High Adhesive Force Research Articles

Micro-adhesive structure inspired by tree frog toe pads fabricated by femtosecond laser processing of PVA sponge

Tree frogs of the species Zhangixalus arboreus are known to generate high adhesive force in wet environments due to the microstructure of their toe pads. Inspired by this toe pads, we fabricated a micro-adhesive structure with hexagonal channels (500, 375, 250, 188, and 125 μm per side) on the surface of a polyvinyl alcohol sponge. Femtosecond laser processing was used to create fine grooves on the surface of the sponge. When the sponge is pressed against the object, the liquid in the sponge is released onto the contact surface. In wet conditions, it is important to maintain the proper thickness of the liquid phase between the microstructure and the object, and this is achieved by the sponge. The characteristics of friction (shear force) between soft and hard objects differ from those between hard materials. When the liquid present on the contact surface is very small, the surface tension of the liquid phase causes the formation of numerous microcapillary bridges, which generate shear forces. The shear force was evaluated by soaking the sponge with water, pressing (300, 400, 500 μm) a flat or uneven surface against the sponge, and then sliding (20, 40 mm/s) the object. The maximum shear force was 0.22 N for the flat surface and 0.34 N for the uneven surface. It was found that the shear force became smaller when the structure became too fine. This phenomenon is due to the agglomeration of the microstructures.

Improved adhesion and charge transfer between PEDOT:PSS and the surface of a platinum electrode through a diazonium chemistry route

Due to the high applicability of poly(3,4-ethylenedioxythiophene):poly(4-styrene sulfonate) (PEDOT:PSS) in organic electronics, current research is focused on providing new ways to further improve its functionality. In this paper, we have described a one-step process of electrochemical grafting of commercially available diazonium salts to the surface of a Pt electrode as a method to increase mechanical stability of PEDOT:PSS, simultaneously decreasing its charge transfer resistance and increasing capacitance. Pretreatment of Pt electrodes with electrografted layers of 4-nitrobenzene-, 4-methoxybenzene-, and 3,5-dichlorophenyl diazonium tetrafluoroborates is shown to improve charge storage capacity (235 mC/cm2 at the scan rate of 10 mV/s), decrease charge transfer resistance (15.0 ± 0.5 Ω) and enhance capacitance (13.3 ± 0.8 mF). The described method is also efficient in providing coatings with better affinity to the electrode and higher adhesion force.

Drying of Compact and Porous NCM Cathode Electrodes in Different Multilayer Architectures: Influence of Layer Configuration and Drying Rate on Electrode Properties

Porous, nanostructured particles ensure the wetting of electrolyte up to the particle core and shortened diffusion paths, which is relevant not only for lithium‐ion batteries but also for postlithium systems like sodium‐ion batteries. The porous structure leads to a high C‐rate capability. However, compared to conventional compact NCM, porous NCM shows a reduced adhesion force but no or only slight negative influence on C‐rate capability by binder migration at higher drying rates. Herein, a multilayer concept is used to increase the adhesion force with equal or better electrochemical performance compared to single‐layer electrodes. Compact particles of high volumetric energy density and porous particles with high C‐rate capability are combined in a simultaneously coated multilayer electrode. Multilayers with compact NCM toward the current collector and porous NCM with reduced binder content toward the separator side show an about 16‐times higher adhesion force at lower drying rate and an about ten‐times higher adhesion force at increased drying rate compared to electrodes produced of porous NCM only. The specific discharge capacity of the multilayers is increased by 88% at the lower and 67% at the higher drying rate for a discharge rate of 3C compared to a single layer with compact NCM.

Biomimetic high water adhesion superhydrophobic surface via UV nanoimprint lithography

Imitating nature and comprehending its workings is a means for human beings to advance the development of functional materials. In this study, UV nanoimprint lithography technology was utilized to successfully replicate the micro-nano hierarchical structure (micro-papillae and nano-wax tube crystals) present on the surface of the natural fresh lotus leaf. A series of UV-curable waterborne polyurethane acrylate (UV-WPUA) surfaces with special wetting and superhydrophobic properties were obtained. The polydimethylsiloxane negative stamp with lotus leaf’s structure was obtained through a stamp replica molding method, and then the UV-WPUA resin covered with the negative stamp was exposed to 172 nm Xe2* excimer and medium-pressure mercury lamps to mimic the micro-nano hierarchical structure of the lotus leaf. The UV-WPUA surfaces displayed high water adhesion superhydrophobic properties, with a water contact angle reaching 160.8° and water adhesive force of 140.0 μN, and exhibiting excellent self-cleaning performance. The results indicate that higher the UV intensity, the more accurately the surface replicates the micro-nano hierarchical structure of the lotus leaf, resulting in larger water contact angle and higher adhesive force. This study paves the way for the advancement of functional surfaces through the simulation of natural materials.

