Adhesion Of Films Research Articles

Nanostructured Copper Selenide Coatings for Antifouling Applications.

The accumulation of microorganisms, plants, algae, or small animals on wet surfaces that have a mechanical function causes biofouling, which can result in structural or other functional deficiencies. The maritime shipping industry must constantly manage biofouling to optimize operational performance, which is a common and long-lasting problem. It can occur on any metal structure in contact with or submerged in ocean water, which represents additional costs in terms of repairs and maintenance. This study is focused on the production of antifouling coatings, made with nanoparticles of copper selenide (CuSe NPs) modified with gum arabic, within a water-base acrylic polymeric matrix. During the curing of the acrylic resin, the CuSe NPs remain embedded in the resin, but this does not prevent the release of ions. The coatings released copper and selenium ions for up to 80 days, and selenium was the element that was released the most. The adhesion of film coatings to metallic substrates showed good adhesion, scale 5B (ASTM D3359 standard). Antimicrobial activity tests show that the coatings have an inhibitory effect on Escherichia coli and Candida albicans. The effect is more noticeable when the coating is detached from the substrate and placed on a growing medium, compared to the coating on a substrate. Scanning electron microscopy (SEM) observations show that nanostructured CuSe coatings are made up of rod-shaped and spherical particles with an average particle size of 101.6 nm and 50 nm, respectively. The energy dispersive X-ray spectroscopy (EDS) studies showed that the ratio of selenium nanoparticles is greater than that of copper and that their distribution is homogeneous.

(136) Development and Evaluation of a Novel Penile Blood Oxygen Sensor for Assessing Tissue Oxygenation

Abstract Introduction Penile blood oxygen concentration is a relatively unexplored clinical parameter that can provide valuable insights into various disease processes. Despite the significant role of oxygenation in maintaining penile tissue health and function, there is a paucity of research focusing specifically on monitoring penile blood oxygen levels. This knowledge gap hinders our understanding of the physiological and pathophysiological mechanisms underlying penile disorders and limits the development of targeted therapeutic interventions. Objective The aim of this project was to develop and test a novel noninvasive penile blood oxygen sensor that can accurately assess the oxygen concentration in the penis, enabling a deeper exploration of its clinical significance and potential implications in disease management. Methods We developed a novel prototype of an oxygen sensor designed specifically for penile blood-oxygen assessment. Ethical approval from the Institutional Review Board (IRB) was obtained prior to conducting the study. The trial participants consisted exclusively of patients scheduled to undergo penile duplex ultrasonography at our center. The study population was categorized into three distinct groups: the first group comprised patients diagnosed with Peyronie's Disease (PD) but without clinical erectile dysfunction (ED), serving as our control group; the second group consisted of patients clinically diagnosed with ED, who utilized the sensor with a band and an adhesive film; and the third group included patients who used the sensor without the adhesive film. Results At the time of submission, preliminary data analysis was performed for multiple patients with ED. The analysis of sensor data revealed a distinctive pattern during the initial calibration period, wherein the penile partial pressure of oxygen (pO2) exhibited a gradual decline, likely due to equilibration of the sensor with the penile oxygen concentration. Following the injection, a sharp increase in penile oxygen concentration was observed. Approximately 3-5 minutes following erection, the data from multiple patients showed a discernible downward trend towards the baseline level in penile pO2 levels, and changes in penile oxygenation could be detected as a result of penile manipulation both prior to and after injection. An examination of a patient’s penile changes in pO2 is summarized in Figure 1. Conclusions The observed temporal sequence of changes in penile oxygenation offers valuable insights into the dynamic physiological responses that occur during distinct stages of the erectile process. These findings contribute to our understanding of the intricate mechanisms underlying penile vascular physiology and their roles in erectile function. An analysis of the full patient cohort is currently ongoing. Disclosure Yes, this is sponsored by industry/sponsor: PETROS. Clarification: Industry funding only - investigator initiated and executed study. Any of the authors act as a consultant, employee or shareholder of an industry for: Disclosures: Consultant for AbbVie, Marius, Tolmar, Endo, Petros, Boston Scientific, Coloplast Investor: Sprout.

