Current Materials Science - Volume 15, Issue 3, 2022

In this communication, we discuss the particular electronic and quantum properties from graphene and carbon allotropes to highly conjugated carbon chemical structures from recent research. Moreover, the chemical modifications of these types of materials were analyzed against the concept of their inert properties, thus identifying that their surfaces could be modified to incorporate different properties, functionalities, and couple electronic effects, among others. Their versatility has been shown based on simple chemical reactions in controlled and targeted conditions of synthesis. Variable designs could be tuned from proof of concepts to functional materials for targeted applications. In addition, a proof of concept was discussed for Electron Transfer (ET) applications to show their electronic properties. Finally, the use of highly conjugated chemical structures to higher hierarchical ordered carbon structures, carbon nanotubes, graphene and carbon allotropes in electron and opto-responsive metamaterials, has been analyzed. Thus, new insights into multi-modal characteristics of materials have been discussed.

Graphene as an organic material has attracted special attention due to its electronic and conductive properties. Moreover, its highly conjugated chemical structures and relatively easy modification have allowed varied design and control of targeted properties and applications. In addition, this nanomaterial with pseudo-electromagnetic fields has led to the emergence of photonics, electronics and quantum interactions with their surroundings, generating new properties of materials. This short review aims at discussing many of these studies of new materials based on graphene for light and electronic interactions, conductions and new modes of nonclassical light generation. These new materials and metamaterials are being developed. For this reason, some representative examples from research with potential applications have been shown and discussed, in addition to their incorporation in real advanced devices and miniaturized instrumentation. Accordingly, this special issue entitled “Design and Synthesis of Hybrid Graphene-based Metamaterials” is intended to review the state-of-the-art in this multidisciplinary field.

Background: Highly conjugated carbon-based molecules and nanostructures could show interesting quantum properties for different developments. Quantum emission, encryption, and participation in signal transmissions could contribute to new quantum and nanotechnology. Methods: Quantum properties were analyzed from experimental data recorded with different optical setup configurations and appropriate lasers. The data discussed were correlated and compared with calculations. Results: In this review, we discuss the quantum properties of graphene and its derivatives produced by their high electronic densities from highly organized carbon-based structures. We also evaluate their coupling properties by combining other nanomaterial sources with atomic compositions that generate different energy levels of quantized states. Quantum emissions, pseudoelectromagnetic field interactions, quantum interferences in Fermi and Landau levels, conduction bands, plasmonic interactions, opto-electronics, electron conductions, and transference implications are also analyzed. Conclusion: The coupling of quantum properties formed from the sub-atomic level towards the transference and transduction to larger scales beyond the nano- and microscale was reviewed. We refer to the future perspectives of the phenomena discussed and their potential applications.

This paper reviews proton-conducting polymer electrolytes comprising different polymers, salts, and acids. The ionic conductivity of plasticized polymer electrolytes has been found to increase with the addition of plasticizers due to the dissociation of ion aggregates or undissociated salt/acid present in the electrolytes, i.e., σ (plasticized polymer electrolytes) > σ (unplasticized polymer electrolytes). Proton-conducting nonaqueous nanocomposite plasticized polymer electrolytes containing poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP), polymethylmethacrylate (PMMA), polyethylene oxide (PEO) polymers; different ammonium salts and acids as proton conductors; ethylene carbonate (EC), propylene carbonate (PC), dimethylformamide (DMF), dimethylacetamide (DMA), dimethyl carbonate (DMC), diethyl carbonate (DEC) as plasticizers; fumed silica and alumina as nano-fillers have been discussed in details. Conductivity studies (effect of salt/acid, effect of plasticizers, effect of nano-fillers, and effect of temperature), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry/thermal gravimetric analysis (DSC/TGA) studies for these electrolytes have been discussed and reported in the paper. Nanocomposite plasticized polymer electrolytes showed high ionic conductivity (in the order of 10^-1 to 10^-2 S/cm) at room temperature along with good thermal and mechanical stability due to the simultaneous addition of both plasticizers and nano-fillers. These nanocomposite polymer electrolytes are the best candidates for use in various electrochemical devices like solid-state batteries, fuel cells, supercapacitors, sensors, separators, and other electrochromic devices.

Background: In the field of crystal engineering, cocrystallization is a unique technique by the help of which physicochemical properties like melting point, solubility, dissolution, etc of the APIs can be modified without changing the intrinsic structure of APIs. Objective: Crystal packing of a solid is modified by crystal engineering techniques which involve modification of intermolecular interactions that help to regulate breaking and creation of noncovalent bonds. Non-covalent interactions such as hydrogen bonding, van der Waals forces, π-π stacking are primarily responsible for the formation of cocrystals. Cocrystals are solid crystalline materials consisting of two or more molecules present in the similar crystal lattice. It is a method of formation of mainly hydrogen bonds between the drug molecule and coformer. This technique can be applied to almost all APIs which have low aqueous solubility. There are several active pharmaceutical ingredients available, which have therapeutic efficacy against several lifethreatening diseases. Among those APIs, which have poor aqueous solubility and low oral bioavailability (BCS class II and class IViv), cannot be efficiently developed into a suitable dosage form. Conclusion: Therefore, this survey gives a united record of the reasoning for plan of cocrystals, past endeavors, later improvements and future viewpoints for cocrystallization research which will be incredibly helpful for the formulation scientists of the pharmaceutical industry.

