Composite Thin Films Research Articles

Operando Stress Evolution in Hard Carbon Anodes – Insight into the Mechanical Degradation Induced Failure Mode in Rechargeable Sodium Ion Batteries

Microstructural instabilities in electrodes arising from cycling induced stress is a primary failure mode in rechargeable batteries. Therefore, a quantitative knowledge of the cycling induced stress evolution in rechargeable battery electrodes is important for understanding the electrode microstructural instabilities during cycling that can potentially inform the electrode design to prolong battery cycle life. The cycling induced stress in electrodes typically arises from the volume changes associated with insertion/extraction of the electroactive species in the electrode matrix. For example, operando measurement of lithiation-delithiation induced stress in graphite electrodes that typically show 10% volume change has previously resulted in useful information that correlates well with the lithiation-delithiation mechanism in graphite anodes1. The size of the shuttling-electroactive species can be taken as an indicator of the cycling induced stress magnitude that drives the electrode microstructural instabilities. In this regard, quantification of the cycling induced stress in rechargeable Na-ion battery electrodes is warranted for understanding mechanical degradation induced failure modes owing to the larger size of the electroactive species, i.e., Na ions (vs. Li-ion).Hard carbons as potential anodes in rechargeable sodium ion batteries has gained considerable attention in the recent past due to their superior Na-ion storage capability (vs. graphite that is a canonical anode in rechargeable lithium-ion batteries). However, hard carbon anodes typically show significant capacity fade that can potentially arise from cycling induced mechanical degradation of the anodes. Operando stress measurements coupled with comprehensive electrode microstructural characterization will provide valuable insights in this context. Here we report on the operando stress evolution in hard carbon anodes in rechargeable sodium ion batteries as probed by Multiple Optical-beam Sensing (MOS) technique that basically involves monitoring the spacings among a group of laser spot (Fig. 1). Preliminary measurements have shown that the stress correlates with the potential with a maximum around 12 MPa in compression during sodiation and tensile stress of ~ 2MPa during desodiation. Operando stress measurements are performed in hard carbon anodes in two different electrode configurations – typical composite anodes (with binder and conductive agents) and hard carbon thin film anodes (without binder and conductive agents). The thin film configuration is considered to evaluate intrinsic stress response in hard carbon anodes in absence of any secondary phase. A comparison of operando stress response in these two types of hard carbon anodes along with comprehensive electrode microstructural characterization will be presented. Additionally, attempts will be made to shed light on the current debate in the mechanism of sodium storage in hard carbon anodes by comparing operando stress response of hard carbons from multiple sources along with their structural characterization (Raman, XPS, surface area etc.). V. A. Sethuraman, N. Van Winkle, D. P. Abraham, A. F. Bower, and P. R. Guduru, Journal of Power Sources, 206, 334–342 (2012). Figure 1

Interfacial polymerization modulated by COFs interlayer to fabricate efficient mono/divalent ions separation nanofiltration membrane

Thin-film composite (TFC) membranes have been recently applied in the mono/divalent ions separation, which is essential for resource recycle, wastewater treatment, and lithium resource extraction. However, the TFC membranes fabricated between the polyethyleneimine (PEI) and trimesoyl chloride (TMC) usually show a low water permeance. Herein, piperazine (PIP) is added in the PEI aqueous phase solution to fabricate a polyamide (PA) layer for the enhancement of water permeance. Meanwhile, the diffusion rate of PIP to the two-phase interface is reduced by the hydrogen bond effect between PIP and MPDTp COFs interlayer, which can weaken the reaction of PIP and TMC and maintain a high ion rejection. Pure water permeance of the obtained PA-PIP/Fe-COF/PES membrane is 16.1 L m−2 h−1 bar−1, and the Li+/Mg2+ separation factor is 73.0, which is almost two times higher than the PA-PIP/PES under Li+/Mg2+ mass ratio of 1:20. Besides, the membrane also keeps satisfactory performance in Na+/Mg2+, Cl−/SO42−, Na+/Ca2+ separation, and ten days of long-term testing. Therefore, this work raises a new strategy to prepare a high-efficiency mono/divalent ions separation nanofiltration membrane.