Formulation and Evaluation of Mucoadhesive Tablets of Acarbose for Type 2 Diabetes

The objective of the study was to develop mucoadhesive tablet of Acarbose (α-glycosidase inhibitor) to enhance the bioavailability and to further reduce the dosing frequency of administration. The Mucoadhesive tablets of Acarbose were prepared by using three different Mucoadhesive polymers such as HPMC E5 LV, Sodium alginate and Guar Gum in varying concentrations and by direct compression technique. The micromeritics evaluation such as angle of repose, bulk density, tapped density, compressibility index and Hausner's ratio showed good to satisfactory flow properties. Swelling index was calculated with respect to time. The swelling index profile of all formulations, prepared as per the experimental design showed an increase in the value of swelling index as the amount of polymer increased. Maximum swelling index was found seen with formulations containing Sodium alginate, the value increases with increasing the amount of sodium alginate. The highest adhesion force i.e. highest strength of mucoadhesive bond was observed with Formulation F9 containing Guar gum as 18.02±0.17 this followed by F6 containing Sodium alginate as 16.33±0.56 and formulation F8 containing Guar gum in the ratio 1:2 as 14.26±0.11. The Adhesion Force increases with increasing the concentration of Mucoadhesive polymers used. The Tablets containing HPMC E5 LV showed least adhesive force than tablets of other formulations. The formulation F6 containing Sodium alginate was taken as optimized formulation based on its mucoadhesive strength and in vitro release was found to be optimum. The optimized formulation was subjected to kinetic drug release studies. The formulation best fitted into zero order kinetics. The drug release was dominated by the erosion and swelling of the polymer. From the release exponent in the Korsmeyer-Peppas model it could be suggested that the mechanism that leads to the release of drug was non-Fickian diffusion. Keywords: mucoadhesive tablet, Acarbose, Gastroretentive

Less Is More: Oligomer Extraction and Hydrothermal Annealing Increase PDMS Adhesion Forces for Materials Studies and for Biology-Focused Microfluidic Applications.

Cues in the micro-environment are key determinants in the emergence of complex cellular morphologies and functions. Primary among these is the presence of neighboring cells that form networks. For high-resolution analysis, it is crucial to develop micro-environments that permit exquisite control of network formation. This is especially true in cell science, tissue engineering, and clinical biology. We introduce a new approach for assembling polydimethylsiloxane (PDMS)-based microfluidic environments that enhances cell network formation and analyses. We report that the combined processes of PDMS solvent-extraction and hydrothermal annealing create unique conditions that produce high-strength bonds between solvent-extracted PDMS (E-PDMS) and glass-properties not associated with conventional PDMS. Extraction followed by hydrothermal annealing removes unbound oligomers, promotes polymer cross-linking, facilitates covalent bond formation with glass, and retains the highest biocompatibility. Herein, our extraction protocol accelerates oligomer removal from 5 to 2 days. Resulting microfluidic platforms are uniquely suited for cell-network studies owing to high adhesion forces, effectively corralling cellular extensions and eliminating harmful oligomers. We demonstrate the simple, simultaneous actuation of multiple microfluidic domains for invoking ATP- and glutamate-induced Ca2+ signaling in glial-cell networks. These E-PDMS modifications and flow manipulations further enable microfluidic technologies for cell-signaling and network studies as well as novel applications.

Influences of Tellurite Glass Frits on the Electrical Properties of Silicon Solar Cells

In this work, a series of tellurite glass frits has been prepared and used as the silver paste in the Ag electrode of the solar cells. The softening temperature of the glass frits have been characterized by the differential scanning calorimeter. The glass frits G3 has the lowest softening temperature, and the corresponding composition of G3 is 42wt.%TeO2-53wt.% PbO-1wt.%B2O3-4wt.%Bi2O3. The surface and cross-sectional microstructures of Ag electrode and the solar cells have been characterized by the scanning electron microscope. The glass frits with lower softening temperature showed the positive influence due to the dense electrode formation and high strength adhesion force. The electrical properties of the solar cells have been also investigated. The solar cells screen printed the silver paste GP3 had the optimum electrical properties, which can be ascribed to the optimized surface and cross-sectional microstructures of Ag electrode. Therefore, the appropriate tellurite glass frits can well improve the electrical performance of solar cells.

