Well-dispersed Nanocomposites Research Articles

Innovative dispersion techniques of graphene nanoplatelets (GNPs) through mechanical stirring and ultrasonication: Impact on morphological, mechanical, and thermal properties of epoxy nanocomposites

Graphene nanoplatelets (GNPs) have attracted tremendous interest due to their unique properties and bonding capabilities. This study focuses on the effect of GNP dispersion on the mechanical, thermal, and morphological behavior of GNP/epoxy nanocomposites. This study aims to understand how the dispersion of GNPs affects the properties of epoxy nanocomposite and to identify the best dispersion approach for improving mechanical performance. A solvent mixing technique that includes mechanical stirring and ultrasonication was used for producing the nanocomposites. Fourier transform infrared spectroscopy was used to investigate the interaction between GNPs and the epoxy matrix. The measurements of density and moisture content were used to confirm that GNPs were successfully incorporated into the nanocomposite. The findings showed that GNPs are successfully dispersed in the epoxy matrix by combining mechanical stirring and ultrasonication in a single step, producing well-dispersed nanocomposites with improved mechanical properties. Particularly, the nanocomposites at a low GNP loading of 0.1 wt%, demonstrate superior mechanical strength, as shown by increased tensile properties, including improved Young's modulus (1.86 GPa), strength (57.31 MPa), and elongation at break (4.98). The nanocomposite with 0.25 wt% GNP loading performs better, according to the viscoelastic analysis and flexural properties (113.18 MPa). Except for the nanocomposite with a 0.5 wt% GNP loading, which has a higher thermal breakdown temperature, the thermal characteristics do not significantly alter. The effective dispersion of GNPs in the epoxy matrix and low agglomeration is confirmed by the morphological characterization. The findings help with filler selection and identifying the best dispersion approach, which improves mechanical performance. The effective integration of GNPs and their interaction with the epoxy matrix provides the doorway for additional investigation and the development of sophisticated nanocomposites. In fields like aerospace, automotive, and electronics where higher mechanical performance and functionality are required, GNPs' improved mechanical properties and successful dispersion present exciting potential.

Catalysing a sustainable future: Harnessing solar energy with novel Co3O4@VO2 nanocomposites for enhanced photocatalytic hydrogen generation and dye degradation

This study focuses on the hydrothermal synthesis and characterization of Concentration dependent Co3O4@VO2 nanocomposites with varying molar ratios of Co3O4 to VO2 (2:1, 1:1, and 1:2) for efficient hydrogen generation and dye degradation. The structural and morphological characteristics of the prepared nanocomposites were analysed using x-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Crystallographic analysis using XRD confirmed the formation of crystalline Co3O4 with a monoclinic structure, while the presence of VO2 was identified by characteristic peaks in the XPS. Microscopic analysis using SEM and TEM revealed well-dispersed nanocomposites with nanoscale dimensions. Photocatalytic activities were evaluated for hydrogen evolution and dye degradation, with the nanocomposite featuring a 2:1 ratio of Co3O4 to VO2 (CV-21) demonstrating significantly enhanced performance. CV-21 exhibited a lower onset potential and higher current density for hydrogen evolution (2270μmol/h/g), indicating improved photocatalytic activity. Additionally, it displayed rapid and superior dye degradation (93% within 10 min) under sunlight compared to Victoria blue B (VBB) dye. The Co3O4@VO2 nanocomposites, particularly CV-21, demonstrate enhanced photocatalytic performance for hydrogen generation and dye degradation compared to pristine VO2 and Co3O4. This improvement possibly due to synergistic effects between Co3O4 and VO2, optimized structural characteristics, and improved interfacial properties in the nanocomposite structure. These findings highlight the promising potential of Co3O4@VO2 nanocomposites, particularly CV-21, for environmental remediation applications.

Enhanced sunlight-driven catalysis for hydrogen generation and dye remediation using synergistic p-Co3O4/n-TiO2 nanocomposites.

