and ZnSnO_(3)sample.Specifically,MWCNTs/ZnSnO_(3)heterostructures exhibit not only high responses of 24.1 and rapid response/recovery speed of 1 s/9 s to 100 ppm acetone,but also relatively good repeatability and long-term stability.The enhanced sensing performance is analyzed in detail.In addition,this work provides the experimental and theory basis for synthesis of high-performance MWCNT-based chemical sensors.

Abnormal magnetic behavior of prussian blue analogs modified with multi-walled carbon nanotubes

This work examines the origin of the abnormal magnetism exhibited by Cu Mn Fe-PBAs modified with multi-walled carbon nanotubes(MWCNTs).The system of Cu Mn Fe-PBAs@MWCNTs coexists with both large and small clusters.Cu Mn Fe-PBAs clusters have an average particle size of 28 nm,and some of the smaller particles are adsorbed on the surface of MWCNTs.Surprisingly,the magnitude of magnetization increases linearly with decreasing temperature.When above the Curie temperature,the magnitude of magnetization is significantly greater than that of PBAs without being modified.This phenomenon can be attributed to magnetostatic interactions between ultra-fine magnetic nanoparticles adsorbed on the surface of MWCNTs.Using the Monte Carlo method,we simulated the magnetostatic interaction of cylindrical adsorbed particles,and the simulation results are almost identical to those observed experimentally.The results indicate that 0.089Cu Mn Fe-PBAs clusters per 1 nm^(2)can be adsorbed onto the surface area of MWCNTs.We demonstrate that MWCNTs adsorbing magnetic particles exhibit magnetic behavior,and suggest a method for producing ultrafine materials.It also introduces a new method of calculating the adsorption efficiency of carbon nanotubes,offering theoretical guidance for future research on nanomaterials with enhanced adsorption efficiency.