Composite biofilm chitosan-microcrystalline cellulose for tomato preservation

The demand for packaging has caused a surge in non-biodegradable plastic waste. To tackle this issue, biofilms provide a safe and effective alternative for packaging and preservation. This research focused on combining chitosan and microcrystalline cellulose (MCC) to produce composite biofilms to preserve fresh fruits. The study involved adding varying quantities of MCC, ranging from 0g to 11g, to chitosan using a glycerol plasticizer. The results showed that adding MCC reduced the adhesion of the chitosan-based film, resulting in a more intact film. The surface morphology of the film showed uniform dispersion of MCC particles. The water adsorption and solubility of the MCC-added films increased while biodegradability decreased. The best biofilm for preservation application was the chitosan film supplemented with 3g of MCC. This film helped limit weight loss, vitamin C content, total acid content, and soluble solids loss in tomatoes during storage. Essentially, the chitosan-MCC film helped to reduce water evaporation, respiration, metabolism with the external environment, and penetration of microorganisms on tomatoes, thus extending their shelf life.

Standardized risk-based antibiotic prophylaxis and adhesive film dressing for the prevention of wound infection following cochlear implantation

There is no consensus in the pertinent literature regarding the optimal antibiotic prophylaxis (AP) for cochlear implantation (CI). This study evaluates the implementation of standardized risk-based AP combined with application of an adhesive film dressing. All CI cases since September 2019 were retrospectively reviewed for postoperative wound complications. While all patients received preoperative AP with ceftriaxone, postoperative AP after CI in patients older than 7years was no longer routinely performed in our clinic. Exceptions were made according to predefined criteria for an increased risk of infection. The wound was covered with atransparent adhesive polyurethane film. In 72% of the 219 cases, we did not perform postoperative AP. The overall wound complication rate was 2.7% (in the groups with and without postoperative AP, 4.9% and 1.9%, respectively). Wound infection did not occur in any of the patients without postoperative AP older than 70years (n = 32), with controlled diabetes mellitus (n = 19), or with reimplantation due to technical defect (n = 19). The film did not need to be changed until the suture material was removed. Standardized risk-based AP can avoid prolonged administration of antibiotics in selected patients. The film dressing permits continual examination and sufficient wound protection.

Effect of the TiSiN interlayer properties on the adhesion and mechanical properties of multilayered TiSiCN thin films

The interlayer design is crucial in optimizing the adhesion of TiSiCN thin films on tool steel. Thus, Ti/TiN/TiSiN interlayer systems were deposited varying the TiSiN interlayer bias voltages (−100 V, −150 V, −200 V) in a magnetron sputtering process to investigate the influence on the mechanical properties and adhesion of the TiSiCN top layer with different thicknesses.A higher bias voltage densifies the TiSiN interlayer structure, thereby increasing its residual stresses (0.11 GPa to 1.46 GPa) and hardness (28.1 GPa to 34.9 GPa). This occurs without affecting the columnar-like microstructure of the TiSiCN top layer and its hardness (25.9 GPa to 29.1 GPa for t = 1.0 μm, 22.6 GPa to 24.8 GPa for t = 2.3 μm). Adhesion classification by Rockwell C indentation of TiSiN declined from HF2 to HF4 due to increased residual stresses, impacting TiSiCN top layer adhesion with a similar deterioration. Scratch tests revealed reduced critical loads Lc2 and Lc3 for the TiSiN interlayer system and also for TiSiCN top layers. The highest critical loads were observed for TiSiCN (1.0 μm) and TiSiCN (2.3 μm) with TiSiN interlayer deposited at a bias voltage of −100 V, measuring (64.4 ± 4.5) N and (73.4 ± 8.3) N for Lc2, and (57.4 ± 5.3) N and (71.6 ± 4.5) N for Lc3, respectively. Increasing bias voltage decreases Lc2 and Lc3 to (23.2 ± 4.5) N and (50.20 ± 2.2) N for TiSiCN (1.0 μm), and (21.4 ± 4.5) N and (58.0 ± 3.6) N for TiSiCN (2.3 μm).Achieving high adhesion strength of TiSiCN multilayered system requires minimizing the residual stress differences between the layers. Therefore, when designing a complex multilayer structure for TiSiCN thin films, careful consideration of the stress state among the layers is crucial, which is achieved by adjusting the bias voltage.

