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A biocompatible and versatile silk‐based functional ink with hydrophilic upconversion nanoparticles (UCNPs) that can be printed or painted on arbitrary substrates, including biological surfaces is demonstrated. Hydrophilic UCNPs, ready to be dispersed in aqueous silk fibroin solution, are synthesized in large quantities via facile hydrothermal synthesis using citric acid. Based on a systematic study of dopant control to achieve robust red emission from citrate‐capped UCNPs, three primary colors are obtained, which serve as the basis for the expansion of the color palette. The synthesized UCNPs are homogeneously dispersed in regenerated silk fibroin solutions derived from Bombyx mori cocoons to produce water‐based functional inks. Cyan, magenta, and yellow (CMY) inks are created by combining red, green, and blue (RGB) inks. Demonstrator devices, where a variety of colorful patterns and codes are revealed only under near‐infrared irradiation, are realized through stencil printing or brush painting on flexible polymer films, fruit, leaves, silkworm cocoons, and pig skin. The patterns and codes are highly heat resistant (≈230 °C) and can be easily washed off with water after use. The printable/paintable inks and functions proposed here will provide new opportunities for applications where sustainability, biocompatibility, and intentional luminescence are simultaneously required. [ABSTRACT FROM AUTHOR]

Four donor-acceptor boron difluoride complexes based on the carbazole electron donor and the [1,3,5,2]oxadiazaborinino[3,4-a][1,8]naphthyridine acceptor were designed, synthesized, and systematically spectroscopically investigated in solutions, in dye-doped polymer films, and in the solid states. The dyes exhibit an intense blue to red solid-state emission with photoluminescence quantum yields of up to 59% in pure dye samples and 86% in poly(methyl methacrylate) films. All boron complexes show aggregation-induced emission and reversible mechanofluorochromism. The optical properties of these dyes and their solid state luminescence can be tuned by substitution pattern, i. e., the substituents at the naphthyridine unit. Exchange of CH3-for CF3-groups does not only increase the intramolecular charge transfer character, but also provides a crystallization-induced emission enhancement. [ABSTRACT FROM AUTHOR]

High-quality conjugated microporous polymer (CMP) films with orientation and controlled structure are extremely desired for applications. Here, we report the effective construction of CMP 3D composite films (pZn/PTPCz) with a controlled porosity structure and preferred orientation using the template-assisted electropolymerization (EP) approach for the first time. The structure of pZn/PTPCz composite thin films and nitrophenol sensing performance were thoroughly studied. When compared to the control CMP film made on flat indium tin oxide (ITO) substrates, the as-prepared pZn/PTPCz composite films showed significantly enhanced fluorescent intensity and much better sensing performance for the model explosive. This was attributed to the metal-enhanced fluorescence (MEF) of porous nanostructured zinc (pZn) and the additional macroporosity of the pZn/PTPCz composite films. This work provides a feasible approach for creating oriented 3D CMP-based thin films for advanced applications. [ABSTRACT FROM AUTHOR]

This study aims to improve the slow-release performance of a film material for a controlled-release fertilizer (CRF) while enhancing its biodegradability. A water-based biodegradable polymer material doped with biochar (BC) was prepared from modified polyvinyl alcohol (PVA) with polyvinylpyrrolidone (PVP) and chitosan (CTS), hereinafter referred to as PVA/PVP–CTSaBCb. An environmentally friendly novel controlled-release phosphate fertilizer (CRPF) was developed using PVA/PVP-CTS8%BC7% as the film. The effect of the PVA/PVP-CTS8%BC7% coating on the service life of the CRPF was investigated. The film was characterized via stress–strain testing, SEM, FTIR, XRD, and TGA analyses. The addition of the CTS modifier increased the stress of PVA/PVP-CTS8% by 7.6% compared with that of PVA/PVP owing to the decrease in the crystallinity of PVP/PVP-CTS8%. The hydrophilic –OH groups were reduced due to the mixing of CTS and PVA/PVP. Meanwhile, the water resistance of the PVA/PVP-CTS8%BC7% was improved. And the controlled-release service life of the CRPF was prolonged. Moreover, the addition of BC increased the crystallinity of the PVA/PVP-CTS8% by 10%, reduced the fracture elongation of the material, and further improved the biodegradability of the PVA/PVP-CTS8%BC7%. When the amount of BC added was 7%, the phosphorus release rate of the CRPF was 30% on the 28th day. Moreover, the degradation rate of the PVA/PVP-CTS8%BC7% polymer film was 35% after 120 days. This study provides basic data for applying water-based degradable polymer materials in CRFs. [ABSTRACT FROM AUTHOR]

A method has been proposed for creating an operationally durable copper coating with antimicrobial properties for the buttons of electrical switches based on the gas dynamic spray deposition of copper on acrylonitrile butadiene styrene (ABS) plastic. It is shown that during the coating process, a polymer film is formed on top of the copper layer. Comparative in situ studies of microbial contamination have shown that the copper-coated buttons have a significant antimicrobial effect compared to standard buttons. Analysis of swabs over a 22-week study in a hospital environment showed that the frequency of contamination for a copper-coated button with various microorganisms was 2.7 times lower than that of a control button. The presented results allow us to consider the developed copper coating for plastic switches an effective alternative method in the fight against healthcare-associated infections. [ABSTRACT FROM AUTHOR]

