Template Films Research Articles

Rapid screening of Salmonella typhimurium based on a bacterial surface-imprinted polymer-functionalized bipolar electrode-electrochemiluminescence platform

A bipolar electrode-electrochemiluminescence (BPE-ECL) sensor, utilizing a polydopamine (PDA) bacterial surface-imprinted polymer (SIP), has been developed for the detection of Salmonella typhimurium (S. typhimurium). To fabricate this sensor, dopamine (DA) served as the monomer, while S. typhimurium played a crucial role as the template molecule. Through a precision-tuned electropolymerization process, a polymer film template was seamlessly crafted on the cathode of BPE, encasing the target bacteria within its matrix. Once the template was delicately removed, a molecular surface-imprinted film emerged on the cathode, forming a PDA SIP capture probe that was remarkably adept at recognizing and binding to the target bacteria. When the target bacteria was present on the cathode, the Fc-aptamer-S. typhimurium acted as a signal probe to specifically recognized S. typhimurium. Applying a constant potential to the BPE, the oxidation product Fc+, generated at the cathode, accelerating the luminescence of the [Ru(bpy)3]2+/TPrA system on the anode. The sensor exhibited a remarkable sensitivity, capable of detecting S. typhimurium concentrations ranging from 101 to 106 CFU mL−1, with a detection limit of 10 CFU mL−1.

A Honeycomb Film Template-Based Method for High-Throughput Preparation of Anti-Salmonella typhimurium 14,028 Phage Microgels

Developing efficient anti-microbials for thoroughly addressing Salmonella contamination is essential for the improvement of food safety. Phage-built materials have shown great potential for biocontrol in environments. Due to challenges in delivery and stability, their widespread use has remained unattainable. Here, we have developed a honeycomb film template-based method for the high-throughput preparation of phage microgels. The honeycomb film template can be simply fabricated in a humid chamber based on a well-established breath figure method. The bacteriophage microgels can be further manufactured by dropping a pre-gelation solution containing bacteriophages into a honeycomb film template. This method can produce over 210,000 phage microgels in every square centimeter template with each microgel containing 1.04 × 107 phages. They can kill 99.90% of the contaminated S. typhimurium 14,028 on chicken samples. This simple, heat-free, and solvent-free method can maintain the strong anti-bacterial efficiency of phages, which can expand the wide application of phage-built microgels for food decontamination.

Template-Assisted Growth of High-Quality α-Phase FAPbI3 Crystals in Perovskite Solar Cells Using Thiol-Functionalized MoS2 Nanosheets.

Formamidinium lead iodide (FAPI) has gained attention for hybrid perovskite solar cell (PSC) applications due to its enhanced stability and narrow bandgap. However, a significant challenge remains in inducing and stabilizing the elusive perovskite "black phase"─photoactive cubic α-FAPI─as the relatively bulky FA+ cations tend to favor the thermodynamically stable nonphotoactive "yellow phase". In this study, we present a templated growth strategy employing thiol-functionalized MoS2 nanosheets as templates. By introduction of 3-mercaptopropionic acid (MPA)-functionalized MoS2 as a growth template, precise control over crystal formation was achieved, favoring the growth of high-quality α-FAPI films. These advanced templated films exhibited substantial improvements in charge transport properties, efficient light absorption, and enhanced charge extraction. As a result, the PSCs achieved a significantly enhanced power conversion efficiency (PCE) compared to the nontemplated control device, increasing from 20.6 to 22.5%. The MoS2-incorporated device also demonstrated excellent shelf stability, maintaining 91% of the initial PCE even after 1600 h of storage without device encapsulation.

Change of composition and surface plasmon resonance of Pd/Au core/shell nanoparticles triggered by CO adsorption.