Capsaicin mimic-based antifouling and antibacterial polyester nanofiltration membranes with tunable crosslinked structures

Polyester thin-film composite (PE TFC) nanofiltration membranes based on the interfacial polymerization (IP) of polyols/polyphenols and acyl chloride continue to attract considerable attention for textile wastewater treatment due to their excellent antifouling properties. Herein, N-(5-methyl acrylamide-2,3,4 hydroxy benzyl) acrylamide (AMTHBA), a polyphenol-inspired capsaicin derivative, was first utilized as an aqueous monomer for the preparation of antifouling and antibacterial PE TFC membranes via the IP process. The moderate reactivity of AMTHBA and its unique solubility enabled a rational control of the crosslinking density of PE membranes, allowing the formation of structures from loose to dense through an adjustment of the AMTHBA concentration. The densely crosslinked AM-TMC PE membrane exhibited favorable desalination performance, with a water permeance of 21.8 L m−2 h−1 bar−1 and a Na2SO4 rejection of 83.8 %. The loosely crosslinked AM-TMC PE membrane exhibited excellent dye/salt separation performance, with high dye rejections (e.g., 98.5 % for MB) and low salt rejections (e.g., 4.0 % for NaCl), as well as high water permeance (30.4 L m−2 h−1 bar−1). In contrast, the capsaicin-containing PE TFC membranes also demonstrated markedly enhanced resistance to bacterial growth and organic fouling. These findings indicate that AM-TMC PE membranes present novel avenues for the advancement of task-specific separation membranes.

Construction of low-resistance nano-transport channels with UiO-66-(NH2)2 “transmembrane” in polyamide layer structure for efficient nanofiltration

Metal-organic frameworks (MOFs) is always a research hotspot as the modifier for fabrication of thin-film nanocomposite (TFN) membrane due to their excellent chemical tunability and suitable pore size. However, the traditional strategy for the involvement of MOFs into interfacial polymerization (IP) process has its limitations, as the addition of MOFs only serve to modulate the structure of the polyamide (PA) layer and to optimize the transport path of water molecules, rather than play an important role in selectively sieving solutes. To solve the problem that MOF embedded under the PA layer cannot directly participate in solute sieving, this study designed a “transmembrane” structure of MOF in the PA layer. Here, the feasibility of 1,3,5-Benzenetricarbonyl chloride modified UiO-66-(NH2)2 was verified based on Gibbs free energy calculations. By adding chlorinated UiO-66-(NH2)2 nanomaterials in the dual IP process, a high-throughput nanofiltration membrane was innovatively constructed. In contrast to conventional thin-film composite membrane prepared by only one IP process, the sieving mechanism no longer relied solely on the free volume of the PA chain segments. Instead, it was determined by the combination of the pore channels of UiO-66-(NH2)2 and the matrix gaps. Based on density functional theory (DFT), the calculated diffusion energy barriers of H2O and Na2SO4 in UiO-66-(NH2)2 and PA matrices reveal the reasons for the improvement of water flux and changes in retention rate of TFN membranes. In addition, the gap size between PA-MOFs was determined by comparing the solvation and de-solvation structures of dye molecules. This work provides a new theoretical basis for explaining the changes in the separation performance of TFN membranes, and offers new ideas for the development of novel TFN membrane structures.

A facile solvent activation process manipulates the structure and filtration performance of oxidized poly (arylene sulfide sulfone) TFC membrane

In this study, solvent-resistant polyamide (PA) thin film composite (TFC) nanofiltration (NF) membranes were successfully prepared based on an ultrasolvent-resistant oxidized poly (arylene sulfide sulfone) (O-PASS) substrate. The effects of different substrates on interfacial polymerization (IP) process were systematically studied. The O-PASS-TFC membranes were activated to different degrees by a controlled activation process using the mixture solvent of DMF/H2O with different ratio of DMF, the solubility power can be designed by adjusting DMF volume fraction, as the activation solvent. The membrane followed pure DMF treatment was found to have the excellent performance: the surface morphology of TFC membrane was activated to smooth and high negative charged, yield nanofiltration (NF) performance with a solution permeance of 8.82 LMH bar−1 (~621 % increase) and a pure water permeance (PWP) of 11.59 LMH bar−1 (~607 % increase), Na2SO4 rejection maintained above 98.7 %. On the other hands, the same O-PASS-TFC membrane activated with solvent mixture volume ratio of DMF/H2O = 0.5 exhibited enhanced Na2SO4 rejection of 99 %, with greater solution permeance of 3.01 LMH bar−1 (~212 % increase). The correlations between the different activation treatment-membrane structure-separation properties of O-PASS-TFC membranes with different solvent activation degrees were investigated in detail. In this work, the ultrasolvent-resistant property of O-PASS substrate was combined to regulate its TFC membrane structure, and then further to endow the TFC membrane with multiple excellent filtration performance by fully utilizing the solvent activation effect of DMF. Through this strategy, it supplies a facile and promising route for preparation of high efficiency TFC membrane.

