- 标题
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Liquid-Crystal Phase Optimization Using the Alignment Relay Technique for the Deposition of Single-Walled Carbon Nanotubes
摘要： The alignment and sorting of carbon nanotubes constitutes a challenging and industrially significant field of research. We have recently created a technique to simultaneously align and sort single-walled carbon nanotubes on a surface through the use of a specially designed organic thin film. This alignment relay technique can be intelligently altered to judiciously target key parameters of nanotube deposition including density, alignment, and length. Here, we demonstrate that by simply altering the nature of the liquid crystal used the average length of the nanotubes can be decreased by half while increasing the density 3-fold, with minimal impact on the diameter sorting.
关键词： liquid crystals,molecular chemistry,iptycenes,surface chemistry,carbon nanotubes
更新于2025-09-23 15:19:57
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Investigations in the fabrication of surface patterns for wettability modification on a Zr-based bulk metallic glass by nanosecond laser surface texturing
摘要： Laser texturing has previously been employed to enhance the wettability of metallic alloys. Such studies reported that modifying the wettability of a surface is a result of changes in both its topography and its chemistry. In this paper, an investigation about laser-induced surface wettability modification is also reported but for a less studied type of material in this context. In particular, nanosecond (ns) laser processing was employed to texture two types of surface patterns, i.e. dimples and grooves, on the surface of a Zr-based bulk metallic glass (BMG) known as Vitreloy 105. The specific focus of the research was on understanding the role played by both surface topography and chemistry modifications in changing the wettability of the original surface. Using static contact angle measurements, it was found that groove patterns enhanced the hydrophilicity of the original BMG, while dimple patterns weakened it. Based on the obtained 3D surface measurements and XPS data, it is suggested that the reduced hydrophilicity of dimple-textured surfaces was driven by the decrease of hydrophilic C=O and O=C-O bonds post laser processing. While these bonds were also reduced for groove-textured patterns, the hydrophilicity was still enhanced following laser irradiation as a result of the dominant role that a much larger induced surface roughness should play in this case.
关键词： Surface topography,Bulk metallic glass,Nanosecond laser surface texturing,Surface chemistry.,Wettability
更新于2025-09-23 15:19:57
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Chemical effects during the formation of various types of femtosecond laser-generated surface structures on titanium alloy
摘要： In this contribution, chemical, structural, and mechanical alterations in various types of femtosecond laser-generated surface structures, i.e., laser-induced periodic surface structures (LIPSS, ripples), Grooves, and Spikes on titanium alloy, are characterized by various surface analytical techniques, including X-ray diffraction and glow-discharge optical emission spectroscopy. The formation of oxide layers of the different laser-based structures inherently influences the friction and wear performance as demonstrated in oil-lubricated reciprocating sliding tribological tests (RSTTs) along with subsequent elemental mapping by energy-dispersive X-ray analysis. It is revealed that the fs-laser scan processing (790 nm, 30 fs, 1 kHz) of near-wavelength-sized LIPSS leads to the formation of a graded oxide layer extending a few hundreds of nanometers into depth, consisting mainly of amorphous oxides. Other superficial fs-laser-generated structures such as periodic Grooves and irregular Spikes produced at higher fluences and effective number of pulses per unit area present even thicker graded oxide layers that are also suitable for friction reduction and wear resistance. Ultimately, these femtosecond laser-induced nanostructured surface layers efficiently prevent a direct metal-to-metal contact in the RSTT and may act as an anchor layer for specific wear-reducing additives contained in the used engine oil.
