Bilayer Films Research Articles

Polarization characteristics of Ni/Pt-based spintronic terahertz emitters based on spin electron dynamics

We report on the terahertz (THz) emission polarization characteristics of spintronic nickel/platinum (Ni/Pt) bilayer films. The films were deposited on MgO substrates via electron beam deposition with varying Ni thicknesses of 5, 7, and 9 nm and a constant Pt thickness of 6 nm. Results from B-field polarity-dependent THz measurements exhibited different THz emission characteristics for the p- and s-polarized components. We attribute the strong, wide-bandwidth B-field dependent p-polarized component to the inverse spin Hall effect and the weak, low-bandwidth B-field independent s-polarized component to the ultrafast demagnetization process. The peak-to-peak THz emission amplitudes were demonstrated to be dependent on the sample rotational angle about the optical axis which suggests sample inhomogeneity from the deposited Ni/Pt spintronic films. These results are crucial for the material design and development of more intense spintronic THz sources.

Energy storage and dielectric properties in PbZrO3/PbZrTiO3 antiferroelectric/ferroelectric bilayer bulk structure using Landau theory

Employing Landau theory and the Landau–Khalatnikov (L–K) equation of motion, we investigate the phase transitions in individual layers of antiferroelectric lead zirconate (PbZrO3), ferroelectric lead zirconate titanate (PbZrTiO3), and an antiferroelectric/ferroelectric PbZrO3/PbZr(0.21)Ti(0.79)O3 bilayer bulk structure. We examine the dielectric hysteresis loop behavior of the three systems, with a specific focus on the PbZrO3/PbZr(0.21)Ti(0.79)O3 bilayer under different stabilities of the PbZrO3 layer. In addition, we explore cases where the coercive field of the bilayer structure is lower than that of the PbZrTiO3 individual layer. The recoverable electric energy for the PbZrO3/PbZr(0.21)Ti(0.79)O3 bilayer increases significantly to 118 J/cm3 at an applied field of 7.5 × 108 V/m at 20 °C. In comparison, the PbZr(0.21)Ti(0.79)O3 layer reaches 71.8 J/cm3 under the same field and temperature conditions. This is much higher than those predicted experimentally by previous studies on thin film single and bilayer structures (15.6 and 28.2 J/Cm3 respectively), indicating that the antiferroelectric/ferroelectric PbZrO3/PbZr(0.21)Ti(0.79)O3 bilayer bulk structure could be used to target specific large-scale, long-term energy storage applications. Upon increasing the value of the coupling coefficient, the transition temperatures of the PbZrO3 layer and the PbZrO3/PbZr(0.21)Ti(0.79)O3 bilayer are increased up to the transition temperature of the PbZr(0.21)Ti(0.79)O3 individual layer (450 °C). This increment in the transition temperature in the bilayer system contributes to its stability in storing energy at higher temperatures. Furthermore, the recoverable energy density of the PbZrO3/PbZr(0.21)Ti(0.79)O3 bilayer increases further with temperature from 20 to 440 °C correlated with the rise in the difference between the spontaneous and the remanent polarizations (Ps − Pr). The significant stored energy observed over a wide temperature range highlights the promise of this bilayer structure for creating high-power capacitors where stability at different temperatures is crucial and possesses greater energy storage capacity.

Stretchable MXene/Carbon Nanotube Bilayer Strain Sensors with Tunable Sensitivity and Working Ranges.

Stretchable strain sensors have gained increasing popularity as wearable devices to convert mechanical deformation of the human body into electrical signals. Two-dimensional transition metal carbides (Ti3C2Tx MXene) are promising candidates to achieve excellent sensitivity. However, MXene films have been limited in operating strain ranges due to rapid crack propagation during stretching. In this regard, this study reports MXene/carbon nanotube bilayer films with tunable sensitivity and working ranges. The device is fabricated using a scalable process involving spray deposition of well-dispersed nanomaterial inks. The bilayer sensor's high sensitivity is attributed to the cracks that form in the MXene film, while the compliant carbon nanotube layer extends the working range by maintaining conductive pathways. Moreover, the response of the sensor is easily controlled by tuning the MXene loading, achieving a gauge factor of 9039 within 15% strain at 1.92 mg/cm2 and a gauge factor of 1443 within 108% strain at 0.55 mg/cm2. These tailored properties can precisely match the operation requirements during the wearable application, providing accurate monitoring of various body movements and physiological activities. Additionally, a smart glove with multiple integrated strain sensors is demonstrated as a human-machine interface for the real-time recognition of hand gestures based on a machine-learning algorithm. The design strategy presented here provides a convenient avenue to modulate strain sensors for targeted applications.

