Materials Science Forum Vol. 1143

Abstract: Bacterial nanocellulose (BNC) is a natural polymer gel with unique properties that are suitable for developing advanced film applications such as edible coating and packaging. However, transforming BNC gel into a suspension and applying it as a film still lacks knowledge of the condition and method since BNC film performance depends on many parameters caused by the transformation process. This work studied two important primary variables, the number of homogenization cycles and the BNC concentrations, for transforming BNC gel into aqueous suspension using a microfluidizer to homogenize nanofibers and water medium. The BNC films obtained from the suspensions were examined for their properties, i.e., morphology, crystallinity index, optical, thermal, and mechanical properties. The results explored that the number of homogenization cycles had a non-significant impact on the characteristics and properties of BNC suspension and film. A significant improvement in film properties was found when using a higher BNC concentration at 1% w/v compared with 0.5% w/v at the equivalent number of homogenization cycles (40 cycles). The degradation temperature of this film increased by 13%, and Young’s modulus and tensile strength increased more than twice compared with the 0.5% w/v sample, increasing from 0.3 to 0.7 MPa and from 9 to 19 kPa, respectively. This finding would benefit the further development of BNC film for coating and packaging applications.

Abstract: Olive oil is widely used in cosmetics, food, and pharmaceuticals, and oil-in-water (O/W) nanoemulsions have gained attention in recent years due to their ease of preparation, cost-effectiveness, and enhanced efficacy. However, the high costs associated with advanced technologies hinder small enterprises from adopting these formulations, limiting global competitiveness. This study aims to develop olive oil-based nanoemulsions (ONEs) as versatile carriers for active ingredients in various industrial applications. The research focused on creating O/W nanoemulsions using the D-phase emulsification (DPE) method, known for its low-energy consumption and simplicity. The impact of surfactants, co-surfactants, glycerol, oil content, initial water addition, and stirring time on the particle size and polydispersity index (PDI) was studied. The optimized formulation with a single surfactant had a particle size of 10.03 ± 3.08 nm and a PDI of 0.343 ± 0.024, while the use of co-surfactants resulted in a particle size of 200.13 ± 3.03 nm and a PDI of 0.145 ± 0.000. The co-surfactant formulation demonstrated stability at 35°C over 4 months. Furthermore, retinol was incorporated into the optimized nanoemulsion, and the physical properties were compared to those of the base formulation. The particle size and PDI remained similar, suggesting that the formulation is robust enough for active ingredient incorporation. This research provides a foundation for future formulation efforts, offering a cost-effective and efficient approach for industrial applications.

Abstract: Herein, a one-pot solvothermal method was employed to synthesize Fe-doped carbon nanodots using waste expanded polystyrene as the carbon source and ferric chloride hexahydrate for iron doping. Three synthesis parameters-reaction time, temperature, and dopant weight-were optimized using Response Surface Methodology (RSM) based on Box-Behnken design, with relative fluorescence (FL) intensity as the response. Model validation showed a percentage error of 0.66% between replication experiments and predicted maximum intensity, confirming the model's reliability to maximize FL intensity in synthesis. FTIR spectroscopy identified the presence of a medium peak at 538 cm^-¹, associated with Fe-O stretching, indicating successful Fe doping, supported by EDX analysis. TEM analysis confirmed the nanosized properties of Fe-CDs, with an average particle size of 1.84 nm, and HR-TEM revealed an onion-like structure with a lattice spacing of 0.369 nm, and the presence of amorphous shells, suggesting structural heterogeneity. The synthesized doped and undoped CDs were employed in a drop-casting method to produce films that were used for carbon monoxide detection. Results displayed significant effects of operating temperature and gas concentration on the gas response of Fe-CDs and CDs films on resistance. The significant statistical difference in gas response between Fe-CDs and undoped CDs suggests that Fe doping enhances electron mobility, due to more pronounced changes in resistivity, yielding higher responses to carbon monoxide gas.