Poly(9,9-di-n-octylfluorenyl-2,7-diyl) (PFO), referred to as light-emitting polymer, was utilized in this study to synthesize thin films for polymer light-emitting applications (PLED). Three thin films named P1, P2 and P3 refer to three different ways of film fabrication. P1 consists of only PFO, P2 consists of brilliant blue FCF blend PFO, while P3 consists of PFO on polyaniline conductive layer; all these thin films were deposited onto ITO-coated glass substrates (20 Ω) using Doctor blade method. Toluene had been used as the solvent of PFO material. P1 exhibits the smoothest surface (6.43 nm), which is consistent with the FESEM result. The surface roughness increases dramatically in the case of P2 (63.00 nm) with the presence of valleys and high peak protuberance. The surface roughness continues to significantly increase (152.00 nm) with deeper valleys for P3. PL intensity of the thin films was found to be dependent on the structural properties, chemical composition and optical features of these films. Film absorption was shown to increase with surface roughness, resulting in increased PL intensity and replacement of chemical bonds. P3 exhibited the highest PL intensity at 439.7 nm, which is attributable to the relatively lower amount of oxygen in the film structure, increasing both surface roughness and absorption of the film, in addition to the substitution of chemical bonds. P2 displayed higher PL intensity than that of P1 as well. Thus, PFO blend and using a polyaniline conductive layer in the PFO film structure enhance the PL intensity, thereby improving the applicability of PFO films-based polymer light-emitting diodes (PLED). [ABSTRACT FROM AUTHOR]

With the increasing use of implantable patches in biomedical applications, the significance of surface modification techniques in improving biocompatibility, enhancing adhesion, and regulating drug release has grown. A significant challenge that these methods must address is ensuring that the process does not harm the delicate fibers or therapeutic agents they contain. Here, we report surface functionalization of implantable, curcumin loaded Polycaprolactone (PCL) patches with pH‐responsive poly(2‐hydroxyethyl methacrylate‐co‐4‐vinylpyridine), p(HEMA‐co‐4VP) polymer thin film. The polymer was coated on the patch surface via photo‐initiated chemical vapor deposition (piCVD) where the polymerization was initiated by the UV degradation of the initiator tert‐butyl peroxide (TBPO) and the monomer HEMA. Additionally, the piCVD method was utilized to crosslink the HEMA without the use of additional crosslinkers. The pH‐responsiveness of the coating was achieved by incorporating 4VP into the copolymer structure. The effect of the coating was demonstrated through degradation and drug release studies. The presence of the polymer coating decelerated the fiber degradation and the pH‐dependent swelling of the coating allowed for the control of drug release rates from the patches. The innovative use of piCVD as a coating method provides a platform for advancing tailored surface modifications in various biomedical applications. [ABSTRACT FROM AUTHOR]

Featured Application: Thin polymer film durability and resistance to certain exposure tests. In this paper, a custom-tailored investigation protocol aimed at the tests of the resistance of bacteriostatic acrylic-based film containing silver nanoparticles is presented. As hospital appliance applications were considered, it was necessary to provide a unique approach, enabling specific media exposure and utilizing high-sensitivity measurement methods to observe fine indications of material wear. Due to the presence of nanoparticles in the tested film, nanometer-resolution surface imaging is necessary. Therefore, the main source of information about its degradation process is atomic force microscopy (AFM) measurements. This particular tool is an appreciated source of information, providing quantitative data about both morphological and mechanical changes in the properties of the surface. Using such an approach, supported by standard diagnostic methods, such as colorimetry and wettability angle determination, it was possible to enable insights into the way the bacteriostatic film deteriorates and evaluate its usefulness in medical appliance applications. Further tests of various films developed by companies can be performed using the described protocol to determine the lifetime of certain products. This paper reveals the company's practical utilization of both standardized and novel test techniques in the evaluation of new products. [ABSTRACT FROM AUTHOR]

Covalent organic polymers (COPs) have emerged as a promising class of materials for memory devices due to their unique electronic properties and potential for tunability. This review highlights recent advances in the field of COPs‐based thin films for memory applications, with a focus on the synthesis and characterization of COP thin films, their electronic properties, and their performance as memory devices. The potential of COPs‐based thin films as flexible memory devices is also discussed. Overall, the recent progress in COPs‐based thin films for memory applications suggests that these materials may have a significant impact on the development of next‐generation memory technologies. [ABSTRACT FROM AUTHOR]

Mesoporous polymer nanofilms combine the advantages of the unique structure of mesopores, the quasi‐2D configuration of the films, and the inherent properties of polymers, and have become a kind of ideal candidate for the high‐performance micro‐nano devices due to their highly accessible surface area and exposed active sites. However, the facile preparation of polymer nanofilms with well‐defined mesostructures has remained a great challenge due to the lack of synthetic strategies. In this study, we developed a simple soft‐template interfacial co‐assembly strategy to in‐situ construct mesoporous polydopamine nanofilms with uniform thickness (30 nm) and regularly distributed mesopore arrays (average pore size of 12 nm) on surfaces with different types and morphologies. Furthermore, a single‐layer mesoporous polymer nanofilm was directly grown on a quartz crystal microbalance substrate and its performance for sensing formaldehyde was studied. The resulted sensor showed excellent sensing response, fast response/recovery dynamics, and great stability, presenting a great promising landscape for trace detection of formaldehyde gas. [ABSTRACT FROM AUTHOR]

The advent of digital technologies has spurred the development of wearable sensing devices marking a significant shift in obtaining real-time physiological information. The principal objective is to transition from blood-centric monitoring to minimally invasive modalities, which will enable movement from specialised settings to more accessible environments such as the practices of general practitioners or even home settings. While subcutaneously implanted continuous monitoring devices have demonstrated this transition, detection of analytes from sample matrices like skin interstitial fluid (ISF), is a frontier that offers attractive minimally invasive routes for detection of biomarkers. This manuscript presents a comprehensive overview of our work in subdermal wearable biosensing patches for the simultaneous monitoring of glucose and lactate from ISF in ambulatory conditions. The performance of the subdermal wearable glucose monitoring patch was evaluated over a duration of three days, which is the longest reported duration reported till date. The subdermal wearable lactate sensing patch was worn for the duration of the exercise. Our findings highlight a critical observation that biofouling effects become apparent after a 24 h period. The data presented in this manuscript extends on the knowledge in the areas of continuous metabolite monitoring by introducing multifunctional polyphenol polymer films that can be used for both glucose and lactate monitoring with appropriate modifications. This study underscores the potential of subdermal wearable patches as versatile tools for real-time metabolite monitoring, positioning them as valuable assets in the evolution of personalised healthcare in diverse settings. [ABSTRACT FROM AUTHOR]