Visible light-responsive polylactic acid@pullulan-chitosan/homojunction g-C3N4 bilayer antimicrobial films for fruit preservation

The development of novel packaging materials with antimicrobial properties is crucial in preventing the microbial-induced spoilage of fruits, vegetables, and foodborne illnesses. In this study, homojunction g-C3N4 (HCN) photocatalysts with excellent photocatalytic performance were incorporated into a matrix consisting of pullulan/chitosan (Pul/CS). These photocatalysts were then electrostatically spun onto polylactic acid (PLA) films to fabricate PLA@Pul/CS/HCN nanofibrous composite films. The design of the bilayer films aimed to combine the physical properties of PLA film with the excellent antibacterial properties of nanofiber films, thereby achieving synergistic advantages. The incorporation of the HCN photocatalysts resulted in enhanced hydrophobicity, barrier function, and mechanical properties of the composite films. Under visible light irradiation, the PLA@Pul/CS/HCN films exhibited approximately 3.43 log and 3.11 log reductions of Escherichia coli and methicillin-resistant Staphylococcus aureus (MRSA), respectively, within 2 h. The excellent antimicrobial performance could be attributed to the synergistic effect of CS and the release of reactive oxygen species (ROS) from HCN. Moreover, the strawberries packaged in the PLA@Pul/CS/HCN film demonstrated diminished quality degradation and a prolonged shelf life following visible light irradiation treatment. This study will provide new insights into the exploration of safe and efficient antimicrobial food packaging.

Intelligent double-layer film based on gellan gum/modified anthocyanin/curcumin/sodium alginate/zinc oxide for monitoring shrimp freshness

In this study, intelligent double-layer films were prepared using modified black rice anthocyanin (MBRA)-curcumin (CUR)-gellan gum (GG) as the inner indicator layer and sodium alginate (ALG)‑zinc oxide (ZnO) as the outer antimicrobial layer. The bilayer films were successfully prepared, as revealed by scanning electron microscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction measurements. The mechanical characteristics, moisture content, and water vapor resistance of GG-MBRA/CUR1@ALG-ZnO, GG-MBRA/CUR2@ALG-ZnO, and GG-MBRA/CUR3@ALG-ZnO films showed significant enhancement compared to GG-MBRA/CUR3 and ALG-ZnO films. The bilayer films exhibited excellent pH responsiveness and reacted effectively to ammonia. The outer layer significantly improved the antioxidant and antibacterial properties of the inner layer. When the films were applied to shrimp, it was found that the double-layer films not only monitored the freshness of the shrimp in real-time but also were influential in extending the shelf life of the shrimp by about 1 d. Therefore, the double-layer film demonstrated potential as a smart packaging material for real-time monitoring of meat product freshness.

Stability and Composting Behaviour of PLA-Starch Laminates Containing Active Extracts and Cellulose Fibres from Rice Straw.

The stability and composting behaviour of monolayers and laminates of poly (lactic acid) (PLA) and starch with and without active extracts and cellulose fibres from rice straw (RS) were evaluated. The retrogradation of the starch throughout storage (1, 5, and 10 weeks) gave rise to stiffer and less extensible monolayers with lower water vapour barrier capacity. In contrast, the PLA monolayers, with or without extract, did not show marked changes with storage. However, these changes were more attenuated in the bilayers that gained water vapour and oxygen barrier capacity during storage, maintaining the values of the different properties close to the initial range. The bioactivity of the active films exhibited a slight decrease during storage, so the antioxidant capacity is better preserved in the bilayers. All monolayer and bilayer films were fully composted within 90 days but with different behaviour. The bilayer assembly enhanced the biodegradation of PLA, whose monolayer exhibited a lag period of about 35 days. The active extract reduced the biodegradation rate of both mono- and bilayers but did not limit the material biodegradation within the time established in the Standard. Therefore, PLA-starch laminates, with or without the valorised fractions from RS, can be considered as biodegradable and stable materials for food packaging applications.