In this study, p-Co3O4/n-TiO2 nanocomposites were synthesized using different ratios of cobalt and titanium precursors through a hydrothermal method. These nanocomposites demonstrated notable potential in photocatalytic applications for hydrogen production and orange-red dye degradation under sunlight. Various techniques, including XRD, Raman spectroscopy, XPS, FESEM, TEM, and BET analysis, were used to comprehensively characterize their structural, morphological, and optical properties. The nanocomposites exhibited both cubic and tetragonal phases of Co3O4 and TiO2, and their combined effect resulted in a narrowed band gap. Additionally, the presence of Co3O4 induced surface plasmon resonance on the TiO2 surface, effectively impeding electron-hole recombination. The nanocomposites displayed an average particle size of ∼20 to 30 nm with substantial visible light absorption. High crystallinity and well-dispersed nanocomposites were confirmed by XRD and Raman, with BET surface areas ranging between 49 and 106 m2 g-1. Notably, the p-Co3O4/n-TiO2 nanocomposite showed superior photocatalytic activity, achieving a maximum hydrogen generation rate of 1120 μmol h-1 g-1 and an 83% degradation efficiency of the orange-red dye within 6 minutes under sunlight. This study emphasizes the enhanced performance of the p-Co3O4/n-TiO2 nanocomposite, indicating its potential in photocatalytic applications, conforming to a pseudo-first-order kinetics model.

Comprehensive analysis of CNT/NS/GO composites: Dispersion effect of graphene oxide for environmental sensor application

This study presents a comprehensive analysis of conductive and hygroscopic nanocomposites using graphene oxide (GO), carbon nanotubes (CNT), and nano-silica. Nanocomposite suspensions for vacuum filtration were prepared by dispersion via ultrasonication in water. The dispersed phase of each nanomaterial was evaluated through ultraviolet absorbance, extinction coefficient, and zeta potential. The dispersion was performed at a ratio of CNT to GO well over 0.4 without any surfactants or additives because of the rich functional groups on the GO surface. In addition, the morphology of the fabricated nanocomposite generated after vacuum filtration, verified through scanning electron microscopy and Raman spectroscopy, showed a lamellar structure of GO and was easily separated as a membrane at composite-to-GO ratios of over 0.4. The fabricated membrane exhibited an excellent moisture collection ability and good responsivity as an environmental (humidity) sensor. This study supports the use of GO for the formation of well-dispersed nanocomposites for various applications.

Effect of nanoparticle modified polyacrylamide on wax deposition, crystallization and flow behavior of light and heavy crude oils

In this article, the potential use of silica and alumina polyacrylamide to inhibit wax crystallization and deposition of real crude oils has been studied for the first time. The performance of nanocomposites on a light and heavy crude oil was evaluated using cold finger apparatus, differential scanning calorimeter (DSC), polarizing microscopy, and rheometer. Nanocomposites effectively reduce wax deposition with 79% and 70% maximum efficiency for heavy and light oil, respectively. The flowability of treated heavy oil was improved, while a less pronounced effect was observed for treated light oil. DSC measurements indicated nanocomposites to delay the wax crystallization onset of heavy oil more noticeable than light oil. Polarized microscopy showed a visible morphological change, as the introduction of nanocomposites caused regular roundly shaped and finely dispersed wax crystals for both light and heavy crude oils. The results indicate that the presence of nanocomposites delays the wax crystallization process by presenting multiple spherical nucleation templates, influencing the wax crystal interactions, and preventing the formation of stable wax networks in agreement with the percolation theory predictions. The better inhibition effect of nanocomposites for heavy oil may result from two mechanisms. First, the well-dispersed nanocomposites act as nucleation centers for wax crystals. Second, asphaltene adsorption on the nanocomposite surface may prevent the formation of the asphaltene-wax three-dimensional network and delays wax crystallization. This research indicates the possibility of using silica and alumina polyacrylamide as an effective chemical agent for the inhibition of wax deposition of crude oil.

