Reduction In Adhesive Strength Research Articles

Effective decapsulation method for photovoltaic modules: Limonene-induced EVA controlled swelling under sonication and debonding mechanism analysis

Waste crystalline silicon (c-Si) solar cells are rich in metal resources. The detachment of ethylene-vinyl acetate (EVA) copolymer is a critical step in the recycling of end-of-life (EoL) c-Si photovoltaic (PV) modules, but a clean and high-efficiency adhesive removal method is absent. In this study, we presented a green solvent-based approach using limonene with ultrasound assistance for the efficient delamination of EVA from c-Si PV modules. By adjusting the concentration of limonene solution, the degree of swelling of EVA was effectively controlled, reducing the risk of battery damage caused by uneven swelling. The application of an ultrasonic physical field to the swelling system expedited the diffusion and penetration of the swelling agent between the EVA layers, while simultaneously supplying energy for the fracture of cross-linking bonds. Under the optimized laboratory-scale condition (70 °C, 0.5 h and 0.1 M limonene), complete separation of the glass and backsheet from the EVA bonding layer was achieved. The intact c-Si solar cells thus have the potential to be fully recovered in subsequent processes. FT-IR tests and density functional theory (DFT) simulations confirmed that under ultrasound conditions, limonene molecules selectively attacked crosslinking bridges and side chains of ethyl vinyl acetate in the EVA molecular chain. This induced the breakdown of the EVA crosslinked network structure, resulting in a reduction in adhesive strength and ultimately achieving interlayer separation in 20min. The findings of this study provide theoretical support and technical insights for the clean and efficient recycling of PV modules.

Mechanism Insights of Antibacterial Surfaces Coated with Dead Probiotics.

To understand the antimicrobial effect of surfaces fabricated with dead probiotics, we prepared surfaces decorated with dead probiotics Lactobacillus rhamnosus GG (LGG) with varied inactivation methods and explored their inhibitory interactions with Pseudomonas aeruginosa (PAO1). By combining several techniques, i.e., digital holographic microscopy (DHM), atomic force microscopy (AFM), RNA sequencing, and metabolomic analysis, we studied the three-dimensional (3D) swimming behaviors, surface adhesion, biofilm formation, and adaptive responses of PAO1 near such surfaces. The results show that planktonic PAO1 decreases their flick and reverse motions by downregulating the chemotaxis pathway and accelerates with less accumulation near dead LGG surfaces by upregulating the flagellar assembly pathway and decreasing cyclic adenosine monophosphate. Distinct from live siblings, the surfaces decorated with dead LGG show a significant reduction in adhesion strength with PAO1 and inhibit biofilm formation with more downregulated genes in the Pseudomonas quinolone signal and biofilm formation pathway. We demonstrate that the antibacterial ability of such surfaces stems from the gradually released lysate from the dead LGG that is unfavorable to PAO1 in close proximity. The releasing rate and order depend on the cell membrane integrity, which closely relates to the inactivation methods.

Evaluation of the shear adhesion strength of impact ice by a new method

Aircraft icing has a detrimental effect on flight safety. The design of aircraft anti-icing/de-icing systems requires a thorough comprehension of the adhesion between the ice and the substrate. In this research, the multi-hole rotating cylinder method (MHRC) is developed in an icing wind tunnel. Simulations of interfacial stress show that ice thickness does not change the evenness of stress, whereas reducing the contact area can impair uniformity. Moreover, the ice layer would not experience any cohesive damage during the experiments. The shear ice adhesion strength is evaluated using the methodology outlined in this research. At lower temperatures, glaze ice demonstrates a rise in its shear adhesion strength, while the change trend is the opposite for rime ice. The lowest adhesion strength is observed at the medium volume diameter (MVD) of 45 µm. Furthermore, the growing liquid water content (LWC), rough surfaces, and surface painting will enhance the interface adhesion of ice to the substrate to varying degrees. Stainless steel substrate exhibits higher adhesion strength with ice as compared to aluminum and titanium. In addition, superhydrophobic surfaces have proven to possess a significant reduction in adhesion strength at higher temperature. The proposed experimental method and platform afford accurate measurements of the shear adhesion strength of impact ice in the icing wind tunnel.