Realization of multi-level phase-change in Sb7Se3/Ge50Te50 bilayer films via decoupling interlayer coupling between Sb7Se3 and Ge50Te50 layers

Multi-level phase-change can not only increase the storage density of phase-change memory, but also has important applications in neuromorphic computing. However, its realization is still very challenging. Here, we study the phase-change behaviors of four bilayer films, Sb7Se3(x nm)/Ge50Te50(90 nm), with x = 30, 50, 70, and 100. The expected three-level phase change is not observed at all. Raman and XRD characterizations reveal the occurrence of interlayer coupling between Sb7Se3 and Ge50Te50 layers. De-coupling structure films, Sb7Se3(x nm)/Si(50 nm)/Ge50Te50(90 nm), are proposed and prepared, where the amorphous Si layer serves as de-coupling the interlayer coupling. Three-level phase change is observed in all de-coupling Sb7Se3(x nm)/Si(50 nm)/Ge50Te50(90 nm) films. Our works demonstrate the effect of interlayer coupling on multi-level phase-change, and the de-coupling idea provides a design way for multi-level phase-change materials.

Remote epitaxy of single-crystal rhombohedral WS2 bilayers

Compared to transition metal dichalcogenide (TMD) monolayers, rhombohedral-stacked (R-stacked) TMD bilayers exhibit remarkable electrical performance, enhanced nonlinear optical response, giant piezo-photovoltaic effect and intrinsic interfacial ferroelectricity. However, from a thermodynamics perspective, the formation energies of R-stacked and hexagonal-stacked (H-stacked) TMD bilayers are nearly identical, leading to mixed stacking of both H- and R-stacked bilayers in epitaxial films. Here, we report the remote epitaxy of centimetre-scale single-crystal R-stacked WS2 bilayer films on sapphire substrates. The bilayer growth is realized by a high flux feeding of the tungsten source at high temperature on substrates. The R-stacked configuration is achieved by the symmetry breaking in a-plane sapphire, where the influence of atomic steps passes through the lower TMD layer and controls the R-stacking of the upper layer. The as-grown R-stacked bilayers show up-to-30-fold enhancements in carrier mobility (34 cm2V−1s−1), nearly doubled circular helicity (61%) and interfacial ferroelectricity, in contrast to monolayer films. Our work reveals a growth mechanism to obtain stacking-controlled bilayer TMD single crystals, and promotes large-scale applications of R-stacked TMD.

Interface Effects in the Stability of 2D Silica, Silicide, and Silicene on Pt(111) and Rh(111).

Ultrathin two-dimensional silica films have been suggested as highly defined conductive models for fundamental studies on silica-supported catalyst particles. Key requirements in this context are closed silica films that isolate the gas phase from the underlying metal substrate and stability under reaction conditions. Here, we present silica bilayer films grown on Pt(111) and Rh(111) and characterize them by scanning tunneling microscopy and X-ray photoelectron spectroscopy. We provide the first report of silica bilayer films on Rh(111) and have further successfully prepared fully closed films on Pt(111). Interestingly, surface and interface silicide phases play a decisive role in both cases: On platinum, closed films can be stabilized only when silicon is deposited in excess, which results in an interfacial silicide or silicate layer. We show that these silica films can also be grown directly from a surface silicide phase. In the case of rhodium, the silica phase is less stable and can be reduced to a silicide in reductive environments. Though similar in appearance to the "silicene" phases that have been controversially discussed on Ag(111), we conclude that an interpretation of the phase as a surface silicide is more consistent with our data. Finally, we show that the silica film on platinum is stable in 0.8 mbar CO but unstable at elevated temperatures. We thus conclude that these systems are only suitable as model catalyst supports to a limited extent.

Enhanced ferroelectric and piezoelectric properties of SrBi2Ta2O9 thin films through crystalline orientation

This study investigates how variations in substrate temperatures and deposition rates during pulsed laser deposition on Nb-doped SrTiO3 substrates affect the crystallinity, and consequently, the ferroelectric and piezoelectric properties of SrBi2Ta2O9 (SBT) thin films. The SBT thin film developed at 850 °C with a deposition rate of 0.34 nm/pulse showed lower remanent polarization and piezoelectric coefficients, a result of its c-oriented crystallinity. In contrast, SBT thin films produced at 750 °C with deposition rates of 0.37 nm/pulse demonstrated enhanced ferroelectric and piezoelectric responses due to mixed a-oriented crystallinity. In particular, the SBT thin film, fabricated at 750 °C with a lower deposition rate of 0.04 nm/pulse, demonstrated the most enhanced ferroelectric and piezoelectric properties due to its highly refined a-oriented crystallinity. Our findings illuminate the relationship between the characteristics of the crystals and functional properties in SBT thin films, highlighting the integration of a-domains within c-domains as a key strategy for optimizing SBT film performance and opening avenues for designing specialized Bi-layered perovskite thin films.

