Carboxyl-functionalized Multi-walled Carbon Nanotubes Research Articles

Remotely fast response healing crosslinked polyurea nanocomposites with recyclability via two-step method

The development of dynamic bonds-based nanocomposites with excellent mechanical properties and multi-stimulated self-healing capabilities is critical for the design of high-performance self-healing materials. In this study, dynamic nanocomposites based on carboxyl-functionalized multiwalled carbon nanotube (CNT-COOH) fillers and a crosslinked polyurea (CPU) matrix were prepared through a facile two-step method involving in situ photo-induced polymerization and hot compression. Herein, the effect of CNT-COOH concentration on the properties of the resulting CPU@CNT nanocomposites was studied. The proposed novel method promoted the formation of a strong interfacial bond between the CNT-COOH and CPU. The dynamic nanocomposites exhibited excellent and rapid photo-induced self-healing abilities and regained their mechanical properties after damage. This can be attributed to the synergistic effect of the dynamic exchange reactions in the CPU matrix and the efficient photo-thermal effect of the fillers. The nanocomposite prepared using 1% CNT-COOH exhibited excellent toughness (up to 36.57 ± 1.28 MJ m−3), high stretchability (ca. 607 ± 50%), high tensile strength (7.36 ± 0.51 MPa), efficient photo-thermal shape memory effect, and good recyclability. Therefore, the facile method demonstrated in this study paves a way for the design of high-performance nanocomposites with rapid self-healing properties for sensing and flexible electronic applications.

Antibiotic delivery evaluation against Mycobacterium fortuitum using nanofluids containing carbon nanotubes

BackgroundMycobacterium fortuitum (M. fortuitum) is a bacterium, which can cause infections in many anatomical regions of the body, including the skin, lymph nodes, and joints. This bacterium, which belongs to a group of bacteria known as nontuberculous mycobacteria, is regarded as an important nosocomial pathogen worldwide owing to its increasing antibiotic resistance. Recently, the antimicrobial effects of carbon nanotubes have been reported in numerous studies. These nanotubes can be very useful in drug delivery; besides, they exhibit unique properties against multidrug-resistant bacterial infections. This study aimed to investigate the antimicrobial effects of carboxyl-functionalized multi-walled carbon nanotubes (MWCNT-COOH) to reduce antibiotic resistance.MethodsIn this study, antibacterial effects of nanofluids containing functionalized MWCNTs at initial concentration of 2 mg/mL and serial dilutions of 54, 28.5, 14.25, 7.12, 3.5 µg/mL, antibiotics alone and combination of nanofluids with antibiotics were investigated.Standard and resistant strains of M. fortuitum were obtained from the microbial bank of the Department of Mycobacteriology and Pulmonary Research, Pasteur Institute of Iran.ResultsIt was observed that nanofluid containing MWCNT-COOH can exert antimicrobial effects on M. fortuitum and significantly reduce bacterial resistance to antibiotics including kanamycin and streptomycin. In the presence of antibiotics and nanofluids containing MWCNT-COOH at a dose of 28.5 µg/mL, no growth was observed.ConclusionOne of the main antimicrobial mechanisms of MWCNT-COOH is penetration into the bacterial cell wall. In this study, by using the nanofluid containing MWCNT-COOH with increased stability, the antibiotic resistance of M. fortuitum was significantly reduced at lower dilutions compared to the antibiotic alone.

Efficient adsorptive elimination of organic pollutants from aqueous solutions on ZIF-8/MWCNTs-COOH nanoadsorbents: Adsorption kinetics, isotherms, and thermodynamic study

The removal of organic pollutants was examined by new zeolitic imidazolate framework-8/carboxyl-functionalized multi-walled carbon nanotubes (ZIF-8/MWCNTs-COOH) nanoadsorbents, which were prepared via controlling the reaction sequence of MWCNTs-COOH with the precursors of ZIF-8. Structural morphology and chemical composition characterizations confirmed the successful preparation of ZIF-8/MWCNTs-COOH nanoadsorbents. The obtained samples manifested a preferable adsorption capacity for Congo red with the maximum adsorption capacity of 1185.58 mg g−1 with an adsorption removal rate of 97.93% at equilibrium adsorption. Further analyses indicated that the adsorption process conformed to the pseudo-second-order kinetic model and Langmuir adsorption isotherm. The thermodynamic analyses were depicted as endothermic, entropy-increasing, and spontaneous. The effects of pH value, interfering ions, and dosage on the adsorption properties were systematically explored. The nanoadsorbent can be expediently reused for eight cycles without a prominent reduction in adsorption activity. The improved performance and high reusability can be ascribed to the increasing specific surface, the presence of electrostatic interaction, hydrogen bonding, and π–π interaction between ZIF-8/MWCNTs-COOH and organic molecules. In addition, the prepared composites also showed a better adsorption performance for tetracycline with the equilibrium adsorption capacity of 471.22 mg g−1 compared to pure ZIF-8 and MWCNTs-COOH.