Direct observation of oil-surface adhesion via sum frequency generation spectroscopy

ABSTRACT Adhesive technology can joint dissimilar lightweight materials that are used in the automotive industry to improve fuel efficiency. However, the strength of the adhesive bonding is often reduced by oil contaminants on the adherend surfaces. Adhesives should repel the oil layer and diffuse onto the adherend surface, but there is no general design for reliable adhesion on contaminated adherends because of the poor molecular-level understanding of oil-surface adhesion. Here, we report the direct observation of oil-surface adhesion at a two-part epoxy adhesive/aluminum oxide (AlOx) interface via sum frequency generation (SFG) spectroscopy, a method that can probe buried interfaces. The AlOx surface is intentionally contaminated with commercial silicone oil. The SFG spectra of the cured epoxy adhesive/oil-contaminated AlOx interface suggest that the silicone oil remains after curing, explaining the reduction in adhesion strength. Triethylenetetramine, a hardener used in this study, can repel the oil layer, whereas bisphenol A epoxy resin is much less effective at removing the oil layer upon contact. Thus, the migration of both adhesive components onto the AlOx surface is key to securing sufficient oil-surface adhesion. We also applied SFG to second-generation acryl adhesive (SGAA)/AlOx interface and found that SGAA completely repels the oil from the aluminum interface.

A Repeatable Self-Adhesive Liquid-Free Double-Network Ionic Conductor with Tunable Multifunctionality

Liquid-free ionic conductors (LFICs) have promising applications in flexible electronics because most ionic conductors currently suffer from ionic liquid leakage or water evaporation issues. However, it has been a formidable challenge for LFICs to achieve long-term repeated self-adhesion on different substrates, especially on soft biological tissues. Based on the double-network design concept, we first fabricate a series of repeatable self-adhesive liquid-free double-network ionic conductors (SALFDNICs), consisting of stretchable first poly(AA-ChCl)-type supramolecular deep eutectic polymer networks and stiff second polydopamine (PDA) networks, which can maintain sufficient dynamic hydrogen bonds and catechol groups in the ionic conductors by preventing the overoxidation of dopamine, thus balancing the contradiction between adhesion and cohesion in liquid-free ionic conductors. Therefore, SALFDNICs can instantly form various interface interaction forces with multiple substrates (adhesion strength up to 757 N/m) and firmly adhere to various substrates for 20 detachment-reattachment cycles with a reduction in adhesion strength of less than 15%. Furthermore, SALFDNICs also have other comprehensive properties, such as optimum self-healing properties (self-healing efficiency of 90%), good stretchability (strain at break of 1200%), and promising conductivity (2.31 × 10-2 S m-1). Therefore, we believe that the extraordinary performance of SALFDNICs is important for improving device integration and the further development of flexible electronics.

Cell division in tissues enables macrophage infiltration.

Cells migrate through crowded microenvironments within tissues during normal development, immune response, and cancer metastasis. Although migration through pores and tracks in the extracellular matrix (ECM) has been well studied, little is known about cellular traversal into confining cell-dense tissues. We find that embryonic tissue invasion by Drosophila macrophages requires division of an epithelial ectodermal cell at the site of entry. Dividing ectodermal cells disassemble ECM attachment formed by integrin-mediated focal adhesions next to mesodermal cells, allowing macrophages to move their nuclei ahead and invade between two immediately adjacent tissues. Invasion efficiency depends on division frequency, but reduction of adhesion strength allows macrophage entry independently of division. This work demonstrates that tissue dynamics can regulate cellular infiltration.

Calcium-doped titanium thin films prepared with the assistance of an oxygen ion beam: The effect of Ca content on microstructure, mechanical properties and adhesion

The effect of adding calcium on the microstructural evolution and properties of the Ti-Ca-O system has been investigated. Calcium-doped titanium (Ti-Ca) thin films were prepared by dual electron beam deposition with the assistance of an oxygen ion beam. The films were characterized by glow discharge optical emission spectroscopy (GD-OES), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), to determine the elemental composition, chemical bonds and crystallinity. Oxygen ion assistance produces non-completely oxidized Ti-Ca films. The addition of calcium led to increased formation and stabilization of titanium oxides in the titanium matrix under conditions of oxygen deficiency. Replacement of Ti by Ca in TiO and TiO2 was observed, rather than the formation of a CaO and TiCaO mixture. Compound formation, crystallite growth and lattice expansion with rising Ca concentration induced an increase in mechanical properties (hardness and reduced elastic modulus) and surface roughness. High Ca concentration (5 at%) led to a significant reduction in mechanical properties, and above 1 at% led to a significant reduction in adhesion strength. The Ti-Ca films showed hydrophobic behaviour. The water contact angle followed the increasing trend of Ca concentration and surface roughness. There is a discussion of the changes in the studied properties.