Functional of thin-film composite Janus membrane with sacrificial layer for inorganic scaling control in membrane distillation

Membrane distillation technology, utilized for treating hypersaline wastewater from seawater desalination, often encounters challenges related to inorganic scaling, adversely affecting membrane performance. Herein, we introduce a innovative approach employing a sacrificial layer on the surface of Thin Film Composite (TFC) membranes to concurrently enhance inorganic scaling resistance and facilitate membrane reusability. The sacrificial layer (Fe3+-TA) consisted of tannic acid (TA) complexed with iron ions (Fe3+) and could be removed and regenerated in situ. The results demonstrated that the Fe3+-TA layer significantly improved the membrane's surface smoothness and densification, maintaining superior anti-scaling performance. The modified membrane exhibited remarkable durability, sustaining six reuse cycles with a flux recovery exceeding 97 % in gypsum scaling tests. Furthermore, the formation of new complexes during gypsum scaling tests confirmed the membrane's augmented scaling retardation capabilities. Thus, integrating of a sacrificial layer into TFC membranes presents a promising strategy for advancing membrane distillation processes in hypersaline wastewater treatment.

Synthesis of reduced graphene oxide (rGO)/polyaniline (PANI) composite electrode for energy storage: Aqueous asymmetric supercapacitor

Composite materials have gained significant interest for energy storage applications due to their possible synergistic effects. This work describes the synthesis of reduced graphene oxide (rGO)/polyaniline (PANI) composite thin films using chemical bath deposition (CBD) method. A field-emission scanning electron microscope revealed that PANI spikes coated on rGO sheets in rGO/PANI composite. The electrochemical studies of a rGO/PANI composite electrode showed a specific capacitance (Cs) of 1130F/g Cs at a scan rate of 5 mV/s in 1 M H2SO4 electrolyte. The combined effect of rGO with PANI, a aqueous asymmetric supercapacitor device (ASC) with configuration of rGO/PANI/H2SO4/WO3 produced 97F/g Cs at a 5 mV/s scan rate and retained 82 % capacitance after 5,000 galvanostatic charge–discharge cycles. The ASC achieved a high specific energy of 23 Wh kg−1 at a specific power of 732 W kg−1. The electrochemical properties of rGO/PANI composite indicate a feasible method for creating asymmetric supercapacitors.

Direct recovery of high-purity lithium via nanofiltration membranes from leaching solution of spent lithium batteries

The recycling of spent ternary lithium batteries (T-LIBs) promises scarce strategic resource recovery, however, efficient and selective recovery of Li+ from T-LIBs leaching solution with complex components is still a considerable challenge. Herein, we present a polyamide nanofiltration membrane based on the positively charged nanoscale dispersion interlayer for the first application in recycling lithium from the leaching solution of spent T-LIBs. The electronegativity is weakened by positive charge within the interlayer, which enhance the effect of Donnan exclusion. The pos-TFNi membrane can effectively permeate Li+ while the interfering divalent ions are almost completely separated, achieving the high purity (separation factor ≥ 93.5) and high recovery rate (79.2%) of Li+ from leaching solution simultaneously, with a 6.2-fold improvement in the separation factor over the pristine TFC membrane, and outperformed the majority of the NF membranes. This work represents a reference for the recycling of the massive accumulation of spent T-LIBs worldwide.