Simultaneously enhanced heat dissipation and tribological properties of polyphenylene sulfide-based composites via constructing segregated network structure

Self-lubricating polyphenylene sulfide (PPS) composites were fabricated by constructing a segregated network structure using the co-deposition method. Both carboxyl-functionalized multi-walled carbon nanotubes (CNTs) and silicon carbide (SiC) were successfully coated on the surface of PPS powders with the aid of self-polymerization of dopamine (PDA) and co-polymerization between PDA and polyethyleneimine (PEI), thereby forming [email protected] hierarchical reinforcing hybrids. Results showed that the thermal conductivity of [email protected] (0.97 W/(m K)) is about 120% higher than that of PPS/CNTs/SiC. The friction coefficient (0.193) and specific wear rate (2.50 × 10−5 mm3/(N m)) of [email protected] are 18.9% and 50% lower than those of PPS/CNTs/SiC, respectively. The enhanced thermal conductivity of [email protected] contributes to rapid dissipation of frictional heat at the sliding interface which protects the polymer substrate from being destroyed or peeled, thereby improving the tribological performance. This work provides new insights into expanding the application of self-lubricating polymer composites in the fields where efficient heat dissipation is also a primary concern.

PH-Sensing Characteristics of Multi-Walled Carbon Nanotube Assembled Across Transparent Electrodes With Dielectrophoresis

Chemical and biological processes are reliant on the pH value of the elements involved in the reaction. Transparent pH sensors with a large detection area are desirable in transparent electronics and microfluidic analytical platforms. This work reports the fabrication of pH sensors using the dielectrophoresis (DEP) method. Carboxyl-functionalized multi-walled carbon nanotubes (MWCNTs) were assembled across indium tin oxide (ITO) electrodes separated with a gap width of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$50 ~\mu \text{m}$ </tex-math></inline-formula> . The DEP process was assisted with airflow and thermal annealing to increase the stability of the aligned MWCNT connections and reduce the variation in sensor resistance. The fabricated pH sensors were exposed to analytes with different pH values. The sensors showed high sensitivity between 170% (pH=4) to 2000% (pH=10) and response times between 4 to 6 s. The long-term performance and repeatability of the sensors were improved, where the sensors can recover their initial resistance after each testing cycle.

Tough, antibacterial and self-healing ionic liquid/multiwalled carbon nanotube hydrogels as elements to produce flexible strain sensors for monitoring human motion

The hydrogel sensors exhibited high conductivity, antibacterial properties, and self-healing ability. • The hydrogel sensors presented excellent electrical conductive and antibacterial properties. • The hydrogel sensors exhibited high electric conductivity without adding inorganic salt. • The hydrogel sensors owned satisfactory self-healing ability. Hydrogel wearable sensors with multifunctional characteristics are highly desirable in the development of the current environment. Besides the constant concern of high conductivity and good mechanical properties, antibacterial properties and self-healing capability are also essential to hydrogel strain sensors. Herein, inspired by the purslane, the multifunctional hydrogel sensors (p(AAm/DMLB)/IL-LPs/c-MWCNTs) were mainly constructed by the copolymerization of dimethylaminoethyl methacrylate (DMLB) and polyacrylamide p(AAm) without adding external antimicrobial agents in a facile strategy. The results exhibited DMLB could contribute not only the antimicrobial properties, but also interact with the carboxyl-functionalized multi-walled carbon nanotubes (c-MWCNTs) and ionic liquid (IL)-latex particles (LPs) by hydrogen bond cross-linking and physical entanglement, respectively, which significantly enhanced the mechanical strength and resilience of the hydrogel sensors. Notably, without adding inorganic salt, the obtained hydrogel sensors owned a wide spectrum of sensory properties and high strain sensitivity (gauge factor = 12.71 at 100–1100%, quick response = 500 ms) owing to the synergistic effect between IL and c-MWCNTs. Moreover, the hydrogel sensors exhibited anti-piercing for efficient energy dissipation, together with self-healing properties. Therefore, the integration of self-healing, conductive and antibacterial hydrogel-based strain sensors will display broad application in sophisticated intelligence, soft robotics, bionic prosthetics, personal health care, and other fields using inexpensive, green, and easily available biomass.