Abstract: Deep eutectic solvents (DES) are widely used in many fields due to their properties such as low cost, easy synthesis, low toxicity, and biodegradability. The following study selected tropine and hydrated metal salts to synthesize a series of new deep eutectic solvents as catalysts for exploring the alcoholysis reaction of PET. Then the effects of the types of DES, catalyst composition, reaction time and temperature on the alcoholysis results of PET were investigated. Using a low melting solvent of tropine/zinc acetate with a molar ratio of 4:1 as a catalyst, a reaction time of 2 h, and temperature of 180°C, the conversion rate of PET was nearly 80%, and the yield of BHET was also 80%, which was further employed to prepare nano carbon dots through simple way.

Abstract: The limitations of iodinated-based contrast media in computed tomography (CT) imaging have prompted studies into alternative contrast agents. Bismuth oxide nanoparticles (BiONPs) have emerged as a potential contrast agent due to their high X-ray attenuation, low toxicity, and cost-effectiveness. This study evaluates the efficacy of BiONPs as a contrast agent in CT imaging compared to traditional iodine-based contrast agents. A phantom study was conducted using synthesized BiONPs and iodine contrast agents (ICA) at a range of concentrations (0.05 to 1.0 mmol/L). The phantom was scanned with a CT scanner using 120 kVp tube potential and the contrast-to-noise ratio (CNR) was calculated to determine the contrast enhancement. The findings show that BiONPs demonstrated superior CNR values compared to iodine contrast agents at all concentrations tested. Specifically, at 0.5 mmol/L, BiONPs achieved a mean CNR of 161.70, significantly higher than iodine’s 51.47 (p < 0.05). Similar trends were observed at lower concentrations, with BiONPs consistently outperforming ICA. The findings highlight the BiONPs as an effective alternative to ICA, particularly at lower concentrations. This study highlights the capability of BiONPs to provide superior image contrast in CT imaging compared to conventional ICA. Its consistent performance across variations of concentration emphasizes its potential for improving diagnostic accuracy in CT imaging.

Abstract: This study investigates the tunable photoluminescence emission properties of carbon dots (CDs) derived from hemicellulose and lignin extracted from agricultural waste. Key aspects examined include production yield, fluorescence characteristics, and fluorescence quenching mechanism in the presence of heavy metal ions. Freeze-dried carbon dots from corn cobs (CC-CDs) exhibited a yield of 3.69%, which increased to 16.8% with alkali treatment (CCN-CDs). The CDs demonstrated excellent aqueous stability and emitted green fluorescence under ultraviolet light irradiation. Ultraviolet-visible spectroscopy revealed distinct absorption peaks at 200-300 nm and 300-350 nm, attributed to aromatic sp² core transitions and surface functional groups. Atomic force microscopy confirmed a spherical morphology with diameters of 35 nm for CCN-CDs and 51 nm for CC-CDs. Fourier-transform infrared spectral analysis identified functional groups such as phenolic hydroxyl, amines, nitrile, and carboxyl, which contribute to the tunable optical properties of the CDs. Photoluminescence spectra showed excitation-dependent emission features, with a redshift observed due to surface oxidation. The fluorescence quenching induced by ferric ions demonstrated a linear relationship between the quenching effect and concentration, with a more pronounced effect at lower concentrations of heavy metal ions, indicating the potential of these carbon dots as sensor. The quenching phenomenon was attributed to the electron transfer processes between ferric ions and CDs, providing insights into the underlying mechanisms governing their fluorescence behavior.

Abstract: The paper delves into various aspects of nanotechnology in mechanical engineering, including the fabrication of nanomaterials and advanced manufacturing techniques. Nanomanufacturing methods offer unprecedented precision and control, enhancing efficiency and performance across industries. From nanoscale manipulation to intricate structure fabrication, nanotechnology is transforming manufacturing processes profoundly. Furthermore, the paper explores the applications of nanotechnology in nano mechanics and nanotribology, elucidating how it enables us to understand and manipulate mechanical behaviours at the nanoscale. Additionally, it discusses the role of nanotechnology in energy systems, where nanomaterials contribute to improved energy storage and conversion efficiency. Beyond traditional mechanical engineering, nanotechnology finds applications in biomechanics, shaping advancements in healthcare through innovative biomedical devices and materials. The interdisciplinary nature of nanotechnology is evident in its potential to address global challenges, such as environmental remediation, by developing nanomaterials for water purification, air filtration, and soil remediation. Looking ahead, the paper discusses future directions for nanotechnology in mechanical engineering, emphasizing the importance of interdisciplinary collaboration, ethical considerations, and responsible governance. It highlights the potential for transformative breakthroughs in medicine, energy systems, and materials science, guided by ongoing research and innovation. In conclusion, nanotechnology is poised to reshape the landscape of mechanical engineering, offering unprecedented possibilities for efficiency, sustainability, and technological advancement. Through careful exploration and application, nanotechnology holds the promise of addressing societal needs while pushing the boundaries of what is possible in mechanical engineering.

