Adhesion Energy Research Articles

Review on the Encapsulation, Microencapsulation, and Nano- Encapsulation: Synthesis and Applications in the Process Industry for Corrosion Inhibition

Background: Surfaces of materials often corrode and deteriorate due to environmental conditions. There are various widely used methods of reducing corrosion rates to increase the lifetime of materials and equipment. Recently, there has been a growth in the use of nanotechnology to protect metals against corrosion. The application of nano-encapsulation techniques in the process industry is one of the important eras of nanotechnology. This review paper focuses on encapsulation, microencapsulation, and nano-encapsulation methods, emphasizing nanoencapsulation applications as corrosion inhibitions in the process industry. Methods: Materials based on the self-healing mechanism were used in advanced applications such as structures, batteries, and coatings. These technologies may be studied in two ways: compounds with intrinsic self-healing properties and extrinsic self-healing materials with additives such as microcapsules filled with healing agents. Nano-coatings have advantages, like accelerated ground hardness, adhesive energy, long-time period and/or high-temperature corrosion resistance, tribological residence enhancement, etc. Nano-coatings can also be carried out in thinner and smoother layers, considering flexibility, accelerated performance, decreased fuel costs, and smaller carbon footprints, as well as occasional maintenance. The review of corrosion characteristics of polymeric nanocomposite material was discussed in this paper. Results: This review paper presents an updated overview summarizing the latest advances in the various micro/nanocarriers used for self-healing corrosion protective coatings. Conclusion: With this information, the investigators will be able to modify the structure of the inhibitor to get the necessary corrosion inhibition capabilities. The need for a physical examination is rising as a result.

Evaluation of the influence of the material composition on the peel behavior of adhesive and cohesive peel systems using experimental fracture mechanics methods

AbstractThe study focusses on a low‐density polyethylene/isotactic polybutene‐1 peel system with low‐density polyethylene as matrix and isotactic polybutene‐1 as peel component sealed against itself (cohesive peel system), and on an ethylene vinyl acetate/linear low‐density polyethylene peel system with ethylene vinyl acetate as matrix and linear low‐density polyethylene as peel component sealed against polyethylene terephthalate (adhesive peel system). Due to a new approach to estimate the true fracture surface using 3D reconstruction, it was possible to determine the true adhesive energy release rate, especially for cohesive peel systems. This enables a direct comparison of the fracture mechanics parameters determined from both types of peel systems. The results reveal that the recipe has a distinct influence on the peel behavior. An increasing amount of the used peel component leads in any case to a decrease of the peel force as well as of the energy release rate for both, sealed adhesive and cohesive peel systems. Using application engineering examples generalizable relationships between structure and properties of peel systems could be estimated and the structure sensitivity of the fracture mechanical parameters could be proven.

Effects of surface chemical modifications on the adhesion of metallic interfaces. An high-throughput first-principle analysis

Chemical interactions between two surfaces in contact play a crucial role in determining the mechanical and tribological behavior of solid interfaces. These interactions can be quantified via the adhesion energy, a measure of the strength by which two surfaces bind together. A precise evaluation of how different species at solid contacts modulates their adhesion would be extremely beneficial for a range of different technological fields. In this work we have used and high-throughput approach to systematically explore the effects of the presence of non-metallic elements, at different concentrations, on the adsorption and adhesion energies of different metallic interfaces. Together with the databases for the adsorption and the adhesion energies, we calculated several other properties such as: charge transferred at the interface, d-band edge shift for the substrate, Bond order and the interfacial density redistribution for the hundreds of systems analyzed. These values were used to define different trends with respect to chemical and concentration parameters that could be useful for the development of engineered interfaces. We noticed how the adsorption of almost all non-metallic elements decreases the adhesion of solid interfaces, particularly Fluorine, Phosphorus and Sulfur. Interestingly, Carbon and Boron were the only two species that increased the adhesion instead.