Physically and Chemically Stable Molybdenum-Based Composite Electrodes for p-i-n Perovskite Solar Cells.

Metal halide perovskite solar cells (PSCs) have garnered much attention in recent years. Despite the remarkable advancements in PSCs utilizing traditional metal electrodes, challenges such as stability concerns and elevated costs have necessitated the exploration of innovative electrode designs to facilitate industrial commercialization. Herein, a physically and chemically stable molybdenum (Mo) electrode is developed to fundamentally tackle the instability factors introduced by electrodes. The combined spatially resolved element analyses and theoretical study demonstrate the high diffusion barrier of Mo ions within the device. Structural and morphology characterization also reveals the negligible plastic deformation and halide-metal reaction during aging when Mo is in contact with perovskite (PVSK). The electrode/underlayer junction is further stabilized by a thin seed layer of titanium (Ti) to improve Mo film's uniformity and adhesion. Based on a corresponding p-i-n PSCs (ITO/PTAA/PVSK/C60/SnO2/ITO/Ti/Mo), the champion sample could deliver an efficiency of 22.25%, which is among the highest value for PSCs based on Mo electrodes. Meanwhile, the device shows negligible performance decay after 2000 h operation, and retains 91% of the initial value after 1300 h at 50-60 °C. In summary, the multilayer Mo electrode opens an effective avenue to all-round stable electrode design in high-performance PSCs.

Lap shear properties of CF/PEKK composites through nanoparticle-enhanced adhesive joints

This study investigates the effects of incorporating halloysite nanotubes (HNTs) into polyetherimide (PEI) adhesive for carbon fiber/polyetherketoneketone (CF/PEKK) composite joints. The CF/PEKK substrate is fabricated through an oven consolidation process, while PEI adhesive films with varying HNTs loadings (0.5, 1 and 3[Formula: see text]wt.%) are prepared using solvent casting with [Formula: see text]-butyrolactone. Homogeneous dispersion of HNTs in PEI is achieved through magnetic stirring and IR heating. The resulting film is hot pressed to form a 100[Formula: see text][Formula: see text]m thick film, and adhesive lap shear joint specimens are manufactured through oven consolidation. Morphology and dispersion of HNTs in PEI are analyzed using SEM and EDS, revealing favorable dispersion at 0.5[Formula: see text]wt.% HNTs and aggregation at higher loadings. Differential scanning calorimetry (DSC) is employed to study the glass transition temperature (Tg) of PEI, showing decreased Tg for solvent-cast PEI and increased Tg with HNTs incorporation. This increase is attributed to the constrained mobility of polymer chains due to HNTs’ influence. Lap shear strength (LSS) is evaluated, demonstrating enhancement with HNTs incorporation: 0.5[Formula: see text]wt.% HNTs (+12.5%) > 1[Formula: see text]wt.% HNTs (+8.33%) > Pure PEI > 3[Formula: see text]wt.% HNTs (−12.5%). The study attributes this enhancement to HNTs’ reinforcement and chemical interactions with PEKK. Aggregation tendencies at 3[Formula: see text]wt.% HNTs lead to decreased LSS. SEM-EDS analysis of fractured specimens indicates a multifaceted bonding joint interface involving PEKK, PEI and HNTs. CF/PEKK composites show adhesive, cohesive and adherend failure modes, with adherend failure being dominant. Notably, fabric-like textures and plastic deformations in PEI with 0.5[Formula: see text]wt.% HNTs contribute to enhanced LSS, while higher HNTs content leads to cohesive failure due to aggregation. This study provides insights into optimizing composite adhesive systems by harnessing nanotube reinforcement and controlling dispersion, thereby influencing interfacial strength.

