Assembly Of Films Research Articles

A general objective-orientated automatic optimization of multi-layer thermochromic smart glazes

VO2-based thermochromic smart glazes have attracted much attention for energy-saving buildings. Their practical applications need high visible luminous transmittance (Tlum) and high solar light modulation efficiency (ΔTsol). High Tlum and ΔTsol are difficult to be realized by a single-layer VO2 film, and constructing multi-layer film assemblies has been a widely adopted way to increase Tlum and ΔTsol. Tlum and ΔTsol of a multi-layer film assembly are multi-dimensional functions of the complex dielectric permittivity and the thickness of each layer, respectively. The current research reported a computer automatic searching of the total minimum of an evaluation function that together takes the cool-state Tlum, hot-state Tlum, and ΔTsol into account. It can be used to optimize a multi-layer assembly composed of any components according to the given objectives and weights for Tlum and ΔTsol. Different multi-layer film systems consisting of SiO2, TiO2, and VO2 layers were optimized. The best film system was proposed to be TiO2/VO2/TiO2/s, and the effects of objectives and weights on Tlum and ΔTsol were also checked. The physical reason that leads to high Tlum and ΔTsol was analyzed based on the optimized reflectance and transmittance spectra. The RGB tristimulus of the optimized multi-layer system can also be obtained from the transmittance spectra. The program can also realize an automatic optimization with some variables being constrained, and the composite layers are also involved under the basis of the Bruggeman effective media theory. The results showed that a satisfied objective-orientated optimization can be realized for a thermochromic layer system; this should be meaningful for the design and preparation of the multi-layer film assemblies according to the different user's demands.

Messy Knowledge-Making with Korsakow

This paper explores interactive documentary production's power dynamics and knowledge-making practices through the ethnographic case study of Christoph, a white media scientist and trained film editor from a Western European country. Christoph's research project, conducted as part of an international and multidisciplinary team, dealt with discourses surrounding a specific restitution case in an African country. The study focuses on Christoph's use of the Korsakow software to create an interactive documentary, examining the complexities he encountered in the field and his efforts to represent them in a powercritical manner. Throughout the production process, Christoph attempted to address power relations by making himself visible in the documentary and ensuring that his authorial influence remained minimal during the film's assembly. He employed a two-fold strategy that included acquiring shaky footage without a tripod and utilizing materials that might be deemed unusable in traditional production environments. Christoph's use of Korsakow as a tool for assembling his interactive documentary served to represent the complexities he found in the field. Despite Christoph's powercritical aspirations, he acknowledged the potential bias inherent in the keywording process, stressing the importance of actively pursuing powercritique as a practice. Korsakow, as an interactive and nonlinear tool, offered an experimental environment in which Christoph could explore alternative ways of filmmaking and knowledge-making. This environment facilitated the development of open, complex, and messy practices, challenging conventional filmmaking norms. This case study raises questions about the knowledge-making practices found in interactive documentaries and how they can inform visual research methodologies. Further research may delve into the methodological implications of these findings and the potential for interactive documentary software to serve as a laboratory for experimental filmmaking practices. By examining Christoph's use of Korsakow and his efforts to navigate power dynamics in creating an interactive documentary, this paper contributes to the broader understanding of knowledge-making in non-linear and interactive film environments.

High Selectivity and Sensitivity in Chemiresistive Sensing of Co(II) Ions with Liquid-Phase Exfoliated Functionalized MoS2 : A Supramolecular Approach.

