Stable Adhesion Research Articles

Si diffusion induced adhesion and corrosion resistance in annealed RF sputtered SiC films on graphite substrate

Silicon carbide (SiC) is one of the promising candidates for graphite protection in different applications involving high temperatures and a highly corrosive environment. An ideal Silicon carbide coating should withstand a corrosive environment without compromising its adhesion. Herein, RF magnetron sputtered silicon-rich SiC thin films were deposited on a graphite substrate followed by annealing at 1000 °C, 1200 °C, and 1400 °C in an inert atmosphere. The impact of annealing temperature on microstructure, adhesion and chemical stability of SiC thin films was demonstrated. Different analytical techniques like Scanning electron microscopy (SEM), X-Ray Diffraction (XRD), Fourier's Transform Infrared (FTIR) spectroscopy and nano-indentation were used to study microstructural evaluation and mechanical characteristics. Moreover, the electrochemical analysis (Tafel and Electrochemical impedance spectroscopy) was performed in 3.5% NaCl solution. The microstructural analysis revealed that the amorphous SiC thin film turned into a crystalline and dense film upon annealing. Scanning electron micrographs showed that silicon-rich regions at SiC film surface started to disappear as Si diffuses into graphite matrix at elevated temperatures. Both these factors contributed to improvement in the adhesion of SiC coating with graphite substrate as annealing temperature increased. In addition, the nano-indentation hardness of 5.2 GPa was obtained for as grown sample, which decreased at 1000 °C, and then increased at 1200 °C and 1400 °C. Furthermore, the electrochemical analysis confirmed the enhancement in corrosion resistance upon annealing at a temperature of 1200 °C and 1400 °C due to Si diffusion and film compactness in these samples.

Copolymerization of Parylene C and Parylene F to Enhance Adhesion and Thermal Stability Without Coating Performance Degradation

Copolymerization of Parylene C and Parylene F to Enhance Adhesion and Thermal Stability Without Coating Performance Degradation

Chemical Bath Deposition of Mesoporous Sno2 to Improve Interface Adhesion and Device Operational Stability

Chemical Bath Deposition of Mesoporous Sno2 to Improve Interface Adhesion and Device Operational Stability

The behavior of composite materials based on polyurethan resin subjected to uniaxial tensile test

This paper aims to develop new materials based on polyurethane resin Neukadur Multicast and hardener ISO 2, subsequently reinforced with cowhide threads but also with copper threads. The polyurethane polymer matrix was chosen for the formation of the materials, due to its chemical resistance, mechanical strength, high adhesion and dimensional stability, these advantages contributing to the use of polyurethane resins for high performance composites. To be able to improve the mechanical characteristics of such newly created materials, in this paper, we will try to determine the values of maximum force and maximum elongation at break for a series of specimens created from these materials. For the beginning, the non-reinforced specimens were made, then the specimens, reinforced with a single cowhide fiber, were manufactured, having as matrix the Multicast Neukadur 2 resin system, then the specimens reinforced with two strands of cowhide were formed with three wires. Thus, 5 specimens were formed for each type of reinforcement with cowhide. Following the tensile testing of the specimens, the aberrant values were removed from the sets, keeping three representative tests for each material tested. The tensile test was performed using the Galdabini Quasar 25 machine. For each test specimen, a load / deformation curve was obtained. Based on the results of the experimental tests, as a general conclusion, it can be observed that, in the case of these composite materials, reinforced with fibers, an increase in mechanical strength will occur, due to the phenomenon of the taking over by the reinforcing fibers of the loads to which the specimen is subjected.

Removal of a Model Biofilm by Sophorolipid Solutions: A QCM-D Study.

