Transition Metal (Cu, Pd, and Ag)-Modified Nb2S2C Monolayer for Highly Efficient Catechol Sensing: A First-Principles Investigation.

Motivated by recent advancements and the escalating application of two-dimensional (2D) gas or molecule sensors, this study explores the potential of the 2D Nb2S2C monolayer for detecting biomolecule catechol (Cc), whose excess concentration is highly dangerous to living beings. We use first-principles density functional theory (DFT) calculations to assess the Cc sensing performance of pure and transition metal (TM = Cu, Pd, Ag)-modified Nb2S2C monolayers. The Nb2S2C monolayer belonging to the new class of synthesized 2D materials, TM carbo-chalcogenides (TMCC), combines distinctive properties from both TM dichalcogenides and TM carbides and exhibits physisorption (-0.66 eV) toward the Cc molecule. Notably, the surface modifications with these TMs significantly enhanced the adsorption energy of Cc. The chemisorption of the Cc molecule on the Pd to Cu-modified monolayer is demonstrated with adsorption energies ranging from -1.09 to -1.3 eV and is due to the robust charge transfer and orbital interactions between the valence orbitals of TMs and Cc. In addition, the modification of the surface by TM leads to an increased work function sensitivity toward the Cc molecule. The study establishes the thermal stability at 300 K and dynamic stability of TM-Nb2S2C through ab initio molecular dynamics (AIMD) simulations and Phonon calculations, respectively. The theoretical estimation of achievable recovery time at 400 and 450 K for Pd and Ag and at 500 K for the Cu-modified Nb2S2C monolayer, respectively, confirms the potential practical application of the sensor for Cc detection. These compelling characteristics position the Nb2S2C monolayer as a promising nanomaterial for detecting Cc molecules in the environment.

Catechol Sensing Performance of Pd-Functionalized Two-Dimensional Polyaramid: A DFT Investigation.

Catechol (Cc) molecule adsorption on a pristine and transition metal (TMs = Sc, Pd, and Cu)-functionalized two-dimensional polyaramid (2DPA) monolayer is systematically studied by the first-principles density functional theory method. The weak physisorption (-0.29 eV) and charge transfer of the Cc molecule with p-2DPA result in a very quick recovery time (150 µs), hindering the Cc sensing capability of p-2DPA. Although TM functionalization greatly improved the adsorption ability, the Pd-functionalized 2DPA was shown to be the best choice for Cc adsorption due to the reasonable adsorption energy of -1.39 eV and expedited charge transfer between the Cc and Pd atom. The change of band gap and, hence, the conductivity of the Pd-2DPA system in response to the adsorption of the Cc molecule demonstrate its higher sensitivity than that of p-2DPA. The work function sensitivity of Pd-2DPA upon the Cc adsorption is also investigated. In addition to the change in the electronic properties, the change in the optical properties of Pd-2DPA after Cc adsorption is also analyzed. The structural stability of Pd-2DPA is validated by performing ab initio molecular dynamics simulations at 300 K. The complete desorption of the Cc molecule from Pd-2DPA is attained by annealing the material at 550 K under visible light (τ = 5.4 s) and at 450 K under UV light (τ = 3.7 s). Moreover, the higher diffusion energy barrier of +1.35 eV confirmed that the functionalized Pd atoms did not diffuse through the crystal to form clusters. This study could lay a theoretical foundation for developing possibly new-generation sensors for detecting Cc molecules.

Nanocellulose-Based Hybrid Scaffolds for Skin and Bone Tissue Engineering: A 10-Year Overview.

Cellulose, the most abundant polymer on Earth, has been widely utilized in its nanoform due to its excellent properties, finding applications across various scientific fields. As the demand for nanocellulose continues to rise and its ease of use becomes apparent, there has been a significant increase in research publications centered on this biomaterial. Nanocellulose, in its different forms, has shown tremendous promise as a tissue engineered scaffold for regeneration and repair. Particularly, nanocellulose-based composites and scaffolds have emerged as highly demanding materials for both soft and hard tissue engineering. Medical practitioners have traditionally relied on collagen and its analogue, gelatin, for treating tissue damage. However, the limited mechanical strength of these biopolymers restricts their direct use in various applications. This issue can be overcome by making hybrids of these biopolymers with nanocellulose. This review presents a comprehensive analysis of the recent and most relevant publications focusing on hybrid composites of collagen and gelatin with a specific emphasis on their combination with nanocellulose. While bone and skin tissue engineering represents two areas where a majority of researchers are concentrating their efforts, this review highlights the use of nanocellulose-based hybrids in these contexts.