Controlling composition and plasmonic response of bimetallic nanoparticles (NPs) is of great relevance to tune their catalytic activity. Herein, we demonstrate reversible composition and plasmonic response transitions from a core/shell to a bimetallic alloyed palladium/gold NP triggered by CO adsorption and sample temperature. The use of self-organized growth on alumina template film allows scrutinizing the impact of core size and shell thickness onto NP geometry and plasmonic response. Topography, molecular adsorption, and plasmonic response are addressed by scanning tunneling microscopy, vibrational sum frequency generation (SFG) spectroscopy, and surface differential reflectance spectroscopy, respectively. Modeling CO dipolar interaction and optical reflectivity corroborate the experimental findings. We demonstrate that probing CO adsorption sites by SFG is a remarkably sensitive and relevant method to investigate shell composition and follow in real-time Pd atom migration between the core and the shell. Pd-Au alloying is limited to the first two monolayers of the shell and no plasmonic response is found, while for a thicker shell, a plasmonic response is observed, concomitant with a lower Pd concentration in the shell. Above 10-4mbar, at room temperature, CO adsorption triggers the shell restructuration, forming a Pd-Au alloy that weakens the plasmonic response via Pd migration from the core to the shell. NP annealing at 550K, after pumping CO, leads to the desorption of remaining CO and gives enough mobility for Pd to migrate back inside the core and recover a pure gold shell with its original plasmonic response. This work demonstrates that surface stoichiometry and plasmonic response can be tuned by using CO adsorption and NP annealing.

Solution-Processed Pb(Zr,Ti)O3 Thin Films with Strong Remnant Pockels Coefficient.

In contrast to the widely studied electrical properties of Pb(Zr,Ti)O3 thin films, which have led to their applicability in various application areas such as thin film capacitors, microelectronics, and ferroelectric memories, the electro-optic (EO) properties are far less studied, which hinders the applicability of Pb(Zr,Ti)O3 films for EO applications such as heterogeneously integrated phase modulators in silicon (Si) photonics. Therefore, the EO properties of Pb(Zr,Ti)O3 films need to be further investigated to pave the way for the applicability of Pb(Zr,Ti)O3 films in EO applications. As the EO properties of ferroelectric thin films strongly depend on their crystal phase and texture, which in turn are influenced by the method of film fabrication. Therefore, in this work, we investigate the EO properties of a promising solution process using a La2O2CO3 template film. We successively characterize the precursor ink, microstructure and EO properties of the solution-processed Pb(Zr,Ti)O3film. The Pb(Zr,Ti)O3 film exhibits a fiber texture and has a large maximum and remnant Pockels coefficient (reff) of 69 pm V-1 and 66 pm V-1, respectively. The integration into a ring resonator-based modulator shows a VπL of 2.019 V cm. The determination of these promising EO properties could further pave the way for the applicability of Pb(Zr,Ti)O3 thin films in Si photonics.

Integration Of Solution‐Processed BaTiO3 Thin Films with High Pockels Coefficient on Photonic Platforms

AbstractThe heterogeneous integration of ferroelectric BaTiO3 thin films on silicon (Si) and silicon nitride (SiN)‐based platforms for photonic integrated circuits (PICs) plays a crucial role in the development of future nanophotonic thin film modulators. Since the electro‐optic (EO) properties of ferroelectric thin films strongly depend on their crystal phase and texture, the integration of BaTiO3 thin films on these platforms is far from trivial. So far, a conventional integration route using a SrTiO3 template film in combination with high vacuum deposition methods has been developed, but it has a low throughput, is expensive and requires monocrystalline substrates. To close this gap, a cost‐efficient, high‐throughput and scalable method for integrating highly textured BaTiO3 films is needed. Therefore, an alternative method for the integration of highly textured BaTiO3 films using a La2O2CO3 template film in combination with a chemical solution deposition (CSD) process is presented. In this work, the structural and EO properties of the solution‐processed BaTiO3 film are characterized and its integration into an optical ring resonator is evaluated. The BaTiO3 film exhibits a fiber texture, has a large Pockels coefficient (reff) of 139 pm V−1, and integration into a ring resonator‐based modulator shows a VπL of 1.881 V cm and a bandwidth of > 40 GHz. This enables low‐cost, high‐throughput, and flexible integration of BaTiO3 films on PIC platforms and the potential large‐scale fabrication of nanophotonic BaTiO3 thin‐film modulators.