Polypropylene/graphene nanoplatelets nanocomposites with high conductivity via solid-state shear mixing

Abstract The research on facile, low-cost, and green process for the uniform dispersion of graphene nanoplatelets (GNPs) into polymer matrix has always been a considerable challenge in practical applications. The Van der Waals interaction between graphene layers can easily cause aggregation of the nanofillers. Here, we propose a new method to solve this problem by involving solid-state shear mixing to obtain a well-dispersed nanocomposite. The comprehensive properties of nanocomposite, including antistatic properties, mechanical properties, and thermal stability, can be significantly enhanced by this method. The surface resistivity of the nanocomposite can be up to 2.4 × 107 Ω sq−1 under 1 wt% content of GNPs, which is significantly better than the value obtained by conventional melting compounding and meets the required standard of less than 3 × 108 Ω sq−1 for actual application antistatic materials. The impact strength of the nanocomposite increased by 120.8% when compared with neat PP. At the same time, the heat distortion temperature and initial decomposition temperature of the nanocomposite with only 0.5 wt% content of GNPs are improved by 11.7°C and 110°C, respectively. In addition, GNPs is a heterogeneous nucleating agent that leads PP to emerge β crystal form. This study provides an effective and practical reference for the broad-scale industrial preparation of polymer-based graphene nanocomposites.

Well-Dispersed Nanocomposites Using Covalently Modified, Multilayer, 2D Titanium Carbide (MXene) and In-Situ “Click” Polymerization

Despite the excellent mechanical and electrical performance of MXene–polymer nanocomposites, methods for producing these materials on a larger scale are limited by low-yielding, delaminated, MXene suspensions that are typically employed for their synthesis. Moreover, the hydrophilicity of MXenes restricts the production of well-dispersed nanocomposites with many polymer matrices. In this contribution, we address such limitations and report, for the first time, a simple method to covalently modify multilayered Ti3C2Tz MXenes with isocyanates, which enables their successful dispersion within a hydrophobic thiourethane matrix. The efficacy of our covalent modification was determined to yield high levels of surface grafts and suggests quantitative conversion of the oxygen-containing terminations. In situ-polymerized thiourethane “click” matrices were used to demonstrate the utility of this modification for accessing well-dispersed nanocomposites under ambient conditions. The ease of producing modified, multilayered, MXenes at scale and the availability of a wide variety of isocyanates render this method scalable and highly modular. Furthermore, the reported isocyanate treatment was found to be a valuable tool for easily quantifying the concentration of reactive (oxygen-containing) terminations on MXene surfaces.

Key Role of the Dispersion of Carbon Nanotubes (CNTs) within Epoxy Networks on their Ability to Release.

Carbon nanotube (CNT)-reinforced nanocomposites represent a unique opportunity in terms of designing advanced materials with mechanical reinforcement and improvements in the electrical and thermal conductivities. However, the toxic effects of these composites on human health have been studied, and very soon, some regulations on CNTs and on composites based on CNTs will be enacted. That is why the release of CNTs during the nanocomposite lifecycle must be controlled. As the releasing depends on the interfacial strength that is stronger between CNTs and polymers compared to CNTs in a CNT agglomerate, two dispersion states—one poorly dispersed versus another well dispersed—are generated and finely described. So, the main aim of this study is to check if the CNT dispersion state has an influence on the CNT releasing potential in the nanocomposite. To well tailor and characterize the CNT dispersion state in the polymer matrix, electronic microscopies (SEM and TEM) and also rheological analysis are carried out to identify whether CNTs are isolated, in bundles, or in agglomerates. When the dispersion state is known and controlled, its influence on the polymerization kinetic and on mechanical properties is discussed. It appears clearly that in the case of a good dispersion state, strong interfaces are generated, linking the isolated nanotubes with the polymer, whereas the CNT cohesion in an agglomerate seems much more weak, and it does not provide any improvement to the polymer matrix. Raman spectroscopy is relevant to analyze the interfacial properties and allows the relationship with the releasing ability of nanocomposites; i.e., CNTs poorly dispersed in the matrix are more readily released when compared to well-dispersed nanocomposites. The tribological tests confirm from released particles granulometry and observations that a CNT dispersion state sufficiently achieved in the nanocomposite avoids single CNT releasing under those solicitations.