Chemical sensing of water contamination by heavy metal ions is key as it represents a most severe environmental problem. Liquid-phase exfoliated two-dimensional (2D) transition metal dichalcogenides (TMDs) are suitable candidates for chemical sensing thanks to their high surface-to-volume ratio, sensitivity, unique electrical characteristics, and scalability. However, TMDs lack selectivity due to nonspecific analyte-nanosheet interactions. To overcome this drawback, defect engineering enables controlled functionalization of 2D TMDs. Here, ultrasensitive and selective sensors of cobalt(II) ions via the covalent functionalization of defect-rich MoS2 flakes with a specific receptor, 2,2':6',2″-terpyridine-4'-thiol is developed. A continuous network is assembled by healing of MoS2 sulfur vacancies in a tailored microfluidic approach, enabling high control over the assembly of thin and large hybrid films. The Co2+ cations complexation represents a powerful gauge for low concentrations of cationic species which can be best monitored in a chemiresisitive ion sensor, featuring a 1 pm limit of detection, sensing in a broad concentration range (1 pm - 1 µm) and sensitivity as high as 0.308 ± 0.010 lg([Co2+ ])-1 combined with a high selectivity towards Co2+ over K+ , Ca2+ , Mn2+ , Cu2+ , Cr3+ , and Fe3+ cations. This supramolecular approach based on highly specific recognition can be adapted for sensing other analytes through specific ad-hoc receptors.

Spherical aluminum oxide nanoparticle synthesis and monolayer film assembly

Spherical aluminum oxide nanoparticle synthesis and monolayer film assembly

Modular Metal-Quinone Networks with Tunable Architecture and Functionality.

Nanostructured materials with tunable structures and functionality are of interest in diverse areas. Herein, metal ions are coordinated with quinones through metal-acetylacetone coordination bonds to generate a class of structurally tunable, universally adhesive, hydrophilic, and pH-degradable materials. A library of metal-quinone networks (MQNs) is produced from five model quinone ligands paired with nine metal ions, leading to the assembly of particles, tubes, capsules, and films. Importantly, MQNs show bidirectional pH-responsive disassembly in acidic and alkaline solutions, where the quinone ligands mediate the disassembly kinetics, enabling temporal and spatial control over the release of multiple components using multilayered MQNs. Leveraging this tunable release and the inherent medicinal properties of quinones, MQN prodrugs with a high drug loading (>89 wt %) are engineered using doxorubicin for anti-cancer therapy and shikonin for the inhibition of the main protease in the SARS-CoV-2 virus.

Modular Metal‐Quinone Networks with Tunable Architecture and Functionality

AbstractNanostructured materials with tunable structures and functionality are of interest in diverse areas. Herein, metal ions are coordinated with quinones through metal‐acetylacetone coordination bonds to generate a class of structurally tunable, universally adhesive, hydrophilic, and pH‐degradable materials. A library of metal‐quinone networks (MQNs) is produced from five model quinone ligands paired with nine metal ions, leading to the assembly of particles, tubes, capsules, and films. Importantly, MQNs show bidirectional pH‐responsive disassembly in acidic and alkaline solutions, where the quinone ligands mediate the disassembly kinetics, enabling temporal and spatial control over the release of multiple components using multilayered MQNs. Leveraging this tunable release and the inherent medicinal properties of quinones, MQN prodrugs with a high drug loading (>89 wt %) are engineered using doxorubicin for anti‐cancer therapy and shikonin for the inhibition of the main protease in the SARS‐CoV‐2 virus.

Layer-by-layer assembly of metal-organic framework thin films: Fabrication and advanced applications

Metal-organic frameworks (MOFs) are a class of crystalline porous coordination materials, which are assembled from inorganic nodes and organic linkers. Numerous applications, such as gas storage, molecule separation, catalysis, optical sensing, and charge transport, benefit from the outstanding properties of MOF materials. More advanced applications, e.g., in the electronics and optoelectronics area, demand homogeneous and monolithic MOF thin films. Recent studies demonstrated that surface-mounted MOFs (SURMOFs) are well suited to fulfill the requirements for the integration of MOFs into devices. As a crystalline thin-film material with tunable thickness, SURMOFs have been widely used in the optimization of chromophore stacking, electrical transport, stimuli-response, etc. The fabrication of SURMOFs is carried out employing a layer-by-layer (LbL) assembly technique, and it can yield MOF thin films with a well-defined orientation, tunable thickness, and editable crystalline heterostructure. We summarize the LbL assembly methods for SURMOF fabrication and the realization of advanced SURMOF architectures, including optical and electronic applications as well as the integration of photoactive SURMOFs and SURMOF-derived materials in technical devices. We conclude with a discussion of the challenges and prediction of the future of SURMOF materials.

