Carbon Nanotube Polymer Research Articles

Advanced developments in carbon nanotube polymer composites for structural applications

Advanced developments in carbon nanotube polymer composites for structural applications

Highly selective ethanol vapour sensing materials for a new generation of gas sensors based on molecularly imprinted polymers

A simple gas sensor consisting of a molecularly imprinted polymer-carbon nanotube composite cast onto a screen-printed electrode has been developed with extremely high selectivity for ethanol vapour over methanol vapour. Ethanol gas sensors typically display selectivity for ethanol over methanol in the range 2–4 times, while the mean ratio of ethanol to methanol response observed with the described device was 672. This selectivity was achieved under ambient conditions. Additionally, the molecularly imprinted polymer was produced using reagents previously applied in the development of a device selective for methanol, with only the template being changed. This demonstrates the versatility of molecular imprinting and provides a foundation for their greater integration into future gas sensors.

Passively harmonic mode-locked GHz U-band femtosecond pulse generation based on soliton self-frequency shift.

We demonstrate a GHz U-band fiber laser harnessing soliton self-frequency shift (SSFS). The seed source is a passively harmonic mode-locked (HML) fiber laser based on carbon nanotubes (CNTs) polymer film. By adjusting the pump power and polarization controller (PC) appropriately, the repetition rate can be tuned up to 1.104 GHz with a side mode suppression ratio (SMSR) of 42.5 dB. The seed source with different repetition rates can be frequency shifted from C-band to U-band in a piece of dispersion-shifted fiber (DSF) after amplification. We selected three repetition rates (457.8 MHz, 700.1 MHz, and 1104.1 MHz) and systematically studied the impact of different repetition rates on SSFS. The broad tuning range of wavelengths covering the entire U-band can be obtained by adjusting the pump power of the main amplifier. To the best of our knowledge, the demonstrated laser is the first U-band femtosecond fiber laser based on passively HML with a repetition rate over 1 GHz.

270 MHz passively mode-locked Er-doped fiber laser using single walled carbon nanotube polymer film.

We demonstrated a short-cavity mode-locked erbium-doped fiber laser based on single walled carbon nanotube polymer composite film saturable absorber with a maximum fundamental repetition rate of 270.5 MHz. To the best of our knowledge, this is the highest fundamental repetition rate among mode-locked erbium-doped ring fiber lasers based on nanomaterial polymer composite films. Samples with non-saturable loss range from 13.2% to 60% and modulation depth from 1.63% to 7.08% are prepared by controlling carbon nanotube concentration and film thickness. We systematically investigate the impacts of saturable absorbers on mode-locking repetition rate. Our results show that when the laser repetition rate continuously increases from 15.45 MHz to 270.5 MHz, samples with higher non-saturable loss will push forward the mode-locking threshold and eventually lose mode-locking. In addition, the increased modulation depth will enhance the pulse shaping ability and result in a shorter pulse. Our results may help for high repetition rate mode-locked fiber laser design and improve the laser characteristics. The demonstrated laser may support applications such as frequency comb, etc.

The Electromagnetic Shielding Properties of Biodegradable Carbon Nanotube–Polymer Composites

In this article, the electromagnetic shielding properties of carbon nanotube–polymer nanocomposites are presented. The composite fabrication technique is spray-drying, the usage of which leads to a uniform dispersion of carbon nanotubes (CNTs) in a polymer matrix. Obtaining good filler dispersion is necessary to form a continuous, electrically conductive network of CNTs inside the polymer matrix. In the described nanocomposites, the network of conductive filler particles acts as an electromagnetic radiation barrier. For this reason, developing a highly effective fabrication method is very important. Also, the method should be simple enough to be easily adopted in an industrial environment. The authors shows in this text that both goals mentioned are achieved. The obtained nanocomposite material not only has electrostatic shielding capabilities but comprises electromagnetic shielding properties, which fulfills the main goal of the presented work. It is also worth mentioning that the developed manufacturing method allows for the usage of different fillers and polymers and thus the fabrication of materials capable of meeting a wide range of requirements.

