Development of a rapid and sensitive detection method for hazardous dyes attracts considerable research interest. In this work, L-Tryptophan-based Carbon dots were developed as a fluorescence sensor for the detection of Malachite green (MG). Green fluorescent L-Trp-C-dots were synthesized by a simple pyrolysis technique using L-Trp as the starting precursor. L-Trp-C-dots exhibited different quenching responses to MG, and other interfering species, consequently offering a selective strategy to detect MG. The proposed sensor shows a limit of detection (LOD) of 0.06 μM and a limit of quantification (LOQ) of 0.22 μM with in the linearity range of 0 to 60 µM concentration. Additionally, the relative standard deviation (RSD) was found to be below 1.7 %. Furthermore, the recovery of MG from the real-time samples (green peas) was investigated.

The structural, thermal and surface-wetting properties of epoxy resin/multiwalled carbon nanotubes (EP/MWCNTs) composites were studied by preparing nanocomposites by the physical mixing assisted by ultrasonication. The materials were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The contact angles of water droplets formed on the sample surfaces were measured to study their surface-wetting properties. FTIR showed the successful cross-linking of the EP matrix and good interaction between MWCNT and epoxy matrix in the nanocomposites. XRD attested that the incorporation of MWCNT in the EP did not influence the nature of the physical and chemical structures of the matrix polymer. Based on TGA results, the composites with chemically modified nanotubes were found to possess slightly higher thermostability than the analogous materials fabricated with the neat MWCNTs. Further, the EP/pristine MWCNT composites exhibited hydrophobic behavior while the EP/chemically modified MWCNT composites were comparatively hydrophilic which is attributed to the introduction of carboxyl groups during the chemical treatment of the nanotubes with strong acid.

Polymeric nanocomposites based on nanoclay are extensively utilized in various structural applications. In this work, the effect of organically modified nanoclay (cloisite 20A) on the chain confinement, mechanics, structure, and thermal properties of epoxy resin cured with diamino diphenyl sulphone (DDS) was analysed. The viscoelastic properties were analysed by dynamic mechanical analysis (DMA). The stiffness parameter and the peak parameters from loss modulus and tan delta indicate effective adhesion of nanoclay with the polymer matrix. The filler-matrix confinement has created a constrained zone around the polymer-matrix interface resulting in the immobilization of polymer chains near the fillers. The chain confinement was determined from tan delta curve. The heterogeneity of the cloisite 20A/epoxy nanocomposites was analysed by Cole-Cole plots. Fine dispersion of cloisite 20A was achieved by intercalation of nanoclay as observed by transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis. Finally, the thermal properties of the nanocomposites were analysed by thermogravimetric analysis (TGA).

Reaction induced phase separation is a characteristic of thermoset/thermoplastic blend systems.

This article focuses on the investigations on mechanical and thermal properties of the epoxy/poly(styrene-co-acrylonitrile) (SAN)/cloisite 20A nanocomposites. The analysis is performed in two particular compositions of epoxy/SAN blends to study the effect of nanoclay addition. The compositions of blends, epoxy/5 phr SAN and epoxy/15 phr SAN, are selected based on the difference in phase separation mechanism and microstructure. An increment in tensile strength is observed for epoxy/5 phr SAN/1 wt% cloisite 20A nanocomposite. Young's modulus is increased in epoxy/15 phr SAN/cloisite 20A nanocomposites. A surge in the toughness and impact properties is observed for the nanocomposites. Beneficial increment in activation energy for thermal degradation is observed for epoxy/SAN blends and epoxy/SAN/cloisite 20A nanocomposites. The nanocomposites are suitable for high temperature applications without much compromise in the mechanical properties.

Unique airborne observations of aerosol size spectral and chemical characteristics over the peninsular Indian region are illustrated in this case study. Multimodal lognormal distributions were required to fit the observed in situ aerosol size distribution. The aerosol composition and mixing state was deduced from the single-particle analyses of aerosols using the transmission electron microscope and soot photometer coupled with satellite retrieved aerosol classification, and back trajectory analyses. Organic carbon was the most prominent aerosol type found at all altitudes. Refractory black carbon aerosols which constituted about 10-12% of the aerosols in the boundary layer were primarily internally mixed with both inorganic and organic coating. Other major aerosol types were dust and sea salt, with the latter primarily found below 2 km. Further, the cloud forming ability of in-situ aerosols is tested through a cloud condensation nuclei closure analysis. The effective hygroscopicity decreased above cloud base due to the absence of sea salt aerosols. The change in large-scale winds with altitude affected the aerosol composition and hygroscopicity. The multimodal aerosol size distribution and hygroscopicity parameter (Kappa = 0.18) obtained for the cloud base aerosols over the rain shadow region are useful for studying aerosol-cloud interactions using regional cloud-resolving models.