Conjugated polymers have demonstrated promising optoelectronic properties, but their brittleness and poor mechanical characteristics have hindered their fabrication into durable fibers and textiles. Here, we report a universal approach to continuously producing highly strong, ultratough conjugated polymer fibers using a flow-enhanced crystallization (FLEX) method. These fibers exhibit one order of magnitude higher tensile strength (>200 megapascals) and toughness (>80 megajoules per cubic meter) than traditional semiconducting polymer fibers and films, outperforming many synthetic fibers, ready for scalable production. These fibers also exhibit unique strain-enhanced electronic properties and exceptional performance when used as stretchable conductors, thermoelectrics, transistors, and sensors. This work not only highlights the influence of fluid mechanical effects on the crystallization and mechanical properties of conjugated polymers but also opens up exciting possibilities for integrating these functional fibers into wearable electronics. [ABSTRACT FROM AUTHOR]

Electrical conductivity is emerging as one of the most essential material's qualities of the 21st century due to the lightning‐fast advancements in the electronics sector and the continuously improving electrical goods. As conductive materials are used in the majority of the modern items we use, including power sources, energy generating systems, electrical circuits, sensors, and many others, continuing advancement in this field is very crucial. The novelty of this work lies in the dispersion of ferrite nanoparticles, which was synthesized using egg albumen to enhance the electrical behavior of PANI polymer films. In this research work, a simple casting approach was used to ex situ polymerize aniline to fabricate ultrathin and flexible CuFe2O4 distributed PANI films for electrical conductivity applications. The combustion approach was used to produce the copper ferrite nanoparticles, while egg albumen was not only used as the fuel but also it was used a capping agent to control the size of ferrite NPs with a size much lower than that already reported. Studies on the structural, morphological, and electrical properties of pure and various weight percent of (1 , 3 , and 5 wt%) CuFe2O4 loaded PANI films were performed. Comparing the different films, the 5 wt% CuFe2O4 dispersed PANI films exhibited remarkable and greatly improved permittivity and electrical conductivity with low dielectric loss. This indicates the 5 wt% CuFe2O4 dispersed PANI films have the prospective uses in high‐tech industries where there is a need for flexible, thin, and lightweight high electrical conducting materials with lesser loss factor. [ABSTRACT FROM AUTHOR]

Applications in soft, flexible optical, and optoelectronic applications demand polymer thin film coatings that can accommodate substantial physical deformations. The preparation of high refractive index polymers (HRIPs) through the quaternization of poly(4‐vinylpyridine) (P4VP) thin films with (di)halomethanes is presented. P4VP thin films are prepared by initiated chemical vapor deposition (iCVD) and then quaternized through exposure to saturated vapors of iodomethane (CH3I), dibromomethane (CH2Br2), and diiodomethane (CH2I2), resulting in refractive indices (RI) as high as 1.67, 1.71, and 2.07, respectively (at 632.8 nm). Fourier‐transform infrared (FTIR) spectroscopy and X‐ray photoelectron spectroscopy (XPS) confirmed the quaternization of pyridine pendant groups on the polymer chain to n‐methylpyridinium with primarily an iodide or bromide counterion, though a minor fraction of polyiodides are also detected. Additionally, these films demonstrate superior thermal stability, retaining their refractive index and thickness after thermal excursions to 200 °C. The halogenated P4VP films exhibit superior mechanical flexibility relative to conventional inorganic coatings (Al2O3 and Ta2O5) and do not fracture at uniaxial tensile strains as high as 10%. This new material chemistry and fabrication approach method may enable advanced optical designs and functionality in a wide range of substrates and device architectures. [ABSTRACT FROM AUTHOR]

Photoluminescence (PL) color can be tuned by mixing fluorophores emitting the three primary colors in an appropriate ratio. When color tuning is achieved on a single substrate, we can simplify device structures. We demonstrated that nanographenes (NGs), which are graphene fragments with a size of tens of nanometers, could be utilized as carriers of fluorophores. The addition of red‐ and blue‐light‐emitting fluorophores on the edge successfully reproduced the purple light. The relative PL intensities of the fluorophores could be regulated by the excitation wavelength, enabling multicolor emission between blue and red light. Owing to the triphenylamine units of the fluorophores, the NGs showed PL enhancement due to aggregation. This characteristic was valuable for the fabrication of solid polymer materials. Specifically, the functionalized NGs can be dispersed into polyvinylidene difluoride. The resultant polymer films emitted red, blue, and purple color. Our study demonstrated the potential applicability of NGs for fluorophore carriers capable of reproducing intermediate colors of light. [ABSTRACT FROM AUTHOR]

Since the development of industry, sound absorption and noise reduction have gradually become an urgent problem to be solved. Lightweight polymer film materials are very effective in response to sound waves, and sound waves can easily cause vibration of the film, which can convert sound energy into vibration and film friction to achieve sound absorption. The application conditions of the film material are very harsh, that is, a support body is required to fix the film and the film needs to be tensioned. The film is very thin and easy to damage. The idea of this research is to transform the film into a bubble structure and use a large number of film bubbles to form a cavity structure material. As a unit of the sound absorption structure, bubbles can avoid damage to the film. In this paper, commercial polyvinyl chloride film bubble materials are used to prepare two kinds of film multicavity structure materials, and the sound absorption performance of this film multicavity structure material is studied. The research results show that this film multicavity structure material has very excellent broadband sound absorption performance, which changes the narrow band sound absorption properties of the usual film single cavity. The average sound absorption coefficient can reach 0.84 in frequency range from 500 Hz to 6400 Hz. This structural material has a single peak sound absorption curve at the middle and low frequency bands, which is the characteristic of resonance sound absorption. And at the middle and high frequency bands, it exhibits the characteristics of broadband sound absorption. The film multicavity structure material has both cavity sound absorption and broadband sound absorption characteristics. [ABSTRACT FROM AUTHOR]

