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Laser machined ultralow water adhesion surface by low pressure processing
摘要： Ultralow water adhesion aluminum surface has been fabricated by eco friendly low pressure processing technique. The laser patterned surface shows interconnected spongy porous nanostructures with micro packets at regular intervals. The micro volume of air present inside the interconnected porous surface structure together with the adsorbed hydrocarbons by low pressure processing leads to ultralow water adhesion surface. Application of bigger droplet volumes to the patterned surface showed a decrease in static contact angle measurement due to larger radius of curvature and axisymmetrical compared to the smaller droplets.
关键词： Sliding angle,Ultrafast laser,Low pressure,Wetting,Adhesion
更新于2025-09-23 15:21:01
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Antireflective Transparent Oleophobic Surface by Non-Interacting Cavities
摘要： Oleophobic surfaces have been so far realized using complex micro-scale and nano-scale re-entrant geometries where primary and secondary structures or overhang geometries are typically required. Here we propose a new design to create them with non-interacting cavities. The suspension of liquid droplets relies on the mechanism of compression of air under the meniscus leading to stable composite oil-air-solid interfaces. To demonstrate the concept, we make oleophobic surfaces, with contact angle for oleic acid of about 130o (and Hexadecane about 110o), using both micro-holes in silicon and nano-holes in glass. Thanks to the subwavelength dimensions and antireflection effect of the nano-holes, the glass substrate also shows a high degree of optical transparency with optical transmission exceeding that of the initial bare substrate. Crockmeter tests without any significant change of morphology, optical and wetting properties after more than 500 passes also confirm the high mechanical durability of the nano-hole surface. The results indicate the possibility of using the proposed oleophobic surfaces for a wide range of applications, including self-cleaning transparent windows, windshields for automobiles and aircrafts.
关键词： Antireflective,cavities,Transparent surface,nanostructured optical surfaces,Oleophobic,self-cleaning,Micro-Nano manufacturing,surface wetting
更新于2025-09-23 15:21:01
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Spreading of biologically relevant liquids over the laser textured surfaces
摘要： Hypothesis: The distribution of biological objects upon the spreading of biologically relevant dispersions over laser textured surfaces is affected by the dispersion composition and substrate chemistry and roughness. Experiments: To examine the role of the substrate texture in biologically relevant liquid spreading, the dynamic behavior of droplets of water and dispersions of bacterial cells and viruses and dynamic behavior of droplet/air surface tension were addressed. A new procedure to simultaneously distinguish three different spreading fronts was developed. Findings: The study of spreading of water and the biologically relevant liquids over the laser textured substrate indicate the development of three spreading fronts associated with the movement of bulk droplet base, the flow along the microchannels, and the nanotexture impregnation. The anisotropy of spreading for all types of liquid fronts was found. Despite the expected difference in the rheological behavior of water and the biologically relevant liquids, the spreading of all tested liquids was successfully described by power-law fits. The droplet base spreading for all tested liquids followed the Tanner law. The advancing of water and dispersions in the microchannels along both fast and slow axes was described by Washburn type behavior. The impregnation of the nanotexture by water and biologically relevant liquids demonstrated universality in power fit description with an exponent n = 0.23.
关键词： Biologically relevant liquid,Spreading,Wetting,Dynamic wetting,E. coli,Image processing,Roughness,Contact angle,Textured surface,Bacteriophage
更新于2025-09-23 15:19:57
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Er:YAG laser cleaning of a marble Roman urn
摘要： There are very few documented instances of the use of an Er:YAG laser in the cleaning of stone artefacts; however, the cases reported in the literature have shown its effectiveness in the removal of surface organic patinas and lichens. A Roman marble funerary urn (67–100 AD) of archaeological importance was covered with an intractable surface layer that obscured its delicate decorative carving. Chromatographic mass spectrometric and Raman spectroscopic techniques allowed the characterisation of those inorganic and organic materials that had undergone photo-oxidation and biological changes, resulting in the thick encrustation. An Er:YAG laser at 2940nm, with a pulse length of 300μsec, was used for cleaning the urn. Preliminary tests were performed with fluences ranging from 0.7 to 6.4J/cm2 and in the presence of a variety of wetting agents. The laser cleaning resulted in a sufficiently clean marble surface with the thick deposit of unwanted material removed. Finally, the sensitivity of the method allowed for a compact layer of calcium oxalate to be retained on the marble’s surface to help protect it.