Carbon Nanotube–Polymer Composite Coating on the Anode Surface for Enhancing the Performance of Zn-Ion Batteries

Carbon Nanotube–Polymer Composite Coating on the Anode Surface for Enhancing the Performance of Zn-Ion Batteries

Introducing a nano-scale surface morphology parameter affecting fracture properties of CNT nanocomposites

Carbon Nanotube (CNT) particles and membranes improve interlaminar fracture toughness of nanocomposites. The novelty of this study is to introduce the effect of a new nanoscale parameter - CNT network (bundle) size to interphase thickness ratio - on modes I and II interlaminar fracture toughness of CNT Polymer Nanocomposites (PNCs). This investigation includes the stochastic distribution function of CNT bundle size, interphase thickness, and modes I and II fracture toughness of PNCs based on an extensive experimental study at the nano- and macro-scales. The Atomic Force Microscopy PeakForce Quantitative Nanomechanics Mapping technique was used to collect 500 datasets for a low-weight percentage of CNT PNC and 180 datasets for a high-weight percentage of CNT PNC. Each dataset included CNT bundle size and interphase thickness at the nanoscale. Double cantilever beam and end-notched flexure experiments were conducted to collect 600 modes I and II fracture toughness data. Two-, three-, and four-parameter Weibull models were used to simulate the nano- and macro-scale material properties of CNT PNCs. Results indicate that (i) a lower CNT bundle size to interphase thickness ratio improves fracture toughness, and (ii) a four-parameter Weibull model is the most efficient model for simulated data.

Electric field influence on the non-zero temperature resistance of carbon nanotube polymer nanocomposites with subbands effect

The effective electrical resistivity of carbon nanotubes (CNT)-based polymer nanocomposites is studied using an analytical model based on the percolation theory. The CNTs are considered as rod-like conductors that are aligned or randomly dispersed in the polymer to transport electrons by tunneling. When assessing non-zero temperature electrical resistivity, the tunneling effect considers the thermally energized electron transmission that occurs between each coupled pair of CNTs by the electrical transport model. The modeling technique consists of three steps: identifying the percolating network from the primary formation of CNTs, initial prediction of resistivity by equivalent resistor network, computation of the displacements of CNTs for the resistance change. Taking into consideration the behavior of tunneling in the percolation transition zone, a good agreement is obtained between the model results and experimental data. The verified code is used to investigate the sensitivity for different orientation states, aspect ratios and mode numbers. The results reveal lower sensitivity for higher mode numbers as collateral with the influence of increasing randomness.

Nonlinear forced vibration of functionally graded hybrid three-phase nanocomposite toroidal shell segments reinforced by carbon nanotubes (CNTs) and graphene nanoplatelets (GPLs)

This study proposes a unique three-phase functionally graded (FG) hybrid nanocomposite material reinforcing the toroidal shell segments to investigate the nonlinear forced vibration using Reddy's higher-order shear deformation theory, von Karman geometrical nonlinearity and Stein-McElman's assumption along with the Hamilton principle. The examined toroidal shell's material consists of polymeric resin, carbon nanotubes (CNTs), and graphene platelets (GPLs) as nanocomposites. The material properties have been derived based on a modified Halpin-Tsai micromechanical model. Four distribution patterns have been studied: uniform (UD), FG-X, FG-O, and FG-V. The continuous distribution of GPLs and CNTs leads to inhomogeneous position-dependent properties throughout the shell thickness. The obtained differential equations of motion have been reduced to ordinary equations using Galerkin's technique. A multi-scales method (MSM) is used to estimate a closed-form solution representing the frequency-amplitude relation, and the state space representation is used along with numerical fourth-order Runge Kutta method (RK4) to obtain the nonlinear dynamic response of the toroidal shell. The accuracy of the current results obtained has been verified by comparing them with the relevant literature and numerical results using (RK4). In addition, the influence of both GPLs and CNTs weight fractions, nanofillers’ distribution types, longitudinal and circumferential wave numbers, elastic foundation parameters, static axial compression load, transverse excitation load, damping ratio, geometrical characteristics of the toroidal shell on the dimensionless natural frequency, nonlinear primary resonance (frequency-amplitude curve), and nonlinear dynamic response are carefully studied. The results found that combining (GPLs & CNTs) into the shell's matrix improves performance, especially in concave shells compared to convex ones. The FG-X pattern reduces peak resonance amplitude and improves natural frequency. A reduction of 12.3 % is observed for convex shells, and 21.5 % for concave shells compared to FG-O.