To achieve superior device performance such as low threshold voltage Vth, high maximum on‐current Ion,max, and long retention time in electrolyte‐gated organic synaptic transistors, efficient electrochemical doping and high state retention are essential. However, these characteristics generally show a trade‐off relationship. This work introduces an effective strategy to increase retention time while promoting efficient electrochemical doping. The approach involves blending two polymer semiconductors (PSCs) that have the same backbone but different types of side chains. Polymer synaptic transistors (PSTs) with the blend film showed the lowest Vth, highest Ion,max, longest retention time, and superior cyclic stability compared to PSTs that used films containing only one of the PSCs. The improvement in electrical and synaptic properties achieved through the blend strategy is consistently reproducible and comprehensive. It is attributed this improvement to the increased redox activity and constrained morphological changes observed in the blended PSCs during electrochemical doping, as confirmed by several electrochemical characterizations. This work is the first to increase retention time in PSTs without increasing the crystallinity of polymer film or sacrificing the electrochemical doping efficiency, which has been regarded as an unavoidable compromise in this field. This method provides an effective way to tune synaptic properties for various neuromorphic applications. [ABSTRACT FROM AUTHOR]

The results of an experimental study of the local electrophysical properties of ultrathin polymer films by atomic force microscopy with a conducting probe are presented. It is established that visualization of current flow sites (conducting channels) is possible in areas from which the surface layer has been mechanically removed. The conducting channels in the current image have the form of individual points with a height corresponding to the locally flowing current. It is found that the location of the observed channels correlates well with the model of conductivity along the grain boundaries of the supramolecular structure of the po-lymer. [ABSTRACT FROM AUTHOR]

Herein, the water vapor transmission rate (WVTR) of aluminum oxide (Al2O3) films on polyethylene terephthalate (PET) substrates is investigated and is focused on the impact of the film defects on the transmission rate. The aluminum oxide films are prepared on PET substrates by magnetron sputtering, and the effects of the film thickness, sputtering power, temperature, and bias voltage on the WVTR are studied. The surface morphologies of the films are examined using atomic force microscopy (AFM), and a method for obtaining the defect ratio of the film from AFM images is proposed. Subsequently, the influences of the defect ratio on the WVTR are quantitatively evaluated based on a 3D diffusion model. The simulated WVTR values are well in agreement with the experimental ones. [ABSTRACT FROM AUTHOR]

Pure and CuCl2 Poly(methyl methacrylate) (PMMA) films have been prepared by the solution cast method. The morphology of the films was investigated by atomic force microscopy (AFM). The roughness, grain size, and average diameter of the pure and doped samples vary between an increase and a decrease with an increase the doping concentration. The root mean square (RMS) roughness of the dope of copper nanoparticle CuCl2 on the PMMA polymer was studied from 3D AFM images,increases from (5.27) nm to (10.42) nm. The homogeneity of the surface grains rises with the inuction in the value of the roughness rate with an increase in the dope. The optical characteristics of the polymer films were analyzed in the (200-1200) nm wavelength range. The transmittance, absorption coefficient, band gap, and Urbach have been estimated. The value of the energy band gap was 3.72 eV for an an undoped sample and it has been decreased to be (3.3, 3.23, and 3.19) eV for (1%, 2% and 3%) of the doping ratio of CuCl2 while Urbach energy was increased after dopping. [ABSTRACT FROM AUTHOR]

To develop materials with improved optical qualities and tunable refractive indices that can be utilized to control the behavior of light or electromagnetic radiations, polymer thin films have been used. High refractive index (RI) nanoparticle-incorporated polymer thin films are usually made by combining high RI inorganic nanoscale structures with a transparent, accessible polymer matrix. Hybrid nanocomposites, which combine the various benefits of inorganic and polymer components, offer a wide range of fascinating possibilities for advanced optoelectronic production and optical engineering such as advanced display device encapsulants; microlens components for complementary metal oxide semiconductor image sensors; plastic lenses for eyeglasses; camera, pick-up, and projector lenses; superior performance modules for sophisticated display devices. The development of polymers with a high refractive index (n) during the last ten years is discussed in this review, which also emphasizes the design idea to raise n values and Abbe's number (v) of polymers. The physics of predictable and controllable refractive tailored films is presently comprehended. Film applications in unconventional fields are explored. An outlook for the science and technology of such types of 2D/3D nanomaterials integrated polymer thin films concludes the review. [ABSTRACT FROM AUTHOR]

In order to improve the preparation efficiency, quality stability, and large-area preparation of superhydrophobic thin films, a roll-to-roll continuous micro–nano imprinting method for the efficient preparation of superhydrophobic polymer films is proposed. A wear-resistant mold roller with hierarchical microstructure is prepared by wire electrical discharge machining (WEDM). The rheological filling model is constructed for revealing the forming mechanism of superhydrophobic polymer films during continuous micro/nano imprinting. The effects of imprinting temperature, rolling speed and the surface texture size of the template on the surface texture formation rate of polymer films are analyzed. The experimental results show that, compared with other process methods, the template processed by WEDM shows excellent wear resistance. Moreover, the optimal micro/nano imprinting parameters are the mold temperature of 190 °C (corresponding film temperature of 85 ± 5 °C), rolling speed of 3 rpm and roller gap of 0.1 mm. The maximum contact angle of the polymer film is 154°. In addition, the superhydrophobic polymer thin film has been proven to have good self-cleaning and anti-icing performance. [ABSTRACT FROM AUTHOR]