Development of Bilayer Polysaccharide-Based Films Combining Extrusion and Electrospinning for Active Food Packaging

The development of active food packaging is desirable for food safety and to avoid food loss and waste. In this work, we developed antioxidant bilayer films combining extrusion and electrospinning techniques. These films consisted of a first layer of thermoplastic cornstarch (TPS), incorporated with microcrystalline cellulose (MCC). The second layer consisted of gallic acid (GA) encapsulated at different concentrations in 1:1 chitosan/poly(ethylene-co-vinyl alcohol) (CS/EVOH) nanofibers. This layer was directly electrospun onto the TPS/MCC film. The morphological, structural, wettability, permeability to oxygen, and antioxidant properties were investigated for the first layer and the bilayer films. Water contact angle measurements revealed the hydrophobic nature of the first layer (θ0 = 100.6°). The oxygen permeability (OP) was accessed through the peroxide value (PV) of canola oil, kept in containers covered by the films. PV varied from 66.6 meq/kg for the TPS/MCC layer to 60.5 meq/kg for a bilayer film. Intermolecular hydrogen bonds, mediated by GA, contributed slightly to improving the mechanical strength of the bilayer films. The bilayer film incorporated with GA at 15.0% reached a radical scavenging activity against the DPPH radical of (903.8 ± 62.2) μmol.L−1.Eq. Trolox.g−1. This result proved the effectiveness of the GA nanoencapsulation strategy.

Profiling contact ridge of soft substrates with metallic thin films using a novel interference technique

HypothesisAs technology moves toward flexibility, embedded systems, and miniaturization, which often have metallic elements integrated with the functional substrates, understanding the contact deformation of such soft substrates coated with thin metallic films is crucial. However, probing nanoscale deformations optically, typically in a few hundred nanometers, poses challenges. Dual Wavelength - Reflectance Interference Contrast Microscopy (DW-RICM) holds promise in unveiling nanoscale deformations. However, when paired with conventional glass probes to measure deformation of underlying soft substrates, DW-RICM faces limitations due to light reflection at the glass-air interface, impeding accurate determination of the contact zone (e.g., contact area, contact ridge). Here we hypothesize that using alternative probes to eliminate unwanted reflections can enhance understanding of soft substrate deformation with thin metallic films (bilayer substrates). ExperimentsIn this work, we investigate the deformation profile of viscoelastic soft substrates with sputter-coated gold thin films (referred to herein as bilayer substrates) using DW-RICM. We employ millimeter-sized black ink-coated glass spheres as probes, absorbing most light under DW-RICM. We focus our laser beams associated with DW-RICM at the contact zone between the probe and the underlying soft substrates. FindingsOur new technique of using black ink-coated glass probes in contact with soft bilayer substrates enables us to accurately extract the deformation profile, particularly the contact ridge. With the increase in the gold sputter coating time, the contact area and contact ridge of gold-polymer bilayer substrates decrease. Further, long-term contact analysis of gold-coated soft substrates reveals a steady increase in the contact ridge height over time, unlike the gradual decrease observed in their bare counterparts until reaching a steady state.

Natural ceramic clay and cucurbituril guest-host reconfiguration for smart light, humidity, solvent and temperature responsiveness

Aiming to endow natural minerals with fast, high-sensitivity, and controllable smart light, humidity, solvent and temperature responsiveness, a novel ceramic clay and cucurbituril (CB) guest-host system (MVCB) inspired by nature was self-assembled and rearranged via an ingenious and simple design successfully. For the first time, the multi-functional MVCB not only displayed a high intelligent multi-stimuli responsiveness as light, humidity, solvent, and temperature switches, but also had multiple selective molecular recognition responses because of different organic vapor with CB and asymmetrical bilayer clay. For instance, due to the factors of guest-host and slow release, the average response speed of self-assembled shuffling the MVCB in methanol was as high as 108°/s compared with bilayer film without CB (20°/s). Besides, the MVCB exhibited controllable swift movement and was bending for grabbing three times its own weight. Moreover, the ultra-wide operating temperature of the MVCB from was ranging −196 to 300 °C under extreme condition. More interestingly, the MVCB presented a unique and compliable self-driven, smart switch, shape memory, environmental awareness and soft robotic gripper owing to the asymmetrical swelling and supramolecular of the CB. This work not only brings a simple, cost-effective, large-scale, and efficient strategy for multi-functionalized natural minerals materials, but also opens potential applications for intelligent response, extremely resistant substances, energy conversion and soft robotics.