Preparation and performance of biaxially stretched CNT-SBS/POE flexible strain sensor with a double percolation structure

Wearable flexible strain sensors have prospective application prospects in human motion monitoring, human-computer interaction, and information transmission. However, facilely manufacturing flexible strain sensors with a high sensitivity and extended sensing range remains challenging. Herein, a flexible strain sensor with a double percolation structure was prepared through simple melting mixing and biaxial stretching. To this end, carbon nanotubes (CNTs) filled styrene butadiene styrene (SBS) and polyolefin elastomer (POE) were employed as the conductive and insulating phases, respectively. The effects of biaxial stretching on sensor performance were systematically studied. During biaxial stretching, the as-obtained CNT-SBS/POE nanocomposites with double percolation structure exhibited better processing performance and stability than conventional CNT-SBS binary composites. Biaxial stretching results in better dispersion and planar orientation of CNTs in polymers, improving the sensing property of strain sensors. The optimized stretching ratio of double percolation structured composites was determined as 1.5, with 3 wt% CNT-SBS/POE sensor exhibiting high sensitivity (gauge factor = 7501.69) over a wide strain monitoring range (0–300% strain). Additionally, the flexible strain sensors could monitor physiological activities and information transmission with good reliability, thereby promising for human-machine interaction, wearable, and medical monitoring.

Curcumin for Treating Breast Cancer: A Review of Molecular Mechanisms, Combinations with Anticancer Drugs, and Nanosystems.

Breast cancer (BC) has become the fifth most prevalent cause of cancer-related morbidity, attracting significant attention from researchers due to its heightened malignancy and drug resistance. Conventional chemotherapy approaches have proven inadequate in addressing all BC subtypes, highlighting the urgent need for novel therapeutic approaches or drugs. Curcumin (CUR), a phytochemical derived from Curcuma longa (turmeric), has shown substantial potential in inhibiting BC cell migration, metastasis, and proliferation. However, the use of CUR in this context comes with challenges due to its dynamic and easily degradable nature, poor aqueous solubility, low bioavailability, rapid metabolism, and swift systemic elimination, collectively limiting its clinical applications. As such, we provide an overview of the properties, synthesis, and characterization of the hybridization of CUR and its analogue with chemo-drug building blocks. We reviewed research from the last five years on CUR's biogenesis with respect to the regulation of BC, revealing that CUR participates in arresting BC cells in the cell cycle and significantly induces apoptosis in BC cells. Information on the chemotherapeutic and antitumor mechanisms of CUR in BC, including regulation of the cell cycle, increased cell apoptosis, and inhibition of multidrug resistance (MDR), was compiled. Additionally, we provide an overview of CUR loaded into nanomaterials that are cotreated with other chemotherapeutic drugs, such as paclitaxel, thymoquinone, and tamoxifen. In this review, we discuss different types of nanoparticles that can be used for CUR delivery, such as polymeric nanoparticles, carbon nanotubes, and liposomes. By comparing the size, entrapment efficiency, drug-loading capacity, release time, biocompatibility, pharmaceutical scale, and reproducibility of various nanomaterials, we aimed to determine which formulations are better suited for loading CUR or its analogue. Ultimately, this review is expected to offer inspiring ideas, promising strategies, and potential pathways for developing advanced anti-BC strategy nanosystems in clinical practice.

Effects of cnt on polymer matrix: a focused review with lasers

In this article, we thoroughly examine the progress of polymer nanocomposites in laser treatment and their properties. The use of CNTs (carbon nanotubes) with polymer materials enhances the properties of polymers, such as mechanical, thermal, and electrical. In this short review, different types of lasers used for the treatment of CNTs polymer nanocomposite are analyzed. Furthermore, this study has extensively investigated the variations in nanocomposites' properties observed by a variety of researchers. The effectiveness of lasers on the surface properties of CNT polymer nanocomposite is also described.