Surface Modification and Adhesion Mechanism of Isotactic Polypropylene with Low-Energy Electron-Beam Treatments.

Recently, smaller-size electron-beam (EB) accelerators have offered EB irradiation in laboratory systems. Therefore, polymer surface treatments with low-energy EB have been developed in the past years. For high adhesion strength, low-energy EB treatment is also a promising method in comparison to plasma surface treatment. In the plasma treatment, the mechanism of the effect on the adhesion properties has been proved and the excess treatments led to the formation of a weak boundary layer and reduction of adhesion strength. In contrast, the low-energy EB possesses high penetration ability. In this work, we focused on the surface treatments of isotactic polypropylene (it.PP) with low-energy EB irradiation for adhesion. The dependence of adhesion strength on the absorbed dose of electron beam was evaluated, and the mechanism of electron beam on the adhesion properties was investigated from various perspectives of surface properties and morphology. Compared to that of plasma-treated it.PP, the adhesion strength of it.PP with electron-beam irradiation increased drastically. We proved that the radical was generated in the substrates after electron-beam treatments and would form covalent bonds between adhesives and substrates, which achieved higher adhesion than plasma treatments. In addition, the electron beam reached effectively a deep region from the top surface of the substrates and provided larger adhesion strength.

Fluoride-responsive debond on demand adhesives: Manipulating polymer crystallinity and hydrogen bonding to optimise adhesion strength at low bonding temperatures

This paper reports the solvent-free synthesis of a series of six fluoride responsive debond-on-demand polyurethane (PU) adhesives that contain a silyl functionalised degradable unit (DU). To optimise the adhesion strength and debonding nature of the adhesives, the chemical composition of the PUs was varied according to the structure of the polyol or the diisocyanate component in the polymer mainchain. 1H NMR spectroscopy was used to study the depolymerisation behaviour in solution state. It showed that tetra-butylammonium fluoride (TBAF) triggered the breakdown of the DU unit without fragmenting the polyol mainchain indiscriminately. On exposure to fluoride ions, the PUs underwent depolymerisation with reductions in Mn ranging from 64 to 90% as measured by GPC analysis. The morphology and thermal properties of the PUs were characterised by differential scanning calorimetry (DSC), rheology and variable temperature (VT) SAXS/WAXS analysis. Each technique demonstrated the reversibility of the supramolecular polymer network under thermal stimuli. PUs containing poly(butadiene) soft segments were amorphous with glass transition and viscoelastic transition temperatures dependent on the nature of the soft segment and diisocyanate starting materials. The PU containing a polyester soft segment exhibited a defined melting point at 49 °C. Mechanical stress-strain analysis of the series of PUs showed each exhibited greater than 70% reduction in toughness after treatment with TBAF for 30 min as a consequence of the chemo-responsive degradation of the polymer mainchain. The material featuring an ester-based polyol demonstrated excellent adhesion at bonding temperatures as low as 60 °C. Moreover, this material could be thermally rebonded if broken by force without loss in adhesion strength over three debond-rebond cycles. Lap shear adhesion tests showed a reduction in adhesive strength of approximately 40% (from 11.4 MPa to 7.3 MPa) on exposure to fluoride ions.

Thermally modified Scots pine and Norway spruce wood as substrate for coating systems

Thermally modified wood (TMW) is increasingly used in exterior applications as an alternative to tropical hardwoods or wood impregnated with biocides. Despite its enhanced biological durability and dimensional stability, a surface treatment of TMW with coating systems can be required in certain applications. This study assessed material characteristics of Norway spruce and Scots pine wood that was thermally modified according to the ThermoWood® process and their effect on the performance of commercially available coating systems: a solventborne oil, a waterborne alkyd-reinforced acrylate paint and a waterborne acrylate paint. Residual extractives and remaining degradation products found in TMW, carry the risk of causing discoloration or of interfering with the curing reactions of coating systems. The penetration of coating systems into TMW was not found to differ from unmodified wood, although an excessive penetration of solventborne oil was found occasionally for TMW. The adhesion strength of waterborne coatings depended on the system that was used. While one system performed sufficiently on TMW, the other coating systems showed a considerable reduction in adhesion strength already after a mild treatment (<200°C). This reduction could not be attributed to the increase in hydrophobicity of TMW that was evident from contact angle measurements, but was rather related to the mechanical interaction of the specific substrate/coating system.

PKD2 and RSK1 Regulate Integrin β4 Phosphorylation at Threonine 1736.