Molecular dynamics simulation of the interaction between aggregates and calcium silicate hydrate and influence of ethylene vinyl acetate copolymer modifier

ABSTRACT It is known that the bonding strength of the aggregate/cement interface affects the overall durability of concrete. However, whether the modification of ethylene vinyl acetate (EVA) copolymer affects the interface interaction between aggregates and cementitious materials is unclear. This study analyzed the interface's static structure, dynamic characteristics, and binding energy. The interaction mechanisms between acid and alkali aggregates and hydrated calcium silicate and the modification effect of EVA were compared. The calculation results of relative density distribution and radial distribution function verified the difference in the structure of EVA-modified acidic or alkaline interfaces. EVA polymer chains significantly blocked the flow of Ca atoms in CaO at the CaO/C-S-H interface and weakened the van der Waals effect at the interface. The mean square displacement and time correlation function analysis indicate that all unmodified interfaces have stable interface structures. After EVA modification, the stability of CaCa-HW decreased significantly, hindered the generation of hydration products, and verified the weak Ca atom transport at the CaO/C-S-H interface. In addition, the adhesion energy of SiO2/C-S-H and CaO/C-S-H after EVA modification decreased by 6% and 14.8%, respectively, quantifying the modification effect of EVA.

Multi-scale analysis and structural application of the synergistic enhancement effect of silane coupling agent on the interface between PVA/rubber and cement

This study employs polyvinyl alcohol (PVA) fibers and silane coupling agent (SCA) to augment rubberized concrete mechanical prowess. A multiscale investigation delves into the synergistic enhancement mechanism of SCA on the interfaces of PVA/cement and rubber/cement, considering macroscopic mechanical properties, microscopic structural characteristics, and nanoscale interface interactions. Initially, fundamental mechanical performance tests reveal a notable enhancement in compressive and flexural strength with the inclusion of SCA and PVA fibers in rubberized concrete. Subsequently, observations of corresponding composite concrete slices are conducted using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR). The results manifest gel and polymer filling interface gaps, with SCA fostering a tighter amalgamation of the two interfaces, effectively rectifying interface defects and elucidating its bonding effects at the microscopic interface. Molecular dynamics (MD) modeling and simulation analyses of PVA/C-S-H and rubber/C-S-H, pre- and post-SCA modification, demonstrate that SCA mitigates interface effects, reinforcing hydrogen bonding, van der Waals interactions, Ca-H coordination bonds, and stability. This augmentation enhances interface adhesion energy, fortifying the weak interface bonding between PVA fibers, rubber, and inorganic silicate (C-S-H). Ultimately, portal frame experiments substantiate that incorporating fiber rubberized concrete into structures not only fails to diminish but marginally enhances the load-bearing capacity of the framework. This research furnishes concrete and innovative solutions for sustainable development while providing a valuable reference for the future application of PVA fiber rubberized concrete materials in practical engineering endeavors.

Superior interface adhesion and protective mechanism of room-temperature-curable polymer composite coating on engineering substrates with lower roughness

In view of the technology bottleneck of the adhesion failure of traditional functional protective coatings on the smoother surface of precise parts served in the marine atmosphere, a room-temperature-curable fluoropolymer/polyurethane (denoted as RFP) polymer composite coating of 20–30 μm is prepared on the metal substrates. Static pull-off and dynamic friction test methods are used to evaluate the interface adhesion of the coating. The coating shows superior adhesive strength of 18–24 MPa on a variety of metal substrates with a wide range of surface roughness (Ra = 0.1–1.6 μm). The friction coefficient of the coating surface is about 0.05–0.08, and the wear life is up to 9–12 km/μm. Furthermore, the adhesion strength of the coating remains 12–14 MPa after 1600 h of salt spray while the wear life of the coating keeps 3–9 km/μm after 720 h of salt spray. The influences of surface roughness (Ra), surface free energy (γOxide), surface potential (φOxide) of the metal substrates and the bonding force at substrate-coating interface on the adhesive energy (Eadh.) are discussed, and the mechanism of "physical-chemical-surface" synergetic enhanced interface adhesion is proposed. The RFP coating is used as the intermediate layer for traditional PU and EP coatings to improve their adhesion on smooth aluminum substrate from 1.39 MPa to 17.5 MPa (increased by 1260 %). Thus, the polymer coating has the potential to provide technical support for the development of long-term anticorrosive coating technology for precision components of marine high-tech equipment.