Bioactive Synthetic Polymer-Based Polyelectrolyte LbL Coating Assembly on Surface Treated AZ31-Mg Alloys

Polyelectrolyte layer-by-layer (LbL) films on pretreated Mg containing 3 wt.% Al and 1 wt.% Zn (MgAZ31) alloy surfaces were prepared under physiological conditions offering improved bioresponse and corrosive protection. Pretreatments of the model MgAZ31 substrate surfaces were performed by alkaline and fluoride coating methods. The anti-corrosion and cytocompatibility behavior of pretreated substrates were evaluated. The LbL film assembly consisted of an initial layer of polyethyleneimine (PEI), followed by alternate layers of poly (lactic-co-glycolic acid) (PLGA) and poly (allylamine hydrochloride) (PAH), which self-arrange via electrostatic interactions on the pretreated MgAZ31 alloy substrate surface. The physicochemical characterization, surface morphologies, and microstructures of the LbL films were investigated using Fourier-transformed infrared spectroscopy (FTIR), atomic force microscopy (AFM), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The in vitro stability studies related to the LbL coatings confirmed that the surface treatments are imperative to achieve the lasting stability of PLGA/PAH layers. Electrochemical impedance spectroscopy measurements demonstrated that pretreated and LbL multilayered coated substrates enhanced the corrosion resistance of the bare MgAZ31 alloy. Cytocompatibility studies using human mesenchymal stem cells seeded directly over the substrates showed that the pretreated and LbL-generated surfaces were more cytocompatible, displaying reduced cytotoxicity than the bare MgAZ31. The release of bovine serum albumin protein from the LbL films was also studied. The initial data presented cooperatively demonstrate the promise of creating LbL layers on Mg-related bioresorbable scaffolds to obtain improved surface bio-related activity.

Layer-by-Layer Assembly of Two-Dimensional Monolayer Films of Gold Nanoparticles for Electrochemical Determination of Melamine

L-Cysteine (L-Cys) and two-dimensional monolayer films of gold nanoparticles (2D MFGS) were employed to modify gold electrodes to build uniform and stable multilayer films by layer-by-layer (LbL) self-assembly, denoted by Au/(L-Cys/2D MFGS)n (n = number of layers). Electrochemical measurements showed that the specific surface area and current amplification capacity of the modified electrode increased with the value of n. In addition, considering the orderliness inside the multilayer 2D MFGS assembly and experimental accessibility, Au/(L-Cys/2D MFGS)n=4 was selected to be the working electrode and dopamine (DA) as the signal quantification molecule for the indirect detection of melamine (MA). The results showed that the oxidation current of DA was inhibited due to the competitive adsorption of melamine upon the working electrode. Under the optimal conditions, the decrease of the dopamine peak anode current is proportional to the melamine concentration from 10−12 to 10−3 M with a detection limit of 0.13 pM. The results demonstrate the potential of 2D MFGS for applications in food and biological analysis. The scheme for fabricating the multilayer electrodes is convenient and environment-friendly, without expensive instrumentation or complex modifications.

Geochemistry and release risk for nutrients in lake sediments based on diffusive gradients in thin films.