Effect of surface hydroxyl group density of support membrane on water permeance of polyamide thin-film composite membrane

Polyamide-based thin-film composite (TFC) membranes are widely used in water treatment processes. Recently, the influence of support membranes on the performance of polyamide layers has garnered considerable attention. Regarding the chemical properties of the support membranes, the surface wettability and the interaction between the amine monomer used for interfacial polymerization and the membrane surface are considered to play crucial roles. In this study, we investigated the effect of the wettability of the support membrane surface and its interaction with the amine monomer on the water permeance of TFC membranes. We prepared TFC membranes on polyketone support membranes with varying surface hydroxyl group densities and aqueous solution wettabilities. While no clear correlation was observed between the support membrane's wettability and the water permeance of the TFC membrane, an increase in hydroxyl group density did result in higher water permeance. The hydroxyl groups interact with PIP, inhibiting PIP diffusion and potentially leading to the formation of a thinner polyamide layer, which enhances water permeance. Therefore, the interaction between the amine monomer and support membrane surface strongly affects the formation of the polyamide layer.

Thin-film composite electro-nanofiltration membrane for one-step and efficient fractionation of dyes and salts in high-salinity textile wastewater

The key to achieve sustainable treatment of high-salinity dye-containing wastewater is effective fractionation of dyes and salts. In this study, a thin-film composite electro-nanofiltration membrane was successfully fabricated by co-deposition of levodopa and ε-polylysine onto a porous ultrafiltration membrane substrate. With the co-deposition of the polylevodopa/ε-polylysine composite coating on the substrate membrane, the surface properties were significantly regulated, resulting in decreased pore size, reduced surface negative charge density and lower specific electric resistance, thus enhancing their ion transfer and dye/salt fractionation efficacy. Specifically, the fabricated LDP-4 membrane (molecular weight cut-off of 408 Da) with a 4-h co-deposition experienced a 99.12 % reactive orange 16 dye rejection and 10.15 % NaCl rejection, indicating an impressive selectivity between dyes and salts. Additionally, the LDP-4 electro-nanofiltration membrane as anion conducting membrane exhibited a fast and efficient electro-driven transfer of Cl− ions. Notably, under an electric field, the fabricated LDP-4 electro-nanofiltration membrane can efficiently fractionate NaCl from the reactive orange 16/NaCl mixed solution, achieving a 98.89 % desalination efficiency and 99.79 % dye recovery. Furthermore, the LDP-4 membrane demonstrated remarkable anti-fouling property and long-term stability over an 8-cycle electro-nanofiltration operation. Therefore, the electro-nanofiltration membranes fabricated by co-deposition of levodopa and ε-polylysine show a promising potential in sustainable resource recovery from high-salinity dye-containing wastewater.

Silk sericin-coated polyamide thin-film composite membranes to simultaneously improve anti-scaling properties, long-term storage, and waste-to-resource recovery

A polyamide thin-film composite (PA-TFC) membrane, which is one of the widely used for desalination and water softening processes, features a lot of carboxyl groups inevitably formed by hydrolysis of unreacted acyl chlorides after interfacial polymerization. However, since carboxyl groups interact with multivalent cations and thereby cause membrane scaling, it is desirable to reduce the density of carboxyl groups on the membrane surface. In this regard, silk sericin (SS) can be an excellent alternative to modifying the surface characteristics to mitigate scaling because it has various hydrophilic amino acids with a much lower density of carboxyl groups per unit mass. Given the properties, we prepared anti-scaling TFC membranes by coating SS on the PA active layer. According to the result, the SS-PA-TFC (16.4% decrease) significantly reduced the flux decline to half of the PA-TFC (36.7% decrease) during the 48-h scaling test under the condition for heterogeneous gypsum crystal nucleation. More importantly, the comparison of operation duration until cleaning obviously revealed the anti-scaling properties of the SS-PA-TFC, which was evidenced by about 7.5 times longer duration than the PA-TFC. Furthermore, the cyclic scaling test in 19 mM CaSO4 showed that the SS-PA-TFC (3.6%) could decrease the irreversible fouling to about one-fifth of the PA-TFC (15.9%). This outstanding anti-scaling performance of the SS-PA-TFC stemmed from the less negatively charged (‐40.8 and ‐28.1 mV for the PA-TFC and SS-PA-TFC, respectively) and much more hydrophilic surface (52.2° and 18.2° for the contact angles of the PA-TFC and SS-PA-TFC, respectively). Suprisingly, the above-mentioned anti-scaling properties of the SS-PA-TFC membrane were achieved without the trade-off between water flux and salt rejection thanks to a very thin SS coating layer (ca. 16 nm). Apart from the anti-scaling properties, SS coating also improved long-term storage and waste-to-resource recovery.