Hierarchical Nylon-6/reduced graphene oxide/polyaniline nanocomposites with enhanced dielectric properties for energy storage applications

Abstract Materials with high specific energy and specific power, along with chemical and structural stability, are in huge demand due to their numerous applications, including solid-state electronic devices and wearable electronics. Nanocomposites comprising of both conducting and non-conducting polymers exhibit excellent charge transfer mechanism along with high dielectric strength and structural stability, which enhances their appropriateness as efficient energy storage materials. Herein, we explore the application of Nylon-6 (PA6), polyaniline (PANI) and reduced graphene oxide (rGO) in preparing ternary nanocomposite (PA6/rGO/PANI) by varying the ratio of PA6 and PANI, for a fixed amount of rGO along with binary (PA6/PANI and rGO/PANI) nanocomposites. Among them, PA6/rGO/PANI 1:2 exhibits an excellent supercapacitance performance owing to its high surface area, low charge transfer resistance, high cyclic stability, and exceptional ionic rate capability. We have observed reasonable dielectric properties (viz., dielectric permittivity and dielectric loss), which is attributed to the stacking property of rGO with PA6 and PANI chains. The in-situ polymerization of PANI ensures the formation of well-dispersed nanocomposites with the hierarchical nanostructures, as revealed by the detailed morphological study. The galvanostatic charge-discharge measurement exhibits remarkable reversibility with capacitance retention of ~ 98%. The fabricated symmetric supercapacitor device based on PA6/rGO/PANI 1:2 exhibits noteworthy specific capacitance (38 F g−1), specific energy (~ 3.66 Wh kg‒1) and specific power (~ 234.84 W kg‒1), suggesting significant charge accumulation over the electrode surfaces, which is attributed to the synergistic effect of PA6 and PANI in the presence of rGO. The excellent electrochemical properties indicate its potential applications in self-powered electronic appliances effectively.

LIGHTWEIGHT ELASTOMER COMPOUNDS REINFORCED WITH CELLULOSE NANOFIBRILS AND A CARBON BLACK HYBRID FILLER SYSTEM

ABSTRACT Cellulose is found in the walls of plant cells, making it the most common biopolymer in the world. It is mechanically stable, resistant to hydrolysis, and boasts—especially in its nanoscopic state—a large reactive surface area and low density. To realize reinforcement in rubbers, the large and polar cellulose surface must interact with the nonpolar elastomer matrix. The dispersion of hydrophilic fillers is, however, still a major challenge in rubber technology. In this work, commercially available nanofibrillated cellulose (NFC) was incorporated into a nonpolar BIIR via latex mixing. Transmission electron microscopy, tensile testing, swelling, and rheometry were used to characterize the compound properties and the reinforcing potential of NFC. The compounds were compared with the established and highly dispersible standard carbon black N550 with a medium specific surface area. In addition, hybrid filler systems with both particle types were prepared. This yielded well-dispersed nanocomposites of a new kind exhibiting high stiffness, good tensile properties, and reduced material weight.