Influence of vacancy defects on 2D BeN4monolayer for NH3adsorption: a density functional theory investigation.

Two-dimensional materials have attracted a great deal of interest in developing nanodevices for gas-sensing applications over the years. The 2D BeN4monolayer, a recently synthesized single-layered Dirac semimetal, has the potential to function as a gas sensor. This study analyzes the NH3sensing capacity of the pristine and vacancy-induced BeN4monolayers using first-principles density functional theory (DFT) calculations. As per the results, the NH3molecule is physisorbed on the pristine BeN4via weak Van der Waals interaction with a poor adsorption energy of -0.41 eV and negligible charge transfer. Introducing Be vacancy in BeN4increased the NH3adsorption energy to -0.83 eV due to the improved charge transfer (0.044 e) from the defective monolayer to the NH3molecule. The structural stability, sufficient recovery time (74 s) at room temperature, and superior work function sensitivity promise the potential application of defective BeN4as an NH3sensor. This research will be a theoretical groundwork for creating innovative BeN4-based NH3gas sensors.

Metal-decorated γ-graphyne as a drug transporting agent for the mercaptopurine chemotherapy drug: a DFT study.

In recent years, carbon-based two-dimensional (2D) materials have gained popularity as the carriers of various anticancer therapy drugs, which could reduce the crucial side effects by directly applying the drugs to the intended tumor cells. In this study, through first-principles density functional theory simulations, we have investigated the adsorption properties of a famous cancer chemotherapy drug called mercaptopurine (MC) on a 2D γ-graphyne (GYN) monolayer. Analyzing the geometric and electronic properties, we can summarize that the MC interaction with the pristine GYN is weak, with a small adsorption energy of -0.15 eV, which is too low for potential applications. Therefore, we have decorated the GYN monolayer with biocompatible metals such as Al, Ag, and Cu to trigger the adsorption capacity. The Al- and Cu-decorated GYN offered improved adsorption towards MC compared to the pristine case. The drug release from these metal-decorated systems was examined by creating an acidic environment. In addition, the desorption temperature of the drug from the system was also evaluated using ab initio molecular dynamics simulations. The calculations demonstrated that the Al-decorated GYN is a potential vehicle for MC drug delivery because of the favourable adsorption energy of -0.63 eV, charge transfer of 0.17e and desorption temperature above 270 K. The current research will stimulate the investigation of other low-dimensional carbon materials for drug-delivery applications.

Iron(II) Mediated Supramolecular Architectures with Schiff Bases and Their Spin-Crossover Properties.

Supramolecular architectures, which are formed through the combination of inorganic metal cations and organic ligands by self-assembly, are one of the techniques in modern chemical science. This kind of multi-nuclear system in various dimensionalities can be implemented in various applications such as sensing, storage/cargo, display and molecular switching. Iron(II) mediated spin-crossover (SCO) supramolecular architectures with Schiff bases have attracted the attention of many investigators due to their structural novelty as well as their potential application possibilities. In this paper, we review a number of supramolecular SCO architectures of iron(II) with Schiff base ligands exhibiting varying geometrical possibilities. The structural and SCO behavior of these complexes are also discussed in detail.

A Simplified Approach for the Aqueous Synthesis of Luminescent CdSe/ZnS Core/Shell Quantum Dots and Their Applications in Ultrasensitive Determination of the Biomarker 3-Nitro-l-tyrosine.