A comprehensive understanding of the mobility of both nitrogen (N) and phosphorus (P) and the inter-relationships between P, N, and iron (Fe) in sediments is important for controlling the "internal loadings" of nutrients in lakes. In this research, diffusive gradients in thin film (DGT) assemblies with binding layers (ZrO-AT, chelex, and ZrO) were designed for PO4-P, Fe, ammonium (NH4-N), and nitrate (NO3-N) at sediment/water interface (SWI) in Western Lake Taihu (China). The biogeochemical processes of N and P related to the physicochemical properties, the dynamic P transfer, the distribution characteristics of P microniches, and the estimation of the release risks in sediments in Western Lake Taihu were simultaneously revealed by the passive sampling technique-DGT with the high spatial resolutions (millimeter and sub-millimeter). Based on DGT concentration (CDGT) related to physicochemical properties in sediments, (1) P biogeochemical reactions included P release from Fe-bound P during Fe reduction, algae biomass decomposition, and phosphatase enzyme activity increased by NH4-N; (2) denitrification and dissimilatory nitrate reduction to ammonium (DNRA) led to exchangeable ammonium (NH4ex) enrichment and NH4-N release; anammox depleted NH4-N transfer; organic matter (OM) mineralization favored NH4-N release; and (3) aerobic nitrification led to NO3-N remobilization; denitrification and DNRA reduced NO3-N release. Redox status, OM, Fe, aluminum, or calcium influenced mobilization of nutrients. The numerical model of DGT-induced fluxes in sediments was used for dynamic P transfers with resupply types ("slow" ~ "fast") controlled by labile P pool, resupply constant, response time, and Dspt rate. The formation of P microniches in two dimensions was revealed. Sediment P release risk index (0.49 ~ 36.85 [lg (nmol cm-3 d-1)]) with "light" ~ "high" risks and diffusive fluxes across SWI (µg m-2 d-1) of 15.0 ~ 639 (PO4-P), - 1403 ~ 5010 (NH4-N), and - 1395 ~ 149 (NO3-N) were derived and lake management strategies were provided. The DGT technique provides the characterization of the mobilization of nutrients and evidence for biogeochemical processes at the fine spatial scales for control of internal loadings in sediments.

Liquid Phase Exfoliation of Chemically Prelithiated Bilayered Vanadium Oxide in Aqueous Media for Li-Ion Batteries

Bilayered vanadium oxides are attractive for energy storage due to their high initial specific capacities, which could be stabilized by integrating the bilayers with conductive nanoflakes often produced in a form of aqueous dispersions. Therefore, exfoliation of the bilayered vanadium oxides in water with high yield is desirable. This work introduces the first aqueous exfoliation of chemically prelithiated bilayered vanadium oxide (i.e., δ-LixV2O5·nH2O or LVO) followed by vacuum filtration to produce a free-standing film, exhibiting a lamellar stacking of the bilayered vanadium oxide nanoflakes as evidenced by scanning electron microscopy. Due to the hydrated nature of bilayered vanadium oxides, the relationship between interlayer water content and the vacuum drying temperature (105 °C vs 200 °C) was studied using X-ray diffraction, thermogravimetric analysis, and Raman spectroscopy. It was found that vacuum drying the LVO nanoflakes at 200 °C enabled more efficient removal of crystallographic water than drying at 105 °C, and did not induce a phase transformation. Scanning transmission electron microscopy confirmed the layered structure of the samples, which was more well-ordered in the 200 °C case and had no clear boundaries between flakes at the atomic scale. Furthermore, electrochemical testing in nonaqueous Li-ion cells revealed that vacuum drying at 200 °C led to improvements in ion storage capacity and electrochemical stability. Improvements in electrochemical charge storage properties of the electrodes obtained via LVO exfoliation and free-standing film assembly in water dried at 200 °C reveal that conventional battery electrode drying protocols need to be revised as new electrochemically active materials are synthesized, such as hydrated layered oxides with expanded interlayer regions. The remaining capacity fading can be attributed to the structural LVO degradation, dissolution of vanadium oxide in electrolyte, and parasitic effects of the remaining interlayer water molecules. Our results establish an environmentally friendly and safe approach to obtain two-dimensional (2D) bilayered vanadium oxide nanoflakes and create a pathway to constructing novel 2D heterostructures for improved performance in energy storage applications.

Conjugated Polymer Nanoparticles: Photothermal and Photodynamic Capabilities According to Molecular Ordering in Their Assembly Structures

We report that conjugated polymer nanoparticles (CPNs) coated with polyethylene glycols (PEGs) exhibit photothermal and photodynamic capabilities according to molecular ordering in their assembly structures. CPN-PEGs were made using three different methods: a dispersion process of phase-separated film assemblies of a conjugated polymer and a phospholipid-conjugated PEG (CPN-I), a dispersion process of a conjugated polymer and a phospholipid followed by surface conjugation with PEGs (CPN-II), and a miniemulsification of the conjugated polymer and the phospholipid-conjugated PEG. Our findings revealed that the ordered molecular assembly structures in CPN-I and CPN-II increased intermolecular interactions and decreased the optical band gap, promoting nonradiative exciton relaxation via the energy-gap law’s internal conversion mechanism and rationalizing CPN-I’s shorter singlet exciton lifetime (13 ps). Meanwhile, CPN-III with a disordered structure generated more singlet oxygen than CPN-I and CPN-II, indicating increased triplet exciton generation upon the polaron recombination. Our findings present that the photothermal and photodynamic properties of CPNs are obviously dependent on the assembly structure order and that CPNs with an ordered assembly of conjugated backbones have a stronger photothermal effect, whereas those with a disordered structure have a better photodynamic effect.