A magnetic multi-layer soft robot for on-demand targeted adhesion

Magnetic soft robots have shown great potential for biomedical applications due to their high shape reconfigurability, motion agility, and multi-functionality in physiological environments. Magnetic soft robots with multi-layer structures can enhance the loading capacity and function complexity for targeted delivery. However, the interactions between soft entities have yet to be fully investigated, and thus the assembly of magnetic soft robots with on-demand motion modes from multiple film-like layers is still challenging. Herein, we model and tailor the magnetic interaction between soft film-like layers with distinct in-plane structures, and then realize multi-layer soft robots that are capable of performing agile motions and targeted adhesion. Each layer of the robot consists of a soft magnetic substrate and an adhesive film. The mechanical properties and adhesion performance of the adhesive films are systematically characterized. The robot is capable of performing two locomotion modes, i.e., translational motion and tumbling motion, and also the on-demand separation with one side layer adhered to tissues. Simulation results are presented, which have a good qualitative agreement with the experimental results. The feasibility of using the robot to perform multi-target adhesion in a stomach is validated in both ex-vivo and in-vivo experiments.

Mechanical response of carbon fiber reinforced epoxy composite parts joined with varying bonding techniques for aerospace applications

As a result of the widespread use of composite materials in primary structures of aerospace platforms, composite joining became more crucial. This study addresses the effect of joining methods on the strength of composite joints experimentally, numerically and analytically. Single lap joint shear strengths of carbon fiber reinforced epoxy composite parts joined by mechanical fastening with a pop and solid rivet, secondary bonding with a paste adhesive, co-curing and co-bonding techniques were compared. In addition, the effect of adhesive thicknesses (0.2, 0.4, 0.6, 0.76 mm) on the single lap shear strength was investigated. Carbon fiber reinforced composite (CFRP) samples were produced according to the ASTM 5868 standard. After the production of samples with varying joining methods, single lap shear tests were implemented. Moreover, the interface damage in the composites was examined by use of a scanning electron microscope (SEM) for the purpose of studying the damage mechanism. Fracture mechanisms corresponding with bonding methods were also assessed by examining the fracture surface of the composite samples. Furthermore, results were analyzed by Hypermesh, ABAQUS and ESAComp. For instance, the co-bonded sample with an adhesive film exhibits an experimental shear strength of 24.03 MPa which deviates only 3 % from the numerical expectation.

Development of anti-bacterial adhesion and antibacterial sulfobetaines modified chitosan/polyvinyl alcohol composite films as packaging materials

Chitosan exhibits a wide source, non-toxic and biodegradable, and is the optimal functional raw material for preparing food packaging materials. However, the pure chitosan film has some disadvantages such as limited antibacterial activity and weak mechanical properties. In this study, sulfobetaines modified chitosan (CS-SBMA) was synthesized by grafting copolymerized betaine methacrylate sulfonate onto the chain of chitosan to improve the anti-bacterial adhesion and antibacterial properties of chitosan, aiming to develop antibacterial and anti-bacterial adhesion films based on CS-SBMA and polyvinyl alcohol (PVA) by the casting method. The structure of CS-SBMA was characterized by 1H NMR and FTIR. The appropriate proportion of CS-SBMA/PVA was determined to be 1/1 and 1/2, by characterizing the composite films with FTIR, XRD, SEM, mechanical, optical, and water resistance behaviors. In addition, CS-SBMA/PVA films showed excellent antibacterial, anti-bacterial adhesion and biofilm control function. The colonies number of E. coli and S. aureus on the surface of CS-SBMA/PVA 1/1 film decreased 94.15 % and 94.27 %, respectively, and 92.93 % of S. aureus and 94.87 % of E. coli colonies were inactivated within 60 min contact. These results indicate that CS-SBMA/PVA film exhibits potential antibacterial and anti-bacterial adhesion properties, which is suitable for food packaging materials.

Growth mechanism, structure, stoichiometry and optical properties of electrochemically grown iron selenide and ferroselite thin films