Electrocatalytic and photoelectrocatalytic investigation of Orange G degradation utilizing a novel BHP@Bi2O3 photoanode employing the CCD-RSM experimental design

In this study, we synthesized a bilayer film consisting of BaHPO4 (BHP) and Bi2O3 through the electrodeposition technique. The produced anode was subjected to characterization using cyclic voltammetry to clarify the deposition reactions. Subsequent to this, structural and morphological analyses were conducted utilizing X-ray diffraction alongside scanning electron microscopy, coupled with energy-dispersive X-ray spectroscopy. Additionally, UV–vis diffuse reflectance spectroscopy was employed to determine the bandgap energies of both semiconductors. Following an electrochemical characterization using linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS), and Mott-Schottky (MS) measurements, the photoanode was employed for the electro-degradation of the anionic dye Orange G (OG), varying key degradation parameters such as current density, pollutant concentration, supporting electrolyte concentration, and pH using the CCD-RSM experimental design method. A degradation efficiency of 98% was achieved within a 20-minute timeframe. Photoelectrocatalytic tests under UV irradiation reduced the degradation time from 20 to 6 min, with a degradation rate of 99%. Additionally, under the same conditions, the BHP@Bi2O3 photoanode exhibited good stability, enduring up to 11 cycles of use.

Eco-Friendly Poly (Butylene Adipate-co-Terephthalate) Coated Bi-Layered Films: An Approach to Enhance Mechanical and Barrier Properties.

In this research work, a coated paper was prepared with poly (butylene adipate-co-terephthalate) (PBAT) film to explore its use in eco-friendly food packaging. The paper was coated with PBAT film for packaging using hot pressing, a production method currently employed in the packaging industry. The coated papers were evaluated for their structural, mechanical, thermal, and barrier properties. The structural morphology and chemical analysis of the coated paper confirmed the consistent formation of PBAT bi-layered on paper surfaces. Surface coating with PBAT film increased the water resistance of the paper samples, as demonstrated by tests of barrier characteristics, including the water vapor transmission rate (WVTR), oxygen transmission rate (OTR), and water contact angle (WCA) of water drops. The transmission rate of the clean paper was 2010.40 cc m-2 per 24 h for OTR and 110.24 g m-2 per 24 h for WVTR. If the PBAT-film was coated, the value decreased to 91.79 g m-2 per 24 h and 992.86 cc m-2 per 24 h. The hydrophobic nature of PBAT, confirmed by WCA measurements, contributed to the enhanced water resistance of PBAT-coated paper. This result presents an improved PBAT-coated paper material, eliminating the need for adhesives and allowing for the fabrication of bi-layered packaging.

Deposition and nanoindentation study of a novel TiNi/Ag bi-layer shape memory film

Compositions, surface morphologies and mechanical properties of a novel designed TiNi/Ag bi-layer film grown by DC magnetron sputtering at various processes have been investigated. Ar pressure and sputtering power had significant effects on quality and composition of TiNi/Ag bi-layer films. The TiNi/Ag bi-layer film processed by sputtering under high Ar pressure (0.36 Pa) was porous, while better density films can only be obtained at low pressure (0.12 Pa). The composition of TiNi/Ag bi-layer films can be adjusted by sputtering power. The load-displacement curves show the multiple “pop-ins”along nanoindentation loading, as indentation depth does not exceed the pure Ag film thickness (∼340 nm). At the maximum loading of 140 mN, martensitic transformation induced by nanoindentation in TiNi/Ag bi-layer films was not found, and depth recovery ratio was 39%. Moreover, based on the load displacement curve analysis, the hardness and elastic modulus values of TiNi/Ag bi-layer films were 4 ± 0.2 Gpa and 79 ± 2 Gpa, respectively. Comparing with martensitic phase of single-layer TiNi thin films at room temperature, the coexistence of parent phase and martensitic phase of TiNi/Ag bi-layer films were mainly due to strong confinement effect of Ag layer deposition on TiNi thin film. The residual stress calculated by using conventional sin2ψ method was around −0.458 GPa. The present study provided an important theoretical basis for the preparation of TiNi/Ag bi-layer film with higher quality and performance.