关键词： Tribology,Femtosecond laser processing,GD-OES,Surface chemistry,XRD,LIPSS,Laser-induced periodic surface structures,Laser-induced oxide layer
更新于2025-09-23 15:19:57
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<p>In vivo Comparison of the Biodistribution and Toxicity of InP/ZnS Quantum Dots with Different Surface Modifications</p>
摘要： In vivo Comparison of the Biodistribution and Toxicity of InP/ZnS Quantum Dots with Different Surface Modifications
关键词： in vivo,surface chemistry,nanotoxicology,biodistribution,InP/ZnS quantum dots
更新于2025-09-23 15:19:57
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Bromine‐Induced Defects in Anion‐Deficient Zinc Oxide as Stable Photocatalysis Promoters
摘要： The physico-chemical properties and photocatalytic performance stability of bromine doped zinc oxide is compared with that of undoped zinc oxide system. Interstitially located bromine induced defects turning to photocatalytic promoter is a rarely studied, but relevant area. Here, high yield one-pot synthesis with cost-effective and straightforward method is adopted for the synthesis. A detailed study on the physico-chemical properties of the prepared photocatalyst materials is done following advanced methodologies. Surface modification of anion deficient zinc oxide in presence of bromine is confirmed from X-ray photoelectron spectroscopy and Raman spectroscopy. This study highlights the synergetic effect attained through Br induced defects with anion deficiencies in ZnO by fine tuning the level of doping. Plausible photocatalytic mechanism for water purification employing efficient electron-hole separation due to interstitially located bromine and anion deficiency in ZnO is proposed. Bromine doped ZnO photocatalyst showed complete degradation of methylene blue (20 ppm) within a short period of time compared to pristine ZnO.
关键词： Bromine,Nanotubes,Surface Chemistry,Photocatalysis,ZnO
更新于2025-09-23 15:19:57
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Exploring the surface chemistry of cesium lead halide perovskite nanocrystals
摘要： Colloidal nanocrystals (NCs) of cesium lead halide perovskites (CsPbX3, X = Cl, Br or I) are emerging as an exciting class of optoelectronic materials, but the retention of their colloidal and structural integrity during isolation, purification and handling still represents a critical issue. The impelling questions concerning their intrinsic chemical instability are connected to the dynamic nature of the bonding between the inorganic surface and the long-chain capping ligands. However, the key aspects of CsPbX3's surface chemistry that directly impact their stability remain elusive. In this contribution, we provide an in-depth investigation of the surface properties of differently composed CsPbX3 NCs, prepared by traditional hot-injection methods. The study, mainly relying on solution NMR spectroscopy, is backed up by elemental analysis as well as morphological, structural and optical investigations. We ascertained that the nature of the ligand adsorption/desorption processes at the NC surface is dependent on its elemental composition, thus explaining the origin of the instability afflicting CsPbI3 NCs. We also evaluated the effect of NC purification as well as of the degradation pathways involving the organic shell on the surface chemistry of CsPbX3 NCs. This study paves the way for new post-functionalization strategies for this promising class of nanomaterials.
关键词： surface chemistry,colloidal stability,degradation pathways,cesium lead halide perovskite nanocrystals,purification,ligand adsorption/desorption,NMR spectroscopy
更新于2025-09-19 17:15:36
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Hybrid gate dielectrics: a comparative study between polyvinyl alcohol/ $$\hbox {SiO}_{2}$$ SiO 2 nanocomposite and pure polyvinyl alcohol thin-film transistors
摘要： Polyvinyl alcohol (PVA) thin films as polymer gate dielectrics, with and without SiO2 nanoparticles were fabricated using spin-coating. Surface roughness and hydrophilicity of PVA and PVA/SiO2 thin films were studied by contact-angle measurements and atomic force microscopy. The dielectric properties were characterized via capacitance and leakage-current measurements on metal–insulator–metal structures. In order to further investigate the application potential of such materials as a replacement for conventional inorganic dielectrics such as SiO2 in organic thin-film transistors, devices were fabricated based on these polymers using α, ω-dihexylquaterthiophene as an active layer. Performance of the devices was realized by electrical measurements and Kelvin probe force microscopy. All transistors showed hole and electron mobilities in the low-voltage range. PVA/SiO2 films showed larger capacitance, less hydrophilicity, rougher surfaces and considerable leakage currents compared with those with neat PVA. Although integrating nanoparticles modified surface electronic properties and showed a shift in surface potential as observed in Kelvin probe force measurements, it appears that non-polymeric and neat polymeric dielectric materials could still be a privilege to nanocomposite polymeric dielectrics for optoelectronic applications.