Hydroxyl-and-carboxyl ligand concatenating multi-lanthanide substituted tellurotungstates and electrochemical detection of noradrenaline

Developing and exploring organic–inorganic hybrid multi-lanthanide (Ln) implanted heteropolyoxometalates (HPOMs) has bloomed into an emerging research field. In this article, two neoteric d-gluconic acids (H6GA) concatenating multi-LnIII implanted heteropolytungstates K14H10[Ln4(H2O)4W6(H2GA)4O12(B-α-TeW9O33)4]·60H2O (Ln = La3+ (1), Pr3+ (2)) were obtained in acidic aqueous system. Attractively, in the polyanion structure of 1 and 2, six WVI and four LnIII centers are connected by four flexible H2GA4− ligands via carboxyl and hydroxyl groups, resulting in the heterometallic [Ln4(H2O)4W6(H2GA)4O12]8+ cluster and then the heterometallic cluster is surrounded by four [B-α-TeW9O33]8– segments. Electrochemical measurements for the 1@CFMCN/GCE sensor (CFMCN = carboxyl-functionalized multiwalled carbon nanotube; GCE = glass carbon electrode) demonstrate that 1@CFMCN/GCE shows benign recognition response to detecting noradrenaline (NDA). This research expands the structural diversity of Ln-implanted HPOMs and presents an electrochemical platform of recognizing NDA in the field of biosensors.

Synthesis and Fabrication of Supramolecular Polydimethylsiloxane-Based Nanocomposite Elastomer for Versatile and Intelligent Sensing

High-performance strain sensors featuring self-healing ability and high stretchability are desired for human motion detection, soft robotics, and diver intelligent applications. Herein, a novel self-healing elastomer was synthesized via a facile one-pot polycondensation reaction between bis(3-aminopropyl) terminated polydimethylsiloxane and 2,4’-tolylene diisocyanate, followed by introducing carboxyl-functionalized multiwalled carbon nanotubes (CNTs). The physically entangled linear molecular chains and multiple hydrogen bonds endowed elastomer with a remarkable healing efficiency of 98.1% and outstanding stretchability of over 1000%. Owing to the conductive network constructed by the uniformly dispersed CNT, the nanocomposite elastomer-based strain sensor achieved a high gauge factor of 2.43 and its sensing performance could be well regained after self-healing. The strain sensor was successfully used for detecting various human motions and distinguishing facial microexpressions. Moreover, the nanocomposite elastomer applied on a grip ball and woolen glove as sensing units rendered them with the ability of grip force detection and sign language recognition. This work offers a new route and a promising self-healing nanocomposite elastomer for the development of recyclable and sustainable high-performance strain sensors and prospects its advanced intelligent applications.

Influence of inter structure of BaTiO3-carbon nanotube hybrid particles on the dielectric properties of PDMS nanocomposites

In this study, two kinds of hybrid particles named as BT@CNT and CNT@BT were prepared by chemical bonding between barium titanates and two types of carboxyl-functionalized multi-walled carbon nanotubes with different structural parameters in the presence of silane as a coupling agent. The effects of structures of hybrid particles on microstructure and dielectric performance of the obtained composites were studied. Herein, the BT@CNT hybrid filler aids in improving the dielectric permittivity and the CNT@BT hybrid filler has a main advantage in suppressing the dielectric loss (Dielectric permittivity 300–573 and loss 39.5–6.9 for BT@CNT/PDMS, Dielectric permittivity 65–120 and loss 1.5–0.75 for CNT@BT/PDMS at 100 Hz). Additionally, the dielectric performances of the composites can be manipulated by controlling the hybrid fillers structure and the hybrid ratio. In sum, this work looks promising for the fabrication of property-tailored materials for wide applications in electrostatic capacitors, embedded devices and charge storage device in future.