In contrast to the hot-injection organometallic routes, synthesizing stable and highly luminescent core/shell nanocrystals with encapsulation of biocompatible groups through an aqueous route is a long-standing challenge. In recent years, relatively high quantum efficiency and unique properties of core/shell nanostructured materials (quantum dots) have contributed toward enhancement in sensing capability. The present work reports a facile aqueous synthesis process of core/shell CdSe/ZnS quantum dots (QDs) with encapsulation of glutathione (GSH). The optimal conditions for the synthesis of the most stable particles were ascertained, and the different experimental analyses suggest that the stable core/shell QDs in question have good crystallinity with a size around 4.7 nm with a shell thickness of 0.7 nm and a photoluminescence quantum yield of about 35%. Further, it is demonstrated that the as-synthesized material has great potential in detecting as low as 0.28 nM 3-nitro-l-tyrosine (3-NT), an important marker for oxidative stress, the level of which in our body signals several chronically diseased conditions. The enthalpy-driven interactions of CdSe/ZnS-GSH QDs with 3-NT were characterized through steady-state and time-resolved luminescence spectroscopy and isothermal microcalorimetry. The devised method of probing 3-NT was further validated with human serum samples. Thus, the proposed strategy may provide a protocol for selective determination of 3-NT under different pathological conditions.

Fluorescence and Nonlinear Optical Response of Graphene Quantum Dots Produced by Pulsed Laser Irradiation in Toluene.

Graphene quantum dots (GQDs), the zero dimensional (0D) single nanostructures, have many exciting technological applications in diversified fields such as sensors, light emitting devices, bio imaging probes, solar cells, etc. They are emerging as a functional tool to modulate light by means of molecular engineering due to its merits, including relatively low extend of loss, large outstretch of spatial confinement and control via doping, size and shape. In this article, we present a one pot, facile and ecofriendly synthesis approach for fabricating GQDs via pulsed laser irradiation of an organic solvent (toluene) without any catalyst. It is a promising synthesis choice to prepare GQDs due to its fast production, lack of byproducts and further purification, as well as the control over the product by accurate tuning of laser parameters. In this work, the second (532 nm) and third harmonic (355 nm) wavelengths of a pulsed nanosecond Nd:YAG laser have been employed for the synthesis. It has been found that the obtained GQDs display fluorescence and is expected to have potential applications in optoelectronics and light-harvesting devices. In addition, nonlinear optical absorption of the prepared GQDs was measured using the open aperture z-scan technique (in the nanosecond regime). These GQDs exhibit excellent optical limiting properties, especially those synthesized at 532 nm wavelength.

Positron annihilation spectroscopic characterization of free-volume defects and their correlations with the mechanical and transport properties of SBR-PMMA interpenetrating polymer networks.

A series of interpenetrating polymer networks (IPNs) and semi-interpenetrating polymer networks (s-IPNs) of styrene butadiene rubber (SBR) and poly(methyl methacrylate) (PMMA) have been synthesized by adopting the sequential interpenetration and in situ polymerization method. The size and the concentration of free volume defects in these systems are monitored and their variations accurately traced using positron annihilation lifetime (PALS) and coincidence Doppler broadening spectroscopic (CDBS) measurements. The morphologies of the IPNs were analyzed with transmission electron microscopy (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). Confocal Raman mapping had been employed to elucidate the mechanism of PMMA interpenetration in the SBR matrix with reference to the blend ratio. The results of free volume analysis lead to the conclusion that the increase of PMMA content in IPN was accompanied by enhancement of interpenetration in the system. Also the morphology changes from dispersed island pattern to a co-continuous one. Besides, the transport parameters and mechanical behavior of IPNs were studied in detail. The results of PALS and CDBS measurements have found to exhibit striking correlations with the sorption, mechanical properties and morphology of the polymer networks. The specific physics involved in the characterization protocol is effectively utilized to explore the chemistry of IPN formation. This new modality of characterization versus composition uplifts and widens the application prospects of elastomer-thermoplastic IPNs.

Grape seed extract-soluplus dispersion and its antioxidant activity.