In this present work, FeSe and FeSe2 thin films were deposited on ITO substrate at different electrolytic bath temperatures at 30 °C and 70 °C by using electrodeposition method. The growth mechanism was investigated via cyclic voltammetry with the potential window was found to be −1600 to 1600 mV versus SCE and the formation of well adherent film was found to be higher bath temperature. XRD result shows the deposited FeSe and FeSe2 films found to exhibit stoichiometric wurtzite and orthorhombic phases respectively. The microscopic observation shows, the uniform particle growth of FeSe and FeSe2 was found to be higher electrolytic bath temperature at 70 °C. The EDX analysis shows the deposited FeSe and FeSe2 films at higher temperature elemental is stoichiometric ratio. The determined bandgap values for FeSe (1.26 eV) and FeSe2 (1.07 eV) deposited at 70 °C. Also, we observed that the refractive indices (n) values was increased for the film deposited from 30 °C to 70 °C resulting, the estimated refractive indices (n) for FeSe and FeSe2 are 3.16 and 3.45 respectively. Furthermore the most significant optical parameters extinction coefficient (k), optical conductivity (σoptical), real (Ɛ1) and imaginary (Ɛ1) dielectric constants and dissipation factor (tan δ) are determined in order to investigate their usefulness in photovoltaic applications.

Experimental assessment of lamination processing method for liquid-based hybrid PV/T modules

Due to the lack of in-depth research on lamination processing methods for PV/T technology, typical flat-plate PV/T modules still face severe lifespan issues that require urgent solutions. Thus, this study proposes a specialized two-stage lamination process method. The efficacy of this process flow in addressing the challenging issue of microscopic hidden cracks in PV cells, which commonly occurred during the processing of PV/T modules, was confirmed through a comprehensive electroluminescence testing procedure. An analysis was conducted to examine the interrelationship between the thermal pressing process, peel strength, and crosslinking degree of the hot-melt adhesive film on both the absorber plate and external surface of the transparent TPT (Tedlar/PET/Tedlar) layer. The results indicated that a high level of peel strength (50 N/cm to 80 N/cm) was achieved between the adhesive film and absorber plate with a selective absorption coating, while ensuring compliance with crosslinking requirements and preventing bubble issues. Therefore, the novel process method proposed in this paper for PV/T modules can effectively address the bottleneck of lifespan issues that have remained unresolved in PV/T technology for years.

Effect of Pigment-Acrylic Binder Ratio on the Surface and Physical Properties of Resin Finished Leather

The current study attempts to investigate the surface phenomenon and physical characteristics of leather finished with brown pigment and different types of acrylic binders. Using the contact angle measurements of three different liquids on the above finished leathers and films, the surface energy and work of adhesion were evaluated. The pigment to acrylic binder ratio (PABR) for best adhesion of finish film on the leather surface was optimized using the contact angle goniometer. Different types of acrylic binder films were coated and their surface behaviour was studied. The crust leather was coated with different types of pigment-acrylic binder (Very Soft, Soft and Medium Soft) finish formulations. The contact angle of both the acrylic films and the PABR finished leathers were measured against Water, Dimethyl sulfoxide (DMSO) and Hexadecane (HD). According to the study’s results, the surface properties of finished leather were directly related to the degree of wetting. The PABR was found to be effective at 1:3 for very soft binder, 1:2.5 for soft, 1:2 for medium soft binders due to higher contact angle and lower surface energy values (γsv). At 1:3 and 1:2.5, the contact angle of very soft and soft binder leather was 82.62° and 83.45° and for medium soft binder it was 82.67° at 1:2 ratio. The surface energy values of optimized PABR of very soft binder (1:3) was 28.29 (mN/M), soft binder (1:2.5) was 27.50 (mN/m) and medium soft binder (1:2) was 29.27 (mN/m). The optimized PABR work of adhesion values of very soft binder, soft binder and medium soft binder was 82.15 (mJm-2), 81.11 (mJm-2), 82.09 (mJm-2). In order to correlate the observed surface properties with leather finish properties, finished leathers were tested for finish adhesion, vamp flexing value, water vapour permeability, wet and dry rub fastness. According to the water vapour permeability, soft and medium binder showed good permeation due to the uncovering of nanopores. But the adhesion, grain crack resistance and grain smoothness were higher in the case of the soft binder. Overall leather properties divulges that the pigment to binder ratio and the type of binder plays an important role in surface properties of the finished leather. This study enables us to determine the optimal PABR for effective finish properties to meet the required leather standards for various usage, as well as better utilisation of finishing chemicals.

