Film Architecture Research Articles

Multiferroicity and Semi‐Cylindrical Alignment in Janus Nanofiber Aggregates

Abstract1D multiferroic fibers are known to exhibit attractive characteristics, including enhanced magnetoelectric (ME) coupling compared to thin film and bulk architectures. A comprehensive understanding of composite fibers, however, has been hindered by the complexity of their structure, leading to limited reports. Here, clear and strong ME coupling is experimentally detected in a composite Janus nanofiber aggregate using second harmonic generation (SHG) polarimetry under different magnetic field orientations. The observation of such a pronounced effect using an all‐optical method has not been previously reported in multiferroic fibers. A series of global fits is performed to the SHG polarimetry results to investigate the behavior of nanofibers within an aggregate. We find the magnetically assembled fibers exhibit semi‐cylindrical alignment as well as the expected lengthwise alignment despite variations in size and composition from fiber to fiber. The ME coupling and the semi‐cylindrical alignment seen in SHG are further corroborated via X‐ray diffraction under similar magnetic field conditions. These findings contribute to the development of complex composite and multifunctional devices using multiferroic nanostructures as building blocks, even those with inhomogeneous shapes and geometries.

Tuning Electrostatics to Promote Ordered Monolayers of Phosphole-Lipids.

Heteroatom-doped π-conjugated systems have been exploited for electronic device applications. Phosphole-containing backbones are particularly intriguing with regard to electron delocalization and ultimately control over the photophysical, redox, and charge transfer characteristics. However, practical application of these materials commonly relies on well-structured, thin film architectures. Self-assembly offers a route to generate ordered 2D structures deposited on solid substrates. The orientation of these deposited films can be manipulated by the introduction of alkyl chains of varying length (to form phosphole-based lipids) and chemical modification of the phosphole-derived headgroup. External controls can also be considered to tune these films' properties, e.g., the electrostatic interactions within the film can be controlled by varying the environment with the addition of simple salt counterions. A series of lipids with phosphole-based π-conjugated headgroups have been designed and exhibit intramolecular conformational changes in response to external conditions. Herein the 2D film structure in Langmuir and Langmuir-Blodgett films is reported in the presence and absence of halide salts. The film morphology obtained from Brewster angle and atomic force microscopy shows the formation of a condensed phase but also 3D aggregates, and grazing incidence X-ray diffraction confirmed the presence of untilted, hexagonally packed chains. The size of the counterion influences its ability to intercalate between the phosphole headgroups, which ultimately provides a means to induce the formation of a well-ordered, single monolayer film without aggregates that can be transferred to the solid substrate.

Tunable Assembly of Photocatalytic Colloidal Coatings for Antibacterial Applications.

In this study, evaporation-induced size segregation and interparticle interactions are harnessed to tune the microstructure of photocatalytic colloidal coatings containing TiO2 nanoparticles and polymer particles. This enabled the fabrication of a library of five distinct microstructures: TiO2-on-top stratification, a thin top layer of polymer or TiO2, homogeneous films of raspberry particles, and a sandwich structure. The photocatalytic and antibacterial activities of the coatings were evaluated by testing the viability of Methicillin-resistant Staphylococcus aureus (MRSA) bacteria using the ISO-27447 protocol, showing a strong correlation with the microstructure. UVA irradiation for 4 h induces a reduction in MRSA viability in all coating systems, ranging from 0.6 to 1.1 log. Films with TiO2-enriched top surfaces exhibit better resistance to prolonged exposure to disinfection and bacterial testing. The remaining systems, nonetheless, present higher antibacterial activity because of a larger number of pores and coating defects that enhance light and water accessibility for the generation and transport of reactive oxygen species. This work establishes design rules for photocatalytic coatings based on the interplay between performance and film architecture, offering valuable insights for several applications, including antibacterial surfaces, self-cleaning/antifogging applications, and water purification.