Preparation and properties of Hydroxyapatite-Ti composite thin films by co-sputtering method for biocompatibility applications

In this paper, we report on enhancing the biocompatibility properties of Hydroxyapatite-Titanium (HA-Ti) thin films fabricated using the co-sputtering method. By adjusting the HA/Ti ratio through varying the sputtering power of Ti, we obtained HA-Ti thin films with different crystal structures, morphologies, and hydrophilic properties. HA-Ti thin films sputtered at different titanium powers of 80, 100, 120, 140, and 160 W will obtain thin films with larger grain sizes and poorer crystallinity, respectively. However, their hydrophilic properties increase as the contact angle decreases from 78° to 20° degrees. In vitro BHK cell tests indicated that the HA-Ti thin film had excellent biocompatibility. Therefore, this material is suitable for biological applications and has significant potential in medical implant technology.

Comprehensive evaluation of the impact of ionic liquid incorporation on the optical properties, Urbach energy, thin film morphology, and surface roughness of poly(vinyl chloride) based on ionic materials

Abstract A newly synthesis composite thin films of poly(vinyl chloride) has been refinement with ionic liquid, where PVC dissolved in THF with various concentrations of IL by casting method to form the composite thin films, without any reaction and IL dangles within PVC matrix. The thin films were examined by the diffusive reflectance device under the wavelength range (238–1300 nm). The XRD, EDX, and AFM techniques were utilized to discover the structure of the PVC matrix after additive IL. The XRD analysis illustrated the amorphous structure of the films, while the EDS analysis illustrated the main composition of pure PVC and composite PVC/IL. The optical properties and optical parameters were studied. The reflectance, extinction factor, transmittance, and imaginary dielectric constant declined, the absorption value was between (80–89 %), and the refractive index, real dielectric constant, and optical conductivity were increased. The indirect energy gap declined from 4.2 eV to 2.2 eV and the direct energy gap declined from 3.7 eV to 2.6 eV. The Urbach energy was increased from 2.09 eV to 15.45 eV revealing an increase in the disorders of electrons. The E d increased from 23.42 eV to 70.68 eV and E o increased from 7.00 eV to 10.88 eV. AFM analysis illustrated the roughness of the films increased after additive IL to the PVC Matrix from 1.08 nm to 4.45 nm and the root mean square of the particles ranged from 1.57 nm to 5.56 nm. The PVC composite thin films are utilized in solar cell and sodium-ion battery applications.

Polyvinyl alcohol-modified β-cyclodextrin incorporated forward osmosis membranes with good chlorine resistance

The applications of β-cyclodextrin (β-CD) in chlorine-resistant membranes have always faced the challenge of agglomeration at high concentrations. In this study, polyvinyl alcohol (PVA) modified β-CD was used as a monomer to prepare forward osmosis (FO) membranes with high chlorine resistance. Scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), automated contact angle meter (CAM), electrodynamic analyzer (EA), X-ray photoelectron spectroscopy (XPS), and true color confocal microscopy (CSM) have been used to characterize the physicochemical properties of the FO membrane. The agglomerated β-CD affected the formation of the selective layer, resulting in reduced water fluxes ranging from 12.4 L m−2 h−1 to 1.75 L m−2 h−1. The modified TFC-PVA-β-CD FO membrane had a complete, defect-free selective layer, and water flux of 16.75 L m−2 h−1 at 1 M NaCl as a draw solution. FTIR spectra showed that the absorption peak intensity of the carbonyl (CO) group generated from β-CD and 1,3,5-Benzene tricarbonyl trichloride (TMC) increased after PVA modification. After 6 hours of chlorination, the reverse salt flux of the thin film composite (TFC) FO membranes abided by the following order: TFC (80.35 g m−2 h−1) > TFC-β-CD (60.95 g m−2 h−1) > TFC-PVA-β-CD (12.45 g m−2 h−1). The results indicated that the PVA effectively promotes uniform dispersion of β-CD. More chlorine-resistant ester bonds (-COO-) were formed in the TFC-PVA-β-CD FO membrane, so it possessed good chlorine resistance. This study provides a green, simple, and environmentally economical method for the preparation of chlorine-resistant FO membranes.