OBJECTIVE: The main objective of this work was to formulate a nanodispersion containing grape seed extract and analyzed its release profile, antioxidant potential of the prepared formulations. METHODS: The grape seed extract (GSE) containing proanthocyanidins (PC's) has been dispersed in polymer matrix soluplus (SOLU) by the freeze-drying method. The morphological analysis was carried out using atomic force microscopy (AFM), scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). The in-vitro release of the nanodispersion formulations was evaluated by simulated intestinal fluid (SIF). The antioxidant activity of GSE and the formulation were evaluated by employing various in-vitro assays such as 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), 2, 2-diphenyl-1- picrylhydrazyl (DPPH), Ferric reducing antioxidant power (FRAP) and peroxidation inhibiting activity. RESULTS: The formulation FIII (1:5) resulted in a stable formulation with a higher loading efficiency of 95.36%, a particle size of 69.90 nm, a polydispersity index of 0.154 and a zeta potential value of -82.10 mV. The antioxidant efficiency of GSE-SOLU evaluated by DPPH was found to be 96.7%. The ABTS and FRAP model exhibited a dose-dependent scavenging activity. Linoleic model of FIII formulation and GSE exhibited a 66.14 and 86.58% inhibition respectively at 200 µg/l. CONCLUSIONS: The main reason for excellent scavenging activity of the formulations can be attributed to the presence of monomeric, dimeric, oligomeric procyanidins and the phenolic group. The present work denotes that GSE constitutes a good source of PC's and will be useful in the prevention and treatment of free radical related diseases.

Structure and dynamics of gold nanoparticles decorated with chitosan-gentamicin conjugates: ReaxFF molecular dynamics simulations to disclose drug delivery.

With the aim of designing an efficient procedure for producing biocompatible drug delivery systems based on nanoparticle carriers for in situ controlled antibiotic release, we have defined a novel computational approach resorting to a reactive force field capable of realistically describing hybrid systems. The modeling procedure was focused on well-known components, namely gold nanoparticles, citrate, chitosan and gentamicin, and the experiments tuned on purpose. On the one hand, gold nanoparticles were synthesized, fuctionalized with chitosan, loaded with gentamicin and characterized by means of transmission electron microscopy (TEM), scanning electron microscopy (SEM), dynamic light scattering (DLS), UV-visible (UV-vis) spectroscopy, and Fourier transform infrared spectroscopy (FTIR). On the other hand, an effective model of a functionalized gold nanoparticle was created and its structure and dynamics were explored by classical reactive molecular dynamics simulations in solution based on the ReaxFF atomistic description. The structure, dynamics and drug release were reproduced realistically disclosing the motion of all the molecular components, their adsorption on the metal support, desorption, intermolecular interactions and self-assembly. The system size was very close to the experimental conditions and all the calculations could efficiently identify the most probable binding modes, the locations of the adsorbed molecules, the characteristic arrangements of the chains and the effects due to the surrounding environment. The role played by the substrate and water molecules in the releasing process was described in detail. In line with the literature it was found that the antibiotic activity was preserved and the drug release from the carrier could be tuned by changing the chitosan/getamicin weight ratio and the deposition pattern of the adsorbed layers.

Tuning of nonlinear absorption in highly luminescent CdSe based quantum dots with core-shell and core/multi-shell architectures.

We present our effort on an efficient way of tuning the nonlinear absorption mechanisms in ultra-small CdSe based quantum dots by implementing core-shell and core/multi-shell architectures. Depending on the size, architecture and composition of the QDs, these materials exhibited resonant and near-resonant nonlinear optical absorption properties such as saturable (SA) and reverse saturable (RSA) absorption for 5 ns pulses of 532 nm. These QDs exhibited a non-monotonic dependence of the effective two-photon absorption coefficient (ß) under nanosecond excitation with a maximum value for a thinner shell. We obtained a nonlinear absorption enhancement of an order of magnitude by adopting the core-shell architecture compared to their individual counterparts. Interestingly, CdSe QDs exhibit SA and/or RSA depending on their size and show a switching over from SA to RSA as the input intensity increases. We explained the enhanced nonlinear absorption in core-shell QDs compared to their individual counterparts in view of enhanced local fields associated with the core-shell structure. Thus, the present nanostructured materials are excellent candidates as saturable absorbers and optical limiters.

Magnetic performance and defect characterization studies of core-shell architectured MgFe2O4@BaTiO3 multiferroic nanostructures.