Biofilms are communities of microorganisms that have been widely studied because they can cause hospital-acquired infections and skin disorders. Polysaccharides secreted by microorganisms are constituents of biofilms, contributing to their adhesion and mechanical stability. Sophorolipids are biosurfactants with the ability to disrupt and remove biofilms. Biosurfactants have been targeted as potential substitutes for classical petrochemical-based surfactants in cosmetics. In this study, we fabricate a β-glucan film as a model biofilm, and quartz crystal microbalance with dissipation monitoring (QCM-D) measurements are used to assess the biofilm removal. The viscoelasticity of the β-glucan films is monitored while sophorolipid solutions are introduced into the system, and we found that the film removal performance increases with the sophorolipid concentration. In addition, Δf (change in frequency)-ΔD (change in energy dissipation) plot analyses reveal that two processes are involved in the removal mechanism. The first process involves the adsorption of water (hydration) on the β-glucan film. The second process involves the removal of the β-glucan film from the sensor surface. Furthermore, it is suggested that sophorolipids interfere with the hydration of the β-glucan film and suppress increases in its viscosity. This is expected to be an essential factor for the removal of the β-glucan film. Sophorolipids, therefore, show potential for use in cosmetics as an eco-friendly agent for biofilm removal.

Control of the Cu morphology on Ru-passivated and Ru-doped TaN surfaces - promoting growth of 2D conducting copper for CMOS interconnects.

Prolonging the lifetime of Cu as a level 1 and level 2 interconnect metal in future nanoelectronic devices is a significant challenge as device dimensions continue to shrink and device structures become more complex. At nanoscale dimensions Cu exhibits high resistivity which prevents its functioning as a conducting wire and prefers to form non-conducting 3D islands. Given that changing from Cu to an alternative metal is challenging, we are investigating new materials that combine properties of diffusion barriers and seed liners to reduce the thickness of this layer and to promote successful electroplating of Cu to facilitate the coating of high-aspect ratio interconnect vias and to allow for optimal electrical conductance. In this study we propose new combined barrier/liner materials based on modifying the surface layer of the TaN barrier through Ru incorporation. Simulating a model Cu29 structure at 0 K and through finite temperature ab initio molecular dynamics on these surfaces allows us to demonstrate how the Ru content can control copper wetting, adhesion and thermal stability properties. Activation energies for atom migrations onto a nucleating copper island allow insight into the growth mechanism of a Cu thin-film. Using this understanding allows us to tailor the Ru content on TaN to control the final morphology of the Cu film. These Ru-modified TaN films can be deposited by atomic layer deposition, allowing for fine control over the film thickness and composition.

Enhancing the durability of hydrocarbon-membrane-based polymer electrolyte water electrolysis using a radical scavenger-embedded interlocking interfacial layer

Cerium oxide-containing interlocking interfacial layer improved mechanical adhesion and chemical stability of the interface. For the first time as a hydrocarbon-based membrane, it operated stably for more than 500 hours.

The Surface Modification of Extruded Polystyrene Foams Through Uv Curing and its Stable Adhesion to Mortar

The Surface Modification of Extruded Polystyrene Foams Through Uv Curing and its Stable Adhesion to Mortar

Pengaruh Trietanolamin Dan Asam Stearat Terhadap Mutu Fisik Dan Stabilitas Mekanik Krim Sari Buah Tomat

Tomatoes contain lycopene which is an antioxidant. Antioxidant preparations can be made in the form of a cream with components of an oil phase, a water phase and an emulsifier. Emulsifiers that can be used are triethanolamine (TEA) and stearic acid. This study aims to determine the effect of triethanolamine and stearic acid as emulsifiers on the physical quality and mechanical stability of tomatoes extract cream. The use of triethanolamine and stearic acid with a ratio of 2%:5%; 3%:10%; 4%:15%. The test are the physical characteristics of tomatoes extract cream included organoleptic, homogeneity, cream type, pH, viscosity, spreadability, adhesion, protection and mechanical stability using the centrifugation method. The results of the phytochemical screening of tomatoes extract were positive for triterpenoids. The test results of the three cream formulas are odorless, semi-solid form, light orange to white color, homogeneous, cream type M/A, pH 5.25 - 6.26; viscosity 5,376 cP - 14,370 cP, spreadability 4 - 5,067 cm, adhesion 4 - 11.6 seconds, protection power 2 - 5.2 seconds. The three cream formulas did not undergo phase separation. The higher concentration of TEA and stearic acid had an effect on viscosity, pH value, adhesion, dispersibility and protection, but had no effect on organoleptic, homogeneity, cream type, and stability. tomatoes extract cream with a concentration of TEA:stearic acid 2%:5% gave the best physical quality.

Middle Ear Packing and External Ear Packing With Fibrin Glue Enhance the Success of Fat Myringoplasty Without Hyaluronic Acid Disc.