A comparison between the titanium-based and the zinc phosphate dispersion conditionings of zinc phosphate baths

ABSTRACT Phosphating is a metallic surface treatment widely used in the industrial environment as it provides greater adhesion of the paint film to the metallic substrate and greater efficiency in inhibiting corrosion. The conditioning agents in the phosphating process contribute to reducing the time to obtain the phosphate layer and favor the refinement of the formed crystals. Commercially, the most used conditioning agent is based on titanium salts, however, it is possible that other compounds may be an alternative in optimizing the industrial process. Therefore, with the aim of reducing the time and temperature of the phosphating process, this work aims to verify the performance of using the conditioning agent based on zinc phosphate in obtaining the phosphatized layer, in terms of corrosion resistance, in comparison with to the titanium-based conditioner. For this purpose, SAE 1010 carbon steel samples were degreased and sandblasted, immersed for 1 minute in the conditioning solution (titanium or zinc phosphate) and phosphated with a commercial solution of tricationic zinc phosphate at different temperatures (40 and 50°C) and immersion times (2, 3 and 4 minutes). The deposited masses of the phosphate coatings were measured and the coatings characterized by scanning electron microscopy (SEM), through electrochemical tests of open circuit potential and potentiodynamic polarization. The results showed that the greater coverage of the substrate, with the formation of denser layers, improves the anticorrosive performance of samples phosphated with both conditioners. For the titanium-based conditioner, the optimal phosphating conditions were 3 min at 50°C, while for the zinc phosphate conditioner, they were 2 min at 40°C. Therefore, for commercial use, immersion in a zinc phosphate-based conditioner is indicated, followed by phosphating for 2 min at 40°C.

Evaluation of the Mechanical Behavior of Soil Stabilized with Asphalt Emulsion Using Multi-Stage Loading

The objective of this research was to assess the mechanical response (resilient and plastic) of soil stabilized with petroleum asphalt concrete using asphalt emulsion under multi-stage loading. To enhance the adhesion of the asphalt film to the soil grains, the stabilized soil underwent air-drying curing for seven days. Dosage was conducted through the indirect tensile strength test using diametral compression. With the optimum content determined in the dosage (2% emulsion), additions and removals of 0.5% asphalt emulsion from this content were performed. Consequently, three specimens were molded with concentrations of 1.5%, 2%, and 2.5% of slow-setting cationic asphalt emulsion. These specimens were then subjected to drained triaxial tests under multi-stage loading, using 5 different stress pairs, totaling 50,000 cycles. Analyzing the regions defined by the total and permanent deformation curves allowed studying the plastic and elastic response, the proportionality between these regions, and the increase in elastic and plastic regions of the soil and stabilized soil in a single test, providing a more accurate interpretation. Regarding the measured deformations, as the deviator stress was increased with each loading cycle, the stabilized samples exhibited an increase in plastic deformations compared to the natural soil (control). It was also observed a proportional increase in the resilient region, indicating that the addition of asphalt made the soil less rigid but provided cohesion that was absent before stabilization. Doi: 10.28991/CEJ-2024-010-01-02 Full Text: PDF

Use of silicon or carbonitriding interface in the adhesion of Ag-DLC film on titanium alloy: a comparative study

Use of silicon or carbonitriding interface in the adhesion of Ag-DLC film on titanium alloy: a comparative study

Improving design features and air bubble manipulation techniques for a single-step sandwich electrochemical ELISA incorporating commercial electrodes into capillary-flow driven immunoassay devices.

Integrating electrochemistry into capillary-flow driven immunoassay devices provides unique opportunities for quantitative point-of-care testing. Although custom electrodes can be inexpensive and are tunable, they require skilled fabrication. Here, we report the incorporation of a commercial electrode into a capillary-flow driven immunoassay (iceCaDI) device for a single end-user step sandwich electrochemical enzyme-linked immunosorbent assay (ELISA). The iceCaDI device is a pump-free portable microfluidic device with an integrated commercial screen-printed electrode and flow driven by capillary action. The iceCaDI device is composed of alternating polyester transparency film and double-sided adhesive film layers that are patterned with a laser cutter. This platform was designed to address known limitations of laminated device fabrication methods and operation. First, we developed a foldable laminated device fabrication using hinges for easy assembly and precise alignment. Second, reagent dispersing was achieved by incorporating a 1 mm wide arrow-shaped notch in the middle of the channel that trapped an air bubble and formed a baffle that facilitated reagent spreading to cover the detection area. Third, small vent holes were added to the top layer of the channels to prevent air bubbles from blocking flow. Finally, we fabricated a CRP immunosensor with a detection range of 0.625 to 10.0 μg mL-1 as a proof-of-concept to demonstrate an automatically driven sandwich electrochemical ELISA using the iceCaDI device. Three concentrations of CRP were successfully measured under flow conditions within 8 min. Our proposed device is a promising approach and a step forward in the development of point-of-care (POC) devices for techniques that traditionally require multiple user steps.