Background: Fe 3sXPS spectrum exhibits doublet peak instead of predicted singlet peak based on spin-orbit coupling theory. This anomalous behavior is considered to be of magnetic origin. However, the effect of residual magnetic moment on the features of Fe3s doublet peak is not understood fully. Objective: This study aims to verify the effect of residual magnetic moment on the spectral features of Fe3s XPS spectrum of magnetic material. Methods: As a case study, we have carried out a high-temperature XPS study of the Fe 3s spectrum of magnetic domain aligned (MDA) sample with composition composed of SrFe10.8Al1.2O19. In addition, the XPS data have been compared with the data acquired at different temperatures of magnetic domain non-aligned (MDNA) sample. Results: The results show that the majority peak intensity and minority peak width of Fe 3s spectrum of MDA are smaller than those of the MDNA sample, and they increase systematically with increasing temperature. However, it is noted that the features of Fe3s spectrum of both MDA and MDNA samples completely overlap near and above the Curie temperature, Tc ~ 670K. Discussion: The residual magnetic flux in the MDA sample alters the interaction between 3s electrons and valence 3d spin. In addition, the presence of residual magnetic moment leads to deviation of the escaped electrons from their path, therefore the majority peak intensity of MDA sample becomes smaller than the MDNA sample at below the Curie temperature. Consequently, the spectral features of MDA samples are different than the MDNA samples at below the Curie temperature. Conclusion: The analysis of XPS data suggests that the residual magnetic moment influences the spectral features of the Fe3s spectrum. These results provide evidence that it is important to consider the contribution of the residual magnetic moment while deriving information from the Fe 3s XPS spectrum of the MDA sample.

Background: Porous scaffolds composed of poly (vinyl alcohol)/Biphasic calcium phosphate (PVA/BCP) were prepared for bone tissue engineering. The effect of BCP was investigated on the morphology of pores, porosity, compression strength, swelling ratio, biodegradation, bioactivity, and in vivo blood count. Objective: the aim of the article is to prepare a porous scaffold with good mechanical properties and suitable for the living body by having biodegradable, bioactive, and biocompatible properties. Methods: The scaffold of PVA foam was prepared using 4g of PVA (Central Drug House, M.W. 13000-23000, Viscosity 3.5-4.5, Hydrolysis 87-89%, PH 4.5-6.5, India) dissolved in 24 ml distilled water with stirrer for 5 minutes. The biphasic-calcium phosphate (BCP) (Ying Tong Chem and Tech, LTD, Density 3.14 g/cm3, China) was added to the solution with heat stirring for 5 minutes with a ratio of 0, 0.05, 0.1 and 0.25 with respect to the weight of PVA. The sulfuric acid (Central Drug House, M.W. 98.08, India) of (8 ml) was added drop by drop using a catalyzer. The citric acid (Central Drug House, M.W. 192.13, India) was added to the mixture with 24g to create esterification bonding. Results: The results showed that the scaffold using BCP had uniform pore size distribution, suitable porosity up to 67%, and showed high swelling ratio. The scaffolds were of biodegradable nature and almost degraded by about 37.5% in four weeks. The scaffold was biologically active in terms of the presence of calcium phosphate in the hydroxyapatite phase as in bone. The in vivo biocompatibility of the PVA/BCP scaffold was tested by comparing the blood count with the normal range of blood in rabbits. After 14 days, the Blood Urea, Creatinine, A total of Bilirubin, and Lymphocytes were higher than the control. Conclusion: The addition of BCP powder has a positive effect on porosity and pore size. The compression strength value increased significantly with the use of BCP from 2.12 to 5.29 MPa. The scaffolds show good biodegradation and well bioactivity. The culture of the biomaterial caused toxicity or an acute inflammatory response, as the blood test results showed that there was infiltration of polymorphous leukocytes, lymphocytes, macrophages, and fibroblasts.

Background: Tubular reactors have wide applications in various industries, namely, ammonia synthesis, oil cracking, gasoline production, and sulfur dioxide oxidation to sulfur trioxide. The most common reactor is the tubular flow reactor. This article aims to study the variation of outlet concentration and temperature on different parameters, like Reynolds number, Prandtl number, and Peclet number, which determine the performance and conversion of reactants. This article shows the temperature and concentration profiles of various parameters. Methods: In the analysis of the first part of the article, a different governing equation of a nonisothermal tubular flow reactor has been described. The non-dimensionless form of the governing equations has been derived by applying different boundary conditions. COMSOL Multiphysics software was used (version -5.6) to solve the coupled governing equations (non-linear PDE). Results: The plots of various parameters like Reynolds number, Prandtl number with outlet temperature, and conversion have been shown. The temperature and concentration profile for certain conditions are also shown. Conclusion: The variation of parameters shows how strongly they depend on the net conversion of reaction. The thermal effects should be taken care of as the heat of the reaction is very sensitive to converting and forwarding the reaction. Proper temperatures must be maintained for highly exothermic reactions; a real-life process is Haber’s process of ammonia production.