Alkali metal–lanthanide co-encapsulated 19-tungsto-2-selenate derivative and its electrochemical detection of uric acid

An alkali-metal–lanthanide (AM–Ln)-embedded 19-tungsto-2-selenate derivative [H2N(CH3)2]8Na[CeNa(H2O)4(OH) WO(H2O)(B-α-SeW9O33)2]·18H2O (1) was synthesized by a self-assembly reaction of Na2WO4·2H2O, Na2SeO3, Ce(NO3)3·6H2O, C2H7N·HCl and 2,6-pyridinedicarboxylic acid in the mixed solvent of water and N,N-dimethylformamide (DMF) (v:v = 8: 2). The polyoxoanion of 1 is constructed by a semilunar [Se2W19O68]14− fragment sandwiching an AM–Ln [CeNa(H2O)4(OH)]3+ dinuclear cluster. The [Se2W19O68]14− unit comprises two trivacant [B-α-SeW9O33]8− moieties and a central {WO6} bridging group, displaying an open configuration for grasping additional metal groups. Moreover, 1 was assembled with carboxyl-functionalized multi-walled carbon nanotube (CMWCNT) to fabricate the 1@CMWCNT composite, and was further modified onto glass carbon electrode (GCE) to construct 1@CMWCNT-GCE electrochemical sensor (ECS) for the detection of uric acid (UA), generating a low detection limit of 1.69 μmol/L for UA. Notably, this work expands the application of polyoxometalate-based composite materials on detecting biomolecules.

Quantification of carboxyl-functionalized multiwall carbon nanotubes in plant tissues with programmed thermal analysis.

In this study, carboxyl functionalized multiwall carbon nanotubes (c-MWCNTs) in plant (lettuce [Lactuca sativa Bionda Ricciolina]) tissues were quantitatively analyzed with programmed thermal analysis coupled with a sequential digestion. Programmed thermal analysis evidenced a linear relationship between c-MWCNT-bound C and elemental C detected. A detection limit of 114-708μg C g-1 plant tissues (dry mass) was achieved for analysis of c-MWCNTs. The method was demonstrated using the tissues of lettuce cultured hydroponically for 3 wk with c-MWCNTs at an exposure of 10 and 20μg ml-1 . This quantitative analysis can be used to provide insights into carbon nanotube exposure through agricultural products and promote its sustainable application.

Organic-Inorganic Hybrid Cerium-Encapsulated Selenotungstate Including Three Building Blocks and Its Electrochemical Detection of Dopamine and Paracetamol.

A novel organic-inorganic hybrid cerium-encapsulated selenotungstate comprising three polyoxotungstate building units Na16H6{[Ce3W4O10(H2O)9(CH3COO)3]2(Se2W7O30)(B-α-SeW9O33)4}·(C5H8NBO3)·119H2O (1) was synthesized by the portfolio approach of an in situ self-assembly reaction and step-by-step synthesis. The hybrid polyoxoanion of 1 is constructed from an acetate-coordinated heterometallic {[(Ce3W4O10)(H2O)9(CH3COO)3]2(Se2W7O30)}10+ core encompassing four trilacunary [B-α-SeW9O33]8- subunits. Interestingly, the heterometallic core contains a remarkable [Se2W7O30]10- building block in which seven WVI atoms form a W7 plane and two SeIV atoms are situated on two opposite faces of the W7 plane. In addition, the electrochemical performances of the 1@CFMCN composite (CFMCN: carboxyl-functionalized multiwalled carbon nanotube) were investigated. The 1@CFMCN/GCE (GCE: glass carbon electrode) sensor demonstrates a promising potential in electrochemically sensing dopamine (DPA) or paracetamol (PCM) or even simultaneously detecting DPA and PCM with low limits of 0.053 μM for DPA and 2.03 μM for PCM over a wide linear range at high sensitivity.

In vitro cytotoxicity assessment of pristine and carboxyl-functionalized MWCNTs

The wide use of carbon nanotubes (CNTs) in consumer products, i.e. composites, coatings, food packaging, etc, raise concerns about the adverse effects that CNTs can induce in humans and environment. Yet, there is no global consensus regarding risks that CNTs may pose, while controversial evidence exists also on the toxic effects associated with chemical surface modification, a prerequisite for their incorporation in different matrices. Moreover, there is limited information available about the underlying mechanisms, especially when cells’ interactions with the nanomaterial is assessed by imaging techniques. The present study aims at evaluating the in vitro cytotoxicity of pristine and oxygen functionalized multi-walled CNTs (MWCNTs) by assessing cell viability and apoptosis in combination with scanning electron microscopy (SEM) observations of stabilised cells. Direct observation of adenocarcinoma human epithelial cells (A549) was performed after incubation with 12.5, 50 and 100 μg/ml MWCNTs, for 0.5, 1 and 3 h, simulating a real exposure scenario during an accident, taking into account industrial safety issues during the production and use of the nanomaterial. Functionalized MWCNTs induced higher time- and dose-dependent toxic effects as compared to pristine. The SEM observations revealed the damaging effect on the cell membrane, offering insights about the toxic mechanism that takes place.