Organic thin-film transistors (OTFTs) have attracted great attention for their inherent advantages and promising applications in emerging fields. Simultaneously realizing low-voltage operation and high-mobility in one OTFT is one of prerequisites for the commercialization, which is a huge challenge so far. An important route to address this challenge is to develop an ideal gate dielectric with a high capacitance and a low interfacial trap density at the dielectric/channel. In this Letter, we demonstrate the low-voltage operating high-mobility OTFTs by elaborately designing and processing a multi-layered gate dielectric. The gate dielectric consists of a high permittivity polymer film, a polymer buffing layer with a high surface energy, and an ultrathin long-chain alkane buffer layer. The effects of both the structures and the processes of gate dielectrics on the performances of OTFTs are investigated in detail. In addition, the relevant physical mechanisms are discussed. Finally, the optimal OTFTs exhibit high mobilities with the average and maximum values up to 5.62 and 6.74 cm2/V s, respectively, at low operating voltages below −5 V. Our findings reveal that designing and processing a reasonable multi-layered gate dielectric is a promising strategy to achieve both high-mobility and low-voltage operation in OTFTs, thereby fostering their development. [ABSTRACT FROM AUTHOR]

Access issues to potable waters around the planet is the motivation for research in desalination technologies. One class of materials that is a research focus for desalination membranes are zeolites that are comprised of silicon (Si), aluminum (Al), and oxygen, and have structures that include regular pores of varying sizes dependent on the type of zeolite. A motivation for this study was to enable characterization of non-conductive materials containing Si or Al (e.g., zeolites) using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) techniques. To avoid significant background signals directly overlapping with these samples, common sample supports and preparation protocols involving Al or Si were precluded. Cross-linked polymer coatings applied via spin coating onto polished copper (Cu) stubs are shown to be durable for reuse even with the use of aggressive cleaning techniques between samples. SEM and EDS analyses of Cu stubs were performed before and after applying the polymer coating, after drop-cast application of zeolite particles and after their subsequent removal by sonication-based techniques. The data from those trials confirmed there was no background signal from Si or Al and no cross-contamination between samples during these analyses, enabling quantitation of Al and Si in the samples. [ABSTRACT FROM AUTHOR]

Polymer film melt stretching exhibits a unique stress–strain behavior, featuring a stress plateau followed by a sudden increase with increasing the strain. This phenomenon poses a challenge to conventional melt-extension theories and methods. To address this, we derive a simplified flow theory according to the symmetric characteristics of thin melt-stretching, and propose a modified multi-mode Leonov model (m-Leonov) that accounts for molecular orientation effects, a crucial factor in accurately simulating the process. In order to improve the computational efficiency, an iterative algorithm was developed to decouple the interdependence between governing and constitutive equations. The computational results reveal that the viscoelastic nature of the film contributes to a delay in the transformation of stretching forces, leading to the observed stress plateau. Significantly, our m-Leonov model successfully predicts both the plateau and the subsequent abrupt increase in stress, across various temperatures and stretching rates. These simulations closely agree with experimental data, underlining the robustness of our approach. Our findings would enhance the understanding of rheological complexities in film stretching, offering potential applications in various materials and polymer processing. [ABSTRACT FROM AUTHOR]

The continuing development of evaporative lithography is important for many areas such as the creation of photonic crystals for optronics and microelectronics, the development of biosensors for medical applications and biotechnology, and for the formation of functional coatings for nanotechnology, including the application of thin, protective polymer coatings. The article proposes a mathematical model that allows us to explain the basic mechanisms of the formation of thin polymer films (less than 50 μm thick) during their deposition onto a composite substrate by methanol evaporation from a solution. If the thermal conductivity of the substrate is spatially non-uniform, this results in inhomogeneous evaporation along the free film surface. Therefore, as the film dries, a patterned polymer coating is left behind on the substrate. The mathematical model described here is based on the lubrication approximation and takes into account the dependence of the solution density on the concentration. The numerical computation results are in qualitative agreement with the experimental data of other authors. The article shows that solutal Marangoni flow plays a primary role in the process under consideration. This study allows us to better understand the mechanisms that can be used in evaporative lithography. [ABSTRACT FROM AUTHOR]

Polymer nanocomposites consisting of polymethyl methacrylate/polyvinylidene fluoride (PMMA/PVDF) polymer doped with silicon oxide (SiO2) nanopowders were prepared using solvothermal. The XRD and FT-IR measurements confirmed the chances of the structure of the PMMA/PVDF blend due to the addition of SiO2. The IR intensity and XRD structural changes affirmed the miscibility and complexation between the pure blend PMMA/PVDF and the blend with SiO2 NPs as a filler. The addition of SiO2 causes a decrease and weakening of the intensity of the diffraction peaks of PMMA/PVDF indicating that the addition can gradually reduce the crystallinity of the composite films. The changes in the structural and optical properties caused a shift in the absorption edge toward a lower wavelength, which resulted in a drop in the energy gap value. The dielectric constant (ε′), dielectric loss (ε′′), the dielectric moduli (M′ and M′′), and the AC conductivity (σac) were measured in the range of frequency from 0.1 to 106 Hz. Increasing of the frequency resulted in lower estimates for both ε′ and ε′′. A charge-transfer complex was formed when SiO2 NPs were incorporated into the PMMA/PVDF blend. The Cole–Cole plot, obtained using a non-Debye technique, exhibited a semicircular shape when plotting the values of M′ and M′′. [ABSTRACT FROM AUTHOR]

Background: Fluconazole is an antifungal agent of triazole class. Fluconazole is one of the most prescribed antifungal agents because of its excellent bioavailability, tolerability and side effect profile. To maintain drug concentrations within therapeutic levels in bone tissue for specific periods, antifungal agents must be re-administered when they are given systemically. Aim: The aim of the present study was to develop a nanoparticle-based implantable drug delivery system of antifungal drug fluconazole for Prosthetic Joint Infection and it's in vitro and in vivo evaluation. Materials and Methods: Fluconazole loaded Chitosan Nanoparticles (CH-NP) were prepared by ionic gelation method and optimized for chitosan: TPP mass ratio, chitosan and fluconazole concentration. CH-NP were evaluated for particle size, polydispersity index, zeta potential, entrapment efficiency, FTIR, DSC, XRD and percent drug release. Nanoparticles were further incorporated in gelatine: chitosan composite film and formulations were optimized for chitosan: gelatin ratio, plasticizer concentration and cross-linker concentration. The developed composite film was tested for water absorption capacity, in vitro and in vivo biodegradation, toxicity and antifungal potency. Results and Discussion: The optimized CH-NP demonstrated 458 nm particle size, 82.39% entrapment efficiency and 77.4% drug release after 4 hr. The chitosan-gelatine ratio of 1:10, glycerine concentration of 5% and formaldehyde concentration of 0.01% resulted in desired in vitro properties and sustained drug release up to 10 hr. The developed formulation showed potent antifungal efficacy and in vitro biodegradation within 3 days. The in vivo biodegradation studies of films in rats showed complete degradation of implant within 7 days of implantation. Histopathology studies revealed no acute toxicity of implanted formulation. Conclusion: The developed Fluconazole loaded chitosan nanoparticle-based polymer composite film could be an effective formulation approach to prevent the fungal infections acquired during surgeries. [ABSTRACT FROM AUTHOR]