A strong, silk protein-inspired tissue adhesive with an enhanced drug release mechanism for transdermal drug delivery

In transdermal drug delivery system (TDDS) patches, achieving prolonged adhesion, high drug loading, and rapid drug release simultaneously presented a significant challenge. In this study, a PHT-SP-Cu2+ adhesive was synthesized using polyethylene glycol (PEG), hexamethylene diisocyanate (HDI), trimethylolpropane (TMP), and silk protein (SP) as functional monomers which were combined with Cu2+ to improve the adhesion, drug loading, and drug release of the patch. The structure of the adhesion chains and the formation of Cu2+-p-π conjugated network in PHT-SP-Cu2+ were characterized and elucidated using different characterization methods including FT-IR, 13C NMR, XPS, SEM imaging and thermodynamic evaluation. The formulation of pressure-sensitive adhesive (PSA) was optimized through comprehensive research on adhesion, mechanics, rheology, and surface energy. The formulation of 3 wt.% SP and 3 wt.% Cu2+ provided superior adhesion properties compared to commercial standards. Subsequently, the peel strength of PHT-SP-Cu2+ was 7.6 times higher than that of the commercially available adhesive DURO-TAK® 87–4098 in the porcine skin peel test. The adhesion test on human skin confirmed that PHT-SP-Cu2+ could adhere to the human body for more than six days. Moreover, the drug loading, in vitro release test and skin permeation test were investigated using ketoprofen as a model drug, and the results showed that PHT-SP-Cu2+ had the efficacy of improving drug compatibility, promoting drug release and enhancing skin permeation as a TDDS. Among them, the drug loading of PHT-SP-Cu2+ was increased by 6.25-fold compared with PHT, and in the in vivo pharmacokinetic analysis, the AUC was similarly increased by 19.22-fold. The mechanism of α-helix facilitated drug release was demonstrated by Flori-Hawkins interaction parameters, molecular dynamics simulations and FT-IR. Biosafety evaluations highlighted the superior skin cytocompatibility and safety of PHT-SP-Cu2+ for transdermal applications. These results would contribute to the development of TDDS patch adhesives with outstanding adhesion, drug loading and release efficiency. Statement of significanceA new adhesive, PHT-SP-Cu2+, was created for transdermal drug delivery patches. Polyethylene glycol, hexamethylene diisocyanate, trimethylolpropane, silk protein, and Cu2+ were used in synthesis. Characterization techniques confirmed the structure and Cu2+-p-π conjugated networks. Optimal formulation included 3 wt.% SP and 3 wt.% Cu2+, exhibiting superior adhesion. PHT-SP-Cu2+ showed 7.6 times higher peel strength than DURO-TAK® 87–4098 on porcine skin and adhered to human skin for over six days. It demonstrated a 6.25-fold increase in drug loading compared to PHT, with 19.22-fold higher AUC in vivo studies. α-helix facilitated drug release, proven by various analyses. PHT-SP-Cu2+ showed excellent cytocompatibility and safety for transdermal applications. This study contributes to developing efficient TDDS patches.

Investigating the Thermal Conductance of the Cu/Si Interface Using the Molecular Dynamics Method

Investigating thermal transport at the Cu/Si interface holds significant importance, as understanding interface thermal conductance is crucial for enhancing materials interface thermal management, designing thermal interface materials, and improving the performance of thermoelectric devices. In this study, we conducted molecular dynamics simulations in conjunction with the Green–Kubo relation to calculate the thermal conductance of the Cu/Si interface. We successfully obtained Cu/Si interface potentials using the lattice inversion method. Our findings revealed that the thermal conductance of the Cu/Si interface is notably influenced by the interface structure. Specifically, the thermal conductance of the Cu(001)/Si(001) interface and the Cu(111)/Si(111) interface are similar, and both are higher than that of the Cu(110)/Si(110) interface. Furthermore, through first-principles calculations of the adhesion energy, we discovered that interface binding strength plays a critical role in determining interface thermal transport properties, and the influence of pressure was also discussed. This study contributes not only to the understanding of the thermal transport mechanisms at the Cu/Si interface but also provides important insights for designing novel interface materials.