The integrin α6β4, a major component of hemidesmosomes (HDs), stabilizes keratinocyte cell adhesion to the epidermal basement membrane through binding to the cytoskeletal linker protein plectin and association with keratin filaments. Disruption of the α6β4-plectin interaction through phosphorylation of the β4 subunit results in a reduction in adhesive strength of keratinocytes to laminin-332 and the dissolution of HDs. Previously, we have demonstrated that phosphorylation of T1736 in the C-terminal end of the β4 cytoplasmic domain disrupts the interaction of β4 with the plakin domain of plectin. Furthermore, we showed that β4-T1736 can be phosphorylated by PKD1 in vitro, and although both PMA and EGF induced T1736 phosphorylation, only PMA was able to activate PKD1. Here, we show that depletion of [Ca2+]i augments PMA- and EGF-induced phosphorylation of β4-T1736 and that this is caused by inhibition of the calcium-sensitive protein phosphatase calcineurin and augmentation of ERK1/2 activation. We also show that in keratinocytes the PMA-stimulated phosphorylation of β4-T1736 primarily is mediated by PKD2 activation downstream of PKCδ. On the other hand, both the EGF-stimulated phosphorylation of T1736 and the EGF-induced dissolution of HDs are dependent on a functional MAPK signaling pathway, and treatment with the RSK inhibitor BI-D1870 prevented EGF-stimulated phosphorylation of β4-T1736. Moreover, phosphorylation of β4-T1736 is enhanced by overexpression of wild-type RSK1, while it is reduced by the expression of kinase-inactive RSK1 or by siRNA-mediated depletion of RSK1. In summary, our data indicate that different stimuli can lead to the phosphorylation of β4-T1736 by either PKD2 or RSK1.

Study on the oxidisation behaviour of particles during thermal spray process

Atomised metallic particles at high-temperature are oxidised easily in thermal spray process, resulting in the generation of defects such as low purity of sprayed metal and reduction in adhesive strength of deposited coating. In this investigation, argon and compressed air were employed as atomisation gas to spray 1Cr18Ni9Ti stainless steel wire by arc spraying. The result indicated that the best atomising effect of spraying particles can be achieved when argon atomising gas was employed. Their particle size were in the range of 20–40 μm, which were about half as large as those using compressed air as atomisation gas. Oxygen content of atomising particles were as follows: 16.66% using argon atomising gas, 25.34% using compressed air and 42.48% using oxygen atomising gas. The presence of Cr diffusion in the coating deposited using argon atomising gas led to a dense interface which determined the adhesive strength of 12.5 MPa.

Effect of alumina, silk and ceria short fibers in reinforcement of Bis-GMA/TEGDMA dental resin

The present study is focused to investigate influence of short fibers such as Alumina Microfibers (AMFs), Silk Microfibers (SMFs) and Ceria Nanofibers (CNFs) as reinforcements in Bis-GMA/TEGDMA resin towards development of composite dental filler. Morphologies of AMFs, SMFs, CNFs and their representative fracture surfaces of the reinforced dental resins/composites were examined by SEM. X-ray Diffraction Analysis was done to analyse the phase of the fibers used in this study and degree-of-conversion of the fiber incorporated base resin was studied by FTIR. Viscosity study of fiber resin mixture, depth of cure and mass change behaviour of the fibers resin composites in artificial saliva were done to analyse the flow ability and physical properties of the fiber resin composites. Mechanical properties of the composites were tested by a universal testing machine. This study demonstrated that incorporation of 10% AMFs, 5% SMFs, and 3.33% CNFs individually in Bis-GMA/TEGDMA dental resin resulted in similar degree of conversion compared to the control. Also the fiber reinforced composites (10% AMFs, 5% SMFs, and 3.33% CNFs) demonstrated significant improvement in mechanical properties compared to Bis-GMA/TEGDMA resin (Control). However, depth of cure was significantly reduced due to incorporation of fibers in the resin. The reinforcement effect of AMFs, SMFs in dental resin was superior due to their uniform distribution and good interfacial bonding between fibers and resin matrix. In case of CNFs, rapid increase in viscosity during mixing of fibers with resin and inhomogeneous mixing were the major problem encountered during formulation, which was mainly associated with high surface to volume ration of the nanofibers. The resultant composite containing CNFs had less improvement in mechanical properties which may be due to less fiber content, formation of agglomerates and improper distribution of the fibers in the composite which subsequently resulted in reduction of adhesive strength.