Adhesion of Rhodococcus bacteria to solid hydrocarbons and enhanced biodegradation of these compounds

Adhesive activities of hydrocarbon-oxidizing Rhodococcus bacteria towards solid hydrocarbons, effects of adhesion on biodegradation of these compounds by rhodococcal cells and adhesion mechanisms of Rhodococcus spp. were studied in this work. It was shown that efficiency of Rhodococcus cells’ adhesion to solid n-alkanes and polycyclic aromatic hydrocarbons (PAHs) varied from 0.0 to 10.6·106 CFU/cm2. R. erythropolis IEGM 212 and R. opacus IEGM 262 demonstrated the highest (≥ 4.3·106 CFU/cm2) adhesion. The percentage biodegradation of solid hydrocarbons (n-hexacosane and anthracene as model substrates) by Rhodococcus cells was 5 to 60% at a hydrocarbon concentration of 0.2% (w/w) after 9 days and strongly depended on cell adhesive activities towards these compounds (r ≥ 0.71, p < 0.05). No strict correlation between the adhesive activities of rhodococcal cells and physicochemical properties of bacteria and hydrocarbons was detected. Roughness of the cell surface was a definitive factor of Rhodococcus cell adhesion to solid hydrocarbons. Specific appendages with high adhesion force (≥ 0.6 nN) and elastic modulus (≥ 6 MPa) were found on the surface of Rhodococcus cells with high surface roughness. We hypothesized that these appendages participated in the adhesion process.

Tuning the Release Force of Microfibrillar Adhesives by Geometric Design

AbstractSwitchable micropatterned adhesives exhibit high potential as novel resource‐efficient grippers in future pick‐and‐place systems. In contrast with the adhesion acting during the “pick” phase, the release during the “place” phase has received little research attention so far. For objects smaller than typically 1 mm, release may become difficult as gravitational and inertial forces are no longer sufficient to allow shedding of the object. A compressive overload can initiate release by elastic buckling of the fibrils, but the switching ratio (ratio between high and low adhesion force) is typically only 2–3. In this work, new microfibrillar designs are reported exhibiting directional buckling with high switching ratios in the order of 20. Their functionality is illustrated by in situ optical observation of the contact signatures. Such micropatterns can enable the successful release of small objects with high placement accuracy.

Achieving Superhydrophobicity of Zr-Based Metallic Glass Surfaces with Tunable Adhesion by Nanosecond Laser Ablation and Annealing.

Tuning the surface wettability and adhesion of metallic glasses (MGs) is a promising approach to enrich their engineering applications. In this study, using nanosecond laser ablation in air, hierarchical micro/nanostructures were directly fabricated on a Zr-based MG surface. Following subsequent annealing, the surface exhibited superhydrophobicity (maximum contact angle: 166°, minimum sliding angle: 2°). Furthermore, the superhydrophobic surface could be tuned from low to high surface adhesion force by controlling the laser-ablated spot interval. By analyzing the laser-ablated structures and surface chemical compositions, the superhydrophobicity was related to the formation of hierarchical micro/nanostructures and the absorption of organic compounds with low surface free energy in air, and the change in surface adhesion force was attributed to the difference in surface roughness. The experimental results showed that the superhydrophobic surface with low adhesion force could be used in self-cleaning applications, while the superhydrophobic surfaces with different adhesion forces could be used in no-loss liquid transportation. This study provides an efficient and low-cost way to fabricate superhydrophobic MG surfaces with tunable adhesion, which will broaden the functional applications of MGs.