Experimental Investigation of Thermal Stability and Enthalpy of Eutectic Alkali Metal Solar Salt Dispersed with MgO Nanoparticles

In this study, nanocomposites containing a pre-defined mass ratio of solar salt (NaNO3-KNO3: 60-40 wt.%) dispersed with magnesium oxide (MgO) nanoparticles with nominal sizes of 100 nm were prepared in solid and liquid states. The proposed amounts of sodium nitrate and potassium nitrate were added to certain amounts of ultrapure deionized (DI) water comprising a 5 wt.% concentration of MgO nanoparticles. Afterward, the prepared mixture was placed in a dry oven to mix in a liquid state to obtain well-dispersed nanocomposites. Scanning electronic microscopy (SEM) was conducted to evaluate the uniformity of synthesized, molten salt–based magnesium oxide–nanoparticles, revealing a uniform dispersion. Enthalpy and melting point measurements were performed using differential scanning calorimetry. The experimental results of solar salt–based MgO indicated decreases in melting point and enthalpy by 7% and 12.4%, respectively. The reduction of enthalpy indicated that, with the addition of magnesium oxide to solar salt, the final nanocomposite tends to have more exothermic reactions and enhanced thermal conductivity performance at the melting point. Lower melting points constitute one of the major concerns regarding molten salt–based nanofluids. MgO nanoparticles with a concentration of 5 wt.% have a melting point decreased by 7%. Mass loss and thermal stability measurements were conducted using thermogravimetric analysis (TGA). The experimentally acquired results revealed an increment of decomposition temperature from 734.29°C to 750.73°C, demonstrating the enhancement of thermal stability at high temperatures.

Novel “On–Off” Colorimetric Sensor for Glutathione Based on Peroxidase Activity of Montmorillonite-Loaded TiO2 Functionalized by Porphyrin Precisely Controlled by Visible Light

Well-dispersed nanocomposites based on Ca-montmorillonite decorated by porphyrin-functionalized titanium dioxide (H2TCPP–TiO2–MMT) were synthesized by a facile strategy. H2TCPP–TiO2–MMT was demonst...

Crystallization, thermal stability, barrier property, and aging resistance application of multi-functionalized graphene oxide/poly(lactide)/starch nanocomposites.

Poly(lactide)-starch matrix, blended with multi-functionalized graphene oxide, was synthesized by solution casting in this study. To improve its interface compatibility, the graphene oxide (GO) was grafted with maleic anhydride and subsequently modified by dodecyl amine. The chemical structure and morphology of functionalized GO (f-GO) were determined by Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The crystallization property, surface wettability, morphology, thermal stability, and dynamic mechanical and aging resistance properties of the nanocomposite were determined. By XRD and morphological analysis, we observed the formation of well-dispersed nanocomposites. Thermo-gravimetric analysis revealed significant improvements in thermal stability. The isothermal and non-isothermal crystallization behavior of the PLA-starch-f-GO nanocomposites demonstrated that the f-GO that was added accelerated the heterogeneous nucleation of the nanocomposites. The surface hydrophobicity, UV-shielding capacity, and aging resistance properties of these nanocomposites were enhanced by the incorporation of the f-GO. The migration rate of plasticizer of the nanocomposites decreased compared with the group without f-GO. The storage modulus for these nanocomposites improved by dynamic mechanical analysis. These insights provide a strategy for constructing high-performance nanohybrids and broadening their application in the food packaging and pharmaceutical industries.

Environmental-friendly recycled Polyester/Mg(OH)2 nanocomposite: Fire-retardancy and thermal stability

Fire retardant composites have had a global concern; these composites are mainly composed of halogens/synthetic fibers fire retardant fillers with synthetic polymers. This work aims to utilize green recycled polyester (Rec PE) matrix, obtained from recycled polyethylene terephthalate and natural oleic acid, with high surface area eco-friendly and non-toxic halogen-free Mg(OH)2 nanoparticles to obtain novel environmental friendly Rec PE-Mg(OH)2 fire retardant nanocomposite with superior properties, for the first time. Mg(OH)2 nanoparticles ~75 nm were synthesized and characterized by XRD, DLS and SEM. Then Rec PE matrix was filled by 5, 10, 15 and 20 wt% nanofiller and finally cured via “in-situ polymerization” to have Rec PE-Mg(OH)2 nanocomposites. The improved ratio is 15% that achieved the most effective fire retardancy due to increase time to ignition and decrease peak heat release rate, specific extinction area, total smoke parameter and mass loss rate, as investigated by come calorimeter. Burning suppressing was confirmed by increasing limiting oxygen index till 34.1%. The prepared nanocomposites have advanced thermal stability regarding increasing thermal decomposition temperatures to higher values through all ignition zones, as detected by TGA. The 15% nanocomposite has improved hardness value by 10.6%; SEM confirmed obtaining of this advanced percentage as well-dispersed nanocomposite. Here, it is demonstrated that protection of our green polymeric matrix from fire diffusion, combustion heat, atmospheric oxygen, emitted gases, weight loss and thermal degradation is the key issue that makes Rec PE-Mg(OH)2 nanocomposite acts as an effective green fire retardant.