Multimodal chemo-/magneto-/phototaxis of 3G CNT-bots to power fuel cells

We report the development of a 3G microswimmer, namely, CNT-bot, capable of undergoing acid-, alkali-, magneto- and phototaxis inside acidic or alkaline baths of peroxide fuel and/or water. The use of carboxyl-functionalised multi-walled carbon nanotubes (MWCNTs) facilitated the propulsion of CNT-bots in an alkaline-water solution by ejecting carbon-dioxide bubbles. Furthermore, doping of magnetite nanoparticles (FeONPs), ferrous ions (Fe2+) and titanium dioxide nanoparticles (TiONPs) induces magnetic, chemical and photonic modes of propulsion. While FeONPs stimulated magnetotaxis at a rate of up to ~10 body lengths per second under the influence of a bar magnet, chemotaxis of a similar speed in a peroxide fuel was achieved by bubble-propulsion of oxygen gas originating from the Fenton reaction. In addition, the light-stimulated photo-Fenton reaction led to phototaxis of CNT-bots. A thin coating of magnesium imparted a half-faced Janus appearance to the CNT-bots, which facilitated motion in normal or acidic water media through the ejection of hydrogen gas bubbles. This chemotaxis could be transformed into pH-stimulated directional motion by establishing an acid or alkali concentration gradient across the peroxide and/or water baths. The capacity of CNT-bots to produce oxygen (hydrogen) bubbles in peroxide (acidic water) fuel was exploited to power a PEM fuel cell to generate electricity. The pure oxygen and hydrogen gases generated by CNT-bots in separate chambers were fed directly into the fuel cell in which the incessant motions of the particle facilitated the creation and release of the pure gases to achieve on-demand electricity generation. The motor could also induce dye degradation through advanced oxidation owing to the production of intermediate hydroxyl radicals during the Fenton reaction.

Kinetics and constraints of CO oxidation over hexameric copper nanocluster catalyst supported on carboxyl-functionalised MWCNT at high temperatures

Kinetics of CO oxidation over hexameric copper nanoclusters supported on carboxyl-functionalised multi-walled carbon nanotubes (Cu6/MWCNTCOOH) was studied between 400 and 475 °C. An excessive amount of O2 in the feed gas hindered access of CO molecules to the active sites (maximum CO conversion ~29% in O2-rich environment (CO:O2 = 1:10 v/v) cf. ~89% in O2-lean environment (CO:O2 = 1.0:1.2 v/v) at GHSV of 3,000–6,000 mL/(gcat·h)). The reaction temperature range was constrained by catalyst deactivation due to the formation of CuCO3 below the lower limit, and combustion of the MWCNT support in the oxidative environment above the upper limit. A kinetic model was developed based on assumptions that the reaction was CO-adsorption limited and followed the Langmuir–Hinshelwood mechanism for CO concentrations ≤14 vol% in the feed gas. The activation energy (Ea) was determined to be 54.3 kJ/mol in the temperature range studied.

First Electrochemical Sensor (Screen-Printed Carbon Electrode Modified with Carboxyl Functionalized Multiwalled Carbon Nanotubes) for Ultratrace Determination of Diclofenac.

A simple, sensitive and time-saving differential-pulse adsorptive stripping voltammetric (DPAdSV) procedure using a screen-printed carbon electrode modified with carboxyl functionalized multiwalled carbon nanotubes (SPCE/MWCNTs-COOH) for the determination of diclofenac (DF) is presented. The sensor was characterized using optical profilometry, SEM, and cyclic voltammetry (CV). The use of carboxyl functionalized MWCNTs as a SPCE modifier improved the electron transfer process and the active surface area of sensor. Under optimum conditions, very sensitive results were obtained with a linear range of 0.1–10.0 nmol L−1 and a limit of detection value of 0.028 nmol L−1. The SPCE/MWCNTs-COOH also exhibited satisfactory repeatability, reproducibility, and selectivity towards potential interferences. Moreover, for the first time, the electrochemical sensor allows determining the real concentrations of DF in environmental water samples without sample pretreatment steps.