Effect of applied electrical potential and humidity on friction of Graphene-Based thin films

Understanding the nanofrictional characteristics of thin films in various conditions is important for fabricating nanoelectronic devices and micro-/nanoelectromechanical systems with high functionality and reliability. This study investigated the nanofrictional characteristics of composite thin films of graphene oxide (GO) and cellulose nanocrystals (CNCs) and of reduced graphene oxide (rGO) and CNCs, namely GO/CNC and rGO/CNC thin films, under an applied electrical potential and humidity by using a conductive atomic force microscope (AFM). For all films, the coefficient of friction (CoF) was affected by the applied electrical potential and enhanced mechanical properties resulting from strong interactions of GO and rGO with CNCs. Furthermore, the friction force increased with the electrical potential at low humidities (relative humidity (RH) < 40 %) because of the electrostatic force effect, while for RH>40 %, the friction force sensitively increased with the electrical potential because of the puckering effect. At high humidities (RH>40 %) and high electrical potentials (>4 V), the friction force decreased as the electrical potential increased, owing to the electron leakage phenomenon. This study also characterized the altered nanofrictional behavior influenced by interfacial phenomena in the films under an electrical potential and humidity, and it provides design guidelines for fabricating nanoelectronic devices and micro/nanoelectromechanical systems.

Surface effect-tailored polymer membranes with an integrated extra-thin separation layer for robust nanofiltration

Nanofiltration (NF) technology has been keeping an unassailable lead in molecular and ionic separations. However, current polymeric NF membranes fall short of expectations in selectivity and stability when it comes to some heavy-duty organic, alkaline, and acidic environments. In this work, an asymmetric poly(ether sulfone) (PES) NF membrane with an integrated and extra-thin separation layer was developed by utilizing a thermal treatment method based on the polymer surface effect. A PES ultrafiltration membrane with a porous patterning surface was first fabricated by nonsolvent induced phase separation, and then thermally annealed at 5 degrees lower than its glass transition temperature to fully activate the motion of surface polymer chains to kinetically heal surface pores. The healing mechanism of surface pores was confirmed as the thermodynamic minimization tendency of surface energy driven by the advanced mobility of PES chains on the surface. The formed separation layer was 88 nm in thickness, far less than conventional integrated asymmetric membranes and comparable to current thin-film composite (TFC) membranes. As expected, the membranes had high rejection to organic molecules and inorganic salts with a molecular weight cut-off of around 600 Da, while maintaining a competitive water permeance up to 8 L m−2 h−1 bar−1 to current TFC membranes. Further, they demonstrated high acid tolerance without performance decline during a 30-h-long test after being immersed in 8 wt% H2SO4 aqueous solution for 24 h. This work offers a new strategy to develop high permeability, selectivity, and environmental-resistance NF membranes to achieve efficient molecular and ionic separations in extreme conditions.

Copper doped hydroxyapatite nanocomposite thin films: synthesis, physico-chemical and biological evaluation.

Cu-doped hydroxyapatite (CuHAp) thin films were obtained using spin coating method. To make these thin films, CuHAp suspensions obtained by sol-gel method were used. The coatings obtained were thermally treated at 500°C. After the thermal treatment, the thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM). Moreover, the stability of the suspensions before being used to obtain the thin films was certified by dynamic light scattering (DLS), zeta potential methods and ultrasound measurements. In the XRD patterns, the peaks associated with hexagonal hydroxyapatite were identified in accordance with JCPDS no. 09-0432. EDS and XPS results confirmed the presence of Cu ions in the samples. Data about the morphological features and chemical composition of CuHAp thin films were obtained by performing scanning electron microscopy (SEM) measurements. Our results suggest that the CuHAp thin films surface is continuous and homogenous. The presence of the functional groups in the CuHAp thin films was confirmed by Fourier-transform infrared spectroscopy (FTIR) and Raman spectroscopy studies. Information about the surface topography of the CuHAp thin films has been obtained using atomic force microscopy (AFM). The AFM images determined that the surface topography of the CuHAp thin layer is homogenous and continuous without presenting any unevenness or fissures. The cytotoxicity of CuHAp thin films was assessed using human gingival fibroblasts (HGF-1) cells. The results of the cell viability assays demonstrated that the thin films presented good biocompatible properties towards the HGF-1 cells. Additionally, the adherence and development of HGF-1 cells on the surface of CuHAp thin films were determined using AFM. The AFM surface topographies highlighted that the CuHAp thin film's surface favored the attachment and proliferation of HGF-1 cells on their surface.