Shaly detritus embedded epoxy-resin coated proppants

Proppant plays a significant role in the hydraulic fracturing process, which can affect the production of oil and gas wells. Due to the high density and low adhesion force, the settling speed of traditional proppants is fast, which will lead to the blockage of a crack channel. In this study, a proppant with double layer structure is fabricated by coating epoxy-resin and shaly detritus on ceramic proppants for the first time, respectively. The epoxy-resin enables the shaly detritus to be coated on the proppant successfully, which can provide a new method for shaly detritus treatment. The adhesive ability of shaly detritus and epoxy-resin coated proppants (SEPs) is improved by 10.4% under the load force of 500 nN, which prolongs the time for the fracture to close. At the same time, the suspending ability of SEPs is two times higher than the uncoated proppants. Once the guar gum solution concentration is 0.3 wt%, the settling time of SEPs is 36.7% longer than that of the uncoated proppants, which can effectively reduce the settlement of proppants in the crack. In addition, the hydrophobicity of the SEPs is enhanced, which reduces the water-oil ratio of crude oil and increases the liquid conductivity tested by deionized water. In summary, this new proppant is expected to promote the development of unconventional oil and gas resources.

Functionalized graphene-oxide nanosheets with amino groups facilitate macroscale superlubricity

Graphene-oxide (GO) has been recognized as an excellent lubrication material owing to its two-dimensional structure and weak interlayer interactions. However, the functional groups of GO that can contribute to anti-friction, anti-wear, and superlubricity are yet to be elucidated. Hence, further improvement in GO-family materials in tribology and superlubricity fields is impeded. In this study, macroscale superlubricity with a coefficient of friction of less than 0.01 is achieved by exploiting the high adhesive force between amino groups within aminated GO (GO-NH2) nanosheets and SiO2. It was observed that GO-NH2 nanosheets form a robust adsorption layer on the worn surfaces owing to the high adsorption of amino groups. This robust GO-NH2 adsorption layer not only protects the contact surfaces and contributes to low wear, but also causes the shearing plane to transform constantly from solid asperities (high friction) into GO-NH2 interlayers (weak interlayer interactions), resulting in superlubricity. A SiO2-containing boundary layer formed by tribochemical reactions and a liquid film are conducive to low friction. Such macroscale liquid superlubricity provides further insights into the effect of functional groups within functionalized GO materials and a basis for designing functionalized GO materials with excellent tribological performances.

A simple manufacturing process of the miniaturised octopus-inspired underwater soft robotic grippers

In this article, we show a new fabrication technique based on CNC machining for the miniaturised octopus-inspired underwater soft robotic grippers. This method provides practical and scale-up production of these grippers. Polydimethylsiloxane/polyethylene terephthalate (PDMS/PET) film (∼7 × 7 cm2) consisting of concave structures in two different geometries (outer and inner) with the suction-based property was produced by using our suggested manufacturing method. The highest adhesion force was obtained on the flat deformable object by the outer concave structured gripper (∼6 kPa) and the flat rigid object by the inner concave structured gripper (∼12 kPa). Moreover, both the grippers exhibit switchable adhesion by changing the retraction velocity as well as high repeatability (over 100 cycles) in underwater conditions. This method will enable practical fabrication of the miniaturised octopus-inspired underwater soft robotic grippers. The proposed manufacturing technique will facilitate the widespread use and commercialisation of the grippers.

Universal linker-free assembly of core-satellite hetero-superstructures.

Colloidal superstructures comprising hetero-building blocks often show unanticipated physical and chemical properties. Here, we present a universal assembly methodology to prepare hetero-superstructures. This straightforward methodology allows the assembly of building block materials varying from inorganic nanoparticles to living cells to form superstructures. No molecular linker is required to bind the building blocks together and thus the products do not contain any unwanted adscititious material. The Fourier transform infrared spectra, high resolution transmission electron microscopic images and nanoparticle adhesion force measurement results reveal that the key to self-organization is stripping surface ligands by adding non-polar solvents or neutralizing surface charge by adding salts, which allow us to tune the balance between van der Waals attraction and electrostatic repulsion in the colloid so as to trigger the assembling process. As a proof-of-concept, the superior photocatalytic activity and single-particle surface-enhanced Raman scattering of the corresponding superstructures are demonstrated. Our methodology greatly extends the scope of building blocks for superstructure assembly and enables scalable construction of colloidal multifunctional materials.

An Ambidextrous STarfish-Inspired Exploration and Reconnaissance Robot (The ASTER-bot).

