Investigating the thermo-physical properties of a new kind of graphitic carbon nitride included ternary hybrid nanofluids and the property correlations.

In this work, a simple and facile approach was employed for the preparation of the ternary hybrids comprising of titanium dioxide, zinc oxide and graphitic nitride (designated as TZG-TH) with varying compositions of the components. In the context of complex and multi-stages involved for preparation of many of the THs in the literature, the present work uses the much simpler mythology for the preparation of TH. Nanofluids (NF) were formulated in ethylene glycol: water base fluid using TZG TH as the solid particles. Scanning electron microscope of TZG TH informs that the particles are agglomerated. High resolution transmission electron microscopy image of TZG-TH reveals the presence narrowly distributed spherical particles (having the sizes in the range 40 nm-100 nm) in sheet like structure The core level X-ray photoelectron spectrum of carbon and nitrogen elements reveal the existence of sp2 -bonded C in the C[bond, double bond]N and pyridinic and graphitic nitrogen in TZG-TH. X-ray diffraction patterns of TZG TH show the existence of anatase and hexagonal phase wurtzite crystalline structure in TH. The thermo-physical properties were determined for of the THNFs in order to elucidate the influence of compositions of the component and concentration ofof TZG-TH on the thermophysical properties. The TZG TH containing larger proportions of ZnO showed the maximum of 9.11 % and 12.1 % higher increase in viscosity than the binary and base fluid, respectively. The density of TZG THs varies from 1.079 to 1.095 cp, which is closer to the base fluid. The influence of TZG TH composition on refractive index and ultrasonic velocity indicates the existence of molecular level interactions between the nanoparticles in the TH and base fluid. The ∼210 % thermal conductivity enhancement was witnessed for the TZG TH, which is significantly higher than that of ZnO mono NF (26.9%) and TiO2 mono NF (33.0%). The influence of composition and concentration of TZG- TH on molecular interaction parameters like adiabatic compressibility, intermolecular free length, free volume, internal pressure and specific acoustic impedance are reported. The TZG TH based NF showed adequate dispersion stability as inferred from dynamic light scattering and UV-visible spectroscopy results. The results on TZG TH included THNF are new to the literature and would be helpful in exploring multifunctional properties with heat transfer capabilities for applications.

Studies on the Functional Properties of Titanium Dioxide Nanoparticles Distributed in Silyl-Alkyl Bridged Polyaniline-Based Nanofluids.

In the present work, a new kind of nanocomposite (NC)-based solid component was prepared for formulating nanofluids (NFs). The NC comprised metal oxide (titanium dioxide, TiO2) dispersed in a conducting polymer with polyaniline (PANI) and chemically linked silyl-alkyl units in it (PSA) that were designated as T-PSA NC. The NFs with ethylene glycol (EG) as a base fluid were prepared with T-PSA NCs with various compositions of TiO2 and PSA as well for various concentrations of T-PSA NCs. The scanning electron microscopic evaluation of the NC revealed that PSA deposition on TiO2 nanoparticles (NPs) decreased particle agglomeration. The PSA coating on the TiO2 NPs did not influence the crystalline structure of the TiO2 NPs, according to the X-ray diffraction patterns. The thermophysical characterization and molecular interaction features of the NFs at 303 K including a novel inorganic-organic T-PSA NC, were detailed. Furthermore, the stability of the T-PSA NC-based NFs was investigated experimentally using the zeta potential, and the particle size distribution change was analyzed using the dynamic light scattering (DLS) method. The T-PSA NCs had particle sizes that were significantly bigger than pristine PSA and pure TiO2. Most of the preparation conditions used to produce the T-PSA NCs resulted in moderately stable suspensions in EG. The results revealed that the ultrasonic velocity increased with the increase in the concentration of T-PSA NC mass % in the NFs, the refractive index and thermal conductivity increased with the increase in the concentration, and the surface tension exhibited a linear change when the ratio of mass % concentration of the T-PSA NCs increased. The combined presence of components that synergistically contribute to the electro, thermal, optical, and rheological properties is expected to attract advanced applications for NFs.

Polyethylene Glycol Coated Magnetic Nanoparticles: Hybrid Nanofluid Formulation, Properties and Drug Delivery Prospects.

Magnetic nanoparticles (MNPs) are widely used materials for biomedical applications owing to their intriguing chemical, biological and magnetic properties. The evolution of MNP based biomedical applications (such as hyperthermia treatment and drug delivery) could be advanced using magnetic nanofluids (MNFs) designed with a biocompatible surface coating strategy. This study presents the first report on the drug loading/release capability of MNF formulated with methoxy polyethylene glycol (referred to as PEG) coated MNP in aqueous (phosphate buffer) fluid. We have selected MNPs (NiFe2O4, CoFe2O4 and Fe3O4) coated with PEG for MNF formulation and evaluated the loading/release efficacy of doxorubicin (DOX), an anticancer drug. We have presented in detail the drug loading capacity and the time-dependent cumulative drug release of DOX from PEG-coated MNPs based MNFs. Specifically, we have selected three different MNPs (NiFe2O4, CoFe2O4 and Fe3O4) coated with PEG for the MNFs and compared their variance in the loading/release efficacy of DOX, through experimental results fitting into mathematical models. DOX loading takes the order in the MNFs as CoFe2O4 > NiFe2O4 > Fe3O4. Various drug release models were suggested and evaluated for the individual MNP based NFs. While the non-Fickian diffusion (anomalous) model fits for DOX release from PEG coated CoFe2O4, PEG coated NiFe2O4 NF follows zero-order kinetics with a slow drug release rate of 1.33% of DOX per minute. On the other hand, PEG coated NiFe2O4 follows zero-order DOX release. Besides, several thermophysical properties and magnetic susceptibility of the MNFs of different concentrations have been studied by dispersing the MNPs (NiFe2O4, CoFe2O4 and Fe3O4) in the base fluid at 300 K under ultrasonication. This report on the DOX loading/release capability of MNF will set a new paradigm in view that MNF can resolve problems related to the self-heating of drug carriers during mild laser treatment with its thermal conducting properties.