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Stability and Microbial Toxicity of HfO <sub/>2</sub> and ZrO <sub/>2</sub> Nanoparticles for Photolithography
摘要： HfO2 and ZrO2 nanoparticles (NPs) have gained attention as components of photoresists for next-generation photolithography. Coating of these NPs with organic ligands has been shown to increase their efficiency in photolithography. This study evaluated the microbial toxicity of HfO2 and ZrO2 NPs coated with benzoate, isobutyrate, or methacrylate towards heterotrophic aerobes, methanogens, and the bioluminescent bacterium, Aliivibrio fischeri. The stability of NPs in the media was assessed as a function of zeta potential, particle size distribution, and leaching analyses. NP dispersions were unstable in all bioassay media, resulting in particle aggregation and settling. Leaching tests showed that dissolution of the organic ligands from the NPs varied widely depending on the nanomaterial and medium considered. The NPs were harmless to aerobic heterotrophs and methanogens at high concentrations (800-1200 mg L-1). In contrast, they displayed low to moderate toxicity to A. fischeri (50% inhibition at 286-1372 mg L-1), with benzoate-coated NPs causing the highest inhibition. Further analyses confirmed that the inhibition observed in assays with A. fischeri should be attributed to the coated NPs rather than to the dissolved organic ligands. Overall, the NP photoresists tested in this study are unlikely to exert acute microbial toxicity at environmentally relevant concentrations (sub-ppm levels).
关键词： stability,photolithography,HfO2,ZrO2,nanoparticles,microbial toxicity,leaching
更新于2025-09-09 09:28:46
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Fabrication and analysis of the structural phase transition of ZrO <sub/>2</sub> nanoparticles using modified facile sol–gel route
摘要： The synthesis of zirconia nanoparticles is achieved through a modified facile sol–gel route. The as-prepared gel is analyzed thermally using TGA and DTA techniques to spot the crystallization process of zirconia nanoparticles. The prepared gel is then annealed at different temperatures and the structure was found to change between tetragonal and monoclinic crystal systems. The first stable tetragonal phase is achieved after annealing for 2 h at 400°C. The annealed powders between 600°C and 800°C demonstrate mixed tetragonal/monoclinic phases. Annealing at 1000°C and higher temperatures up to 1200°C resulted in pure monoclinic phase. Cubic phase was not detected within the annealing temperature range in this study. The elemental analysis of the annealed powder confirmed the formation of zirconia nanoparticles with the chemical formula ZrO2. The FTIR spectra of the annealed samples introduced a variation in the vibrational bands especially around the phase transition temperature. HR-TEM images reported the formation of nano-zirconia crystals with apparently large particle sizes. The optical energy gap of zirconia nanoparticles is investigated and determined.
关键词： ZrO2 nanoparticles,HR-TEM,sol–gel synthesis,EDAX,optical energy gap
更新于2025-09-09 09:28:46
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Phytosynthesis of Au and Au/ZrO <sub/>2</sub> bi-Phasic System Nanoparticles with Evaluation of Their Colloidal Stability
摘要： Due to its easy availability, preparation, handling and non-toxic nature, Equisetum arvense horsetail extract was chosen as a reducing, stabilizing and functionalizing agent for Au and bi-phasic Au/ZrO2 nanoparticle phytosynthesis–inorganic nanoparticle synthesis mediated by plant extract. We studied Au and bi-phasic Au/ZrO2 nanoparticles in colloids by various physical-chemical and analytical methods over 5 weeks. Dynamic Light Scattering and Scanning Transmission Electron Microscopy compared core and hydrodynamic diameters of nanoparticles. (cid:2)-potential measurement indirectly determined nanoparticles stability in liquid medium. Ultraviolet–Visible Spectroscopy characterized basic absorbance maxima for both Au and the bi-phasic Au/ZrO2 system. Finally, total metal concentration was determined using Inductively Coupled Plasma Mass Spectrometry. (cid:2)-potential measurements proved satisfactory stability of both Au (?13(cid:3)4 to ?17 mV) and Au/ZrO2 nanoparticles (?14(cid:3)1 to ?17(cid:3)5 mV) over the experimental period. Scanning Transmission Electron Microscopy with Selected Area Diffraction analysis con?rmed nanoparticles crystalline nature, and we determined 24 nm and 40 nm core nanogold diameters in Au and Au/ZrO2 nanoparticle colloids. Dynamic light scattering analysis con?rmed the dichotomy between particle sizes in liquid medium in the hundreds of nanometers measured, and long-term measurements con?rmed reasonable colloid stability—a paramount parameter for potential nanoparticles applications; especially in heterogeneous catalysis.
关键词： Stability,Au/ZrO2 Nanoparticles,Phytosynthesis,Colloid,Au Nanoparticles
更新于2025-09-04 15:30:14