Andiroba Oil (Carapa guianensis) and ginger extract (Zingiber officinale)-loaded nanoemulsion: Elaboration, characterization, antioxidant activity, and cell viability investigation

This study employs nanoengineering techniques to enhance the aqueous compatibility of andiroba oil and ginger extract, both renowned for their phytotherapeutic properties, aiming at biomedical applications. The natural products were characterized using HPLC-MS, CG-MS, UV-Vis, and FTIR. Optimal surfactant concentrations (lecithin and Tween® 20) were established to produce more biocompatible and stable oil-in-water nanoemulsions. The nanodroplets were characterized at multiple hierarchical levels, including their shape (spherical), size (∼130 nm), polydispersity (PDI = 0.20), and surfactant interfacial film architecture through a cross-analysis of DLS, ELS, SAXS, TGA, UV-Vis, and FTIR. Zetametry and DLS were used to investigate the mechanism of colloidal stabilization of the nanodrops and evaluate the stability of the nanoemulsion under varying pH and ionic strength conditions during storage at different temperatures. The quantification of phenol and flavonoids, coupled with assessments of antioxidant activity, demonstrated an additive effect, indicating that both andiroba oil and ginger extract retain their significant antioxidant efficacy within the nanoemulsion formulation. The effect of the nanoformulation on the viability and morphology of mouse fibroblast NIH-3T3 was also examined. The IC50 of the nanoemulsion at 48 h (765 μg/ml) is higher than the values reported for other nanoemulsions of andiroba oil or ginger extract. This innovative nanoemulsion system combining andiroba oil and ginger extract offers the potential for additive or synergistic effects while exerting minimal impact on healthy cell viability.

Improved Cell Adhesion on Self-Assembled Chiral Nematic Cellulose Nanocrystal Films.

Chirality is ubiquitous in nature, and closely related to biological phenomena. Nature-originated nanomaterials such as cellulose nanocrystals (CNCs) are able to self-assemble into hierarchical chiral nematic CNC films and impart handedness to nano and micro scale. However, the effects of the chiral nematic surfaces on cell adhesion are still unknown. Herein, this work presents evidence that the left-handed self-assembled chiral nematic CNC films (L-CNC) significantly improve the adhesion of L929 fibroblasts compared to randomly arranged isotropic CNC films (I-CNC). The fluidic force microscopy-based single-cell force spectroscopy is introduced to assess the cell adhesion forces on the substrates of L-CNC and I-CNC, respectively. With this method, a maximum adhesion force of 133.2 nN is quantified for mature L929 fibroblasts after culturing for 24h on L-CNC, whereas the L929 fibroblasts exert a maximum adhesion force of 78.4 nN on I-CNC under the same condition. Moreover, the instant SCFS reveals that the integrin pathways are involved in sensing the chirality of substrate surfaces. Overall, this work offers a starting point for the regulation of cell adhesion via the self-assembled nano and micro architecture of chiral nematic CNC films, with potential practical applications in tissue engineering and regenerative medicine.

Space in the “DAU” project (dir. Ilya Khrzhanovsky). Contexts

The article is devoted to the analysis of space in the “DAU” project, directed by Ilya Khrzhanovsky in cooperation with Yekaterina Oertel, Alexei Slyusarchuk and Ilya Permakov, among others. Feature films and documentaries that constitute the project were shot in the years 2009–2012, mainly in Kharkiv, in a closed scientific institute, built exclusively for this purpose. The aim of the article is to examine selected spatial solutions in the project, to contextualize them, and, consequently, to link the film architecture with the behavioral sphere and the corporeality of the characters. The methodological tool, supporting the research of the text, is the category of the underground, embedded in the work Notes from the Underground by Fyodor Dostoyevsky. In the process of interpretation, the author draws attention to the connections between the mechanisms of oppression functioning in the totalitarian system and the symbolic language of the body and architecture.

Single-Component Electroactive Polymer Architectures for Non-Enzymatic Glucose Sensing.