Iridium Oxide Coordinatively Unsaturated Active Sites Govern the Electrocatalytic Oxidation of Water

AbstractA special membrane electrode assembly to measure operando X‐ray absorption spectra and resonant photoemission spectra of mesoporous templated iridium oxide films is used. These films are calcined to different temperatures to mediate the catalyst activity. By combining operando resonant photoemission measurements of different films with ab initio simulations these are able to unambiguously distinguish µ2‐O (bridging oxygen) and µ1‐O (terminal oxygen) in the near‐surface regions of the catalysts. The intrinsic activity of iridium oxide scales with the formation of µ1‐O (terminal oxygen) is found. Importantly, it is shown that the peroxo species do not accumulate under reaction conditions. Rather, the formation of µ1‐O species, which are active in O−O bond formation during the OER, is the most oxidized oxygen species observed, which is consistent with an O−O rate‐limiting step. Thus, the oxygen species taking part in the electrochemical oxidation of water on iridium electrodes are more involved and complex than previously stated. This result highlights the importance of employing theory together with true and complementary operando measurements capable of probing different aspects of catalysts surfaces during operation.

Pyrene monomer-excimer dynamics to reveal molecular organization in mesoporous hybrid silica films.

Self-assembly and characteristics of hybrid mesoporous silica film templates remain a subject of inquiry. The short time scale of the inorganic condensation and formation of micelles makes our understanding of this process insufficient. To provide an insight into the evaporation-induced self-assembly of such films, we synthesized an efficient molecular probe of the triethoxysilane precursor bearing a pyrene derivative. The probe was introduced into the porous film at the synthesis stage through the sol-gel co-condensation method. At different synthesis stages, the emission of pyrene moieties was measured by fluorescence spectroscopy, revealing the placement of probes within the film. We also report dynamic excimer formation upon template removal. Moreover, we evaluate the influence of several parameters on the pyrene excimer formation phenomenon. The pore geometry, probe concentration, and the presence of another organosilane precursor are investigated in this work.

Utilization of Interfacial Films of Organo‐Modified Carbon Nanotubes as Adsorption Templates for a Number of Biomolecules while Maintaining their Activity

AbstractWe investigated the versatility of a monolayer of organo‐modified single‐walled carbon nanotubes (SWCNTs) on a water surface as a template to maintain activity by adsorbing various biomolecules from the subphase. Organo‐modified SWCNTs with amphiphilic properties formed a Langmuir film on the subphase containing biomolecules, and adsorbed and immobilized biomolecules via electrostatic interactions. In this study, the interactions of trypsin, lysozyme, cytochrome C protein, glucose oxidase sugar chain polymer, deoxyribonucleic acid, and chitosan with SWCNTs at the air/water interface were investigated. The uniqueness of this study is that it shows the possibility of wide‐ranging applications by utilizing an organo‐modified SWCNT interfacial film as an adsorption template for various biomolecules. The expansion behavior of the surface pressure‐area isotherms indicated the existence of interactions between the organo‐modified SWCNTs monolayer on the water surface and the biomolecules. The morphology and spectroscopic properties of the films transferred onto solid substrates clearly indicate the adsorption and immobilization of biomolecular groups. DNA and chitosan were not immobilized on the organo‐modified SWCNTs film template; however, the other four enzyme/protein molecules were adsorbed onto the solid substrate and maintained their fine second‐order structures, even under harsh conditions.