Structural and mechanical characterization of Al/Al2O3 nanotube thin film on TiV alloy

In this study, the fabrication and characterization of Al/Al2O3 nanotubular arrays on Ti–6Al–4V substrate were carried out. To this end, aluminum thin films were deposited as a first coating layer by direct current (DC) magnetron sputtering with the coating conditions of 300W, 150°C and 75V substrate bias voltage. Al2O3 nanotube array as a second layer was grown on the Al layer by electrochemical anodisation at the constant potential of 20V within different time periods in an electrolyte solution. For annealing the coated substrates, plasma treatment (PT) technique was utilized under various conditions to get the best adhesion strength of coating to the substrate. To characterize the coating layers, micro scratch test, Vickers hardness and field emission of scanning electron microscopy (FESEM) were used. Results show that after the deposition of pure aluminum on the substrate the scratch length, load and failure point were 794.37μm, 1100mN and 411.43μm, respectively. After PT, the best adhesion strength (2038mN) was obtained at RF power of 60W. With the increase of the RF power up to 80W, a reduction in adhesion strength was observed (1525.22mN). From the microstructural point of view, a homogenous porous structure with an average pore size of 40–60nm was formed after the anodisation for 10–45min. During PT, the porous structure was converted to dense alumina layer when the RF power rose from 40 to 80W. This led to an increase in hardness value from 2.7 to 3.4GPa. Based on the obtained data, the RF power of 60W was the optimum condition for plasma treatment of Al/Al2O3 nanotubular arrays on Ti–6Al–4V substrate.

Effect of No-Clean Flux Residues on the Performance of Acrylic Conformal Coating in Aggressive Environments

The influence of no-clean flux residues on the performance of acrylic conformal coating used for printed circuit board (PCB) assemblies was investigated under aggressive exposure conditions using plain coated laminates and PCBs with comb shaped surface insulation resistance (SIR) pattern. Plain laminate substrate and SIR PCBs were cleaned or dosed with no-clean flux residues prior to coatings. Performance studies were carried out by total immersion in deionized water at 60°C for 10 days followed by microscopic investigations and potentiostatic studies on coated SIR patterns at 12 V potential bias and by measuring the resulting leakage current. Foe both plain laminates and SIR patterns, detailed investigation of the corrosion morphology was carried out. The amount of water intake by the coating was calculated by the weight-gain method. The amount of no-clean flux residue resulting at various temperatures was quantified using ion chromatography by extracting the residue, and surface morphology of the residues was investigated using optical microscopy. The flux residue in general consists of both resin and activator components such as carboxylic acids. Coated samples with flux residues after exposure showed blisters all over the surface and reduction in adhesion strength. The coated SIR PCBs with flux residues also showed failure due to electrochemical migration more quickly than on the clean PCBs.

Moisture induced length changes of tile adhesive mortars and their impact on adhesion strength

The durability of tilings is affected by the size and type of ceramic tiles. We therefore performed a study on adhesion and shrinkage mechanisms of large-sized fully vitrified tiles (30cm×30cm), which were applied on a concrete substrate using two different polymer-modified tile adhesive mortars (floor and wall application). The spatial distributions of adhesion strength and mortar hydration degree, as well as the length changes of the composite specimen were determined under various curing conditions. The deformations caused by wetting and drying events are restrained by the stiff tile. Thus, stresses result especially at the edges of the tile, which may cause micro-cracking at the interface of tile and mortar resulting in a reduction of adhesion strength.

Using scratch testing to measure the adhesion strength of calcium phosphate coatings applied to poly(carbonate urethane) substrates

Bioactive coatings are applied to components of modern orthopædic implants to improve the host tissue response to the implants. Such coatings cannot be applied to polymeric implants by high-temperature techniques, because the use of high temperatures may critically degrade the polymer substrate. Regardless of the coating technique that is used, the coating must be sufficiently well adhered to the underlying substrate to provide any practical benefit.This paper investigates the use of scratch testing to measure the adhesion strength of calcium phosphate (CaP) coatings that were applied to a poly(carbonate urethane) (PCU) substrate by an aqueous process at temperatures of 19, 28, 37, and 50 °C. This work represents the first time that scratch testing analysis has been used to study CaP coatings deposited by an aqueous, low-temperature process on to a polymer substrate.Scratch testing was shown to be a useful technique for obtaining comparative, rather than absolute, values of adhesion strength for hard coatings formed on a compliant substrate. Generally, the coating temperature was not found to influence the CaP–PCU adhesion strength. Although CaP coatings formed at 19 °C exhibited considerably lower adhesion strengths than CaP coatings formed at 28, 37, and 50 °C, this finding was attributable to the inconsistency of CaP coatings formed on the PCU substrates at 19 °C.The coating–substrate adhesion strength was measured for CaP coatings of four different coating ages (0, 1, 2, and 3 years). CaP coatings that were aged for 0, 1, or 2 years exhibited similar coating–substrate adhesion strengths to each other. In contrast, CaP coatings that were aged for 3 years demonstrated considerably lower coating–substrate adhesion strengths. The observed reduction in adhesion strength with age was thought to be attributable to suspected “drying out” of the CaP coatings.