Selective near-infrared laser programming for shape-memory polymer–carbon nanotube composite material 4D printing

Abstract Light stimulation can realise the remote control of the deformation of the specific position of 4D printing structure. Shape-memory polymer–carbon nanotube (CNT) composite materials, with outstanding near-infrared photothermal conversion rate and shape-memory ability, is one type of the most popular light responsive smart materials. However, current studies focused on the photothermal effect and shape-memory applications of light-responsive shape-memory polymer composite (SMPC) sheet structures, and there is no research on the photothermal effect in the depth direction of light-responsive SMPC three-dimensional structures. Here, we prepared a UV curable, mechanically robust, and highly deformable shape-memory polymer (IBBA) as the matrix of light responsive SMPC. CNTs were added as photothermal conversion materials. We explore the photothermal effect of near-infrared laser on the surface and depth of IBBA–CNT composites cube. Shape-memory experiments show that different folded shapes can be obtained by selective near-infrared laser programming. Selective near-infrared laser programming three-dimensional movable type plate shows a programming application in depth direction of three-dimensional light-responsive intelligent structure. This research extends the application of near-infrared laser in 4D printing to the depth direction of intelligent structures, which will bring more complex and interesting 4D printing structures in the future.

Piezoresistive Theory and Numerical Calculation for Carbon Nanotube Polymer Composite.

A three-dimensional theory has been established for the piezoresistivity of carbon nanotube (CNT) polymer composites. Based on the Mori-Tanaka method in meso-mechanics theory and considering quantum tunneling effect between CNTs, an approach to calculate equivalent electrical conductivity of composites was proposed. On this basis, a piezoresistive theory, which incorporates the effect of composites' geometric nonlinearity, was developed for CNT polymer composites. The theory is dependent only on some basic physical parameters of the materials. A finite element formula of the theory for the numerical calculation of piezoresistivity was presented from the analysis of both elastic and electric fields. Numerical simulations demonstrated that the results predicted by the theory were in good agreement with those of the experimental tests. Parameter sensitivity analysis revealed that when both the potential barrier height of the matrix and the initial average separation distance between CNTs increased, the piezoresistivity obviously increased. However, with the increase in aspect ratio and CNT conductivity, the piezoresistivity decreased gradually. A practical engineering application of this theory is also provided.

Individually-addressable composite microneedle electrode array by mold-and-place method for glucose detection

Microneedle (MN)-based electrochemical biosensors enable minimally invasive and in situ monitoring of biomolecules from interstitial fluid (ISF) that is strongly correlated to their concentrations in the blood. When an array of MNs is used as either working or counter electrodes for electrochemical sensing, it is often difficult to have narrow spacing between them and this can lead to poor measurement accuracy due to increased resistance, low sensitivity, and slow response time. This study aims to develop a method to fabricate independently functioning MN electrodes with narrow intervals between them for high precision electrochemical sensing. A mixture of photocurable polymer (SU-8) and single-wall carbon nanotubes (SWCNTs) was optimized for pressure-assisted transfer (PAT) molding and electrical conductivity. Single composite MNs were molded by PAT molding, and then attached on pre-patterned electrodes. After the ‘mold-and-place’ of the composite MN structures, plasma etching and electropolymerization of PEDOT:PSS were performed to enhance the electrochemical activity. Prussian blue (PB) and glucose oxidase (GOx) were electrodeposited on surface-treated MNs to enable glucose detection. MN electrodes showed limit of detection (LOD) at 0.225 mM and linearity up to 20 mM. Finally, MN electrodes were constructed on a flexible polyimide film and demonstrated the feasibility of detecting glucose in an in vivo mouse study.

Piezoresistive Characteristics of Carbon Nanotube Polymer Composites with Different Filler Content and Aspect Ratio for Pressure Sensors

Polymer composites enriched with conductive fillers hold immense potential for flexible pressure sensors, because of the remarkable piezoresistive effect they possess. Research on polymer composite pressure sensors has been actively ongoing because of their flexibility and high electrical resistance performance. This paper presents a comprehensive comparison of the piezoresistive characteristics of conductive composites for pressure sensors, focusing on the influence of carbon nanotube (CNT) content and aspect ratio. Polymer composites with conductive fillers, specifically CNTs, have demonstrated significant potential for pressure sensing applications based on the piezoresistive effect. By systematically varying the CNT concentration and aspect ratio, we investigated the impact of these parameters on the piezoresistive behavior of the composites. A pressure in the range of 0-200 kPa was applied to the conductive composite, and resistance change due to pressing was measured. The best performing samples were evaluated in 150 cycle tests to verify repeatability and durability. Experimental analysis and characterization revealed the intricate relationship between CNT content, aspect ratio, and the resulting piezoresistive properties. Through this study, we aim to enhance understanding of how CNT concentration and aspect ratio influence the performance of CNT/PDMS composites as pressure sensors, thereby facilitating the development of optimized sensing materials for various pressure sensing applications.