Effect of oxidation kinetic aging on the adhesion behaviour of asphalt-aggregate interfaces from molecular view

ABSTRACT Asphalt oxidation kinetic aging effect on the adhesion behavior of asphalt-aggregate interfaces at atomistic scale was investigated in this study. The asphalts were aged at different aging durations. The sulfoxide and carbonyl functional group content as well as SARA fractions of the asphalts at different aging times were studied through the tests of Fourier Transform Infrared Spectroscopy (FTIR) and Saturate, Aromatic, Resin and Asphaltene (SARA) fractions. Asphalt molecular models of virgin, rapid-rate aged, slow-rate aged and full-aged were established based on SARA fractions and FTIR results, to construct asphalt quartz and asphalt-calcite interface systems at different aging stages. The simulation results showed that the nanostructure of asphalt is influenced by the aggregate type and asphalt oxidative aging. The growth rates of adhesion energy of asphalt-quartz and asphalt-calcite systems increase rapidly first and then slowly with aging time, but the growth rates are different. Meanwhile, the Van der Waals energy is the major energy source of adhesion energy, and the contribution of van der Waals and electrostatic energy to adhesion energy is different. The aging of asphaltene and resin promotes the adhesion ability to quartz or calcite, while the aging of aromatic components is not conducive and the saturate has almost no effect.

Structures, electronic properties, and delithiation thermodynamics of the heteroepitaxial α-Al2O3//LiMn2O4 (001) and (111) interfaces

Surface coatings play a pivotal role in enhancing the performance of secondary lithium-ion batteries by mitigating undesirable electrolyte activity towards the cathode materials. Metal oxide candidates have been investigated extensively, with α-Al2O3 emerging as a particularly promising coating material owing to its exceptional mechanical and thermal stability alongside low electrical conductivity. Despite the extensive exploration of this application of α-Al2O3, insight into the interplay between the coating layer and the cathode substrate remains incomplete. To address this lack of knowledge, this study employs density functional theory calculations with a Hubbard Hamiltonian and long-range dispersion corrections (DFT+U-D3) to comprehensively investigate the interfacial geometries, stabilities, and electronic properties of α-Al2O3-coated LiMn2O4 (001) and (111) interfaces of varying thicknesses. The individual surfaces were modelled first before constructing the interfaces. We found that the α-Al2O3 (112¯0) and (0001) surfaces match the LiMn2O4 (001) and (111) facets well, exhibiting {1132} and {3121} configurations, respectively, with corresponding misfits of 2.40 and 2.75 %. We calculated the largest adhesion energies of 0.16 and 0.10 eV/Å2 for monolayers with the {1132} and {3121} configurations, respectively, with the stability decreasing as the thickness of the α-Al2O3 layer increases. Further analysis reveals a minor charge accumulation on the substrate, attributed to charge accumulation on the oxygen atoms that participate in the Al-O bond. In contrast, we observed a depletion of charge on the manganese atoms that form the MnO6 units. The vacancy formation energies increase following partial delithiation, prompting minor charge depletion on neighbouring Mn atoms in the form of charge redistribution. The calculated work function increases with respect to the pristine surfaces, indicating that the coated interfaces are less reactive.

New insights on bonding mechanism of FCC and BCC high entropy alloy microparticles upon supersonic impact using micromechanical adhesion test

Coating buildup in cold spraying (CS) relies on particle bonding upon impact, thus making it a significant area of study. High entropy alloys (HEAs) are a class of materials with superior work-hardening ability and resistance to softening, making their particle impact and bonding particularly important to understand for their cold sprayability. In this study, the splat adhesion strength is measured with a scratch test for FCC CoCrFeMnNi and BCC AlCrFeMnNi HEA microparticles deposited on mirror-polished SS304 substrates. Nanoindentation tests were conducted to estimate the tensile and shear strengths of the HEA powders. The results showed that particle deformation and jetting were dominant in the FCC HEA/SS304 system, while substrate deformation was dominant in the BCC HEA/SS304 system. Focused ion beam cross sections of particles confirmed that the FCC HEA had good bonding and underwent significant deformation and grain refinement at the substrate/particle interface, while the BCC HEA had limited bonding only in the sheared zone of the particles.In spite of the very limited deformation of BCC splats, their average adhesion strength was measured to be 451 ± 141 MPa, which is significantly higher than that of FCC splats, with an average value of 308.7 ± 69.3 MPa. Fracture surface analysis revealed that FCC splats consistently exhibit ductile fracture, regardless of whether it occurs at the particle, substrate, or interface. In contrast, for BCC splats, fracture was ductile when occurring at the interface and substrate sides, while it was cleavage when occurring on the particle side. These findings suggest that the toughness and shear strength of the bonding developed at the interface were higher than those of the particle. It was found that the flattening ratio (FR) of the particles decreases for both FCC and BCC HEA splats with an increase in particle size, resulting in a decrease in adhesion strength. Metallurgical bonding has been identified as the primary factor contributing to the adhesion strength of both FCC and BCC HEA splats. Particle penetration, indicative of mechanical interlocking, appears to have little or no effect on adhesion strength. However, it does positively influence the increase in adhesion energy of the splats.