Organic mixed ionic-electronic conductors (OMIECs) have emerged as promising materials for biological sensing, owing to their electrochemical activity, stability in an aqueous environment, and biocompatibility. Yet, OMIEC-based sensors rely predominantly on the use of composite matrices to enable stimuli-responsive functionality, which can exhibit issues with intercomponent interfacing. In this study, an approach is presented for non-enzymatic glucose detection by harnessing a newly synthesized functionalized monomer, EDOT-PBA. This monomer integrates electrically conducting and receptor moieties within a single organic component, obviating the need for complex composite preparation. By engineering the conditions for electrodeposition, two distinct polymer film architectures are developed: pristine PEDOT-PBA and molecularly imprinted PEDOT-PBA. Both architectures demonstrated proficient glucose binding and signal transduction capabilities. Notably, the molecularly imprinted polymer (MIP) architecture demonstrated faster stabilization upon glucose uptake while it also enabled a lower limit of detection, lower standard deviation, and a broader linear range in the sensor output signal compared to its non-imprinted counterpart. This material design not only provides a robust and efficient platform for glucose detection but also offers a blueprint for developing selective sensors for a diverse array of target molecules, by tuning the receptor units correspondingly.

Silver Nanowire-Based Transparent Electrodes for V2O5 Thin Films with Electrochromic Properties.

The development of electrochromic systems, known for the modulation of their optical properties under an applied voltage, depends on the replacement of the state-of-the-art ITO (In2O3:Sn) transparent electrode (TE) as well as the improvement of electrochromic films. This study presents an innovative ITO-free electrochromic film architecture utilizing oxide-coated silver nanowire (AgNW) networks as a TE and V2O5 as an electrochromic oxide layer. The TE was prepared by simple spray deposition of AgNWs that allowed for tuning different densities of the network and hence the resistance and transparency of the film. The conformal oxide coating (SnO2 or ZnO) on AgNWs was deposited by atmospheric-pressure spatial atomic layer deposition, an open-air fast and scalable process yielding a highly stable electrode. V2O5 thin films were then deposited by radio frequency magnetron sputtering on the AgNW-based TE. Independent of the oxide's nature, a 20 nm protective layer thickness was insufficient to prevent the deterioration of the AgNW network during V2O5 deposition. On the contrary, crystalline V2O5 films were grown on 30 nm thick ZnO or SnO2-coated AgNWs, exhibiting a typical orange color. Electrochromic characterization demonstrated that only V2O5 films deposited on 30 nm thick SnO2-coated AgNW showed characteristic oxidation-reduction peaks in the Li+-based liquid electrolyte associated with a reversible orange-to-blue color switch for at least 500 cycles. The electrochromic key properties of AgNW/SnO2 (30 nm)/V2O5 films are discussed in terms of structural and morphological changes due to the AgNW network and the nature and thickness of the two protective oxide coatings.

Innovative Architecture for Phosphor‐in‐Glass Films Enabling Superior Luminance and Color Quality Laser‐Driven White Light

AbstractLaser‐driven white light exhibits exceptional brightness and directionality, making it particularly well‐suited for spotlight applications. Yet, attaining high‐quality white light remains challenging due to the sluggish heat dispersion and inconsistent light uniformity of color converters. In this study, an innovative phosphor‐in‐glass (PiG) film architecture is introduced, aiming to achieve superior quality laser‐driven light, where the traditional Y3(Ga,Al)5O12:Ce3+ (YAGG:Ce3+) PiG film is topped with a Al2O3‐in‐glass (AiG) film. The heightened thermal conductivity of the AiG film facilitates quicker dissipation of heat, consequently elevating the luminescence saturation threshold from 14 to 16 W mm−2 and luminous flux from 1243.8 to 1475.9 lm. The increased light scattering attributed to the AiG film also effectively disperses both laser and emitted light, significantly enhancing the angular consistency of color rendering index (Ra). This improvement is evident as the coefficient of variation (Cv) decreases dramatically from 16.69% to 0.25%. Moreover, by integrating CaAlSiN3:Eu2+ (CASN:Eu2+) into the PiG film and fine‐tuning the YAGG:Ce3+ and CASN:Eu2+ ratio, a high‐quality laser‐driven white light achieving an impressive color rendering index (Ra) of 88.7 and offering an adjustable correlated color temperature (CCT) has been developed. This innovation holds tremendous potential as a versatile spotlight solution for both indoor and outdoor settings.