Effect of Oxidants on Properties of Electroactive Ultrathin Polyazulene Films Synthesized by Vapor Phase Polymerization at Atmospheric Pressure.

A non-benzenoid aromatic hydrocarbon azulene, naturally found in plants and mushrooms, is known for its derivatives applications in medicines. However, the processability of its chemically synthesized high-capacitance polymer is constrained by the sparingly soluble nature of its polymeric form. Oxidative chemical synthesis on a desirable substrate overcomes this difficulty. In this report, polyazulene (PAz) thin films are synthesized by vapor phase polymerization at atmospheric pressure using oxidants, such as CuCl2, CuBr2, FeCl3, and FeTOS. The effect of oxidants on morphologies of PAz films is studied using atomic force microscopy and microscope imaging. Each oxidant produced distinct microstructures in the films. The films synthesized using Cu(II) salts showed organized and knitted structures, whereas Fe(III) salts formed casted sheet-like disordered arrangements. The films synthesized using CuCl2 created uniform porous film assemblies. The pre-peak formations and their splitting observed in the cyclic voltammograms revealed phase segregations in the films. Oxidant-dependent structural and chemical differences such as charge carrier formation, doping levels, and polymer chain length in the PAz films are studied by using UV-Vis and FTIR spectroscopy. The results indicated that 240 and 180 mM are the optimum concentration of CuCl2 to produce high capacitance and well-organized single- and triple-layered PAz films, respectively.

Multilayer Langmuir Film of Monodisperse Au Nanoclusters: Unusual Growth via Bilayers

The assembly of nanomaterials into thin films is an important area in the nanofabrication of novel devices. The monodispersity of nanoparticles plays an essential role in the resulting quality of the assembled mono- and multilayers. Larger polydispersity leads to smaller lateral correlation lengths and smaller domains of aligned nanoparticles, thus resulting in more point and line defects. Perfectly monodisperse nanoparticles should therefore minimize the number of defects in the assembled films. Despite tremendous progress in reducing the polydispersity of nanoparticles, there has been limited research on the assembly of thin films out of perfectly monodisperse nanoclusters. Here, we show a formation of Langmuir films using perfectly monodisperse gold nanoclusters with composition Au32(nBu3P)12Cl8 exhibiting a diameter of 1.8 nm. Using both in situ and ex situ small-angle X-ray scattering, we show that the monolayer formed on a Langmuir-Blodgett trough exhibits long-range order. Moreover, after compressing the monolayer, we found that the stress accumulated prior to the monolayer collapse triggers a transition to a short-range order not previously reported. If such monolayer is compressed further, the second layer is not formed as in the case of standard nanoparticles. Instead, a growth of islands by an odd number of layers is observed, leading to a thin film with a structure consisting of two different orientations of the hexagonal lattice. Such anomalous behavior may have implications for the possibilities of thin-film formation.

Scalable Assembly of High-Quality Graphene Films via Electrostatic-Repulsion Aligning.

Assembling pristine graphene into freestanding films featuring high electrical conductivity, superior flexibility, and robust mechanical strength aims at meeting the all-around high criteria of new-generation electronics. However, voids and defects produced in the macroscopic assembly process of graphene nanosheets severely degrade the performance of graphene films, and mechanical brittleness often limits their applications in wide scenarios. To address such challenges, an electrostatic-repulsion aligning strategy is demonstrated to produce highly conductive, ultraflexible, and multifunctional graphene films. Typically, the high electronegativity of titania nanosheets (TiNS) induces the aligning of negatively charged graphene nanosheets via electrostatic repulsion in the film assembly. The resultant graphene films show fine microstructure, enhanced mechanical properties, and improved electrical conductivity up to 1.285 × 105 S m-1 . Moreover, the graphene films can withstand 5000 repeated folding without structural damage and electrical resistance fluctuation. These comprehensive improved properties, combined with the facile synthesis method and scalable production, make these graphene films a promising platform for electromagnetic interference (EMI) shielding and thermal-management applications in smart and wearable electronics.