The influence of fillers on the structures of siloxane films is studied. Three versions of fillers are considered: ethyl alcohol, chitosan, and sodium bicarbonate with its subsequent removal. It is shown that the use of alcohol leads to a change in the surface structure and formation of numerous "pit" pores. The use of sodium bicarbonate or chitosan as fillers makes it possible to create developed networks of pores intersecting with each other and having access to the surface. The possibility of controlling the thickness of porous layers by varying the concentration of the introduced filler is shown. A conclusion is drawn that the studied versions of modification of the structure of siloxane films open up wide opportunities for creating drug delivery systems or other active agents, including those with controlled prolonged action. [ABSTRACT FROM AUTHOR]

Surface-grafted polymer brushes (PBs) are a versatile class of thin coatings that exhibit unique properties due to their densely grafted polymer chains. PBs are typically formed through surface-initiated polymerizations, particularly reversible deactivation radical polymerizations, and macromolecules adopt extended conformations that differentiate them from classical polymer films. This review explores various applications of PBs, emphasizing their macromolecular ordering, dynamic conformational changes, anisotropic properties, and so forth. The growing interest in utilizing PBs for functional coatings is discussed in various fields, including electronic, biological, and environmental applications. In electronic applications, PBs find relevance in photovoltaics, energy storage devices, organic light-emitting diodes, and organic electronics, showcasing their potential in advancing electronic technologies. In biological applications, they contribute to the formation of antifouling and antibacterial coatings, as well as superior lubrication and cellular adhesion, making them valuable in biomedical settings. Other applications include biosensors, bioimaging systems, and drug delivery systems, highlighting their significant contributions to medical advancements. Additionally, PBs play an important role in environmental applications such as water and wastewater treatment. A variety of recent examples of the applications of surface-grafted PBs are presented, providing insights into their unique properties and architectures that contribute to their success in demanding areas of science and technology. [ABSTRACT FROM AUTHOR]

PHB depolymerase enzymes are able to breakdown the PHB polymers and thereby get significant economic value in the bioplastics industry and for bioremediation as well. This study shows the purification of novel extracellular PHB depolymerase enzyme from Aeromonas caviae Kuk1-(34) using dialysis followed by gel filtration and HPLC. The purification fold and yield after HPLC were 45.92 and 27.04%, respectively. HPLC data showed a single peak with a retention time of 1.937 min. GC-MS analysis reveals the presence of three compounds, of which 1-Dodecanol was found to be most significant with 54.48% area and 8.623-min retention time (RT). The molecular weight of the purified enzyme was obtained as 35 kDa with Km and apparent Vmax values of 0.769 mg/mL and 1.89 U/mL, respectively. The enzyme was moderately active at an optimum temperature of 35 °C and at pH 8.0. The stability was detected at pH 7.0–9.0 and 35–45 °C. Complete activity loss was observed with EDTA, SDS, Tween-20 at 5 mM and with 0.1% Triton X 100. A biodegradation study of commercially available biodegradable polymer films was carried out in a liquid medium and in soil separately with pure microbial culture and with purified enzyme for 7, 14, 28, and 49 consecutive days. In a liquid medium, with a pure strain of Aeromonas caviae Kuk1-(34), the maximum degradation (89%) was achieved on the PHB film, while no changes were observed with other polymer films. With purified enzyme in the soil, 71% degradation of the PHB film was noticed, and it was only 18% in the liquid medium. All such weight analysis were confirmed by SEM images where several holes, pits, grooves, crest, and surface roughness are clearly observed. Our results demonstrated the potential utility of Aeromonas caviae Kuk1-(34) as a source of extracellular PHB depolymerase capable of degrading PHB under a wide range of natural/ lab conditions. [ABSTRACT FROM AUTHOR]

Photoconductive materials have important application value because of their special property of variable conductivity under light. Due to the limitations of the construction of single-component photoconductive materials, photoconductive materials are often combined with organic polymer materials to prepare composite materials. In this work, a series of photoconductive nanofibers array films (PNAFs) are prepared by combining polyvinyl pyrrolidone (PVP), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), polyoxyethylene (PEO) + PMMA, and polyvinylidene fluoride (PVDF) + PVP polymer substrates with 2,7-dibromo-9-fluorenone (DF), respectively, innovative combination of photoconductive materials with different polymers. PNAFs have excellent green fluorescence and electrical conductivity under light irradiation but no performance under no light irradiation. The transformation of performance can be achieved by the presence or absence of lighting. The effects of the combination of different substrates and photoconductive materials on the conductivity and fluorescent properties of the products are investigated for the first time. This provides ideas for the research of photoconductive materials in the future, and suitable combinations of inorganic and organic substances can be selected according to actual needs. [ABSTRACT FROM AUTHOR]