In situ measurements of aerosol particle chemistry and cloud microphysics made during the Cloud–Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX) in 2015 over the Western Ghats and its rain shadow region are presented in this study. The high ratio of cloud condensation nuclei (CCN) to large sized aerosol (above 0.1 µm) concentrations indicates Aitken mode aerosols as the major contributor towards the observed CCN. Morphology and chemical composition of airborne aerosol samples collected from different altitudes and the warm cloud layers indicated distinct particle chemistry on the dry and wet days. The majority of the particles sampled were heterogeneous and internally mixed with two or more aerosol species indicating multiple sources and atmospheric aging, even during the wet days. Si-rich particles (up to 73%) were the dominant species in samples collected during dry days when the shallow clouds with narrow drop size distribution were observed. A higher concentration of Na-rich particles (up to 50%) was observed on wet days when the clouds were majorly multiple layers of stratus, which had broader cloud droplet spectra. Internally mixed carbonaceous and iron/cobalt-rich aerosols from local pollution sources were found on both wet and dry days suggesting boundary layer venting of aerosols. Large droplets were observed near the cloud base over the Western Ghats compared to those formed over the rain shadow region.

The ability of polymeric systems to mimic self-healable biological systems can be traced back to the early 1980s. This chapter focuses on the basic fundamentals of self-healing polymeric systems. The important milestones of developing polymeric smart systems with self-healing ability are reviewed. Among these, various polymeric systems such as elastomers, thermoplastics, thermosets, and supramolecular polymeric systems have gained considerable significance in various applications such as structural components, coatings, and various other applications. Discussing of both chemical and nonchemical self-mendable polymeric systems, the recent reports in their related fields are also emphasized. The future perspectives and challenges toward designing self-mendable polymeric systems have serious implications on material safety, performance, and life time.

The viscoelastic effects during reaction induced phase separation play an important role in toughening epoxy-based blends. The large difference in molecular weight/glass transition temperature between the blend components before the curing reaction results in dynamic asymmetry, causing viscoelastic effects during phase separation accompanying the curing reaction. This review will focus on the key factors responsible for viscoelastic phase separation in epoxy-based blends and hybrid nanocomposites. Time-resolved characterization techniques such as rheometry, small angle laser light scattering, optical microscopy etc., are mainly used for monitoring the viscoelastic effects during phase separation. Incorporation of nanofillers in epoxy thermoplastic blends enhances the viscoelastic phase separation due to the increase in dynamic asymmetry. Different theoretical models are identified for the determination of processing parameters such as temperature, viscosity, phase domain size, and other parameters during the viscoelastic phase separation process. The effect of viscoelastic phase separation has a very strong influence on the domain parameters of the blends and thereby on the ultimate properties and applications.

Unique airborne observations made congruent to 330 km south of Mt. Everest during the Cloud-Aerosol Interaction Precipitation Enhancement EXperiment (CAIPEEX) 2014 are presented in this case study. These observations provide the vertical profile and elemental composition of aerosols from single particle analysis during the break period. An "aerosol dome" was also documented from the horizontal transect across the Varanasi city. The boundary layer was dominated by light scattering fine mode aerosols mainly a mixture of dust and pollution. The individual particle characterization revealed complex mixing states within the same aerosol aggregate. Externally mixed aerosols were present at the cloud bases. Elemental composition of aerosol particles collected from free atmosphere contained signatures of aged pollution with heavy metals, carbonaceous particles and radioactive elements. Cloud processed aerosols were also noted in the neighborhood of deep convective clouds. Shallow and deep cumulus clouds developing in the haze layer revealed distinct dropsize distributions. Shallow cumulus clouds embedded in the haze layer showed narrow droplet size distribution and were narrower than the ones observed for premonsoon conditions. Deep cumulus tops in the neighborhood of rapidly developing convection showed broad, bimodal droplet size distribution attributing to droplet evaporation and entrainment effects. Aerosol sampling near these cloud tops showed aggregates of particles that are internally mixed.

The amount of crystallinity and non-isothermal crystallization kinetics of shellac have been studied using differential scanning calorimetry and X-ray diffraction, respectively. High-resolution transmission electron microscope has been used to obtain the particle size and distribution. Fourier transform infrared spectroscopy is used to determine chemical compositions of shellac. Polarized optical microscopy images have been used to see the growth of spherulites at different temperatures. Two-step crystallizations (C1 and C2) were observed for shellac. Both modified Avrami and combined Avrami–Ozawa model have been applied to determine the parameters for crystallization kinetics of shellac. Different cooling rates ranging from 5 to 15 °C min−1 have been used to study the non-isothermal kinetics of shellac. The Avrami exponents for the two crystallizations are determined from the modified Avrami analysis. The values of these exponents are in the range of 2.29–2.54 for both the crystallizations C1 and C2. The rate of crystallization for C1 is greater than that for C2 as observed from modified Avrami and combined Avrami–Ozawa method.

