Carbon nanotubes (CNTs) hold the promise of delivering exceptional mechanical properties and multi-functional characteristics. Ever-increasing interest in applying CNTs in many different fields has led to continued efforts to develop dispersion and functionalization techniques. To employ CNTs as effective reinforcement in polymer nanocomposites, proper dispersion and appropriate interfacial adhesion between the CNTs and polymer matrix have to be guaranteed. This paper reviews the current understanding of CNTs and CNT/polymer nanocomposites with two particular topics: (i) the principles and techniques for CNT dispersion and functionalization and (ii) the effects of CNT dispersion and functionalization on the properties of CNT/polymer nanocomposites. The fabrication techniques and potential applications of CNT/polymer nanocomposites are also highlighted.

Dispersion and functionalization of carbon nanotubes for polymer-based nanocomposites: a review

Carbon nanotube–polymer composites: Chemistry, processing, mechanical and electrical properties

Green synthesis of metal nanoparticles using plants

Thermal conductivity of carbon nanotubes and their polymer nanocomposites: A review

Nanomaterials (NMs) have gained prominence in technological advancements due to their tunable physical, chemical and biological properties with enhanced performance over their bulk counterparts. NMs are categorized depending on their size, composition, shape, and origin. The ability to predict the unique properties of NMs increases the value of each classification. Due to increased growth of production of NMs and their industrial applications, issues relating to toxicity are inevitable. The aim of this review is to compare synthetic (engineered) and naturally occurring nanoparticles (NPs) and nanostructured materials (NSMs) to identify their nanoscale properties and to define the specific knowledge gaps related to the risk assessment of NPs and NSMs in the environment. The review presents an overview of the history and classifications of NMs and gives an overview of the various sources of NPs and NSMs, from natural to synthetic, and their toxic effects towards mammalian cells and tissue. Additionally, the types of toxic reactions associated with NPs and NSMs and the regulations implemented by different countries to reduce the associated risks are also discussed.

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Review on nanoparticles and nanostructured materials: history, sources, toxicity and regulations.

Continuous flow scale-up of biofunctionalized defective ZnO quantum dots: A safer inorganic ingredient for skin UV protection.

In this work, lead-free Na0.4Bi0.5 TiO3-K0.1Bi0.5TiO3 (NKBT) piezoelectric ceramics were prepared by the solid-state reaction method and their structural, ferroelectric and dielectric properties were systematically studied. NKBT sintered at 1150℃ for 4 h exhibited highly dense (96% - 98% of the theoretical density) and uniform grains of size 1.1 μm. The coexistence of tetragonal (P4bm) and rhombohedral (R3c) phases due to the presence of morphotrophic phase boundary for the chosen composition has been confirmed by the Rietveld refinement studies. Enhanced ferroelectric properties such as remnant polarization (Pr) and coercive field (EC) are found to be 37 μC/cm2 and 30 kV/cm, respectively. The optimized synthesis procedure for NKBT ceramics resulted in enhanced strain (%) and converse piezoelectric coefficient (d33*) of 0.3 % and 554 pm/V which is attributed to smaller grain size and switching of non 180o domains. NKBT ceramics with such excellent piezoelectric properties can be considered as a promising candidate for actuator applications.

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Enhanced Ferroelectric and Converse Piezoelectric Properties of Dense Lead-Free Na 0.4 K 0.1 Bi 0.5 TiO 3 Ceramics for Actuator Applications

Conductivity relaxation in phosphazene based polymer electrolytes

Potassium sodium niobate (KNN) ceramics were prepared by solid state synthesis followed by liquid phase sintering using V2O5 as a sintering aid. Sintering at 1120 oC for 4 hours using V2O5 caused significant improvement in relative density with maximum relative density reaching to more than 94%. Dense polycrystalline ceramics having grain size about 2 µm were obtained as a result of liquid phase sintering. Gradual improvement in dielectric constant was observed with increase in V2O5 content coupled with increase in electrical conductivity. Maximum remnant polarization of 18 µC/cm2 was recorded for ceramic sintered with 5 wt% V2O5.

Effect of addition of V2O5 on the densification, dielectric and ferroelectric behavior of lead free potassium sodium niobate ceramics

Lead free perovskite Ba(La1/2Nb1/2)O3 was prepared by conventional ceramic fabrication technique at 1375°C for 7 h in air atmosphere. The crystal symmetry, space group and unit cell dimensions were estimated using Rietveld analysis. X-ray diffraction analysis indicated the formation of a single phase monoclinic structure with space group P2/m. Energy dispersive X-ray analysis and scanning electron microscopy studies were carried to study the quality and purity of the compound. Permittivity data showed low temperature coefficient of capacitance (T CC = 11%) up to 100°C. The circuit model fittings were carried out using the impedance data to find the correlation between the response of real system and idealised model electrical circuit. Complex impedance analyses suggested the dielectric relaxation to be of non-Debye type. The correlated barrier hopping model was employed to successfully explain the mechanism of charge transport in Ba(La1/2Nb1/2)O3. The AC conductivity data were used to ev...

Ajit R. Kulkarni

Papers

Continuous flow scale-up of biofunctionalized defective ZnO quantum dots: A safer inorganic ingredient for skin UV protection.

Enhanced Ferroelectric and Converse Piezoelectric Properties of Dense Lead-Free Na 0.4 K 0.1 Bi 0.5 TiO 3 Ceramics for Actuator Applications

Conductivity relaxation in phosphazene based polymer electrolytes

Effect of addition of V2O5 on the densification, dielectric and ferroelectric behavior of lead free potassium sodium niobate ceramics

Structural and electrical properties of lead free ceramic: Ba(La1/2Nb1/2)O3