Nitric oxide (NO) is a unique biochemical mediator involved in the regulation of vital processes. Light-controllable NO releasers show promise in the development of smart therapies. Here, we present a novel biocompatible material based on polydimethylsiloxane (PDMS) doped with BODIPY derivatives containing an N-nitroso moiety that is capable of the photoinduced generation of NO. We study the green-light-induced NO-release properties with the following three methods: electrochemical gas-phase sensor, liquid-phase sensor, and the Griess assay. Prolonged release of NO from the polymer films after short irradiation by narrow-band LED light sources and a laser beam is demonstrated. Importantly, this was accompanied by no or little release of the parent compound (BODIPY-based photodonor). Silicone films with the capability of controllable and clean NO release can potentially be used as a highly portable NO delivery system for different therapeutic applications. [ABSTRACT FROM AUTHOR]

Abstract We establish a sample‐ and data‐processing pipeline that allows for high‐throughput optical microscope measurement of porous films, provided they are sufficiently optically scattering. Here, self‐limiting electrospray deposition (SLED) is used to manufacture scattering films of different morphologies. This technique compensates for the scattering of the films through background subtraction of the reflection image with the transmission image. This process is implemented through a combination of an ImageJ and MATLAB data pipeline; the Canny edge‐detector is used as the image‐processing algorithm to identify the boundaries of the film. This process is verified against manually measured images; a comparative study between cross‐sectional scanning electron microscopy (where scattering effects are diminished) and optical microscopy also verifies that our optical microscopy technique can be used to consistently, non‐destructively measure film thickness regardless of film morphology. In addition, this technique can be used in combination with dense film measurements to measure film porosity.

Polymer-based capacitors are very promising for high-power systems due to their high power density and ultrafast charge–discharge speed, yet reaching high dielectric constant and high breakdown strength simultaneously in dielectric polymers required by high-performance capacitors still remains a huge challenge. Herein, poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) were coaxial electrospun in core–shell structured fibers to create locally inhomogeneous microstructures deliberately. Through adjusting the functional group HFP/TrFE monomer ratio, P(VDF-HFP)/P(VDF-TrFE) hybrid polymer films with topological composition distribution have been elaborately designed, enabling gradient polarization distribution from core to shell. Compared with homogeneous hybrid films of the same composition, the core–shell structure significantly boosts breakdown strength, thus resulting in a significantly improved energy storage capacity. At an HFP/TrFE monomer ratio of 10:1, an optimal comprehensive energy storage performance has been achieved with Ue ∼ 20.7 J/cm3 and efficiency 67.8%; moreover, the film could maintain its energy storage performance after 106 charge/discharge cycles without reduction. Molecular dynamic simulation and finite element analysis have been employed in combination to reveal the dipole moments distribution at the molecular level and polarization distribution at the microscale, which further demonstrates that elaborate polarization distribution adjustment is an effective strategy toward high-performance electrostatic energy storage capacitors. [ABSTRACT FROM AUTHOR]

Abstract A series of siloxane‐containing polyimide films (PIS) were prepared by copolymerising with rigid aromatic dianhydride, siloxane diamines and six different aromatic diamines. The effects of siloxane structures, fluorine and imide content, rigid or flexible segment on the heat resistance, moisture absorption, dielectric performance, mechanical and bonding properties were systematically studied. The results show that PIS films maintain good heat resistance with Tg between 292 and 420°C and 5% weight loss temperature higher than 500°C. The moisture absorption and dielectric constant can be significantly reduced due to the presence of siloxanes and fluorinated groups, with the absorption rate as low as 1.2% and dielectric constant of 2.85 at 1 MHz. When measured at 10 GHz, the dielectric constant ranges from 3.10 to 3.50, and dielectric loss varies from 0.0059 to 0.0098. The PIS‐6 film has the best comprehensive performance due to the low imide content, introduction of trifluoromethyl and ether bonds. The peeling strength of bonding PIS‐6 film with a copper foil can reach 9.2 N/cm. It is proven that siloxane‐containing PIS films with high heat resistance, low dielectric and outstanding adhesion are achieved, which can be applied for flexible integrated circuit boards, high‐frequency electronics and microelectronics fields.

Due to their functional and processing versatility, organic semiconductors have gained much interest in recent years. Tailoring the charge transport in a polymeric semiconductor system is imperative for developing optimized devices. Factors such as selection of solvent species and annealing temperature play a significant role in deciding the morphology of the polymer semiconductor and hence the device performance. Bottom-gate bottom-contact organic field-effect transistors were fabricated with regioregular poly(3-hexylthiophene) (P3HT) as the active material. The effects of using chlorobenzene and o-dichlorobenzene as the solvents for P3HT and annealing temperatures on the device performance were evaluated. The devices made using chlorobenzene showed greater field-effect mobility compared to those fabricated with o-dichlorobenzene. This behavior can be attributed to the disentanglement of polymer chains in a solvent with better matching solubility parameters and subsequent ease of arranging in ordered structures during processing. Furthermore, annealing the o-dichlorobenzene devices at temperatures closer to the crystallization temperature of P3HT showed an increase in field-effect mobility. At temperatures closer to the crystallization temperature, a polymer film in a semidry state can allow increased ordering of the chains leading to enhanced charge transportation. [ABSTRACT FROM AUTHOR]

Polymers are susceptible to oxidation, and its impact on their mechanical behavior presents a significant challenge for their long-term performance. Interestingly, in simple tension UV-aged polyethylene plates do not show any significant changes in modulus. But their nano-indentation data reveal up to a twofold increase in near-surface stiffness with increasing exposure time. To understand this apparent conflict, we combined mechanical testing and electron microscopy of pristine and UV-aged unstabilized semicrystalline polymer films and plates. Our study provides new insights into the complex relationship between two competing mechanisms that concurrently appear during the UV aging of semicrystalline polymers: oxidation-induced stiffening and weakening. The former mechanism, oxidation-induced stiffening, is likely caused by UV-induced chemi-crystallization and cross-linking, which increases local crystallinity. On the other hand, oxidation-induced weakening is due to the profuse cracking that accumulates with exposure time. Our findings have important implications for the development of predictive models of polymer aging and improving their long-term performance. [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal CrystEngComm, which focuses on the design and understanding of solid-state and crystalline materials. It includes a variety of papers on topics such as cocrystals, crystal structures, stimuli-responsive properties, and piezoelectric properties. The journal is published by The Royal Society of Chemistry, a leading chemistry community. The document also mentions approved training courses offered by the society. [Extracted from the article]

