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Surface topography following pulsed laser texturing: Implications for adhesion and wettability
摘要： A model for predicting surface topography following nanosecond pulsed laser texturing of metals is applied to calculating the areal surface roughness, Sa, average ablation depth, Da, and Wenzel roughness factor or adhesion area ratio, r, for a range representative cases relating to adhesion and wettability. Optimisation of the laser scanning strategy, number of laser passes and focused spot size is performed by considering the ratio of increases in Sa and r with respect to the average ablation depth: ???? ????? values of ???? ????? focused spot size in both the scanning and lateral directions. Increases in Sa, r and ???/???? can be achieved by performing multiple laser passes, while r and ???/???? can be increased independently of Sa and ???? ????? by reducing the focused laser spot size. These results suggest that r and Sa can be optimised effectively and independently in line with a given application. Finally, laser texturing experiments are performed on AA 6082 aluminium alloy and 316L austenitic stainless steel specimens with the aim of confirming model outcomes, after which tensile tests are performed on adhesive-bonded joints prepared with the same laser treatments. Further to demonstrating the benefits of laser texturing, it is shown that optimum results are not necessarily associated with a single value of Sa or r, but are instead a compromise between maximising these parameters and limiting the ablated volume.
关键词： Adhesion,Topography,Surface Roughness,Laser Texturing,Wetting
更新于2025-09-11 14:15:04
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Bacterial Photolithography: Patterning <i>Escherichia coli</i> Biofilms with High Spatial Control Using Photocleavable Adhesion Molecules
摘要： Biofilms are not only a leading cause of chronic infections and biofouling, but they also have a tremendous positive potential in biotechnology for biocatalysis and waste treatment. Biofilms are spatially structured communities of microbes, which exchange chemicals and communicate with each other. By spatially controlling bacterial adhesion to surfaces, and therefore the microstructure of biofilms, a promising method of understanding social interactions between bacteria and designed biofilms is developed. The bacterial photolithography approach described here allows to photopattern specific bacteria adhesion molecules, to control surface adhesion, and to guide the formation of biofilms. To do this, α-D-mannoside, which is recognized by the Escherichia coli FimH receptor, is linked to a nonadhesive polyethylene glycol surface through a photocleavable 2-nitrobenzyl linker. When a pattern of UV light in a specific shape is projected onto these surfaces, the light-exposed areas become nonadhesive and bacteria only adhere to the dark, unexposed areas in the photopattern. Bacterial photolithography enables bacterial patterning with high spatial resolution down to 10 μm without mechanical interference. Additionally, patterning biofilms with complicated geometries allows studying the importance of microscale spatial organization on the collective behavior of bacteria such as quorum sensing.
关键词： photocleavable groups,bacterial adhesion,quorum sensing,biofilm,photopatterning
更新于2025-09-10 09:29:36
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Adhesion between graphene and polymers: A surface analysis perspective
摘要： Efficient adhesion between polymers and two-dimensional materials, such as graphene, is fundamental and crucial for the development of flexible devices or special coating materials as well as defining the quality of the transfer processes for these materials. Here, contact angle (CA) measurements of four distinct polymers, low-density polyethylene – LDPE, polypropylene – PP, poly (butylene adipate-co-terephthalate) – PBAT and poly (vinylidene-fluoride-co-trifluoroethylene) – PVDF-TrFE, and graphene achieved by chemical vapor deposition (CVD) were used to understand the adhesion phenomena between such materials. The CA measurements were carried out at specific thermal conditions mimicking a transfer process that is based on direct contact of CVD graphene and polymers above their melting temperature (Direct Dry Transfer – DDT). Surface analysis allowed the efficiency of such transfer method to be pre-estimated owing to an understanding of the adhesion properties of both materials by comparing their polar and dispersive components values. However, rheological properties and chemical structures seemed to be equally important in this evaluation, either by molecular weight modification or introduction of chemical groups onto the surface of polymer films. The results allowed for an understanding of the role of the main factors in adhesion phenomena between graphene and polymers and how they can be used to improve graphene coating during transfer processes.