Self-adhesive, stretchable waterborne polyurethane-based flexible film as wearable conformal strain sensor for motion and health monitoring

Wearable tensile strain sensors are of great importance in both motion monitoring and next-generation, personalized health diagnostics. The accuracy, reliability and stability of the signals obtained from these sensors are significantly dependent on the conformal contact between the flexible sensor and the skin surface. In this study, we have developed a flexible double-layer film as a wearable tensile strain sensor by a simple solution-blending method and a layer-by-layer spraying method. D-sorbitol was incorporated into a waterborne polyurethane (WPU) emulsion to enhance film adhesion, achieving a strength of 7.91 N/m, and to disrupt hydrogen bonds between the WPU chains. This disruption facilitates more straightforward conformational changes of the chains under stress, thereby substantially enhancing the mechanical flexibility of the film. The sensing layer was subsequently constructed by spraying silver microparticles, exhibiting extremely high sensitivity (gauge factor = 103.01) over a 19.3% strain range. This sensor can effectively monitor joint motions and subtle muscle movements as tensile strain sensors.

Glancing angle intermediate layer deposition approach for CVD diamond coating of high-speed steel substrates

This work demonstrates a new approach to the synthesis of highly adhesive diamond coatings on high-speed steel (HSS) substrates using a glancing angle deposition (GLAD) technique. The parameters of deposition of a molybdenum intermediate layer with a high level of surface roughness at a minimum layer thickness are determined. A maximum roughness of 38.1 nm with a minimum Mo layer thickness of 2 μm was achieved at an incidence angle of 15° and three sample positions. The duration of Mo sputtering at each rotation was 15, 10, 30 min. It is shown that a 2 μm Mo interlayer deposited by GLAD technique increases microcrystalline diamond film adhesion to HSS substrate compared to normally deposited Mo interlayer of the same thickness. The average delimitation area of the diamond film synthesized on a normally deposited molybdenum layer exceeds the corresponding parameter for the coating synthesized on the GLAD Mo layer by more than 8 times. Additionally, the process of diamond-Mo interlayer mechanical interlocking is also considered.

Synergistic effect of deposition temperature and substrate bias on structural, mechanical, stability and adhesion of TiN thin film prepared by reactive HiPIMS

Titanium nitride (TiN) thin films continue to attract unprecedented attention due to their favourable mechanical, thermal, electrical and chemical properties. These properties depend, among others, on the morphology and the architecture of the thin film, which can be tuned with different configurations of the deposition parameters. This study presents an experimental investigation to tune the properties of TiN thin film deposited using reactive High-power impulse magnetron sputtering (HiPIMS) at different deposition temperatures (without heating (RT) and 400 °C) and substrate bias potentials (of floating, ground, −20 V, −40 V and −60 V). It is demonstrated that the morphological, structural, and mechanical properties of TiN can be tailored by controlling the deposition temperature and substrate potential bias to deposit dense thin films. A maximum hardness of 30 GPa was achieved for the thin film deposited at RT with a bias voltage of −60 V. The failure mechanism of the fracture toughness exhibited an isotropic behaviour at an applied load of 1 and 2 N respectively, for thin films deposited at RT. In contrast, an anisotropic behaviour was observed in the thin film deposited at a temperature of 400 0C.Overall, the thin film deposited at a temperature of 4000C showed an improved fracture toughness resistance (KIC) than the thin films deposited at RT. The use of bias potential was also observed to be beneficial for improving the KIC of the TiN thin films.