Preparation of novel cellulose from outer skin and seeds of Manilla tamarind (Pithecellobium dulce)-Ag/TiO2/Chitosan nanocomposite and its biological properties

The current study was aimed to prepare a novel composite thin film from Manilla tamarind (MC) outer skin and seeds with silver nanoparticles (AgNPs) and TiO2 nanoparticles and blended with chitosan (Ch). NaBH4 was used to prepare MC/AgNPs composite utilizing the reduction process. Solvent casting method was used to prepare a thin film of the composite material MC/AgNPs//TiO2/Ch. Field emission scanning electron microscopy (FE-SEM) displayed the diffusion of Ch and AgNPs and TiO2 on the surface of MC network. The average particle size of AgNPs distributed on the MC is between 47 and 48 nm. Nanotitania was prepared by sol-gel method using titanium tetraisopropoxide and isopropanol. Antibacterial studies show that the nanocomposite exhibited higher inhibition effects against Staphylococcus Aureus and Escherichia Coli than isolated Manilla cellulose. The photodegradation of nanocomposite showed 77 % within just 10 min. Antioxidant studies were analyzed by using DPPH radical at 517 nm. The percentage of antioxidant activity of MC and nanocomposite showed as 27.15 % and 30.41 % respectively with DPPH radical. The high capability of antibacterial and photocatalytic effects finds application in food packaging applications and wastewater treatment.

Flexible and sensitive three-dimension structured indium tin oxide/zinc aluminum oxide/Cu composites thin-films pressure sensors for healthcare monitoring

Flexible pressure sensors play a crucial role in large-scale commercial applications, such as health monitoring, robotics, and smart devices. However, mass production of piezoelectric sensors for industrial applications is limited by their complex and cost-intensive fabrication processes. In this study, sensitive, simple, and wearable piezoelectric sensors were prepared by magnetron sputtering of indium tin oxide/zinc aluminum oxide (AZO)/Cu composite thin films onto three-dimension structured polydimethylsiloxane) substrate. The prepared flexible sensors delivered output voltages of −200 mV and +200 mV during 1000 loading and unloading cycles, respectively, showing an outstanding sensitivity and cycling performance. The piezoelectric performance of AZO films is primarily determined by the doping concentration of aluminum in AZO; the output voltage of the sensor with the optimal doping concentration was approximately 340 % higher than that of the undoped sample. Finite-element simulations demonstrated that the substrate with a square platform exhibited the most uniform stress distributions as well as the highest stress on its microstructure surface, which resulted in a high stress and sensitivity of the thin-film sensors. Experiments revealed that the incorporation of a microstructure enhanced the output voltages of the sensors. In particular, the output voltage delivered by the flexible sensors with square microstructures was approximately 60 % higher than that exhibited by those without microstructures.

High selectivity in NO2 gas sensing applications using polythiophene-MnO2 composite thin films

Many harmful gasses are released during the burning of fossil fuels. Thus, it is essential to create gas sensors with high efficiency and low power consumption. The easy chemical bath deposition approach was used to produce the MnO2-incorporated polythiophene (PTh/MnO2) composite thin film, and its potential application in NO2 gas sensing at the operating temperature was comprehensively examined. The physicochemical properties were examined using FT-IR, FE-SEM, EDAX, AFM, and other instruments. The effects of adding MnO2 on the physicochemical and NO2-sensing properties were studied. Out of all the oxidizing and reducing gases, the PTh/MnO2 composite sensor showed the highest NO2 selectivity when tested at operating temperature (NH3, Cl2, H2S, NO2, and methane). Every PTh/MnO2 composite thin film demonstrated improved NO2 sensing capabilities, with a maximum sensitivity of 95.67 percent for 100 parts per million of gas and a response of 20.93 percent for 0.5 parts per million of gas. Furthermore, they all reacted remarkably well to decreased NO2 gas concentrations.