Proceedings, 2019, IOCN 2018

Synthesis of nanostructured materials is not straightforward, which involves the complicated use of surfactant templates. Currently, only non-renewable resources that are hazardous and toxic are used to produce the surfactant templates in the industries. This study presents an environmentally friendly and efficient route for the synthesis of the nanostructure of both silica and hematite using rice starch as a promising biomaterials template. The rice starch-templated synthesis yield both hematite and silica with nano-size and high surface area. In particular, the nanostructured silica showed a pseudo-spherical morphology with a nano-size from 13 to 22 nm, amorphous structure and surface area of 538.74 m²/g. On the other hand, the nanostructured hematite showed a spherical-shaped morphology with a nano-size from 24 to 48 nm, and surface area of 20.04 m²/g. More importantly, the use of rice starch-template for a greener approach in the synthesis of nanomaterials was successfully outlined. Full article

Recent studies have expanded our understanding of the effects of nanoparticles on hydrogel mechanical properties. However, further studies are needed to validate the generality of these findings, as well as to determine the exact mechanisms behind the enhancements afforded by the incorporation of nanoparticles. In this study, we performed rotational rheological characterizations of chemically crosslinked poly(acrylamide) hydrogels incorporating silica nanoparticles to better understand the role of nanoparticles on the enhanced properties of hydrogel nanocomposites. Our results indicate that incorporating nanoparticles can lead to enhancements in hydrogel elastic moduli greater than the maxima obtainable through purely chemical crosslinking. Moreover, we find that the increases in elastic moduli due to the addition of nanoparticles not only depend on particle concentration, but also on the monomer and chemical crosslinker concentration. Finally, our data indicates a strong role for pseudo-crosslinking mediated by noncovalent interactions between the nanoparticles and hydrogel polymers on the observed reinforcements. Collectively, our results shed further insight into the role of nanoparticles on enhancements of mechanical properties of hydrogels and may thereby facilitate engineering specific mechanical properties in a wide range of hydrogel nanocomposite systems. Full article

In the current study, Anatase/rutile TiO₂ and Anatase/rutile TiO₂@Glucose composites were successfully prepared by a simple method using mechanical technique. The as-prepared composite materials powders were characterized by Powder X-ray diffraction analysis (PXRD), Scanning electronic microscopy (SEM), and Solid-state UV-visible spectroscopy. X-ray patterns showed the fractional phase transformation from TiO₂ anatase to rutile. SEM observations revealed that the particle shape was affected by the ball milling process. Energy-dispersive X-ray spectroscopy (EDS) analysis exhibits quantitatively the elemental composition of Ti and O. UV-Visible spectroscopy confirmed that the bandgap is slightly affected using Tauc. Full article

Al-SBA-15 materials were functionalized by ball milling with several niobium loadings (0.25–1 wt.%) and/or with several F^- loadings, using NH₄F as a precursor. The catalysts synthesized in this study were characterised by X-ray diffraction (XRD), N2 porosimetry, and diffuse reflection infrared spectroscopy (DRIFT) among others. The prepared materials shown, form moderate to high catalytic activities in the microwave-assisted transformation of valeric acid to ethyl valerate via esterification. The incorporation of fluoride anions either into Al-SBA-15 or on Nb1%/Al-SBA-15 led to a linear increase in valeric acid conversion with the F⁻ content. Thus, F⁻ modified mesoporous aluminosilicates efficiently catalyze the transformation of valeric acid into alkyl valerate esters as renewable fuels. Full article

The morphology and properties of polypropylene (PP)/organoclay nanocomposites prepared by melt processing were investigated with a special interest on the different effects of the use of different grafted PP as compatibilizers, i.e., maleic anhydride or silane-grafted species, PP-g-MA or PP-g-Si. When either PP-g-MA or PP-g-Si was added, better improvement of properties was achieved. The addition of PP-g-Si was found to increase the crystallization temperature upon the clay addition in comparison to PP-g-MA. Moreover, the PP-g-MA proved to be more efficient than PP-g-Si. The degree of reinforcement was found to be dependent on the interaction forces between the polymer matrix/clay, which resulted in intercalated/partial exfoliated structures for PP-g-Si while increasing clay content induced a change from exfoliated to intercalated using PP-g-MA, as revealed by transmission electron microscopy observations and X-ray diffraction analysis. Full article

Due to the demand for wearable and implantable microelectronic devices (MED), there is growing interest in the development of thin-film lithium-ion microbatteries (LiBs) with high-energy density. The high cost of production is an issue restraining thin-film LiBs’ wide application. Inkjet printing is a method of applying materials to the substrate surface: ink droplets formed on piezoelectric nozzles fall on the substrate, whereafter evaporation of the solvent thin layer of film is formed. The proposed technology can simplify the production of LiBs for MED and reduce their cost. The present work reports the results of inkjet printing 3D cathode development for LiBs. The 3D printed cathodes were produced using synthesized Li-rich cathode material (Li_1.2+xMn_0.54Ni_0.13Co_0.13O₂, 0 < x < 0.05) which has a larger capacity (>250 mAh/g) in comparison with the materials used in modern lithium-ion cells. For LiB electrode printing, the non-aqueous solvent-based inks were used. The prepared cathode material was dispersed in N-methyl-2-pyrrolidone. The effect of various additives such as ethylene glycol, diethylene glycol, propylene glycol on the viscosity and stability of the ink was studied. Inkjet printing was performed with the use of a Dimatix Material Printer 2831. Substrate temperature, number of layers and other parameters were varied to determine the optimal printing conditions. Full article