Nanocomposites of acid free CNC and HDPE: Dispersion from solvent driven by fast crystallization/gelation

Among several applications, the use of cellulose nanocrystals (CNC) as reinforcement in composite materials with thermoplastic matrix stands out. However, both the conventional method for CNC production and the processes for composite production with non-water-soluble matrix show several drawbacks. The common method for CNC preparation based on the hydrolysis of cellulose with high concentrated sulfuric acid produces sulfated nanocrystals with low thermal stability and generates large amounts of acidic effluents. Although the presence of ionic groups on the surface of the nanocrystals prepared in sulfuric acid increases the stability of their suspensions in water, it promotes the degradation of the CNC in melt processing temperatures of thermoplastic composites, such as extrusion or injection molding. Here we describe the use of high thermal stable cellulose nanocrystal prepared by subcritical water as reinforcement for high density polyethylene (HDPE) using a three step processing: i) solvent exchange in order to produce a suspension of CNC in xylenes, ii) dissolution of HDPE followed by iii) the fast crystallization/gelation/flocculation, leading to the isolation of the composite. This process leads to the production of a well-dispersed nanocomposite with higher thermal stability (higher than 250 °C) and improved mechanical properties. An increase of ~20% in Young's modulus was observed when compared with the neat matrix.

A review on new mesostructured composite materials: Part II. Characterization and properties of polymer–mesoporous silica nanocomposite

Hybrid inorganic–organic materials are promising systems for a variety of applications due to their extraordinary properties with intricate composite architectures composed of nanoscale inorganic moieties with organic polymers synergistically intertwined to provide both useful functionality and mechanical integrity. These materials have a high potential for future applications and therefore attract considerable interest in polymer science research during the last years. Among the various explored inorganic nanostructures, the mesoporous silica has been considered as a fascinating material to construct novel ordered and well-dispersed nanocomposites due to their high surface areas, periodic and size-controllable pore channels. This review is written with the intention to give an overview of the characterization and material properties of polymer–mesoporous silica nanocomposites. Among polymer–mesoporous silica composites, various categories including polyaniline, polypyrrole, polystyrene, polypropylene, polyethylene, epoxy, rubber, and acrylate polymer were discussed in detail.

Improved dielectric and energy storage properties of poly(vinyl alcohol) nanocomposites by strengthening interfacial hydrogen-bonding interaction

Dielectric capacitor has drawn much attention recently both in academia and in industry because of its high power density and excellent cycle performances. In order to meet the demand for high energy density, high-ε (dielectric permittivity) nanoparticles are dispersed into polymer matrices to form nanocomposites with both high ε and high Eb (breakdown strength). Polymer-nanoparticle interface has great influence on energy storage properties. In order to find out whether we can prepare well-dispersed nanocomposites by forming a thin coating layer (less than 2 nm) on the surface of nanoparticles with strengthened interfacial interaction, such as hydrogen-bonding interaction, a specific coating molecule, i.e., 3,4,5-trihydrobenzoic acid (or Gallic Acid, GA), was selected for surface modification of BaTiO3 (BT) in this research. A coating layer of only 1.6 nm in thickness formed by the reaction between phenolic hydroxyl groups in GA and surface hydroxyl groups on BT to produce modified BT@GA nanoparticles. Hydrogen-bonding interaction did form between GA and the hydroxyl groups in PVA matrix. This ensured fine dispersion, higher ε, higher Eb and higher energy storage density for PVA + BT@GA nanocomposites. For PVA + 40%BT@GA, ε reached 51 at 1 kHz, while Eb was 144 MV/m, which is twice as that of PVA + 40%BT. The discharging energy density of PVA + 40%BT@GA reaches 0.554 J/cm3 at 50 MV/m, about fourth times as that of pristine PVA.