Adhesion Energy-Assisted Low Contact Thermal Resistance Epoxy Resin-Based Composite.

Although intense efforts have been devoted to the development of thermally conductive epoxy resin composites, most previous works ignore the importance of the contact thermal resistance between epoxy resin composites and mating surfaces. Here, we report on epoxy resin/hexagonal boron nitride (h-BN) composites, which show low contact thermal resistance with the contacting surface by tuning adhesion energy. We found that adhesion energy increases with increasing the ratio of soybean-based epoxy resin/amino silicone oil and h-BN contents. The adhesion energy has a negative correlation with the contact thermal resistance; that is, enhancing the adhesion energy will lead to reduced contact thermal resistance. The contact thermal conductance increases with the h-BN contents and is low to 0.025 mm2·K/W for the epoxy resin/60 wt % h-BN composites, which is consistent with the theoretically calculated value. By investigating the wettability and chain dynamics of the epoxy resin/h-BN composites, we confirm that the low contact thermal resistance stems from the increased intermolecular interaction between the epoxy resin chains. The present study provides a practical approach for the development of epoxy resin composites with enhanced thermal conductivity and reduced contact thermal resistance, aiming for effective thermal management of electronics.

The Role of Surface Free Energy in Binder Distribution and Adhesion Strength of Aqueously Processed LiNi0.5Mn1.5O4 Cathodes

This study identifies the critical aspects of binder distribution and mechanical integrity in aqueously processed LNMO cathodes, employing a comprehensive approach involving surface characterization techniques, adhesion strength testing, and electrochemical characterization. The investigation includes the use of the Washburn and Sessile Drop methods for surface free energy analysis, revealing key insights into the interfacial free energy of adhesion between cathode constituents. The results explain the formation of carbon-binder-domains and their impact on adhesion strength, with a particular focus on the conductive additives’ (CA) surface area. The study demonstrates the effectiveness of reducing CA surface area and employing alternative conductive additives, such as vapor-grown carbon fibers (VGCF), in improving adhesion strength and mitigating capacity fade attributed to delamination during cycling. Furthermore, the research emphasizes the role of heat treatment beyond the melting point of the polyvinylidene fluoride (PVDF) latex binder, showcasing its influence on wetting and enhancing mechanical integrity. The presented methodology provides a valuable tool for predicting and optimizing binder distribution, offering insights into improving the overall performance and reliability of aqueously processed cathodes for advanced lithium-ion batteries.

Pressure‐dependent adhesion between solid‐supported PC‐lipid bilayers and vesicles under electric fields

AbstractFusion of lipid bilayers in membranes is important in processes from vesicle‐cell interactions (as in drug delivery) to exosome‐cell signaling, while transient transmembrane electric fields are known to occur spontaneously. Two contacting phosphatidylcholine (PC) lipid membranes are known to fuse into one under external electric fields, suggesting that the interaction between them is modified by the field as they approach, prior to the fusion event. Here we measure directly the adhesion energy between dimyristoylphosphatidylcholine (DMPC) and between distearoylphosphatidylcholine (DSPC) surface layers attached to solid substrates both without and with a transmembrane electric field. We find a marked pressure‐dependent adhesion behavior in the electric field, which we attribute to fusion intermediates that are formed, shedding new light on membrane electro‐fusion.