Multiferroics that permit manipulation of the magnetization vector exclusively by electric fields have spawned extensive interest for memory and logic device applications. In line with this understanding, we herein report the encapsulation of non-ferroelectric magnesium ferrite (MgFe2O4) nanoparticles in a ferroelectric shell of BaTiO3 to produce a system with engineered dielectric, magnetic, magneto-electric and ferroelectric properties. The interface effect on the strain transfer was observed to strongly influence the magneto-electric coupling and the electric and magnetic properties of the system. The model polyhedral image of MgFe2O4@BaTiO3 has helped to get an insight into the core-shell structure. The multiferroicity induced by the excellent coupling between the ferroelectric and magnetostrictive phases at the core-shell interface unlocks wide prospects for device downscaling and information storage applications. The influence of magnetostrictive stress on the magneto-electric coupling effects and domain dynamics was further studied using transmission electron microscopy (TEM) and atomic force microscopy images. Interestingly, the realization of a superparamagnetic multiferroic system has been a breakthrough and facilitates ultra high density magnetic data storage technologies. Evidence for spontaneous polarization and the ferroelectric trait exhibited by the multiferroic samples was revealed from the P-E hysteresis loop. The investigation of defect evolution in the system was carried out using positron annihilation lifetime spectroscopy (PALS) and coincidence Doppler broadening spectroscopy (CDBS) of annihilation radiation and the studies revealed thermal diffusion of positrons into the interfacial regions within the core-shell structure and the "formation and pick-off annihilation of orthopositronium atoms". It is concluded that interface engineering is a strong means for manipulation of the magnetic, dielectric and magneto-electric properties in multiferroic heterostructures for high density electrical energy and magnetic data storage.

Development of titanium dioxide nanowire incorporated poly(vinylidene fluoride-trifluoroethylene) scaffolds for bone tissue engineering applications.

Critical size bone defects that do not heal spontaneously are among the major reasons for the disability in majority of people with locomotor disabilities. Tissue engineering has become a promising approach for repairing such large tissue injuries including critical size bone defects. Three-dimension (3D) porous scaffolds based on piezoelectric polymers like poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) have received a lot of attention in bone tissue engineering due to their favorable osteogenic properties. Owing to the favourable redox properties, titanium dioxide (TiO2) nanostructures have gained a great deal of attention in bone tissue engineering. In this paper, tissue engineering scaffolds based on P(VDF-TrFE) loaded with TiO2 nanowires (TNW) were developed and evaluated for bone tissue engineering. Wet-chemical method was used for the synthesis of TNW. Obtained TNW were thoroughly characterized for the physicochemical and morphological properties using techniques such as X-Ray diffraction (XRD) analysis and transmission electron microscopy (TEM). Electrospinning was used to produce TNW incorporated P(VDF-TrFE) scaffolds. Developed scaffolds were characterized by state of art techniques such as Scanning Electron Microscopy (SEM), XRD and Differential scanning calorimetry (DSC) analyses. TEM analysis revealed that the obtained TiO2 nanostructures possess nanofibrous morphology with an average diameter of 26 ± 4 nm. Results of characterization of nanocomposite scaffolds confirmed the effective loading of TNW in P(VDF-TrFE) matrix. Fabricated P(VDF-TrFE)/TNW scaffolds possessed good mechanical strength and cytocompatibility. Osteoblast like cells showed higher adhesion and proliferation on the nanocomposite scaffolds. This investigation revealed that the developed P(VDF-TrFE) scaffolds containing TNW can be used as potential scaffolds for bone tissue engineering applications.

In Situ Synthesis of Silver Nanospheres, Nanocubes, and Nanowires over Boron-Doped Graphene Sheets for Surface-Enhanced Raman Scattering Application and Enzyme-Free Detection of Hydrogen Peroxide.