As more roboticists are turning to Nature for design inspiration, it is becoming increasingly apparent that multisystem-level investigations of biological processes can frequently lead to unexpected advances in the development of experimental research platforms. Inspired by these efforts, we present here a holistic approach to developing an autonomous starfish-inspired soft robot that embodies a number of key design, fabrication, and actuation principles. These key concepts include integrated and sequentially deployable magnetic tube feet for site-specific and reversible substrate attachment, individually addressable flexible arms, and highly efficient and self-contained fluidic engines. These individual features offer a level of synergistic motion control not previously seen in other starfish-inspired robots. For example, our bistable dome-like tube feet are capable of achieving high adhesion forces to ferrous surfaces and low removal forces. These tube feet are further integrated with a fluidic engine to drive the entire arm while maintaining the ability to accurately control the arm position with a 270° range of motion. Furthermore, the arm and fluidic engine are modular, allowing each of the five arms to be replaced in seconds or enabling the exploration of a variety of limb geometries. Through the incorporation of these different design elements, the ASTER-bot (named for its star-like body plan) is capable of locomotion on ferrous surfaces, above and below water, and on nonplanar surfaces. This article further describes the design, fabrication, and integration strategies and characterizes the energetic and locomotory performance of this pentaradial robotic prototype.

Synthesis of Polycaprolactone-Hydroxyapatite (PCL-HA) Biodegradable Nanofibres Via an Electrospinning Technique for Tissue Engineering Scaffolds

The interest in biodegradable polymer nanofibres with tissue cell regeneration potential has increased in recent years. However, there are issues in the development of scaffolding to provide a favourable environment for cell proliferation and attachment. Such issues can be overcome by the addition of hydroxyapatite (HA), which is widely used in biomaterial applications. Biodegradable nanofibres of polycaprolactone (PCL) and hydroxyapatite (HA) have been produced by electrospinning. In this study, PCL was mixed with HA to synthesise nanofibres by single nozzle electrospinning. Furthermore, PCL-HA nanofibres were mixed with fibronectin to investigate the effect of adhesion of fibronectin to the surface of the PCL-HA nanofibres. The structure and morphology of nanofibres were determined by scanning electron microscopy (SEM), the chemical properties of nanofibres were analysed by Fourier transform infrared (FTIR), and the diameter and adhesive force of nanofibers and fibronectin were determined by an atomic force microscope (AFM). The SEM examination revealed the formation of cylindrical and smooth nanofibres with dense fibre networks when 10% HA was used, as HA can generate fibre. FTIR analysis indicated the presence of PCL and HA inside the nanofibres produced by electrospinning. The AFM examination showed that the PCL-HA nanofibres with 100 µg/ml of fibronectin gives the highest adhesion force which is important for the scaffold to resist the force from the external environment. This outcome resulted indicates that the PCL-HA nanofibers with fibronectin are promising for tissue engineering scaffold application. Hence, further investigations are needed to ensure the compatibility of living cells to survive and grow on the PCL-HA nanofibrous mats.

Rapid preparation and antimicrobial activity of polyurea coatings with RE-Doped nano-ZnO.

SummaryThe recent COVID‐19 virus has led to a rising interest in antimicrobial and antiviral coatings for frequently touched surfaces in public and healthcare settings. Such coatings may have the ability to kill a variety of microorganisms and bio‐structures and reduce the risk of virus transmission. This paper proposes an extremely rapid method to introduce rare‐earth doping nano‐ZnO in polyamines for the preparation of the anti‐microbial polyurea coatings. The nano‐ZnO is prepared by wet chemical method, and the RE‐doped nano‐ZnO was obtained by mixing nano ZnO and RE‐dopants with an appropriate amount of nitric acid. This rapidly fabricated polyurea coating can effectively reduce bacteria from enriching on the surface. Comparing with pure nano‐ZnO group, all the polyurea coatings with four different rare‐earth elements (La, Ce, Pr and Gd) doped nano‐ZnO. The La‐doped nano‐ZnO formula group indicates the highest bactericidal rate over 85% to Escherichia coli (E. coli) and Pseudomonas aeruginosa (Pseudomonas). Followed by Ce/ZnO, the bactericidal rate may still remain as high as 83% at room temperature after 25‐min UV‐exposure. It is believed that the RE‐doping process may greatly improve the photocatalytic response to UV light as well as environmental temperature due to its thermal catalytic enhancement. Through the surface characterizations and bioassays, the coatings have a durably high bactericidal rate even after repeated usage. As polyurea coating itself has high mechanical strength and adhesive force with most substrate materials without peel‐off found, this rapid preparation method will also provide good prospects in practical applications.