Altering the interfacial rheology of Pseudomonas aeruginosa and Staphylococcus aureus with N-acetyl cysteine and cysteamine.

Chronic lung infection due to bacterial biofilms is one of the leading causes of mortality in cystic fibrosis (CF) patients. Among many species colonizing the lung airways, Pseudomonas aeruginosa and Staphylococcus aureus are two virulent pathogens involved in mechanically robust biofilms that are difficult to eradicate using airway clearance techniques like lung lavage. To remove such biological materials, glycoside hydrolase-based compounds are commonly employed for targeting and breaking down the biofilm matrix, and subsequently increasing cell susceptibility to antibiotics. In this study, we evaluate the effects of N-acetyl cysteine (NAC) and Cysteamine (CYST) in disrupting interfacial bacterial films, targeting different components of the extracellular polymeric substances (EPS). We characterize the mechanics and structural integrity of the interfacial bacterial films using pendant drop elastometry and scanning electron microscopy. Our results show that the film architectures are compromised by treatment with disrupting agents for 6 h, which reduces film elasticity significantly. These effects are profound in the wild type and mucoid P. aeruginosa, compared to S. aureus. We further assess the effects of competition and cooperation between S. aureus and P. aeruginosa on the mechanics of composite interfacial films. Films of S. aureus and wild-type P. aeruginosa cocultures lose mechanical strength while those of S. aureus and mucoid P. aeruginosa exhibit improved storage modulus. Treatment with NAC and CYST reduces the elastic property of both composite films, owing to the drugs' ability to disintegrate their EPS matrix. Overall, our results provide new insights into methods for assessing the efficacy of mucolytic agents against interfacial biofilms relevant to cystic fibrosis infection.

Protecting Li-metal anode with LiF-enriched solid electrolyte interphase derived from a fluorinated graphene additive.

As the holy-grail material, the Li-metal anode has been considered the potential anode of the next generation of Li-metal batteries (LMBs). However, issues of undesirable dendrite growth and unsatisfactory reversibility of the Li-plating/stripping process during the electrochemical cycling impede further application of LMBs. Herein, we innovatively introduce fluorinated graphene (F-Gr) species as a sacrificial effective electrolyte additive into EC/EMC-based electrolyte, which effectively triggers LiF-enriched (composition) and organic/inorganic species uniform-distributed (structure) SEI film architecture that features robustness and denseness, as well as good stability. With the F-Gr additive, efficient Li-metal anode protection (dendrite-free morphology on Li-metal surface and improved Li plating/stripping reversibility during electrochemical cycling) and significantly enhanced long-term lifespan of LMBs is achieved. Remarkably, classical electrochemical techniques, combined with the surface-sensitive characterizations (XPS and TOF-SIMS), comprehensively and systematically highlight critical structure-activity relationships between the SEI architecture (both composition and structure) and electrochemical performance. These techniques provide deep insights into the optimal electrolyte designation of Li-metal anode in LMBs.

Mobile Point-of-Care Device Using Molecularly Imprinted Polymer-Based Chemosensors Targeting Interleukin-1β Biomarker.

Molecularly imprinted polymers (MIPs) have garnered significant attention as a promising material for engineering specific biological receptors with superior chemical complementarity to target molecules. In this study, we present an electrochemical biosensing platform incorporating MIP films for the selective detection of the interleukin-1β (IL-1β) biomarker, particularly suitable for mobile point-of-care testing (POCT) applications. The IL-1β-imprinted biosensors were composed of poly(eriochrome black T (EBT)), including an interlayer of poly(3,4-ethylene dioxythiophene) and a 4-aminothiophenol monolayer, which were electrochemically polymerized simultaneously with template proteins (i.e., IL-1β) on custom flexible screen-printed carbon electrodes (SPCEs). The architecture of the MIP films was designed to enhance the sensor sensitivity and signal stability. This approach involved a straightforward sequential-electropolymerization process and extraction for leaving behind cavities (i.e., rebinding sites), resulting in the efficient production of MIP-based biosensors capable of molecular recognition for selective IL-1β detection. The electrochemical behaviors were comprehensively investigated using cyclic voltammograms and electrochemical impedance spectroscopy responses to assess the imprinting effect on the MIP films formed on the SPCEs. In line with the current trend in in vitro diagnostic medical devices, our simple and effective MIP-based analytical system integrated with mobile POCT devices offers a promising route to the rapid detection of biomarkers, with particular potential for periodontitis screening.