关键词： graphene,coatings,adhesion,nanomaterials,polymers
更新于2025-09-10 09:29:36
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A Synthetic Fluorescent Nanoplatform Based on Benzoxaborole for Broad-Spectrum Inhibition of Bacterial Adhesion to Host Cells
摘要： The rising prevalence of antibiotic-resistant bacteria pathogens has attracted increasing concern in the whole world. The anti-adhesion strategy without triggered bacterial resistance is currently considered a promising alternative to treat bacteria-induced infections. Here, we developed a novel bacteria-binding florescent polymeric nanoplatform for non-lethal anti-adhesion therapy of bacterial infections. This versatile platform will allow simultaneous bacterial agglutination and fluorescent reporting for both Gram-positive and Gram-negative bacteria by taking advantage of strong interaction between the benzoxaborole groups and diol moieties on bacterial surfaces. Furthermore, impressive performance of inhibiting biofilm formation was entirely shown in the generic cell-binding glues. The trapping nanoparticles were capable of taking invasive bacteria pathogens away from the infected host cells with negligible damage to neither bacterial nor host cells, which will not trigger drug resistance, indicating a far-reaching future of the potential application for anti-adhesion therapy of whole-bacterial infection diseases.
关键词： biofilm inhibition,fluorescent polymeric nanoplatform,anti-adhesion therapy,benzoxaborole,antibiotic-resistant bacteria
更新于2025-09-10 09:29:36
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Fabrication of a Bilayer Structure of Cu and Polyimide to Realize Circuit Microminiaturization and High Interfacial Adhesion in Flexible Electronic Devices
摘要： With commercialization of the 5th generation mobile communication system and the further spread of the Internet of Things, industrial innovation is arriving with new business fields related to concepts such as high-speed communication, self-driving vehicles, and remote medicine. One of the challenges is the realization of flexible devices with high-definition circuits, which requires new fabrication techniques for Cu films on polymer substrates to meet demands and an understanding of the Cu/polymer interfacial nanostructure to assure product quality. We have developed a promising technique for the fabrication of Cu film on polyimide (PI), which consists mainly of very simple semiconductor device processes. This technique allows for control of the Cu thickness with nanometer precision to form miniaturized Cu circuits with potential advantages in terms of interfacial adhesion and material/production costs. The Cu/PI interfaces fabricated by conventional vapor deposition and the new technique are systematically analyzed using synchrotron hard-X-ray photoelectron spectroscopy (HAXPES), scanning transmission electron microscopy (STEM), and time-of-flight secondary ion mass spectroscopy (TOF-SIMS). With conventional vapor deposition, it was discovered that evaporated Cu atoms decompose the PI and an oxidation layer with a thickness of several nanometers that deteriorates the interfacial adhesion could be visualized at the Cu/PI interface. With the new technique, the decomposition of PI and interfacial oxidation are significantly suppressed. Furthermore, the proposed technique can be broadly applied to the investigation of metal/polymer interfaces fabricated by polymer coating on a metal substrate, which has so far been impossible.
关键词： STEM,TOF-SIMS,Flexible printed circuits,Microminiaturization,Interfacial adhesion,HAXPES,Flexible electronics
更新于2025-09-10 09:29:36
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Novel Method for Adhesion between PI-PDMS Using Butyl Rubber for Large Area Flexible Body Patches
摘要： This paper reports the use of rubber—Polybutadiene as an intermediate adhesive layer for improving the adhesion between polyimide (PI) and silicone polydimethylsiloxane (PDMS) which is required for a reliable fabrication of flexible/stretchable body patches for various applications. The adhesive bond initiated by the butyl rubber (BR), apart from being extremely strong, is also chemically resistant and mechanically stable as compared to the state of the art processes of improving adhesion between PI and Silicone.
关键词： cross-linking,rubber,PI-PDMS adhesion,stretchable,diffusive adhesion,flexible
更新于2025-09-09 09:28:46
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The photo-stability of acrylic tri-block copolymer blends for the consolidation of cultural heritage
摘要： A variety of adhesives are used for the conservation of paintings. These materials include natural adhesives such as animal glues, waxes, and gums which may chemically degrade over time resulting in unwanted discoloration and mechanical failure. Synthetic adhesives have been introduced to address these concerns. However, most consolidating adhesives have not been specifically formulated and tested to meet the high demands of conservation, ultimately resulting in undesirable physical and mechanical properties. Additionally, some synthetic adhesives are less stable and may cross-link making it difficult to remove years after application. This paper investigates the photo-stability of commercially available tri-block acrylic copolymers (PMMA-PnBA-PMMA) to assess their potential long-term serviceability as consolidants for flaking paint. These copolymers were combined with synthetic low molecular weight resins to reduce viscosity of the adhesive and provide tack. The polymer blends underwent accelerated aging under simulated indoor conditions. Blends were analysed for degradation using Fourier-transform infrared spectroscopy and size exclusion chromatography. Upon irradiation, acrylic copolymers (PMMA-PnBA-PMMA) undergo shifts to higher and lower molecular weight, suggesting that degradation occurs by polymer cross-linking and chain scission. Furthermore, the acrylic copolymer degradation rate was influenced by the type of low molecular weight resin. However, with the addition of a hindered amine light stabilizer these blends exhibited minimal changes in molecular weight. Lastly, the peel strength of the blends were investigated and shown to have comparable peel strength to a popular commercial material, Paraloid? B-72, often used in consolidation thus showing their promise for use within cultural heritage.