The use of supporting materials in the process of making food containers from a mixture of PLA-starch and testing the quality of the coating: A review

The fulfillment of the food packaging industry’s needs for the use of non-petrochemical, biodegradable plastics from renewable sources that are also economically viable can be achieved through the utilization of polylactic acid-starch (PLA-starch). However, the perceived limitations of PLA-starch in terms of long-term food packaging have prompted recent innovations in which research is conducted on supportive materials that extend the shelf life of food packaging while still considering the health value of the added substances. This innovation provides significant advantages in using more durable food packaging materials that do not have adverse effects on food and human health. The utilization of ferulic and cinnamic acid compounds has been studied to reduce the environmental impact of food packaging while extending the shelf life of food. A three-layer film of PLA/starch/PLA (PSP) was designed based on the complementary barrier properties of the polymers, resulting in a film system with improved barrier properties. Electrospinning was effective in producing fibrous mats that encapsulated the acids, while film spraying resulted in the formation of crystalline structures of the active compounds strongly adhered to the surface. The electrospinning- and spray-coated films exhibited effective inhibition against the growth of E. coli and L. innocua. The TPScf-PLAes blend showed good antioxidant capacity when used in meat packaging and reduced microbial counts during cold storage. Silane-doped bilayer films demonstrated higher thermal stability compared to PPS. Therefore, the bilayer films and supporting materials have significant potential to extend the shelf life of food, maintaining its quality and safety for a longer period.

Enhancing wear and corrosion resistance of TiO2–Al2O3 hybrid coatings by the development of TiO2–Al2O3 bilayer film coatings

Sol-gel fabricated TiO2–Al2O3 bilayer coatings were deposited on 316L surfaces with several combinations of layers. Microstructural, corrosion, and wear features of the fabricated film coatings were examined compared to the TiO2–Al2O3 hybrid coating containing 65 % TiO2, which achieved the highest protection against corrosion and wear in the previous study. The electrochemical properties were determined through electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests, whereas dry sliding tests were performed using an Al2O3 ball under 1 N. Regardless of the production parameters, rutile and α-Al2O3 phases were produced in all manufactured coatings with similar thicknesses. The coatings consisting of TiO2 at the top layers showed better anti-corrosive performance due to a dense, low-porosity, and continuous morphology of TiO2 nanoparticles, while the coatings containing Al2O3 at their top layers were determined to exhibit higher wear resistance. All bilayer film coatings increased the anti-corrosion and anti-wear performance of the hybrid coating.

Designing an antimicrobial film for wound applications incorporating bacteriophages and ε-poly-l-lysine

Alginate-based dressings have been shown to promote wound healing, leveraging the unique properties of alginate. This work aimed to develop and characterize flexible individual and bilayered films to deliver bacteriophages (phages) and ε-Poly-l-lysine (ε-PLL). Films varied in different properties. The moisture content, swelling and solubility increased with higher alginate concentrations. The water vapour permeability, crucial in biomedical films to balance moisture levels for effective wound healing, reached optimal levels in bilayer films, indicating these will be able to sustain an ideal moist environment. The bilayer films showed improved ductility (lower tensile strength and increased elongation at break) compared to individual films. The incorporated phages maintained viability for 12 weeks under vacuum and refrigerated conditions, and their release was sustained and gradual. Antibacterial immersion tests showed that films with phages and ε-PLL significantly inhibited Pseudomonas aeruginosa PAO1 growth (>3.1 Log CFU/cm2). Particle release was influenced by the swelling degree and diffusional processes within the polymer network, providing insights into controlled release mechanisms for particles of varying size (50 nm to 6 μm) and charge. The films developed, demonstrated modulated release capabilities for active agents, and may show potential as controlled delivery systems for phages and wound healing adjuvants.

Molecular dynamics simulations into rolling scraping of nickel-copper bilayer film

In order to investigate the nanoscale friction mechanism and deformation behavior of nickel-copper bilayer film under rolling scraping, the effects of different factors during friction process such as the translation velocity, rotation velocity, radius of abrasive grain, contact depth, texture direction and crystallographic orientation are analyzed through molecular dynamics methods in terms of contact force, atomic lattice structure, internal substrate dislocation, kinetic energy and temperature. Results show that the contact force increases with the increase of the translation velocity or the decrease of the rotation velocity. Abrasive grains in a purely rolling state cause the most serious damage to the substrate. The contact force increases with the increase of contact depth or the decrease of abrasive grain radius. The crystallographic orientation has a significant effect on rolling scraping process and there is a crystallographic orientation with the minimum contact force. The degrees of substrate dislocation and the numbers of lattice reconstruction atoms under different factors and levels vary widely.