Effect of food environment on the ability of microorganisms to form biofilms

AbstractThe aim of this study is to understand the effect of the food product's, even in trace amounts, in the biofilm formation potential of Escherichia coli and Staphylococcus aureus. Bacterial adhesion was tested using three different food media, in which bacterial cells were adapted before determining how this would affect their adhesion score and biofilm formation potential: sterilized milk, mineral water, and pasteurized commercial orange juice. After characterization of the bacteria and the adhesion support by the contact angle, the adhesion score obtained by the theoretical mathematical model XDLVO developed by van Oss was compared to that obtained by the experimental approach, in order to examine the role of non‐specific (thermodynamic) and specific (biological) interactions in adhesion. Changes in the membrane composition of bacteria, as a function of acclimation conditions, were evaluated by infrared spectroscopy. Results reveal variability in the spectral region between 900 and 1200 cm−1 specific to capsular polysaccharides (CPS) or lipopolysaccharides (LPS), and also in the range between 2800 and 3000 cm−1 characteristic of membrane lipids and phospholipids. Biofilm formation by S. aureus and E. coli was affected by commercial UHT milk. This led to increased hydrophobicity and total adhesion energy within the environment of these strains. However, no correlation was observed between the adhesion scores obtained through experimental and theoretical approaches. This underscores the necessity of considering the specific characteristics of individual food products in understanding the phenomenon of biofilm formation. Understanding, the mechanism, the variations in bacterial surface characteristics, and the conditions that favor or disadvantage the formation of biofilms, may have important implications, in the development of preventive and curative strategies, to control of food‐borne infections.

Adhesion energy controls lipid binding-mediated endocytosis

Several bacterial toxins and viruses can deform membranes through multivalent binding to lipids for clathrin-independent endocytosis. However, it remains unclear, how membrane deformation and endocytic internalization are mechanistically linked. Here we show that many lipid-binding virions induce membrane deformation and clathrin-independent endocytosis, suggesting a common mechanism based on multivalent lipid binding by globular particles. We create a synthetic cellular system consisting of a lipid-anchored receptor in the form of GPI-anchored anti-GFP nanobodies and a multivalent globular binder exposing 180 regularly-spaced GFP molecules on its surface. We show that these globular, 40 nm diameter, particles bind to cells expressing the receptor, deform the plasma membrane upon adhesion and become endocytosed in a clathrin-independent manner. We explore the role of the membrane adhesion energy in endocytosis by using receptors with affinities varying over 7 orders of magnitude. Using this system, we find that once a threshold in adhesion energy is overcome to allow for membrane deformation, endocytosis occurs reliably. Multivalent, binding-induced membrane deformation by globular binders is thus sufficient for internalization to occur and we suggest it is the common, purely biophysical mechanism for lipid-binding mediated endocytosis of toxins and pathogens.

Effect of aging on micromechanical behavior of asphalt surfaces using an atomic force microscope

The micro-mechanical properties of asphalt surfaces are significantly impacted by short-term aging during construction and long-term aging in service. This, in turn, affects macroscopic characteristics such as asphalt-aggregate adhesion and water stability of asphalt mixtures. The study investigated different aging processes had different impacts on the micromechanical properties of the asphalt on the surface. The short-term aging process had the most significant effects, while the subsequent long-term aging had similar but less important effects. The adhesion, surface energy, and Young's modulus of five different types of asphalt using atomic force microscopy (AFM) in their original state, after short-term aging through the Rolling Thin Film Oven Test (RTFOT), and after long-term aging through the RTFOT+Pressure Aging Vessel (PAV). The results showed that ZH and SK asphalts had a distinct "bee structure", and aging had varying effects on adhesion, surface energy, and Young's modulus in different areas (peak, valley, and other region). Before and after asphalt aging, the adhesion and surface energy approximately followed the order other region > peak > valley, while Young's modulus approximately followed the peak>valley> other region. This indicates that the bumpy "bee structure" does not always correspond to higher modulus or lower adhesion. It was also found that ZH asphalt and SK asphalt with a "bee structure" exhibited better aging resistance compared to KL asphalt without a "bee structure". The study also revealed that aging led to decreased adhesion and surface energy, while increasing Young's modulus. This finding indicates that as asphalt ages, adhesion decreases and asphalt elasticity increases. Additionally, it was observed that the modified asphalt showed less change in adhesion, surface energy, and Young's modulus after aging compared to the matrix asphalt, indicating that SBS modifiers contribute to improving the aging resistance of asphalt. These results will provide a good reference for understanding the microscopic changes in asphalt aging properties.