Recently, hyaluronic acid disc has been known to enhance the success rate of fat myringoplasty. However, hyaluronic acid disc (Epidisc) is not covered by south Korean medical insurance. To date, fat myringoplasty using middle ear packing has rarely been reported. In this study, we studied whether middle ear packing with dexamethasone soaked gelfoam and fibrin glue over the fat graft could promote the success rate of tympanic membrane perforation (TMP) closure without hyaluronic acid disc, regardless of perforation size. Between January 2005 and July 2020, a total of 209 patients who underwent fat myringoplasty due to chronic TMP at a tertiary referral center were enrolled, and the success rate and audiologic outcomes were analyzed. The mean successful tympanic membrane (TM) closure rate was 88.0%. The success rate by different age groups showed no significant difference. Further, the size of perforation showed no significant difference, and the perforation site (anterior or posterior) was not significant. The preoperative mean thresholds of air conduction (AC), bone conduction (BC), and air-bone gap (ABG) were 55.71, 12.98, and 42.73 dB respectively. The postoperative mean thresholds of AC, BC, and ABG were 23.67, 12.98, and 10.69 dB, respectively. Change in preoperative and postoperative hearing showed was statistically significant. Middle ear packing by gelfoam combined with external ear canal packing using fibrin glue enabled stable adhesion between the remnant TM and the fat graft. Regardless of the size of the TMP, the success rate of the fat myringoplasty by our technique can be enhanced without use of hyaluronic acid disc.

Membrane surface roughness promotes rapid initial cell adhesion and long term microalgal biofilm stability

In biofilm membrane photobioreactors development, conscientious works revolving around the effect of external environment factors on microalgal biofilm growth were assessed but more comparative research about the role of carrier surfaces properties such as surface roughness is necessary. Thus, commercial polyethersulfone (PES) membranes with two different molecular-weight-cut-offs (1 kDa and 30 kDa) were selected as the main representatives of surface roughness in a 20 days long-term biofilm cultivation experiment under dynamic flow condition for the biofilm evolvement of three benthic diatoms (Amphora coffeaeformis, Cylindrotheca fusiformis and Navicula incerta). Results depicted that rougher 30 kDa PES enable higher cell attachment degree for C. fusiformis (25.85 ± 2.75 × 109 cells m−2), followed by A. coffeaeformis (11.86 ± 2.76 × 109 cells m−2) and N. incerta (10.10 ± 0.65 × 109 cells m−2). Bounded extracellular polymeric substances (bEPS) gathered were relatively higher than soluble EPS (sEPS) while bEPS accumulated at least 10% higher on smooth 1 kDa PES than rough 30 kDa PES for the purpose of enhancing the biofilm disruption resistivity under liquid flow. Moreover, cell adhesion mechanism was proposed via computational fluid dynamics in parallel with EPS analysis. Copious amount of asperities and stagnant zones present on rough 30 kDa surfaces accelerated biofilm development and the consistency of the results have a great valence for interpretation of microalgal biofilm lifestyle on porous surfaces.

Ultrastretchable, Adhesive, Fast Self-Healable, and Three-Dimensional Printable Photoluminescent Ionic Skin Based on Hybrid Network Ionogels.

Developing multifunctional stretchable ionic skin (I-Skin) to mimic the sensations of the human skin is of great interest and shows promising potential in wearable sensors and human-machine interfaces (HMIs). However, common ionogels prepared with small-molecule cross-linkers and single networks can hardly satisfy the requirements of adjustable mechanical properties, strong adhesion, fast self-healability, and good stability in extreme environments. Herein, an ultrastretchable (>10,000%), ultrastrong adhesive (>6.8 MPa), ultrafast self-healable (10 s), high thermally stable (-60 to 250 °C), and three-dimensional (3D)-printable photoluminescent ionogel with shape memory properties has been designed. The ionogel consists of hyperbranched polymer covalent-cross-linked poly(zwitterionic ionic liquid)-co-poly(acrylic acid) and multiple dynamic bonding cross-linked networks. The excellent performance of the ionogel-based high-stretchable strain sensor and the triboelectric nanogenerator (TENG)-based self-powered touch sensor is further demonstrated over a wide temperature range (-40 to 150 °C). More importantly, ionogel-based I-Skin can work as an HMI for human gesture recognition and real-time wireless control of robots under extreme vacuum conditions and can also self-heal immediately along with function recovery after mechanical damage.