关键词： Er:YAG,cultural heritage,wetting auxiliary agent,laser cleaning,calcium oxalate,marble
更新于2025-09-23 15:19:57
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Superspreading and Drying of Trisiloxane-Laden Quantum Dot Nanofluids on Hydrophobic Surfaces
摘要： Nano?uids hold promise for a wide range of areas of industry. However, understanding the wetting behavior and deposition formation in the course of drying and spreading of nano?uids, particularly containing surfactants, is still poor. In this paper, the evaporation dynamics of quantum dot-based nano?uids and evaporation-driven self-assembly in nanocolloidal suspensions on hexamethyldisilazane-, polystyrene-, and polypropylene-coated hydrophobic surfaces have been studied experimentally. Moreover, for the very ?rst time, we make a step toward understanding the wetting dynamics of superspreader surfactant-laden nano?uids. It was revealed that drying of surfactant-free quantum dot nano?uids in contrast to pure liquids undergoes not three but four evaporation modes including last additional pinning mode when the contact angle decreases while the triple contact line is pinned by the nanocrystals. In contrast to previous studies, it was found out that addition of nanoparticles to aqueous surfactant solutions leads to deterioration of the spreading rate and to formation of a double co?ee ring. For all surfaces examined, superspreading in the presence and absence of quantum dot nanoparticles takes place. Despite the formation of co?ee rings on all substrates, they have di?erent morphologies. In particular, the knot-like structures are incorporated into the ring on hexamethyldisilazane- and polystyrene-coated surfaces.
关键词： Self-assembly,Superspreading,Quantum dots,Wetting dynamics,Evaporation,Nano?uids
更新于2025-09-23 15:19:57
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Temperature field distribution in polymer particles during surface-selective laser sintering
摘要： The dynamics of polymer particle heating by laser irradiation during surface-selective laser sintering (SSLS) has been studied both experimentally and theoretically. Water aerosol wetting of the polymer particle surface was applied to increase the absorbance of thulium fiber laser radiation at 1.96 μm. Theoretical modeling of the laser-induced thermal processes was performed in thermolabile polylactic-co-glycolic acid powder coated with a thin water layer. Temperature gradients on the surface and inside the sintered particle volume were evaluated and analyzed. It was shown that for certain optimized SSLS parameters an effective sintering process can be achieved by delicate melting of the particle surface only, without noticeable changes in the chemical and phase compositions of the internal domains.
关键词： surface-selective laser sintering,thermal imaging,polymer particles,wetting,analysis of thermal processes
更新于2025-09-23 15:19:57
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Flexible Alla??Solutiona??Processed Organic Solar Cells with Higha??Performance Nonfullerene Active Layers
摘要： All-solution-processed organic solar cells (from the bottom substrate to the top electrode) are highly desirable for low-cost and ubiquitous applications. However, it is still challenging to fabricate efficient all-solution-processed organic solar cells with a high-performance nonfullerene (NF) active layer. Issues of charge extraction and wetting are persistent at the interface between the nonfullerene active layer and the printable top electrode (PEDOT:PSS). In this work, efficient all-solution-processed NF organic solar cells (from the bottom substrate to the top electrode) are reported via the adoption of a layer of hydrogen molybdenum bronze (HXMoO3) between the active layer and the PEDOT:PSS. The dual functions of HXMoO3 include: 1) its deep Fermi level of ?5.44 eV can effectively extract holes from the active layer; and 2) the wetting issues of the PEDOT:PSS on the hydrophobic surface of the NF active layer can be solved. Importantly, fine control of the HXMoO3 composition during the synthesis is critical in obtaining processing orthogonality between HXMoO3 and the PEDOT:PSS. Flexible all-solution-processed NF organic solar cells with power conversion efficiencies of 11.9% and 10.3% are obtained for solar cells with an area of 0.04 and 1 cm2, respectively.