A highly stable solid-state supercapacitor device based on robust layer-by-layer electrodeposited poly-(3, 4-ethylenedioxythiophene)-reduced graphene oxide–molybdenum disulfide nanocomposite electrode

A ternary nanocomposite film of PEDOT-rGO-MoS2 for a symmetrical solid-state supercapacitor device has been fabricated via in-situ interconversions by employing efficient electrochemical approach. The higher porosity offered by popcorn like microstructures of PEDOT has enabled better stacking within PEDOT-rGO-MoS2 composite resulting in superior supercapacitive performance. The obtained electrode exhibits good volumetric capacitance (887.6 F cm−3) and high volumetric energy density (123 mWh cm−3) with high-power density (2930 mW cm−3). The efficiency in the supercapacitor performance originates from the synergy of the trio forming a well-integrated optimized energy storage system. Assembly of composite films into a solid-state symmetrical device with PVA-KCl gel-electrolyte has resulted in excellent cyclic stability, good capacitive retention of 98.3 % and coulombic efficiency of 100.2 % over 10,000 cycles. The obtained symmetrical device offered high areal energy density (1.1 μWh cm−2) has been successfully evaluated for its practical utility in the configuration of four devices connected in series with an output of 25 min to illuminate green LED. The findings pave a promising way for the development of energy efficient microelectronics by using the present device structure in future energy storage applications.

Molecular Organization in Exponentially Growing Multilayer Thin Films Assembled with Polyelectrolytes and Clay.

Multilayer thin film assembly by the layer-by-layer (LbL) technique offers an inexpensive and versatile route for the synthesis of functional nanomaterials. In the case of polymer-clay systems, however, the technique faces the challenges of low clay loading and lack of tunability of the film characteristics. This is addressed in the present work that achieves exponential growth in clay-containing polyelectrolyte films having high clay loading and tailored properties. Our approach involves the incorporation of a weak polyelectrolyte and a clay with relatively high charge density and small particle size. The system of investigation comprises poly(diallyldimethylammonium chloride) (PDDA) as the polycation and laponite clay and poly(acrylic acid) (PAA) or poly(sodium-4-styrene sulfonate) (PSS) as polyanions that are used alternately to create multilayers. Successful high clay loading and exponential growth were achieved by two different approaches of polyanion incorporation in the multilayers. A progressive increase in the degree of ionization of PAA was shown to contribute to the exponential growth. Our findings also include novel pathways to manipulate thickness, surface topography, and clay content. The strategy presented here can lead to novel approaches to fabricate tailor-made nanomaterials for distinct applications.

In Situ Monitoring of Layer-by-Layer Assembly Surface Modification of Nanophotonic-Microfluidic Sensor.

An elaboration of the photonic based sensors is the most promising direction in modern analytical chemistry from the point of view of real clinical applications. The highest sensitivity is demonstrated by sensors based on photonic integrated circuits (PICs). This type of sensor has been recently successfully combined with microfluidics, which decreased the analyte volume for analysis down to microliter units. The most significant disadvantage regarding these photonic sensors is low specificity. One of the methods that could be useful for such type of problem is the layer by layer (LBL) assembly. The peculiarity of a PIC based sensor is the ability to precisely control surface modification by using measurements of a minimum resonance position shift. The bovine serum albumin (BSA) and tannic acid (TA) molecules were selected for LBL assembly because on one side they form a stable LBL assembly film based on hydrogen bonds, while the other side of both TA and BSA molecules can be used for conjugation with target molecules. A microring resonator (MRR) and a Mach-Zehnder interferometer (MZI) based on a silicon nitride platform combined with a microfluidic system were elaborated and used for monitoring the LBL film assembly. Obtained results have a good correlation with measurements carried out by atom force microscopy. Thus, the ability of using PIC based sensors for in situ control of surface modification was demonstrated and can be considered in point-of-care (POC) devices that have a very good perspective for both early pathological state diagnosis and evaluation of treatment efficiency.