Modeling cell protrusion predicts how myosin II and actin turnover affect adhesion-based signaling

Orchestration of cell migration is essential for development, tissue regeneration, and the immune response. This dynamic process integrates adhesion, signaling, and cytoskeletal subprocesses across spatial and temporal scales. In mesenchymal cells, adhesion complexes bound to extracellular matrix mediate both biochemical signal transduction and physical interaction with the F-actin cytoskeleton. Here, we present a mathematical model that offers insight into both aspects, considering spatiotemporal dynamics of nascent adhesions, active signaling molecules, mechanical clutching, actin treadmilling, and nonmuscle myosin II contractility. At the core of the model is a positive feedback loop, whereby adhesion-based signaling promotes generation of barbed ends at, and protrusion of, the cell’s leading edge, which in turn promotes formation and stabilization of nascent adhesions. The model predicts a switch-like transition and optimality of membrane protrusion, determined by the balance of actin polymerization and retrograde flow, with respect to extracellular matrix density. The model, together with new experimental measurements, explains how protrusion can be modulated by mechanical effects (nonmuscle myosin II contractility and adhesive bond stiffness) and F-actin turnover.

Adhesion stabilization in the early postoperative period in a rat model

Introduction:Adhesion formation is a complex series of events that results from cellular and molecular processes where, in contrast to the normal case, events that support adhesion genesis dominate over adhesion lysis. Tissue injury, haemorrhage, tissue desiccation and inflammatory processes, among others, play a role in its induction. Since the presence of adhesions can be associated with a number of negative complications, the primary aim is to prevent their development. There are several preventive targets for the process, but in many cases therapy is only provided immediately after the procedure. In this study, we present an experimental rat model of adhesion, where the aim is to understand the stabilization period of adhesion. All animals underwent the same surgical procedure, inducing tissue injury, minor haemorrhage and tissue desiccation, differing only in the timing of reoperations and sampling. On postoperative days 1–7, we assessed macroscopically and histopathologically the type of adhesions formed, the adhesive tissue, the stability of the adhesion. We found that stabilization was a process lasting several days, with unstable and moderately stable adhesions predominating by postoperative day 4. Knowing this allows to broaden the therapeutic window, targeting the most appropriate period in the early postoperative period, possibly combining treatments, to make adhesion prevention even more effective.

Superhydrophobic coatings fabricated by paraffin wax and silica nanoparticles with enhanced adhesion stability

One of the challenges that limits the applicability of nanoparticle-based superhydrophobic surfaces in commercial manufacturing is their poor adhesion. Herein, we demonstrate a simple method that involves the integration of silica nanoparticles and paraffin wax to form an interconnecting network of wax-nanoparticles. The resulting superhydrophobic surface exhibits a static water contact angle of 157.8˚ with improved resistance against tape peeling, linear abrasion, and water sonication compared to those of coatings consist of merely nanoparticles, inferring augmented adhesion of the superhydrophobic films in ambient environment. The simple, scalable, one-step, and eco-friendly fabrication of superhydrophobic coatings with industrially available materials provides promising routes towards practical applications.

The Effects of Adding Heartwood Extractives from Acacia confusa on the Lightfastness Improvement of Refined Oriental Lacquer.

In this study, a renewable polymeric material, refined oriental lacquer (ROL), used as a wood protective coating, and the Acacia confusa Merr. heartwood extractive, which was added as a natural photostabilizer for improving the lightfastness of ROL, were investigated. The best extract conditions for preparing heartwood extractives and the most suitable amount of addition (0, 1, 3, 5, and 10 phr) were investigated. The lightfastness index including brightness difference (ΔL *), yellowness difference (ΔYI), and color difference (ΔE *), and their applied properties of coating and film were measured. In the manufacture of heartwood extractives, the yield of extractives with acetone solvent was 9.2%, which was higher than that from toluene/ethanol solvent of 2.6%, and also had the most abundant total phenolic contents (535.2 mgGAE/g) and total flavonoid contents (252.3 μgRE/g). According to the SEM inspection and FTIR analysis, the plant gums migration to the surface of films and cracks occurred after UV exposure. The phenomena for photodegradation of ROL films were reduced after the addition of heartwood extractives. Among the different amounts of the heartwood extractives, the 10 phr addition was the best choice; however, the 1 phr heartwood extractive addition already showed noticeable lightfastness improvement. The drying times of ROL were extended and film performances worse with higher additions of heartwood extractives. Among the ROL films with different heartwood extractive additions, the ROL film with 1 phr addition had superior films properties, regarding adhesion and thermal stability, compared with the films of raw oriental lacquer.