PDMS/MWCNT nanocomposite films for underwater sound absorption applications

Polydimethylsiloxane (PDMS) nanocomposite films for underwater sound absorption applications are presented. Films were fabricated by a spin coating method and characterized using XPS, FTIR, TGA, SEM, tensile testing, and elastic cold-neutron scattering. The XPS results reveal the addition of surfactant and carboxyl-functionalized multi-walled carbon nanotube (MWCNT-COOH) increased the components of C and O atoms by 4.12% and 2.81%, respectively, compared to the native PDMS film. The addition of MWCNT-COOH and surfactants to the PDMS also significantly improved the thermal stability (700 °C) of the nanocomposite material compared to pure PDMS. Tensile property measurements of PDMS nanocomposites indicate that the addition of 2 wt% of MWCNT-COOH significantly improves the elastic modulus by 48% compared to the pure PDMS. The addition of surfactant nonetheless decreases the Young’s modulus by 34% compared to pure PDMS, due to changes in the microstructure of the PDMS matrix. The advantage of the decreased Young’s modulus is to avoid acoustic impedance mismatch. The surface morphology detected by SEM indicates that the surfactant can improve the dispersion of MWCNT-COOH in the PDMS films. Further, the elastic cold-neutron scattering results demonstrate the diffusive motions near the glass transition temperatures (Tg) of the nanocomposite films, providing in-depth details of the dynamic alignment of the inclusions within the material matrix. The PDMS/MWCNT-COOH/surfactant nanocomposite exhibited a sound absorption coefficient of 0.25, which was far higher than the PDMS control materials. This positive result indicates these PDMS nanocomposite films have promising future underwater sound absorption applications.

Silk-inspired stretchable fiber-shaped supercapacitors with ultrahigh volumetric capacitance and energy density for wearable electronics

Inspired by the naturally occurring silk, in this work, a novel parallel-like fiber-shaped supercapacitor (PFSS) was developed by using two silk-derived fiber electrodes. The ternary electrode, PANI@F-MWCNT@silk, was prepared by decorating raw silk yarn with 13 wt% of carboxyl-functionalized multi-walled carbon nanotube (F-MWCNT) and 16 wt% of polyaniline (PANI), which were utilized as a conductive interlayer and a pseudocapacitive wrapping layer, respectively. In a three-electrode configuration, the PANI@F-MWCNT@silk showed a large area-normalized capacitance of 95.5 mF cm−2, and an ultrahigh volumetric capacitance of 63.7 F cm−3 at 0.1 mA (0.1 mA = 5.3 mA cm−2 and 3.5 A cm−3), which were obviously higher than numerous polyester fiber electrodes, and also comparable to or even better than many metal wire electrodes reported so far. The symmetric parallel-like all-solid-state supercapacitor device based on PANI@F-MWCNT@silk demonstrated an attractive capacitive performance with a high energy density of 1.22 mWh m−2 at a power density of 127 mW m−2. Moreover, benefiting from the extraordinary mechanical properties of silk, this ternary electrode exhibited a very large elongation of 33% with a high tensile strength of 225 MPa, and the silk-inspired PFSS could maintain more than 80% of its initial capacitance under an applied strain of 20%, suggesting a superb capacitive stability against deformations. Notably, the proposed fibrous substrate, which has abundantly existed in nature, may open up a new strategy to develop high-efficiency fiber-shaped power storage devices for wearable electronics.

An amplified electrochemical sensor employing a polymeric film and graphene quantum dots/multiwall carbon nanotubes in a deep eutectic solvent for sensitive analysis of paracetamol and 4-aminophenol

Herein, a nanocomposite consisting of graphene quantum dots, a deep eutectic solvent and carboxyl functionalized multiwall carbon nanotubes (GQDs + DES + MWCNTs-COOH) was prepared.

Influence of Two Different Nanofillers on the Crystallization Behavior and Dynamic Mechanical Properties of Biodegradable Poly(ethylene adipate)

In this work two biodegradable poly(ethylene adipate) (PEA) based nanocomposites containing the same low loading of cellulose nanocrystals (CNC) and carboxyl-functionalized multi-walled carbon nanotubes (f-MWCNT) were prepared through a solution and casting method, respectively. The crystallization behavior and dynamic mechanical properties of neat PEA and the nanocomposites were studied in detail and compared with each other. Both CNC and f-MWCNT finely dispersed in PEA matrix. The addition of CNC or f-MWCNT not only increased the melt crystallization peak temperature but also decreased the crystallization half-time of PEA, suggesting that the crystallization of PEA was apparently enhanced by CNC or f-MWCNT due to the heterogeneous nucleating agent effect. Both CNC and f-MWCNT increased the storage modulus and glass transition temperature of PEA matrix in the nanocomposites. As a nucleating agent, f-MWCNT was more efficient than CNC, while CNC was stronger than f-MWCNT as a reinforcer.