Zwitter Ion-Promoted Hybrid 2D Materials for Energy Applications

Layer-by-layer assembly of thin films have received growing interest in a variety of applications worldwide. Methods for depositing films, patterning, unconventional assemblies, and approaches are gaining immense scientific advancements. The porous structures, tunable surface areas, remarkable thermal and mechanical stabilities, abundant reserves, and cost-effectiveness makes clays one of the most sought-after materials for plethora of applications. Interestingly, several naturally occurring silicates, viz. clay minerals have layered structure with possibility of interchangeable intercalated ions and tunable chemical properties. Among these clay minerals, Bentonite is very promising owing to its abundance, low cost, high surface area, porosity, and unique layered structure. Clay is composed of alternating tetrahedral silica (T) and octahedral alumina (O) sheets arranged in 1:1 ratio (T-O). The tetrahedral sheets are formed from Si4+ ions coordinated with oxygen, however in the octahedral sheet Al3+ metal ion is the central atom. Notably, naturally occurring Bentonite have some of the octahedral sites occupied by the Mg2+ and Fe2+ ions. The presence of these ions shows the tunable property of the octahedral layer that can concomitantly widen its applicability in the energy fields. Herein, we have put a focused effort in developing a sustainable, cost-effective, environmental benign, and biocompatible clay films having unique physical and chemical properties. We present a unique approach to develop clay galleries infused with intercalating quaternary ammonium salts. The insertion of such zwitter ions enhances the interlayer spacing, while simultaneously allowing to form durable clay films. The hybrid clay films have been characterized using the powder X-ray diffraction, X-ray photoelectron spectra, ATR-FTIR spectra, DSC-TGA, dynamic mechanical analyses, and imaging techniques. Effect of varying the carbon chain length in these zwitter ions have been verified to have a significant impact in controlling the interlayer spacing in the clay films. Further, the intercalation using zwitter ions led to the alternations in the electron environment of the dielectric silicate layers that has been confirmed using electrochemical and impedance spectroscopy studies. Owing to the high electronic resistance and high ionic conductivity present in the films, a series of impedance spectroscopy experiments were conducted in variety of electrolytes. The ionic conductivity of the hybrid clay films is remarkable, and a correlation have been established with the ionic size of the conducting ions. In metal ion batteries, where dendritic growth causes thermal degradation of the batteries, the hybrid clay films possess high thermal and mechanical stability that makes them versatile for energy materials. can provide The abundance and sustainability of clay minerals and a cost-effective approach to engineer these hybrid films may provide efficient avenues to develop new generation of battery separators and capacitors for future.

Spin‐spray‐assisted layer‐by‐layer assembly of thick polymer films with self‐healing, UV‐protection, and anti‐fog properties

AbstractLayer‐by‐layer (LbL) deposition of oppositely charged polyelectrolytes has been widely used to make responsive and multifunctional smart films. Herein, a high‐performance and multifunctional LbL film was fabricated by using a spin‐spray‐assisted (SSA‐LbL) assembly method with poly(diallyldimethylammonium chloride) (PDDA) and poly(acrylic acid) (PAA). The SSA‐LbL method was found to be more efficient and time‐saver in making a homogeneous thick film in tens of micrometers, compared to the conventional immersive assembly method which makes thin films in the nanometer range. When scratches occur, the film shows a quick and durable self‐healing capability due to the dynamic movement of the flexible polyelectrolyte complex chains at the edges of the scratches. An effective UV‐block performance was incorporated into the film by using the graphene oxide (GO) and titanium dioxide (TiO2) nanoparticles as UV‐blocking additives. Due to the hydrophilic feature of PDDA/PAA molecules, the film also showed the anti‐fog property in different environmental conditions. The effect of the concentration of GO and TiO2 nanoparticles on self‐healing and UV‐protection properties were investigated. Also, the optimum range of concentration of GO and TiO2 nanoparticles in polyelectrolyte solutions was determined to fabricate the film with the combined features of self‐healable, UV‐blocking, and anti‐fog.