Facile preparation of thermoplastic conductive composite film for actuating and self-powered sensing

Soft actuators based on bilayered film architecture have drawn extensively interests owing to their high sensitivity, remarkable compatibility, simple architecture and so on. However, most bilayered soft actuators are frequently fabricated via some complicated methods, and the preparation of soft actuators via a facile technology is still a big challenge. Herein, PVDF/LDPE bilayered film was successfully fabricated based on blow film molding. CNTs dispersions were uniformly sprayed on the PVDF layer of PVDF/LDPE bilayered film as electrode layer. In addition, PVDF can be used as piezoelectric/actuation layer of PVDF/LDPE/CNTs film because of its stronger swelling ability in acetone vapor than LDPE. Driven by acetone vapors, PVDF/LDPE/CNTs films show rapid self-powered sensing property (response and recovery time of 1.2 s and 1 s, respectively) and excellent sensing durability (>500 cycles). Interestingly, a paper doll was combined with PVDF/LDPE/CNTs film acting as artificial muscle. According to the output of the piezoelectric signal, the pull-up states of the paper doll can be detected, indicating highly efficient energy conversion and sensing ability of PVDF/LDPE/CNTs films. This work paves a new way for facile preparation of soft actuators with both driving and sensing functions.

Amplifying bactericidal activity: Surfactant-mediated AgBr thin film coating over two-dimensional vertically aligned ZnO nanorods for dark-light dual mode disinfection

Thin film coatings with potent antibacterial properties find critical applications in diverse domains such as medical devices, frequently touched surfaces, and food packaging for combating microbial proliferation across diverse scenarios. Two-dimensional photocatalytic antimicrobial coatings, offering a substantial actual-to-apparent surface ratio, hold immense potential for achieving this objective. However, realizing antibacterial performance not just under light but also in dark conditions remains a challenge. To address this, we present AgBr-coated vertically aligned ZnO nanorods (NRs) thin film architecture, employing a unique surfactant-mediated solution-phase spin-coating approach for achieving uniform deposition of AgBr onto ZnO NRs. The resulting ZnO NRs/AgBr heterojunction architectures have been characterized for their microstructural, morphological, elemental, optical, and wettability attributes. The studies have ascertained the tunability of AgBr content by modulating the concentration of its surfactant-based precursor solution. Further, valence band (VB) analyses revealed an increase in the electron density near to the VB edge. The dual role of AgBr as an antimicrobial agent and a photosensitizer, effectively enhancing the visible-light photodisinfection efficacy of ZnO NRs, has been evident through the dark-light dual mode antibacterial studies. Electron paramagnetic resonance measurements have shown hydroxyl radicals being majorly responsible for the visible-light photodisinfection performance. Encouragingly, reusability assessments showcase significant promise, while artificial sweat-wiping studies on the structures unveil heightened photodisinfection efficacy. This enhancement could be attributed to components like urea and lactic acid, speculated to augment the photocatalytic efficiency by minimizing charge recombination.