Effect of carbon nanotube type and length on the electrical conductivity of carbon nanotube polymer nanocomposites

Carbon nanotube (CNT) type and length are two key factors that affect the electrical behavior of CNT/polymer nanocomposites. However, numerical studies that consider these two factors simultaneously are limited. This paper presented a stochastic multiscale numerical model to predict the electrical conductivity and percolation threshold of polymer nanocomposites containing single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs). The combined effects of CNT type and length on the electrical conductivity and percolation threshold of the polymer nanocomposites were investigated. The model predictions were validated against experimental data of commercially available CNTs. Our results showed that the effect of CNT type varied based on both the length and aspect ratio of the CNTs. Long SWCNTs exhibited the greatest enhancement of the polymer’s electrical conductivity with the lowest percolation threshold among all the CNT types studied.

The influence of electrode geometry on the electrochemical performance of fabric-based screen-printed coplanar supercapacitors

Coplanar supercapacitors are promising flexible energy storage systems due to the excellent flexibility and tailored shapes and sizes of electrodes. However, the influence mechanism of electrode’ geometry parameter on the electrochemical performance of the flexible coplanar supercapacitors needs to be elucidated to realize the performance enhancement. Herein, the flexible coplanar supercapacitors with different thicknesses, widths and lengths of screen-printed electrodes were constructed on the cotton fabric substrates utilizing multi-walled carbon nanotubes ink and polymer gel electrolytes. The relationship between electrodes' geometry and overall electrochemical performance of flexible coplanar supercapacitors was detailed analyzed and demonstrated by employing equivalent series circuit model and electrode kinetic theory. Furthermore, due to the favorable aspect ratio and relatively low electrode and electrolyte resistance, the fabric-based coplanar supercapacitor with electrode size of 4 × 10 mm shows optimal electrochemical performance with areal capacitance of 3.08 mF cm−2 at 20 mV s−1, fast electrode response and effective kinetic process. Most importantly, the fabric-based supercapacitor exhibits excellent flexibility and cycling performance with capacitance retention rate over 79.6 % after 4000 charge and discharge cycles, indicating application potential in wearable electronic devices. The analysis and assessments of electrodes' geometry provides theoretical reference for the electrode design and optimization of flexible coplanar supercapacitors.

Investigation of electromagnetic interference shielding effectiveness and electrical percolation of carbon nanotube polymer composites with various aspect ratios

Investigation of electromagnetic interference shielding effectiveness and electrical percolation of carbon nanotube polymer composites with various aspect ratios

Determination of Aflatoxins in Milk by PS-MWCNT/OH Composite Nanofibers Solid-Phase Extraction Coupled with HPLC-FLD.

In this work, a sensitive analytical method based on packed-nanofiber solid-phase extraction (PFSPE), after derivatization with trichloroacetic acid and high-performance liquid chromatography with a fluorescence detector (HPLC-FLD), has been established for the determination of aflatoxins (AFs) in milk. Polystyrene polymeric multi-walled carbon nanotube (PS-MWCNT/OH) composite nanofibers were fabricated by electrospinning and used to prepare homemade extraction columns. The extraction efficiency of the HPLC-FLD analysis method was sufficiently investigated and validated. After the implementation of optimal conditions, all of the analytes were separated efficiently and the components of the milk matrix did not disturb the determination. The obtained linear ranges of the calibration curves were 0.2-20 ng/mL for AFTB1 and AFTG2, 0.1-10 ng/mL for AFTB2, and 0.4-40 ng/mL for AFTG1. The recoveries ranged between 80.22% and 96.21%. The relative standard deviations (RSDs) for the intra-day and inter-day results ranged from 2.81-6.43% to 3.42-7.75%, respectively. Generally, 11 mg of sorbent and 200 μL of elution solvent were used to directly extract all of the AFs from the milk matrix. Reported herein is the first utilization of PS-MWCNT/OH-PFSPE HPLC-FLD to simultaneously analyze the occurrence of aflatoxins in milk.