This paper investigates the correlation of morphologies with mechanical and dielectric properties of plasticized poly vinyl chloride/MWCNT (PPVCN) nanocomposites. Special focus is given to filler induced networking and its effect on the dielectric properties of nanocomposites. Mechanical properties with different MWCNT loadings from 0.25% to 5% are correlated with fracture morphologies to understand the fracture mechanism and factors influencing the mechanical properties of the nanocomposites. At 5% MWCNT loading, the nanocomposite shows improvement in strength with exceptional enhancement in modulus. The best mechanical properties of the nanocomposite at 5% MWCNT loading is supported by morphological features, such as matrix cracks and crack bridging by MWCNTs. These features also supported the enhancement in toughness of the nanocomposite imparted by better polymer/MWCNT interfacial interactions. The dielectric properties of nanocomposites increase with increasing MWCNT loading. The nanocomposite with 5% MWCNT loading shows a six times high filler contribution factor when the system reaches its percolation limit. This supports the idea that polymer bridged MWCNT network formation has a pronouncing effect on the permittivity of the nanocomposites. PPVCN nanocomposite with 5% MWCNT loading exhibits the best mechanical and dielectric properties.

Polyurethane/graphene nanocomposites were synthesized using commercial thermoplastic polyurethane (TPU, Apilon 52DE55), and two types of graphene derivatives: graphene nanoplatelets (GNP) and reduced graphene oxide (RGO). Fourier Transformation Infrared Spectroscopy Fourier Transformation Infrared Spectroscopy (FTIR) spectroscopy, TEM, and SEM microscopy and XRD techniques were used to chemically and structurally characterize GNP and RGO nanofillers. The properties of the new TPU nanocomposite materials were studied using thermal analysis techniques (Dynamical Mechanical Analysis (DMA), Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TG)) to describe the influence of graphene nanofillers on polyurethane matrix. Our investigation describes the comparison of two types of graphene derivatives, commercial one (GNP) and synthesized (RGO) on thermoplastic polyurethanes. These nanofillers provides opportunities to achieve compatibility with the TPU matrix. The property enhancements are attributed commonly to high aspect ratio of graphene nanoplatelets and filler–polymer interactions at the interface. The obtained nanocomposites exhibit higher thermal and mechanical properties due to the good dispersion of both nanofillers into TPU matrix. It was found that the addition of 2 wt % of the nanofiller could lead to a significant reinforcement effect on the TPU matrix. Also, with high content of nanofiller (GNP and RGO), the Payne effect was observed.

In the present work, optimised polyaniline–cadmium ferrite (PANI–CdFe2O4) composite was prepared by chemical polymerization method. Comparative structural and morphological studies of PANI, CdFe2O4 and the composite were carried out by Fourier transform infrared spectroscopy, X-ray diffraction study and scanning electron microscopy. Highly crystalline nature of the composite composed of nanosized particles was confirmed by transmission electron microscopy studies. The dielectric loss tangent at room temperature for PANI, CdFe2O4 and the composite were investigated in the frequency range 50 Hz–5 MHz. The Maxwell–Wagner type polarisation in PANI and CdFe2O4 was confirmed by the decrease in their dielectric loss tangents with increasing frequency. But for the composite, a loss tangent peak due to relaxation losses implying resonance between hopping frequency of charge carriers and applied alternating current electric field was obtained. Debye type single relaxation in PANI and the distribution of relaxation in the composite were confirmed by their respective complex plane impedance plots and the plots simulated, equivalent RC network predicted and numerical values of R and C determined.

Electrospun battery separators have drawn considerable attention due to their high porosity, surface area, and electrochemical performance.

The effect of cloisite 20A clay on rheology and dynamic mechanical properties of epoxy and poly-(styrene-co-acrylonitrile) (SAN) blend system cured with diamino-diphenyl sulphone (DDS) was investigated. The effect of modified clay (cloisite 20A) on two different compositions of initially miscible epoxy/SAN system has been investigated based on the differences in the mechanism of phase separation during curing. The dynamics of phase separation was followed by optical microscopy coupled with a heating stage. The developed microstructures obtained after complete curing were examined by scanning electron microscopy (SEM) after preferential etching of SAN phase with dichloroethane. The processing parameters occurring during the curing reaction was analyzed by dynamic in-situ rheometry. The viscoelastic properties of fully cured blends and composites were further determined by dynamic mechanical analysis (DMA). Localization of filler among the blend phases was established from dynamic mechanical analysis.

Graphene and derived materials have recently emerged as a new promising class of materials featuring unique electrical, mechanical, magnetic and thermal properties. Electrochemical energy conversion and storage devices, in particular supercapacitors and Li-ion batteries, are widely regarded as one of main areas where graphene related materials may find application. The present work describes synthesis and structural properties of reduced graphene oxide (rGO) and rGO/Fe3O4. These materials are subsequently tested in symmetrical capacitors and hybrid capacitors with alkaline electrolyte as well as in a conventional Li-ion cell setup. It is demonstrated that certain electrochemical devices can clearly benefit form graphene materials in terms of power capability. On the other hand, particle agglomeration and increased reactivity hinders making full usage of the graphene capability.