Improved detection performance of self-driven InZnO / p-GaN heterojunction UV photodetector by lanthanum doping

By using the sol-gel spin-coating method, La-InZnO films with different La (0 at%, 2 at%, 4 at%, and 6 at%) doping concentrations were grown on p-GaN / sapphire film templates, and self-driven p-GaN / n-ZnO heterojunction ultraviolet (UV) detectors were prepared. The effects of La doping concentration on the microstructure, optical, and electrical properties of synthesized La-InZnO films were studied. In addition, the optical sensing characteristics and photoelectric response performance of four p-n heterojunction UV detectors were compared. La doping can decrease the content of oxygen vacancies. It also reduces the carrier concentration and mobility of the films. At zero bias voltage, the 2 at% doped device has the best performance, with a peak responsivity of 46 mA/W at 366 nm, a high spectral selectivity full width at half maximum (FWHM) of only 6.92 nm, and a fast response with the rise and decay times of 1.15 ms and 2.42 ms, respectively. This study demonstrates a feasible method for improving the performance of self-driven heterojunction UV detectors.

Vertically Integrated Nanowires on Si Wafers and Into Circuits

Vertically integrated copper (Cu) and nickel (Ni) nanowires (NWS) were fabricated on silicon using anodized aluminum oxide (AAO) thin film templates integrated onto silicon wafers. Both the AAO and NWs were mechanically robust and demonstrated to withstand further fabrication processes used for integrated circuits. The AAO pores were measured to be ~30 nm with size distributions narrowing from ±12 to ±6 nm after a second anodization. The NWs, therefore, had similar diameters and distributions inside these integrated AAO films. Magnetic hysteresis loops demonstrated the out-of-plane anisotropy of the vertically oriented Ni wires in the presence of pore outgrowth that had in-plane anisotropy. When used as vias and integrated with coplanar waveguides (CPWs), the Cu NWs had lower losses than standard vias above 60 GHz.

Self-assembling nanofibrous bacteriophage microgels as sprayable antimicrobials targeting multidrug-resistant bacteria

Nanofilamentous bacteriophages (bacterial viruses) are biofunctional, self-propagating, and monodisperse natural building blocks for virus-built materials. Minifying phage-built materials to microscale offers the promise of expanding the range function for these biomaterials to sprays and colloidal bioassays/biosensors. Here, we crosslink half a million self-organized phages as the sole structural component to construct each soft microgel. Through an in-house developed, biologics-friendly, high-throughput template method, over 35,000 phage-built microgels are produced from every square centimetre of a peelable microporous film template, constituting a 13-billion phage community. The phage-exclusive microgels exhibit a self-organized, highly-aligned nanofibrous texture and tunable auto-fluorescence. Further preservation of antimicrobial activity was achieved by making hybrid protein-phage microgels. When loaded with potent virulent phages, these microgels effectively reduce heavy loads of multidrug-resistant Escherichia coli O157:H7 on food products, leading to up to 6 logs reduction in 9 hours and rendering food contaminant free.

A crack templated copper network film as a transparent conductive film and its application in organic light-emitting diode

In this paper, a highly transparent, low sheet resistance copper network film fabricated by a crack template, which made by drying an acrylic based colloidal dispersion. The fabricated copper network film shows excellent optoelectronic performances with low sheet resistance of 13.4 Ω/sq and high optical transmittance of 93% [excluding Polyethylene terephthalate (PET) substrate] at 550 nm. What’s more, the surface root mean square of the copper network film is about 4 nm, and the figure of merit is about 380. It’s comparable to that of conventional indium tin oxide thin film. The repeated bending cycle test and adhesive test results confirm the reliability of the copper network film. As a transparent conductive film, the copper network film was used as an anode to prepare organic light-emitting diode (OLED). The experiment results show that the threshold voltage of the OLED is less than 5 V and the maximum luminance is 1587 cd/m2.

DNA patterning utilizing mixed monolayer template by phase separation between hydrocarbons and fluorocarbons and evaluation of second-order structural maintenance ability