An effective in situ synthesis strategy is demonstrated for the preparation of silver nanostructures (nanospheres (NSs), nanocubes (NCs), and nanowires (NWs)) on the surface of boron-doped graphene (BG). Further, these functional nanomaterials are employed for the surface-enhanced Raman scattering (SERS) and non-enzymatic electrochemical detection of H2O2. The results confirm the superior performance of BG-Ag nanostructures as SERS platform. Among various geometries of silver nanoparticles studied in this work, we find that the AgNCs over BG (BG-AgNC) present outstanding SERS performance for detecting 4-mercaptobenzoic acid, with a limit of detection of 1.0 × 10-13 M. Furthermore, BG-AgNC exhibits excellent capability to detect melamine as low as 1.0 × 10-9 M. Electrochemical results confirm that the BG-AgNW-based platform exhibits a superior biosensing performance toward H2O2 detection. The enhanced performance is due to the presence of graphene, which improves the conductivity and provides more active sites. The synthesis of doped graphene with metallic nanoparticles described in this work is expected to be a key strategy for the development of an efficient SERS and electrochemical sensor that offers simplicity, cost-effectiveness, long-term stability, and better reproducibility.

Fracture resistant, antibiofilm adherent, self-assembled PMMA/ZnO nanoformulations for biomedical applications: physico-chemical and biological perspectives of nano reinforcement.

Antimicrobial, antibiofilm adherent, fracture resistant nano zinc oxide (ZnO NP) formulations based on poly methyl methacrylate (PMMA) matrix were developed using a facile ex situ compression moulding technique. These formulations demonstrated potent, long-term biofilm-resisting effects against Candida albicans (9000 CFU to 1000 CFU) and Streptococcus mutans. Proposed mechanism of biofilm resistance was the release of metallic ions/metal oxide by 'particle-corrosion'. MTT and cellular proliferation assays confirmed both qualitatively and quantitatively equal human skin fibroblast cell line proliferations (approximately 75%) on both PMMA/ZnO formulation and neat PMMA. Mechanical performance was evaluated over a range of filler loading, and theoretical models derived from Einstein, Guth, Thomas and Quemade were chosen to predict the modulus of the nanoformulations. All the models gave better fitting at lower filler content, which could be due to restricted mobility of the polymer chains by the constrained zone/interfacial rigid amorphous zone and also due to stress absorption by the highly energized NPs. Fracture mechanics were clearly described based on substantial experimental evidence surrounding crack prevention in the initial zones of fracture. Filler-polymer interactions at the morphological and structural levels were elucidated through FTIR, XRD, SEM, TEM and AFM analyses. Major clinical challenges in cancer patient rehabilitation and routine denture therapy are frequent breakage of the prostheses and microbial colonization on the prostheses/tissues. In the present study, we succeeded in developing an antimicrobial, mechanically improved fracture resistant, biocompatible nanoformulation in a facile manner without the bio-toxic effects of surface modifiers/functionalization. This PMMA/ZnO nanoformulation could serve as a cost effective breakthrough biomaterial in the field of prosthetic rehabilitation and local drug delivery scaffolds for abused tissues.

Electrospun polyvinyl alcohol membranes incorporated with green synthesized silver nanoparticles for wound dressing applications.

Electrospun membranes have the potential to act as an effective barrier for wounds from the external environment to prevent pathogens. In addition, materials with good antibacterial properties can effectively fight off the invading pathogens. In this paper, we report the development of a novel electrospun polyvinyl alcohol (PVA) membrane containing biosynthesized silver nanoparticle (bAg) for wound dressing applications. Plant extract from a medicinal plant Mimosa pudica was utilized for the synthesis of bAg. Synthesized bAg were characterized by Ultraviolet-Visible (UV) Spectroscopy and Fourier Transform Infrared Spectroscopy (FTIR). The morphology of bAg was obtained from Transmission Electron Microscopy (TEM) and found that they were spherical in morphology with average particle size 7.63 ± 1.2 nm. bAg nanoparticles incorporated PVA membranes were characterized using several physicochemical techniques such as Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS) and X-Ray Diffraction (XRD) analysis. Experimental results confirmed the successful incorporation of bAg in PVA fibers. PVA nanofiber membranes incorporated with bAg showed good mechanical strength, excellent exudate uptake capacity, antibacterial activity, blood compatibility and cytocompatibility.

Transport characteristics of organic solvents through carbon nanotube filled styrene butadiene rubber nanocomposites: the influence of rubber-filler interaction, the degree of reinforcement and morphology.