Tunable electrocaloric effect in selective ferroelectric bilayers via electrostatics for solid-state refrigeration and microelectronics thermal management

Ferroelectric (FE) electrocaloric materials research has been blossoming worldwide for solid-state refrigeration and potential cooling systems replacing thermoelectric Peltier coolers in microelectronics. In this work, we report the outcomes from a systematic study of combined phase transition (thermodynamics) based on the phenomenological Landau theory and distributed electric field (electrostatics of thin film interfaces) in FE bilayer films. Specifically, the compositional variation of ferroelectric bilayers results in broken spatial inversion symmetry leading to asymmetric thermodynamic potentials due to a combination of normal (first- and second-order phase transition) and relaxor (dispersive dielectric constant) ferroelectric behaviors devised for efficient electrocaloric cooling effects. Extensive theoretical analyses conducted for bilayers consisting of insulating materials highlight modified phase transition temperature behavior and self-poling by effective electric field amplification arising due to bilayers’ electrostatic coupling yielding significant changes in isothermal entropy (ΔS) and adiabatic temperature (ΔT). The theoretical calculation insights supported with experimental results signify, through case studies for a combination of materials experimental parameters, that amplification of the local electric field and materials engineering maximize the number of coexisting phases at or away from the morphotropic phase boundary of constituent layers in bilayer thin film architectures, which can be applicable toward other classes of materials and multilayer systems. These are effective ways for efficient cooling, in general, and for microelectronics thermal management either directly or by developing a thermal switch with phase change materials integrated with thermoelectric coolers for residual heat dissipation, both at the system and on-chip levels.

3D-printed film architecture via automatic micro 3D-printing system: Micro-intersection engineering of V2O5 thin/thick films for ultrafast electrochromic energy storage devices

Existing approaches to develop electrochromic (EC) energy storage devices typically focus on the modification of active materials toward a porous morphology, crystallinity, heteroatom-doping, and hybridization/composites with functional materials; however, these approaches may be unsuitable for the full commercialization of EC energy storage devices owing to their complex and expensive processes and incompatibility with large-scale and mass production. Herein, we fabricate 3D-printed film architectures for ultrafast EC energy storage devices, including micro-intersections of vanadium oxide (VO) thin/thick films, via an automatic micro 3D-printing system without active material modification. The micro-intersection originates from the one-pot 3D-printing of vertical lines, creating VO grid-micropatterns with nanoscale thin/thick films on fluorine-doped tin oxide (FTO)/glass. The micro-intersection density was engineered by adjusting the number of printed-lines per unit area and optimized micro-intersection density (OD-3DVO) allows enhanced behaviors of electrons and Li-ions as follows: (i) the thin film architecture alleviates rate-limiting processes that produce sluggish electron transfer and ionic diffusion kinetics by shortening transport channels between FTO and the electrolyte, thereby accelerating ultrafast charge transport. (ii) Micro-width/nano-depth 3D-wells induce capillary force pumping and deep electrolyte infiltration at the interface, thereby enhancing electrolyte wettability. (iii) grid-micropatterned film morphology provides extensive redox sites and high visible transmissivity; thus, the OD-3DVO active layers in EC energy storage devices featured simultaneously enhanced optical and energy storage performances, especially ultrafast switching speeds (0.7 and 0.9 s for coloration and bleaching) and record-high areal energy density at high areal power density (14.03 µWh/cm2 at 25 mW/cm2).