Adsorption of DNA molecules on mixed phase-separated monolayers composed of a hydrocarbon-containing comb copolymer with an s-triazine ring and a fluorinated s-triazine derivative and their fluorescence emission behavior were investigated. DNA molecules derived from salmon testes were selectively adsorbed only on the diamino-s-triazine ring of the hydrogenated copolymer in the monolayer from the subphase. A mixed monolayer of a hydrocarbon-based comb copolymer and an s-triazine derivative with fluorocarbons exhibited phase separation behavior on water surfaces and indicated expansion behavior, reflecting interactions on the subphase containing DNA molecules. The phase-separated morphology changed depending on the mixing ratio of the hydrogenated copolymer and fluorinated s-triazine derivative. After DNA adsorption, the height of the domain formed by the hydrocarbon chain was selectively increased. In addition, because the DNA molecules adsorbed on the phase-separated template film maintain their fluorescence emission ability, the second-order structure, which is the origin of the emission ability, was evaluated using circular dichroism spectroscopy. The phase-separated, template-adsorbed DNA molecules maintained the same positive Cotton effect as in solution and were predicted to retain exquisite and delicate steric structure, leading to functional occurrence.

Tailoring Ordered Wrinkle Arrays for Tunable Surface Performances by Template-Modulated Gradient Films.

Complex wrinkled microstructures are ubiquitous in natural systems and living bodies. Although homogeneous wrinkles in film-substrate bilayers have been extensively investigated in the past 2 decades, tailoring heterogeneous wrinkles by a facile method is still a challenge. Here, we report on the controllable heterogeneous wrinkles in template-modulated thickness-gradient metal films sputter-deposited on polydimethylsiloxane substrates. It is found that the stress of the gradient film is strongly position-dependent and the wrinkles are always restricted in thinner film regions. The morphological characteristic and formation mechanism of the heterogeneous wrinkles are analyzed and discussed in detail based on the stress theory. Ordered wrinkle arrays are achieved by adjusting the deposition time, copper grid period, template shape, and lifting height. The surface performances (e.g., the friction property) are well controlled by the wrinkle arrays. This work could promote better understanding of the spontaneously heterogeneous wrinkles in template-modulated gradient films and controllable fabrication of various wrinkle arrays by independently tuning film deposition conditions and template parameters.

Anisotropic dye adsorption using templated smectic nanoporous polymer films: effects of pore size and pore charges on the adsorption

Nanoporous polymer films with anisotropic, charge- and size-selective adsorption toward dyes have been developed using a templating method.

Templated growth of polyaniline for enhanced gas sensing response in flexible sensors: experiments and simulations

Gas sensors using polyaniline structures fabricated from non-templated structures (homogeneous solution growth) and templated structures (heterogeneous growth using a functionalized substrate) have shown different sensing performances in the literature, and the sensing mechanism explaining variation of their sensing performance is not well understood. This is the motivation of the present work. In this study, camphor sulphonic acid doped polyaniline structures, synthesized utilizing both non-templated and templated growth approach, fabricated on polyethylene terephthalate substrates were used for gas sensing. The detailed characterizations of the sensing films were done by FE-SEM, FTIR, UV–vis spectroscopy and then the films were utilized for the sensing of NH3, CO2 and NO2 gases in N2 medium. Vertical arrangement of the facile polyaniline structures in templated grown films was useful for gas sensing application. Gas sensing responses were studied and found to improve in comparison to that of non-templated structures. For both templated and non-templated grown films, a response trend was observed as NO2 > NH3 > CO2. Computational studies were performed and showed that templated grown structures formed cages due to entanglement of the functional groups, which were not seen with non-templated grown structures. Cages serve as the strong van der Waals dominated binding sites for the analytes due to the presence of the surrounding aromatic rings. In addition, with binding energy calculations, the sensing interactions for different analytes were observed to be higher for the templated grown films, compared to that of the non-templated grown ones. Also based on energy considerations, the barrier of interactions for the different analytes was studied for the templated grown films and the reason for the trend of preferential response to different analytes was explained through energy barrier consideration. Results from both simulations studies and experimental observations showed a similar response trend towards gas sensing.