Epoxy-functionalized Ti3C2 nanosheet for epoxy coatings with prominent anticorrosion performance

The application of MXene in anticorrosion coatings has attracted recent research interest. Limited information exists on the effect of MXene functionalization on anticorrosion performance. In this work, epoxy-functionalized Ti3C2 nanosheets (E-Ti3C2) were prepared by grafting with (3-glycidyloxypropyl) trimethoxysilane and incorporated into solvent-borne epoxy coatings with low mass fractions of 0.3 wt%, 0.5 wt% and 0.7 wt%. The anticorrosion properties of the coatings were investigated by electrochemical impedance spectroscopy and salt spray tests. The highest impedance was achieved for the 0.5 wt% E-Ti3C2 coating, at nearly three orders of magnitude higher than a pure epoxy coating. In contrast, the coating with unmodified Ti3C2 yielded an impedance improvement of approximately one order of magnitude. Salt spray tests manifested the same anticorrosion results. The enhanced anticorrosion improvement by epoxy-functionalization should result from the better dispersibility and chemical bonding between the E-Ti3C2 and matrix. The mechanical properties and adhesion force of the coatings were also evaluated. A better scratch resistance, higher adhesion force and reduced flexibility resulted after E-Ti3C2 incorporation.

Enhanced ethanol production from lignocellulosic hydrolysate using Meyerozyma caribbica biofilm immobilized on modified epoxy foam

In comparison to planktonic cells, microbial biofilm immobilization is known to enhance ethanol production. To maintain this capability during long-term fermentation, the detachment of the biofilm must be prevented. In this study, the enhancement of the biofilm immobilization of the yeast Meyerozyma caribbica YLP01GX on bio-based epoxy foam (EF) was performed through plasma surface modification to improve the production of ethanol from oil palm empty fruit bunch hydrolysate. This newly synthesized EF serves as a suitable carrier due to its superior properties and cost-effectiveness. The modification could induce yeast cell attachment more rapidly with more extracellular polymeric substance (EPS) being produced in the presence of the yeast extract. Therefore, the immobilization period can be shortened. In comparison to untreated EF-immobilized cells (NEF-IC), the modified EF-immobilized cells (MEF-IC) showed an improved binding affinity for proteins in the EPS, which resulted in a higher adhesion force between the carrier and the yeast cell surface. The stable biofilm attachment on the modified EF can prevent biofilm detachment and improve the tolerance of the yeast to inhibitors in the hydrolysate, leading to enhanced ethanol production compared to NEF-IC. Additionally, the MEF-IC was reused several times with similar fermentation activity being observed. This approach offers a more efficient and economical fermentation process.

Effect of Sputter Deposition on the Adhesion and Failure Behavior between Cu Film and Glassy Calcium Aluminosilicate: A Molecular Dynamics Study

Understanding the physical vapor deposition (PVD) process of metallic coatings on an inorganic substrate is essential for the packaging and semiconductor industry. In this work, we investigate a Copper (Cu) film deposition on a glassy Calcium Aluminosilicate (CAS) by PVD and its dependence on the incident energy. Molecular dynamics simulation is adopted to mimic the deposition process, and pure Cu film is grown on top of CAS surface forming intermixing region (IR) of Cu oxide. In the initial stage of deposition, incident Cu atoms are diffused into CAS bulk and aggregated at the surface which leads to the formation of IR. When the high incident energy, 2 eV, is applied, 20% more Cu atoms are observed at the interface compared to the low incident energy, 0.2 eV, due to enhanced lateral diffusion. As the Cu film grows, the amorphous thin Cu layer of 1 nm is temporarily formed on top of CAS, and crystallization with face-centered cubic from amorphous structure follows regardless of incident energy, and surface roughness is observed to be low for high incident energy cases. Deformation and failure behavior of Cu-CAS bilayer by pulling is investigated by steered molecular dynamics technique. The adhesive failure mode is observed, which implies the bilayer experiences a failure at the interface, and a 7% higher adhesion force is predicted for the high incident energy case. To find an origin of adhesion enhancement, the distribution of Cu atoms on the fractured CAS surface is analyzed, and it turns out that 6.3% more Cu atoms remain on the surface, which can be regarded as a source for the high adhesion force. Our findings hopefully give the insight to understand deposition and failure mechanisms between heterogeneous materials and are also helping to further improve Cu adhesion in sputter experiments.