SYNTHESIS OF CINEMA AND ARCHITECTURE IN THE ENVIRONMENT

The article highlights examples of the phenomenon of the synthesis of two visual arts - cinema and architecture. The work considers the main examples in the following subtopics: cinema as a way of increasing the attractiveness of architecture; architecture in cinema as a mirror of society; mutual borrowing in cinema and architecture; and their classification is given. 
 One of the main reasons for the appearance of this article is the need for deeper and holistic coverage of such issues, as well as the relationship and synthesis of cinema and architecture. There is a large amount of research on synthesis and assumptions that apply to one thing: either cinema or architecture. Also, sometimes you can find various essays or publications that partially touch on similar issues, namely, the synthesis of cinema and architecture. However, for the most part, they are rather specific and limited, they explore similar issues using the example of only some specific films, talk about how architecture is depicted in films, etc. Nevertheless, there are works that comprehensively and thoroughly investigate exactly the interaction between cinema and architecture, as well as how they directly influence each other, but they are quite a few. 
 That is why it became necessary to investigate in more detail the phenomenon of the interaction of these two disciplines from a slightly different perspective. Instead of exploring how they alternately use each other as tools, the article explores whether cinema and architecture can be considered equal visual arts that, in addition to being used, can also complement and mutually borrow ideas from each other. 
 That is why this article is one of the necessary steps that will help to better research this topic, and can later be used as a basis for the rest of more in-depth research. 
 The paper examines the phenomenon of the synthesis of two arts: cinema and architecture. In particular, attention was paid to such phenomena as: the influence of cinema on increasing the attractiveness of the architectural environment, as well as the reflection of architecture in cinema and the mutual influence of film art and architecture. 
 It has been established that architecture in cinema can not only act as a background space where events take place but can also be an active participant in the film. Moreover, the synthesis of cinema and architecture can very often act as a kind of mirror of society, not just reflecting a believable reality, but also raising questions and rethinking certain moods and narratives that were present in society at certain times. 
 In addition, these findings provide additional information about the possible influence of cinema on increasing the attractiveness of the architectural environment, space, or area. In particular, this is demonstrated in the example of the phenomenon of film tourism. In other words, certain locations or buildings used as scenery and background in cult and popular films, such as Lord of the Rings trilogy, themselves become attractions over time, increasing the interest of tourists in these places. In conclusion, the article shows various forms of interaction between cinema and architecture, as well as the possible roles of architecture in films.

Achieving superlubricity and high adhesion strength of hydrogenated amorphous carbon film with Al/Cr/Si-doping

Excellent tribological properties of hydrogenated amorphous carbon films make it an important candidate for friction reduction in industry. However, the great challenge of achieving both high adhesion strength and super-low friction limits its wide applications. In this work, a novel Al, Cr and Si co-doped hydrogenated amorphous carbon (AlCrSi/a-C:H) film was prepared by high-power impulse magnetron sputtering (HiPIMS) method. The AlCrSi/a-C:H film showed favorable mechanical performance and high adhesion (∼80 N), which was attributed to the controlled elements doping and special transition layers produced by HiPIMS method. Meanwhile, superlubricity was obtained with coefficient of friction 0.0014. Detailed characterizations suggested that doping elements played significant roles in tribo-chemical reactions during friction. On one hand, doping elements can promote shear-induced graphitization and formation of graphite-like layers at the friction interface. On the other hand, the preferential oxidation of doping elements can protect the formed graphite-like layers from oxidation and the formed oxides nanoparticles can also be wrapped by carbon layers to prevent abrasive wear. It was the synergistic effects of graphitization and oxidation actions that led to superlubricity state of the film. The proposed AlCrSi/a-C:H film architecture with strong adhesion and superlubricity properties provides design criteria of superlubricious films for industrial applications.

Parameters influencing the fracture of Mo films and their wider significance

Fragmentation testing has been used for decades to assess thin film fracture and delamination. Hooke’s law is generally used to determine a film fracture stress from the crack onset strain observed in micrographs or measured as an electrical resistance increase. While this method is in theory suitable in the elastic regime, it neglects important film characteristics, such as residual stress, microstructure, or film architecture. Thus, there is a need to improve fracture analysis using fragmentation to avoid significant errors in measuring fracture stress or apparent fracture toughness of thin films. In-situ X-ray diffraction fragmentation experiments can measure the film fracture stress even for individual layers being part of a multilayer. Which characteristics influence the apparent fracture behavior will be demonstrated on Mo thin films on polyimide.Graphical abstract

Glancing angle deposition for tuning electronic transport properties of Si thin films

We report on electronic transport properties of B-doped Si thin films 400 nm thick sputter-deposited by glancing angle deposition (GLAD). For each film, a fixed deposition angle α is used during the growth. A series of 9 films are prepared changing α from 0° to 80° with increments of 10°. DC electrical resistivity, charge carrier mobility and concentration are systematically measured in the temperature range from 290 K to 410 K. For deposition angles higher than 40°, a tilted columnar morphology appears and becomes more defined, especially for the most grazing angles. The highest deposition angles also lead to more resistive films with charge carrier mobility and concentration significantly changing for α>30°. Experimental results are discussed assuming the evolution of structural defects vs. deposition angle in the columnar architecture of Si GLAD films.