Shape-Memory Behavior of Polylactide/Silica Ionic Hybrids

Commercial polylactide (PLA) was converted and endowed with shape-memory properties by synthesizing ionic hybrids based on blends of PLA with imidazolium-terminated PLA and poly[e-caprolactone-co-d,l-lactide] (P[CL-co-LA]) and surface-modified silica nanoparticles. The electrostatic interactions assist with the silica nanoparticle dispersion in the polymer matrix. Since nanoparticle dispersion in polymers is a perennial challenge and has prevented nanocomposites from reaching their full potential in terms of performance we expect this new design will be exploited in other polymers systems to synthesize well-dispersed nanocomposites. Rheological measurements of the ionic hybrids are consistent with the formation of a network. The ionic hybrids are also much more deformable compared to the neat PLA. More importantly, they exhibit shape-memory behavior with fixity ratio Rf ≈ 100% and recovery ratio Rr = 79%, for the blend containing 25 wt % im-PLA and 25 wt % im-P[CL-co-LA] and 5 wt % of SiO2–SO3Na. Dielectr...

The Role of the Topological Constraints in the Chain Dynamics in All-Polymer Nanocomposites

We investigate all-polymer nanocomposites, formed by linear chains and single-chain polymer nanoparticles (SCNPs), by means of large-scale simulations. To distinguish the role of the soft penetrable character of the SCNPs in the topological constraints from other specific contributions present in experiments, the simulations for different compositions of the mixture are performed at constant density and with identical segmental mobility and monomer excluded volume for the SCNPs and linear chains. Every composition leads to a well-dispersed nanocomposite with fully penetrated nanofillers. Hence, unlike in the case of hard nanofillers, the SCNPs do not exert confinement effects on the linear chains and only contribute to the topological constraints. We discuss the intramolecular dynamics of the linear chains in terms of the tube model. We determine the entanglement length of the linear chains by analyzing their isoconfigurational mean paths (IMP) and the primitive paths (PP) as a function of the concentrati...

A facile preparation of montmorillonite-supported copper sulfide nanocomposites and their application in the detection of H2O2

Well-dispersed nanocomposites (CuS-MMT nanocomposites) based on copper sulfide (CuS) and Ca-montmorillonite (Ca2+-MMT) were prepared via a simple and facile method and were characterized by transmission electron microscopy (TEM), high resolution TEM, powder X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS). The as-prepared CuS-MMT NPs were for the first time demonstrated to possess intrinsic peroxidase-like activity towards typical peroxidase substrates such as 3,3′,5,5′-tetramethylbenzidine (TMB) for hydrogen peroxide (H2O2). Interestingly, the CuS-MMT nanocomposites as peroxidase mimics could rapidly catalyse to oxidise the substrate TMB into blue oxTMB only in 30s observed by the naked eye. The reaction catalyzed by the CuS-MMT nanocomposites followed the Michaelis–Menten kinetics, which showed good affinity towards both TMB and H2O2, respectively. Taking the advantage of the high peroxidase-like activity, the as-prepared CuS-MMT nanocomposites were designed to establish a novel colorimetric sensor for H2O2 with a wide linear range from 3×10−5 to 2×10−4M. Moreover, the rapid, simple and sensitive TMB-H2O2-[CuS-MMT] colorimetric platform holds great promising applications in the pharmaceutical, clinical and industrial detection of H2O2.