Mechanical, magnetic and magnetostrictive properties of porous Fe-Ga films prepared by electrodeposition

Magnetostriction, known as the ability of magnetic materials to expand or contract in response to magnetic field, is a key property of Fe-Ga alloys exploited in various types of transducers. Usually, thin films of Fe-Ga deposited on rigid substrates suffer from a clamping effect that hinders the propagation of strain. Herein, Fe-Ga films with macroporous, not fully constrained, geometry are prepared by electrodeposition on metallized silicon substrates templated with sub-micrometer-sized polystyrene spheres. For comparison, fully-dense and inherently nanoporous films are prepared by sputtering and electrodeposition, respectively. The electrodeposition mechanism is discussed in terms of electrochemically active species distribution and partial current densities. The composition of the Fe-Ga films has been tuned (2–40 at.% Ga) by varying the electrodeposition parameters. A complete assessment of the nanomechanical and magnetic properties of the films with variable composition and porosity has been performed for an optimized performance. The magnetostriction has been studied by X-ray diffraction applying an in-situ magnetic field. The results demonstrate a larger magnetic-field-induced crystal deformation in templated (macroporous) films compared to the non-templated and fully-dense counterparts. The observed effects in porous Fe-Ga films are very appealing for the design of various strain-engineered nanomaterials, e.g., energy transducers or magnetoelectric composites.

A thin and flexible solid electrolyte templated by controllable porous nanocomposites toward extremely high performance all-solid-state lithium-ion batteries

Composite solid-state electrolytes (CSEs) with high ionic conductivity and low interfacial resistance have been pursued for next‐generation high energy density all solid-state lithium-ion batteries (ASSLIBs). Herein, we report a novel strategy of developing thin, flexible, and conductive CSEs by using lignin nanoparticles (LNPs) to regulate pore characteristics of cellulose nanofibril (CNF) film template. The CNF-LNP film was first prepared, then LNPs were removed, thanks to the excellent LNP solubility in γ-Valerolactone (GVL), resulting in the formation of uniform and porous cellulose nanofibril (CNF) film, which is then utilized for preparing Li7La3Zr2O12 (LLZO) membrane, with a superior morphological architecture (pore size, uniformity). Poly (ethylene oxide) (PEO) is then infiltrated into the membrane, producing thin, flexible, and conductive CSEs. Due to the controllable interconnected architecture of LLZO membrane from the LNP regulated CNF film template and its good compatibility with PEO, the as-prepared CSEs exhibit a high lithium ionic conductivity of 1.83 × 10−4 S cm−1 at ambient temperature. The continuous and uniform lithium transfer pathways, with excellent electrolyte/electrode interface contact contribute to long-term cycling stability of symmetric lithium batteries. Hence, the assembled ASSLIBs from the as-prepared CSEs show high discharge specific capacities of 157 and 159.5 mAh g−1 with LiFePO4 and LiNi0.5Mn0.3Co0.2O2 respectively, with attractive cycling stabilities and capacity retention at ambient temperature.

Electrochemically controlled solid phase microextraction based on nanostructured polypyrrole film for selective extraction of sunset yellow in food samples

Solid-phase microextraction (SPME) is extensively employed in analytical chemistry to improve extraction efficiency. The development of SMPE methods is still a great challenge thanks to its poor selectivity. Herein, we have reported the application of electrochemically controlled solid-phase microextraction (EC-SPME) based on a conducting molecularly imprinted polymer (CMIP) film for the selective extraction and determination of sunset yellow (SY) in food samples using a UV–Vis spectrophotometer. The CMIP film was electrochemically prepared in the presence of SY anions as the template anions during the electropolymerization of pyrrole onto the stainless steel fiber surface using the potentiostat method. The imprinting process was carefully investigated via FESEM, CV, and EIS approaches. In the developed EC-SPME method, the extraction of SY occurred at CMIP when the potential was applied, and as a consequence, the sensing performance was dramatically enhanced as compared to that obtained via SPME. The film template with SY showed high selectivity for SY compared to studied interferents. The EC-SPME method responded linearly to SY with a limit of detection of 0.34 µmol L−1. Also, the developed method had a sufficient sensitivity level to determine analyte in food samples. Finally, the suitability of the proposed method for the analysis of orange-flavored jelly powder, peach juice powder, and beverage samples was demonstrated. To validate the proposed method, the results were compared with those obtained through HPLC–UV analysis.