关键词： nonfullerene organic solar cells,all-solution-processed,hydrogen molybdenum bronze,charge extraction,wetting
更新于2025-09-23 15:19:57
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Unidirectional transport and effective collection of underwater CO2 bubbles utilizing ultrafast-laser-ablated Janus foam
摘要： Manipulating gas bubbles in aqueous ambient is of great importance for applications in water treatment, gas collection and matter transport. Here, a kind of Janus foam is designed and fabricated by one-step ultrafast laser ablation of one side of cooper film, which is treated to be superhydrophobic. The Janus foam exhibits not only the capability of unidirectional transport of underwater bubbles, but also gas collection with favorable efficiency up to ~15 mL cm-2 min-1. The underlying physical mechanism is attributed to the cooperation of the buoyancy, adhesion and wetting gradient forces imposed on the bubbles. As a paradigm, the underwater chemical reaction between unidirectional CO2 gas flow and alkaline phenolphthalein solution is demonstrated via the Janus foam. This facile and low-cost fabrication approach for Janus foam will find broad potential applications for effective bubble transport, carbon capture and controllable chemical reactions in aqueous conditions.
关键词： Janus foam,Unidirectional bubble transport,Ultrafast laser,Wetting gradient force,Directional bubble collection
更新于2025-09-23 15:19:57
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Reactive wetting of binary Sn Cr alloy on polycrystalline chemical vapour deposited diamond at relatively low temperatures
摘要： Synthetic diamond has excellent mechanical, thermal, and electrical properties, which makes it an ideal material in a wide range applications from abrasive grinding tools to modern electronic devices. Hence, understanding the wettability of metals on the synthetic diamond is of great importance for the development of diamond-related materials and devices. In this study, the wettability and spreading kinetics of binary SneCr alloy on chemical vapour deposed (CVD) polycrystalline diamond compacts were investigated using a sessile drop method. In situ observation of contact angle at elevating temperatures indicated trace addition of Cr dramatically improved the wettability of Sn on CVD diamond, and the SneCr alloy started to wet CVD diamond at approximately 750 °C. Isothermal spreading kinetic analysis revealed that the spreading of SneCr alloy on CVD diamond was controlled by the kinetics of chemical reaction at advancing triple line. Microstructure characterization indicated that the formation of nano-sized scallop-like Cr7C3 grains was responsible for the improved wettability of SneCr alloy on CVD diamond substrate. The wetting temperature was found to play a determinant role in the interfacial carbide formation, and hence the reactive wetting of SneCr alloy on CVD diamond at temperatures from 700 to 900 °C.
关键词： Reactive wetting,Interface reaction,Chromium carbides,CVD diamond
更新于2025-09-19 17:15:36
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Tailored PEDOT:PSS hole transport layer for higher performance in perovskite solar cells: Enhancement of electrical and optical properties with improved morphology
摘要： Precise control over the charge carrier dynamics throughout the device can result in outstanding performance of perovskite solar cells (PSCs). Poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is the most actively studied hole transport material in p-i-n structured PSCs. However, charge transport in the PEDOT:PSS is limited and ine?cient because of its low conductivity with the presence of the weak ionic conductor PSS. In addition, morphology of the underlying PEDOT:PSS layer in PSCs plays a crucial role in determining the optoelectronic quality of the active perovskite absorber layer. This work is focused on realization of a non-wetting conductive surface of hole transport layer suitable for the growth of larger perovskite crystalline domains. This is accomplished by employing a facile solvent-engineered (ethylene glycol and methanol) approach resulting in removal of the predominant PSS in PEDOT:PSS. The consequence of acquiring larger perovskite crystalline domains was observed in the charge carrier dynamics studies, with the achievement of higher charge carrier lifetime, lower charge transport time and lower transfer impedance in the solvent-engineered PEDOT:PSS-based PSCs. Use of this solvent-engineered treatment for the fabrication of MAPbI 3 PSCs greatly increased the device stability witnessing a power conversion e?ciency of 18.18%, which corresponds to ～37% improvement compared to the untreated PEDOT:PSS based devices.
关键词： PEDOT:PSS treatment,Hole transport layer,Perovskite solar cells,Non-wetting,PEDOT:PSS surface
更新于2025-09-19 17:13:59