Solar cells are of growing importance as a renewable energy source, and cuprite (Cu2O) stands out as a promising material due to its cost-effectiveness, abundance, and appealing optoelectronic characteristics. This research uses diverse analytical methods to adjust the influence of the number of plasma focus shots on Cu2O films' crystal structure, morphology, and optoelectronic attributes. X-ray diffraction revealed that both Cu2O and CuO films exhibited a polycrystalline nature with cubic (111), (110), and (200) orientations. Morphological analysis unveiled that film surface characteristics were impacted by the number of shots, leading to the formation of smaller Cu2O grains as the number of shots increased. The transmittance spectra of Cu2O thin films displayed remarkable optical transparency, approximately 80%. The optical bandgap of the films was determined to be 2.57 eV, decreasing to 2.08 eV with an increase in the number of shots, aligning well with values reported for photovoltaic absorber layers. Optoelectronic properties, including optical and electrical conductivities, optical mobility, optical carrier concentrations, refraction loss, optical resistivity, plasmon, and damping frequencies, were computed. The results underscore the significant impact of the number of plasma focus shots and hold great promise for enhancing the performance of Cu2O-based solar cells. [ABSTRACT FROM AUTHOR]

Lithium dendrites pose a major hurdle for enhancing the energy density of lithium metal batteries, and the artificial solid electrolyte interface layer offers a potential solution. In this work, a cost‐effective and environmentally friendly guar gum film is applied to the artificial protective layer. The guar gum artificial solid electrolyte interface (SEI) layer formed naturally, enriched with OH and AOA groups, displayed exceptional electrochemical stability, and achieved an impressively high transference number of 0.88 for lithium‐ion movement. In symmetric cells, the Li@GG‐Cu anode displays remarkable cycling performance even during extended periods. This is evidenced by its ability to maintain a surface capacity of approximately 850 h (1 mA cm−2, 1 mAh cm−2). In addition, when utilizing a complete cell setup comprising a LiFPO4 cathode (weighing 1.5 mg cm−2) and anode coated with a guar gum film, the capacity retention of an impressive 96.2% showcases outstanding preservation of battery performance over time even after 700 cycles. This performance surpasses that of a lithium foil electrode (87.1%) and a copper anode with lithium deposition (0%). Our work exhibits a promising material for a novel configuration of artificial SEI, effectively stabilizing lithium metal anode. [ABSTRACT FROM AUTHOR]

In this study, we present a 5,8-bis(3,4-ethylenedioxythiophene)quinoxaline monomer with two 4-(octyloxy)phenyl side chains (EDOTPQ) that can be electropolymerized on ITO glass in standard electrolytes containing lithium salts and propylene carbonate as solvent. The electrochemically deposited PEDOTPQ layers show very good adhesion and homogeneity on ITO. The green-colored polymer thin films exhibit promising electrochromic (EC) properties and are interesting for applications such as adaptive camouflage, as well as smart displays, labels, and sensors. Novel organic–inorganic (hybrid) EC cell configurations were realized with Prussian blue (PB) or titanium-vanadium oxide (TiVOx) as ion storage electrodes, showing a highly reversible and fast color change from green to light yellow. [ABSTRACT FROM AUTHOR]

A novel additive manufacturing route using a tailored resin containing Poly(vinylidene fluoride) Trifluoroethylene (PVDF‐TrFE) to 3D print piezoelectric films is demonstrated. Piezoelectric films are printed within 2 seconds in a single step by simultaneously focusing initiating and inhibiting excitations within the liquid resin to locally confine the photochemical reaction. The printed films are patterned with an array of holes with a diameter of 30 µm and a pitch of 55 µm. The piezoelectric response is homogeneous across the film, indicating that the print pattern does not impact the PVDF‐TrFE microstructure. Although the printed films contain only a small volume fraction of PVDF‐TrFE (3 wt.%), their piezoelectric response (d33 = 20.3 pC/N) is comparable to the highest literature values reported for PVDF‐TrFE films. The printed PVDF‐TrFE films are predominantly β‐phase, and no electrical poling, post‐processing, piezoelectric or inorganic additives are used in the fabrication. Analysis using piezoresponse force microscopy (PFM) and scanning electron microscopy (SEM) reveals that the enhanced piezoelectric response is due to the preferential formation of oriented PVDF‐TrFE phases during printing. These results demonstrate how the dedicated design of photoactive resins in combination with volumetric additive manufacturing can be applied to rapidly fabricate functional 3D structures. [ABSTRACT FROM AUTHOR]

Certain naturally occurring volatile organic compounds are able to mitigate food spoilage caused by microbial growth. Their considerable vapor pressure enables them to create an antimicrobial atmosphere within a package, and this property can be used for the development of active food-packaging technologies. The volatility of these molecules, however, makes their stabilization difficult and limits their effectiveness. Whilst much research is being undertaken on the use of natural antimicrobial volatiles for inhibiting microbial growth in food, less attention has been paid to the design of controlled-release mechanisms that permit the efficient application of these compounds. Most studies to date either spray the volatile directly onto the fresh product, immerse it in a solution containing the volatile, or embed the volatile in a paper disc to create a vapor in the headspace of a package. More sophisticated alternatives would be delivery systems for the sustained release of volatiles into the package headspace. Such systems are based on the encapsulation of a volatile in organic or inorganic matrices (cyclodextrins, electrospun non-wovens, polymer films, micelles, molecular frameworks, etc.). However, most of these devices lack an efficient triggering mechanism for the release of the volatile; most are activated by humidity. All of these techniques are revised in the present work, and the most recent and innovative methods for entrapping and releasing volatiles based on reversible covalent bonds are also discussed. [ABSTRACT FROM AUTHOR]