Interplay of Trans- and Cis-Interactions of Glycolipids in Membrane Adhesion.

Glycolipids mediate stable membrane adhesion of potential biological relevance. In this article, we investigate the trans- and cis-interactions of glycolipids in molecular dynamics simulations and relate these interactions to the glycolipid-induced average separations of membranes obtained from neutron scattering experiments. We find that the cis-interactions between glycolipids in the same membrane leaflet tend to strengthen the trans-interactions between glycolipids in apposing leaflets. The trans-interactions of the glycolipids in our simulations require local membrane separations that are significantly smaller than the average membrane separations in the neutron scattering experiments, which indicates an important role of membrane shape fluctuations in glycolipid trans-binding. Simulations at the experimentally measured average membrane separations provide a molecular picture of the interplay between glycolipid attraction and steric repulsion of the fluctuating membranes probed in the experiments.

Self-Healing Silicone Elastomer with Stable and High Adhesion in Harsh Environments

Adhesive and self-healing elastomers are urgently needed for their convenience and intelligence in biological medicine, flexible electronics, intelligent residential systems, etc. However, their inevitable use in harsh environments results in further enhancement requirements of the structure and performance of adhesive and self-healing elastomers. Herein, a novel self-healing and high-adhesion silicone elastomer was designed by the synergistic effect of multiple dynamic bonds. It revealed excellent stretchability (368%) and self-healing properties at room temperature (98.1%, 5 h) and in a water environment (96.4% for 5 h). Meanwhile, the resultant silicone elastomer exhibited high adhesion to metal and nonmetal and showed stable adhesion in harsh environments, such as under acidic (pH 1) and alkaline (pH 12) environments, salt water, petroleum ether, water, etc. Furthermore, it was applied as a shatter-proof protective layer and a rust-proof coating, proving its significant potential in intelligent residential system applications.

CD271 antibody-functionalized microspheres capable of selective recruitment of reparative endogenous stem cells for in situ bone regeneration

In the strategy of in situ bone regeneration, it used to be difficult to specifically recruit bone marrow mesenchymal stem cells (BM-MSCs) by a single marker. Recently, CD271 has been considered to be one of the most specific markers to isolate BM-MSCs; however, the effectiveness of CD271 antibodies in recruiting BM-MSCs has not been explored yet. In this study, we developed novel CD271 antibody-functionalized chitosan (CS) microspheres with the aid of polydopamine (PDA) coating to recruit endogenous BM-MSCs for in situ bone regeneration. The CS microspheres were sequentially modified with PDA and CD271 antibody through dopamine self-polymerization and bioconjugation, respectively. In vitro studies showed that the CD271 antibody-functionalized microspheres selectively captured significantly more BM-MSCs from a fluorescently labeled heterotypic cell population than non-functionalized controls. In addition, the PDA coating was critical for supporting stable adhesion and proliferation of the captured BM-MSCs. Effective early recruitment of CD271+ stem cells by the functionalized microspheres at bone defect site of SD rat was observed by the CD271/DAPI immunofluorescence staining, which led to significantly enhanced new bone formation in rat femoral condyle defect over long term. Together, findings from this study have demonstrated, for the first time, that the CD271 antibody-functionalized CS microspheres are promising for in situ bone regeneration.