Acid-base properties and modeling by quantum chemistry of adhesion interactions at the interface of thermoplastic-aluminum systems

Thermoplastic-aluminum systems are used in the manufacture of corrosion-resistant lightweight constructions in aerospace and automotive industries. The adhesion strength of such systems is determined by the mechanism of adhesion interaction. In this article, adhesion interactions between the surfaces of polyethylene terephthalate, poly(propylene carbonate), poly(methyl methacrylate), polystyrene, polypropylene and aluminum were studied to identify a correlation between the acid-base properties of the studied surfaces, the mechanism of adhesion interaction and energy characteristics in thermoplastic-aluminum systems using experimental and theoretical approaches. The experimental approach consisted of finding the values of the free surface energy components, the acidity parameters of thermoplastics and aluminum by the E.J. Berger and van Oss-Chaudhuery-Good methods. The theoretical approach consisted of the study of adhesion interactions in thermoplastic-aluminum systems using the quantum chemistry method B3LYP-GD3/6-31G(d,p). It was theoretically established the functional groups to be the active sites on the thermoplastics surface. At the same time, the strongest adhesion interaction is manifested in systems formed by a carbonyl oxygen atom.The experimental values of the components of the free surface energy of thermoplastics and aluminum are in good agreement with the theoretical values of the energy and force of the adhesion interaction of the systems under consideration.

Analysis of the correlation between mechanical and physicochemical properties of particles based on a diesel oxidation catalytic system

The mechanical and physicochemical properties of diesel engine exhaust particles before and after diesel oxidation catalyst (DOC) treatment are analyzed. It is considered important to explore the interrelationships between these attributes in order to understand their relevance. Understanding of these properties provides insights into the deposition characteristics of particles within the system and the evolution of the particles after the DOC treatment, which may help the selection of appropriate aftertreatment strategies. In this paper, particle samples were collected before and after the DOC to explore the variations in the mechanical and physicochemical properties of the particles under different operating conditions. Atomic force microscopy, thermogravimetric analysis, transmission electron microscopy, and Raman spectroscopy were employed to investigate the attraction force, adhesion force, adhesion energy, oxidative reactivity, primary particle size, nanostructure, and graphitization degree of the particles. The results indicated that under post-injection conditions, the attraction force, adhesion force, and adhesion energy of the particles increased significantly. However, when the particles passed through the DOC, these properties decreased to varying degrees. By analyzing the combination of physicochemical properties, it was determined that the attraction force of the particles was primarily influenced by the primary particle size and the particle's graphite structure. The adhesion force was found to be closely related to the content of soluble organic matter. Additionally, the soluble organic matter affected the degree of particle agglomeration by altering the adhesion energy of the particles.

Abstract 194: Single-cell mechanical analysis reveals that astrocytes and glioblastoma cells have similar viscoelastic properties

Abstract Despite recent advances in treatment, the survival rate of glioblastoma (GBM) patients remains low due to the cancer’s resistance to current treatment modalities. Solid tumors like GBM are known to harbor physical abnormalities at the tissue and cell level. An understanding of GBM cell mechanics may therefore lead to the identification of novel disease mechanisms, biomarkers, and therapeutic strategies to improve treatment outcomes. In this study, we aimed to compare the mechanics of human GBM cells and their normal counterpart, immortalized human astrocytes (IHAs). To accomplish this, we used a parallel-plate flow system to expose single cells to physiological fluid shear stress and recorded the resulting deformation using a camera-coupled microscope. We then utilized digital image correlation analysis to create strain-time profiles of individual cells and fit the profiles with a three-parameter generalized Maxwell model to characterize their nuclear and cytoplasmic viscoelastic properties. We also used fluorescence microscopy and atomic force microscopy to quantify actin density and alignment and adhesion energy in both cell types, respectively. Our results showed that, contrary to extracranial cancer cells, the viscoelastic properties of GBM cells are similar to their normal counterpart. This may explain why metastasis in GBM patients is rare and conventional treatment options are unsuccessful. We also found that actin organization and localization and adhesion energy is different between GBM cells and IHAs. Thus, future research which links the genetic and microenvironmental factors that modulate these unique mechanical features may lead to the development of rational and novel clinical strategies against GBM. Citation Format: Julian Najera, Killian Onwudiwe, Luke Holen, Alice A. Burchett, Dorielis Rodriguez, Maksym Zarodniuk, Saeed Siri, Meenal Datta. Single-cell mechanical analysis reveals that astrocytes and glioblastoma cells have similar viscoelastic properties [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 194.