Contractility modulates cell adhesion strengthening through focal adhesion kinase and assembly of vinculin‐containing focal adhesions

Actin-myosin contractility modulates focal adhesion assembly, stress fiber formation, and cell migration. We analyzed the contributions of contractility to fibroblast adhesion strengthening using a hydrodynamic adhesion assay and micropatterned substrates to control cell shape and adhesive area. Serum addition resulted in adhesion strengthening to levels 30-40% higher than serum-free cultures. Inhibition of myosin light chain kinase or Rho-kinase blocked phosphorylation of myosin light chain to similar extents and eliminated the serum-induced enhancements in strengthening. Blebbistatin-induced inhibition of myosin II reduced serum-induced adhesion strength to similar levels as those obtained by blocking myosin light chain phosphorylation. Reductions in adhesion strengthening by inhibitors of contractility correlated with loss of vinculin and talin from focal adhesions without changes in integrin binding. In vinculin-null cells, inhibition of contractility did not alter adhesive force, whereas controls displayed a 20% reduction in adhesion strength, indicating that the effects of contractility on adhesive force are vinculin-dependent. Furthermore, in cells expressing FAK, inhibitors of contractility reduced serum-induced adhesion strengthening as well as eliminated focal adhesion assembly. In contrast, in the absence of FAK, these inhibitors did not alter adhesion strength or focal adhesion assembly. These results indicate that contractility modulates adhesion strengthening via FAK-dependent, vinculin-containing focal adhesion assembly.

Structural Determinants of Integrin Binding to the Talin Rod

The adaptor protein talin serves both to activate the integrin family of cell adhesion molecules and to couple integrins to the actin cytoskeleton. Integrin activation has been shown to involve binding of the talin FERM domain to membrane proximal sequences in the cytoplasmic domain of the integrin β-subunit. However, a second integrin-binding site (IBS2) has been identified near the C-terminal end of the talin rod. Here we report the crystal structure of IBS2 (residues 1974-2293), which comprises two five-helix bundles, “IBS2-A” (1974-2139) and “IBS2-B” (2140-2293), connected by a continuous helix with a distinct kink at its center that is stabilized by side-chain H-bonding. Solution studies using small angle x-ray scattering and NMR point to a fairly flexible quaternary organization. Using pull-down and enzyme-linked immunosorbent assays, we demonstrate that integrin binding requires both IBS2 domains, as does binding to acidic phospholipids and robust targeting to focal adhesions. We have defined the membrane proximal region of the integrin cytoplasmic domain as the major binding region, although more membrane distal regions are also required for strong binding. Alanine-scanning mutagenesis points to an important electrostatic component to binding. Thermal unfolding experiments show that integrin binding induces conformational changes in the IBS2 module, which we speculate are linked to vinculin and membrane binding.

Adhesive bonding of aluminium with structural acrylic adhesives: durability in wet environments

The durability of EN AW 6082-T651 aluminium alloy joints bonded with a toughened acrylic adhesive was investigated upon exposure to wet environments (humidity, water immersion and salt water immersion). Environmentally-friendly surface treatments were used to avoid hexavalent chromium. Single lap shear tests were used to determine the durability of the adhesively bonded joints. Specimens were exposed to 31% and 95% relative humidity and submerged in deionized water and 3 wt% sodium chloride solution at 25°C and 50°C, for 10, 30 and 90 days. The data collected in the experiments showed that the durability was higher for surfaces treated with γ-methacryloxypropyltrimethoxysilane (γ-MPS) and sulfo-ferric etchant (P2 etch) than other surface treatments. Both these treatments improved considerably the durability in all environments tested. The results indicate that specimens even without surface treatment maintained a significant residual strength after exposure to low humidity environment (room temperature at 31% RH). The joints exposed to a high humidity environment showed a higher reduction in adhesive strength than those immersed in deionized water and saline solution.