Whole Blood Adhesion to VCAM-1 and P-Selectin and RBC Mechanical Fragility Can be Compromised in Long COVID-19 Patients with Sickle Cell Disease

Introduction: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can cause severe vascular complications associated with endothelial dysfunction and systemic inflammation. COVID19-specific IgG are detectable within a week of infection. Long COVID-19 has been described in patients continuing to exhibit symptoms after the virus is no longer detectable in the respiratory secretions, including fatigue, dyspnea, headache, and brain fog. The recent FAIR Health study reviewed a total of 1,959,982 COVID-19 patients for the prevalence of long COVID symptoms and reported that 23.2% had at least one post-COVID symptom [1]. The underlying biologic mechanisms of long COVID remain unclear, thus treatments are limited to symptomatic relief and supportive care. Many long COVID symptoms are consistent with systemic inflammation and impaired oxygen delivery observed in individuals with sickle cell disease (SCD), in turn associated with elevated blood cell adhesion and decreased red blood cell (RBC) stability. The aim of this study was to determine if deleterious changes in in blood cell properties related to adhesion and membrane stability under stress can be associated with the symptoms of long COVID-19. In this work we evaluated 7 SCD patients that were diagnosed with SARS-Cov-2 and tracked their recovery using semiquantitative IgG and blood cell function assays.Methods: Blood samples were collected by the Foundation for Sickle Cell Disease (SCD) Research from SCD (homozygous SS, n=6) patients coming for regular or urgent clinic visit with SARS-CoV-2 serological and blood cell functions tests performed per the standard of care. Semiquantitative IgG assay was performed using DXi-80 (Beckman Coulter). Flow adhesion of whole blood to VCAM-1 (FA-WB-VCAM)and P-Selectin (FA-WB-Psel) substrates were determined by counting the cells that remain adherent in a microfluidics channel after perfusion with whole blood 1:1 diluted with HBSS buffer and washed by reversed flow at 1 dyne/cm 2. Red blood cell mechanical fragility (RBC MF) was measured as hemolysis induced by an oscillating cylindrical magnet with periodic non-invasive probing of cell-free hemoglobin fraction. Six individuals with SCD recovering from SARS-Cov-2 with biomarker data available both before and for more than 3 months after the infection (179±62 days) were included in the study.Results: IgG levels varied from less than 0.1 to 37, with positive values being defined as IgG > 1. The median estimated half-life of IgG decline was 53 days ranging from 25 to 90 days (the last, for the hospitalized patient). Averaged for IgG positive (IgG+) and IgG negative (IgG-) conditions, combining pre- and post-infection IgG- conditions, values of patient hemoglobin (Hb), FA-WB-VCAM, FA-WB-Psel, and RBC MF cell properties lacked statistical significance (under both a paired t-test and population statistics). Hb levels remained essentially unchanged regardless of the time from infection or IgG status. However, FA-WB-VCAM, FA-WB-Psel, and RBC MF were all significantly elevated after SARS-Cov-2 seroconversion and remained elevated despite declining IgG levels (e.g., Fig. 1). These increases in biomarker values were statistically significant for both FA-WB-VCAM and RBC MF, and were approaching significance for FA-WB-Psel (p<0065). These increases were highly patient-specific with potential return to pe-infection values observed in some cases at about 5-6 months after the infection. A qualitative review of the medical records indicated a new subjective report of fatigue in 5 of 6 patients. Longer observations are required to determine if abnormal blood cell adhesive properties and RBC membrane instability are mechanisms of long-COVID-19 pathophysiology.Conclusions: Whole blood adhesion to both p-selectin and VCAM-1 as well as RBC membrane stability can be significantly impaired in convalescent SARS-Cov-2 patients suggesting an association with long COVID-19. New and emerging treatments that modify whole blood adhesive properties and RBC membrane stability should be investigated for their potential to accelerated recovery from long COVID-19.Health F. A Detailed Study of Patients with Long-Haul COVID: An Analysis of Private Healthcare Claims; White Paper. June 15, 2021 DisclosuresTarasev: Functional Fluidics: Current holder of stock options in a privately-held company. Ferranti: Functional Fluidics: Current holder of stock options in a privately-held company. Allen: Functional Fluidics: Current Employment. Gao: Functional Fluidics: Current Employment. Topping: Functional Fluidics: Current Employment. Ferranti: Functional Fluidics: Current Employment. Makinde-Odesola: Functional Fluidics: Other: conduct research for academic program. Hines: Functional Fluidics: Current holder of stock options in a privately-held company.