关键词： ambipolar thin-film transistor,scanning probe microscopy (SPM),surface chemistry,electrical and structural properties,Polymer dielectrics
更新于2025-09-19 17:15:36
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Design and direct additive manufacturing of three-dimensional surface micro-structures using material jetting technologies
摘要： The ability to directly print 3D microstructures across the surface of large dimension substrates opens up numerous possibilities not feasible with conventional 2D or 2.5D printing or coating techniques. Demonstrated herein is a method to print 3D microstructures onto clear poly(methyl methacrylate) (PMMA) plates using material jetting technologies. Contact angle and profilometry analysis indicated that the VeroCyan? photopolymer had enhanced wetting of the PMMA surface leading to greater droplet spreading affecting the geometries printed compared to VeroCyanTM integrated models. Strategies to manipulate the interfacial interactions and hence adhesion of the VeroCyan? photopolymer were investigated by varying PMMA surface free energy through physio-chemical and chemical techniques including (i) corona discharge, followed by post-treatments with 3-(trimethoxysilyl)propyl methacrylate, polyethyleneimine graft chemicals, and (ii) plasma treatments with air and plasma polymerisation of 1,7-octadiene. The surface chemistry and wetting behaviour played a crucial role in influencing interfacial interactions with the VeroCyan? photopolymer hence its adhesion to the PMMA surface.
关键词： surface chemistry,material jetting,interfacial interactions,Additive manufacturing,adhesion
更新于2025-09-19 17:15:36
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Probing the Deposition Kinetics of Nanoparticles by Plasmonic Imaging and Counting Single Nanoparticles
摘要： Understanding the nanoparticle deposition process is important for predicting the transport and fate of nanoparticles in natural and engineered aquatic environments. Traditional methods for deposition studies are based on ensemble analysis of nanoparticles. Here, a single nanoparticle imaging method was used to probe the deposition kinetics of nanoparticles by directly counting single nanoparticles with powerful surface plasmon resonance microscopy (SPRM). The ability of SPRM to provide single nanoparticle imaging and its vertical sensitivity enabled us to differentiate collision and attachment events and, consequently, determine the attachment efficiency without any additional control experiments. As a proof-of-concept application of SPRM in measuring nanoparticle deposition, the relationship of the solution chemistry and surface chemistry with the attachment efficiency of nanoparticles was correlated. These results demonstrated that nanoparticle deposition kinetics at the single-particle level can be obtained with SPRM and that this technology can also be used to investigate other particle-particle or particle-surface interactions in aquatic environments.
关键词： surface plasmon resonance microscopy,single nanoparticle imaging,surface chemistry,attachment efficiency,nanoparticle deposition,solution chemistry
更新于2025-09-19 17:13:59
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Sustainable Quantum Dot Chemistry: Effects of Precursor, Solvent, and Surface Chemistry on the Synthesis of Zn3P2 Nanocrystals
摘要： The quest of exploring alternative materials for the replacement of toxic cadmium- and lead-based quantum dots (QDs), is necessary for envisaging a sustainable future but remains highly challenging. Tackling this issue, we present the synthesis of Zn3P2 nanocrystals (NCs) of unprecedented quality. New, reactive zinc precursors yield highly crystalline, colloidally stable particles, exhibiting oxide-free surfaces, size tunability and outstanding optical properties relative to previous reports of zinc phosphide QDs.
关键词： Surface Chemistry,Precursor,Zn3P2 Nanocrystals,Sustainable Quantum Dot Chemistry,Solvent
更新于2025-09-19 17:13:59