The transport behaviour of some aromatic and aliphatic solvents through carbon nanotube filled styrene butadiene rubber composites has been investigated. The aim of the present work is to investigate the role of the sorption technique in analysing the compatibility and the reinforcing effect of MWCNTs as a filler in the SBR matrix. It also focuses on the investigation of the relationship between the dispersion of CNTs in the SBR matrix and its transport behaviour. The diffusion and transport of organic solvents through the membranes have been investigated in detail as a function of CNT content, nature of solvent and temperature in the range of 28-60 °C. Solvent uptake, diffusion, sorption and permeation constants were investigated and were found to decrease with the increase of CNT loading. Transport properties could be related to the morphology of the nanocomposites. At high concentration CNT particles form a local filler-filler network in the rubber matrix. As a result, the transport of solvent molecules through the polymer is hindered. The rubber-solvent interaction parameter, enthalpy and entropy of sorption have also been estimated from the transport data. The values of rubber-solvent interaction parameters obtained from the diffusion experiments have been used to calculate the molecular mass between the crosslinks of the network polymer. The better reinforcement at higher filler loading was confirmed from the cross-link density values. The extent of reinforcement was evaluated using Kraus and Cunneen and Russel equations. The Affine and Phantom models for chemical crosslinks were used to predict the mobility of the crosslinks. The Phantom model gave better fitting indicating that the chains can move freely through one another, i.e. the junction points fluctuate over time around their mean position without any hindrance from the neighbouring molecule. The diffusivity datas of the systems have shown dependence on the temperature and microstructure of the nanocomposite. Finally, the diffusion data have been compared with theoretical predictions.

Exploring the Potential of Sustainable Biopolymers as a Shield against Electromagnetic Radiations.

The increasing demand for biodegradable and environmentally friendly materials is shifting the focus from traditional polymer composites to biocomposites in various applications, especially in electromagnetic shielding. Effective utilization of biopolymers demands improved properties and can be achieved to a certain extent by functionalization. Biopolymers such as cellulose, polylactic acid, and starch are some of the potential candidates for mitigating electromagnetic pollution in next-generation electronic devices because of their high aspect ratio, flexibility, light weight, high mechanical strength, thermal stability, and tunable microwave absorption to the electromagnetic interference (EMI) shielding composites. This Review provides an overview of the current advancements in EMI shielding materials and outlines recent research on EMI shielding composites that utilize various biodegradable polymer structures.

Aggregation induced emission "Turn on" ultra-low detection of anti-inflammatory drug flufenamic acid in human urine samples by carbon dots derived from bamboo stem waste.

Carbon dot-based fluorescence sensors have attracted research interest for the selective determination of anti-inflammatory drugs in biological fluids and environments. The overdose and accumulation of anti-inflammatory drugs in tissues can cause chronic side effects including abdominal pain, and renal damage. Herein, we report a new fluorescent probe, bamboo stem waste-derived carbon dots (BS-CDs) for highly sensitive detection of Flufenamic acid (FA), a hazardous anti-inflammatory drug. The UV-vis absorption spectra of BS-CDs show a redshifted absorption peak at 283 nm upon the addition of FA suggesting strong binding interaction between BS-CDs and FA molecule. The BS-CDs showed a fluorescence enhancement (∼2-fold) detection for FA (400 µM) in the linear concentration range (0.40 â†’ 0.65 µM) with a limit of detection (LoD; 17 nM) and binding constant (Ka = 1.33 × 10-3 M-1). The time-resolved fluorescence decay analysis showed that the average lifetime of BS-CDs has slightly changed (4.42 â†’ 4.67 ns) by the interaction with FA through the aggregation-induced emission (AIE) process. The interference, pH, and effect of time results suggest that BS-CDs are highly selective probes for FA detection and do not show any interference involvement during FA detection. The confirmation of the structure and morphology changes of BS-CDs after interaction with FA was carried out by XRD, FESEM, HRTEM, FTIR, and Raman spectroscopy. The practicability of the BS-CDs probe was proved by the detection of FA in human urine samples with recovery of 103-109 %. This suggests that the proposed BS-CDs-based 'turn-on' sensor could be used to determine the FA in biological fluids.