Graphene oxide (GO), the oxidized form of graphene, shows unique properties, such as strong mechanical strength, high thermal conductivity, amphiphilicity, and surface functionalization capability that make it very attractive in various fields, ranging from medicine to optoelectronic devices and solar cells. However, its insolubility in non-polar and polar aprotic solvents hinders some applications. To solve this issue, novel functionalization strategies are pursued. In this regard, the current study deals with the preparation and characterization of hexamethylene diisocyanate (HDI)-functionalized GO. Different reaction conditions were tested to optimize the functionalization degree (FD), and detailed characterization was conducted via Fourier-transformed infrared (FT-IR) spectroscopy to confirm the success of the functionalization reaction. The HDI-GO could further react with other organic molecules or polymers via the remaining oxygen groups, which makes them ideal candidates as nanofillers for high-performance GO-based polymer nanocomposites. Full article

The development of nanoscale power sources with a long battery life is now required for novel nanoelectronic devices, such as wireless sensors, biomedical implants, and smart cards. Lithiated metal oxides (Li–Me–O) are widely used in lithium-ion batteries (LIBs). Depending on the type of metal, Li–Me–O can be applied as cathode, anode, or electrolyte materials. Atomic layer deposition (ALD), due to its precision control over thickness, purity, and uniformity over large areas of applied coatings, can be applied for the synthesis of a different thin film LIBs materials. In the present work, the deposition of Li–Sn–O (anode) and Li–Al–O (electrolyte) by ALD is considered. The prepared films were investigated with the use of X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry. Full article

Zirconium oxide (ZrO₂) is a wide and direct band gap semiconductor used for the fabrication of optoelectronic devices. ZrO₂ based optoelectronic devices span a wide optical range depending on the band gap of ZrO₂ material. The band gap of ZrO₂ can be tuned by fabricating it to the nanoscale. In this paper, we synthesized the ZrO₂ nanostructures on quartz substrate using ZrO₂ ions produced by the ablation of ZrO₂ pellet due to high temperature, high density, and extremely non-equilibrium argon plasma in a modified dense plasma focus device. Uniformly distributed monoclinic ZrO₂ nanostructures with an average dimension of ~14 nm were obtained through X-ray diffraction and scanning electron microscopy studies. The monoclinic phase of ZrO₂ nanostructures is further confirmed from photoluminescence (PL) and Raman spectra. PL spectra show peaks in ultra-violet (UV), near-UV, and visible regions with tunable band gap of nanostructures. A similar tunability of band gap was observed from absorption spectra. The obtained structural, morphological, and optical properties are compared to investigate the potential applications of ZrO₂ nanostructures in optoelectronic devices. Full article

A polyelectrolyte complex (PEC) membrane based on sulfonated poly (ether ether ketone) and polyaniline (SPEEK-PANI) was developed for pH sensing applications. Aniline was polymerized in the presence of the SPEEK membrane by using in situ chemical oxidative polymerization to yield an ionically crosslinked SPEEK-PANI membrane. The fabricated membrane exhibited sensitivity in the physiological pH range of 2–8. The PEC membrane pH sensor showed good absorption properties in the near-infrared region (NIR). The membrane showed fast response during a de-doping process (≈90 s), while longer response times are essential for doping processes from the alkaline/neutral pH region to the acidic pH region, which is attributed to the presence of highly acidic sulfonic acid groups with a high buffering capacity in the PEC membrane. The SPEEK-PANI membrane exhibited slightly higher water uptake compared to the neat SPEEK membrane. The membrane exhibited good stability, as it was stored in 1M HCl solution for more than 2 years without physical or visual deterioration. A preconditioning step in 1M HCl ensured that the results were reproducible and allows the pH sensor to be used repeatedly. The PEC sensor membranes are suitable for applications that start at low pH values and move upwards to higher pH values in the 2–8 pH range. Full article

Thin films from double hydrophilic copolymer of complex branched structures containing poly(N,N-dimethyl acrylamide) and poly(ethylene oxide) blocks were used as humidity sensitive media, and two types of Bragg reflectors with different optical contrast and operating wavelengths were implemented as transducers of humidity changes. The required film thickness was pre-optimized through theoretical modelling in order to achieve the highest sensitivity. Single films and Bragg reflectors were characterized by transmittance measurements at different humidity levels in the range from 5% to 95% relative humidity. The influence of the number of the layers in the stack, the operating wavelength and optical contrast on sensitivity was studied. The potential and advantages of using top-covered Bragg reflectors as humidity sensors with simple optical read-out are demonstrated and discussed. Full article