Abstract: In this study, Titanium dioxide nanoparticles (TiO₂ NPs) were synthesized using Piper longum leaf extract as both a capping and reducing agent through a green synthesis approach. The synthesized TiO₂ NPs were thoroughly characterized using multiple techniques: X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV-Diffuse reflectance spectroscopy (UV-DRS), field emission scanning electron microscopy (FESEM), High-Resolution Transmission Electron Microscopy (HR-TEM), Brunauer-Emmett-Teller (BET) analysis, and X-ray photoelectron spectroscopy (XPS). XRD analysis confirmed the anatase phase of TiO₂ with an average crystallite size of 57 nm. UV-DRS revealed a band gap of 3.39 eV, indicative of TiO₂ nanoparticle formation. FTIR spectroscopy identified biomolecules such as flavonoids, phenol compounds, and tannins around the nanoparticles. SEM images showed a variety of shapes, including hexagons, pentagons, triangles, and tetragons. EDX analysis confirmed the presence of titanium, carbon, and oxygen, verifying the purity of the TiO₂ nanoparticles. BET analysis determined a specific surface area of 59 m²/g. The antibacterial efficacy of the TiO₂ nanoparticles was assessed using the agar well diffusion method, demonstrating significant antibacterial activity against Pseudomonas aeruginosa, Streptococcus mutans, Staphylococcus aureus, and Klebsiella pneumoniae. Additionally, the photocatalytic degradation of methylene blue dye by the TiO₂ NPs achieved an efficiency of 96%.

Abstract: Doping organic crystals with amino acids to develop green materials utilizes the distinctive properties of amino acids to enhance both the sustainability and functionality of these materials. Green materials are crafted through environmentally friendly methods that minimize waste, emissions, and energy use, thereby reducing their overall environmental footprint. This doping process improves various properties of the organic crystals, including optical, electrical, and thermal characteristics, while also enhancing stability and mechanical strength. Amino acids can endow organic crystals with specialized functions, such as selective binding in sensors or improved catalytic activity, broadening their application potential. For this study, Creatininium Benzene Sulphonate single crystals were synthesized via slow evaporation at room temperature and doped with L-Serine. Structural characterization through XRD and FTIR confirmed the incorporation of the amino acid into the organic crystal. Structural refinement datas like FWHM,Crystallite size and lattice strain were obtained through Xpert Hi score Software .Thermal parameters, including Gibbs free energy, entropy, enthalpy, and activation energy, were assessed for both Creatininium Benzene Sulphonate and L-Serine-doped Creatininium Benzene Sulphonate using the Coats-Redfern method. The doping led to the material existing in four distinct phases, with enhanced catalytic activity at low temperatures verified by the Quantum Eyring Formula. This quantum-level analysis aids in designing more effective catalysts by revealing how they interact with reactants, optimizing catalytic processes. By understanding diffusion mechanisms alongside quantum tunneling, scientists can develop catalysts that enhance reaction rates, even at lower temperatures, by improving molecular diffusion. This dual focus on tunneling and diffusion allows for the creation of more selective and efficient catalysts, essential for green chemistry. Ultimately, these insights contribute to the development of sustainable materials with enhanced performance in various industrial applications. Optical properties such as refractive index, extinction coefficient, and bandgap were compared between L-Serine-doped Creatininium Benzene Sulphonate and the undoped crystal. Additionally, SHG values of the doped and undoped crystals were measured and compared to KDP Single Crystal. LDT values of the doped and undoped crystals were also compared with those of KDP and Urea single crystals. The results suggest that the optical properties, SHG, and LDT values of the L-Serine-doped crystal remain favorable, confirming also its suitability as a green material. This project aims to investigate how doping amino acids into Creatininium Benzene Sulphonate single crystals justifies their optical, thermal, and dielectric properties to determine their green material potential.