关键词： Adhesion,Consolidating adhesive,T-peel strength,Acrylic copolymer,Low molecular weight resin,Painting,Photo-chemical stability,Hindered amine light stabilizer,Urea-aldehyde,Conservation,Hydrogenated hydrocarbon
更新于2025-09-09 09:28:46
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Cold welding of organic light emitting diode: Interfacial and contact models
摘要： This paper presents the results of an analytical and computational study of the contacts and interfacial fracture associated with the cold welding of Organic Light Emitting diodes (OLEDs). The effects of impurities (within the possible interfaces) are explored for contacts and interfacial fracture between layers that are relevant to model OLEDs. The models are used to study the effects of adhesion, pressure, thin film layer thickness and dust particle modulus (between the contacting surfaces) on contact profiles around impurities between cold-welded thin films. The lift-off stage of thin films (during cold welding) is then modeled as an interfacial fracture process. A combination of adhesion and interfacial fracture theories is used to provide new insights for the design of improved contact and interfacial separation during cold welding. The implications of the results are discussed for the design and fabrication of cold welded OLED structures.
关键词： adhesion,OLED,thin films,Cold welding,interfacial fracture
更新于2025-09-09 09:28:46
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Molten Steel Level Detection From Thermal Image Sequence Based on the Characteristics of Adhesive Flux
摘要： High-temperature medium and time-varying covering flux lead to the difficulty of molten steel level measurement. For the measurement, in our previous work, a novel principle by using temperature gradient was proposed by us, and a refractory sensor was inserted into the metallurgical container to sense the temperature gradients of the flux and the molten steel. However, sometimes liquid adhesive flux on the sensor surface disables the extraction of true temperature gradients. To fix this problem, two new models, the adhesion thickness model and the adhesion flowability model, which are inspired by the adhesion mechanism of the flux, are proposed to detect the steel-flux interface. A unified approach, sequential clustering of the shapes of the pixel gray-time curves, is introduced to conduct the detection. On this basis, the thermal image sequence with 4-D spacetime information of the sensor is used for clustering. First, gray values of each pixel in the sequence are sorted in the time dimension, and grouping of the pixels in space dimension is done. Then, the region of interest is extracted from the image sequence to remove the invalid pixels, and sequential clustering is conducted with each group. Finally, the confidence of the clustering results is measured and the clustering results with the confidence higher than the threshold are retained to detect the steel-flux interface. By utilizing the two new models, the standard deviation of the measurement errors reduces from 4.8 to 3.7 mm.
关键词： thermal image sequence,steel-flux interface detection,Adhesion characteristic,4-D spacetime information,sequential clustering
更新于2025-09-09 09:28:46
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UV-Curable Nanoimprint resist with Liquid Volume-Expanding Monomers
摘要： For ultraviolet nanoimprint lithography (UV-NIL), the resist volume shrinkage during curing not only influences the pattern fidelity but also induces defects in the demolding process due to strong adhesion. To address this issue, a novel nanoimprint resist was formulated and characterized in this work. The new resist formulation contains 3,9-diethyl- 3,9-bis(allyloxymethyl)-1,5,7,11- tetraoxastetraoxaspiro [5,5] undecane (DB-TOSU), which is a liquid spiro-orthocarbonate monomer that undergoes volume expansion upon acid-catalyzed polymerization. By mixing DB-TOSU with conventional volume-shrinking epoxy monomers at various weight ratios, the formulated resists had much reduced or even zero volume shrinkage. The resist volume shrinkage, elastic modulus, and demolding force decreased with increasing DB-TOSU weight ratio in resist formulation. When DB-TOSU reached 50 wt.%, the demolding force was reduced by 69% with an adequate elastic modulus (75 MPa) and low shrinkage (1.86%). This novel resist formulation has the potential to allow high-fidelity pattern replication and reduce demolding defects in UV-NIL.
关键词： surface patterning,resist,UV-curable,nanoimprint,adhesion
更新于2025-09-09 09:28:46