Polymer Patterns Research Articles

Chemistry and bioactivity of lindenane sesquiterpenoids and their oligomers.

Covering: 1925 to July 2023Among the sesquiterpenoids with rich structural diversity and potential bioactivities, lindenane sesquiterpenoids (LSs) possess a characteristic cis, trans-3,5,6-carbocyclic skeleton and mainly exist as monomers and diverse oligomers in plants from the Lindera genus and Chloranthaceae family. Since the first identification of lindeneol from Lindera strychnifolia in 1925, 354 natural LSs and their oligomers with anti-inflammatory, antitumor, and anti-infective activities have been discovered. Structurally, two-thirds of LSs exist as oligomers with interesting skeletons through diverse polymeric patterns, especially Diels-Alder [4 + 2] cycloaddition. Fascinated by their diverse bioactivities and intriguing polycyclic architectures, synthetic chemists have engaged in the total synthesis of natural LSs in recent decades. In this review, the research achievements related to LSs from 1925 to July of 2023 are systematically and comprehensively summarized, focusing on the classification of their structures, chemical synthesis, and bioactivities, which will be helpful for further research on LSs and their oligomers.

Radiation-Driven Polymerisation of Methacrylic Acid in Aqueous Solution: A Chemical Events Monte Carlo Study.

This study employed a coarse-grained Monte Carlo (MC) simulation to investigate the radiation-induced polymerisation of methacrylic acid (MAA) in an aqueous solution. This method provides an alternative to traditional kinetic models, enabling a detailed examination of the micro-structure and growth patterns of MAA polymers, which are often not captured in other approaches. In this work, we generated multiple clones of a simulation box, each containing a specific chemical composition. In these simulations, every coarse-grained (CG) bead represents an entire monomer. The growth function, defined by the chemical behaviour of interacting substances, was determined through repeated random sampling. This approach allowed us to simulate the complex process of radiation-induced polymerisation, enhancing our understanding of the formation of poly(methacrylic acid) hydrogels at a microscopic level; while Monte Carlo simulations have been applied in various contexts of polymerisation, this study's specific approach to modelling the radiation-induced polymerisation of MAA in an aqueous environment, utilising the data obtained by quantum chemistry modelling, with an emphasis on micro-structural growth, has not been extensively explored in existing studies. This understanding is important for advancing the synthesis of these hydrogels, which have potential applications in diverse fields such as materials science and medicine.

Advanced mid-infrared plasmonic waveguides for on-chip integrated photonics

Long-wave infrared (LWIR, 8–14 µm) photonics is a rapidly growing research field within the mid-IR with applications in molecular spectroscopy and optical free-space communication. LWIR applications are often addressed using rather bulky tabletop-sized free-space optical systems, preventing advanced photonic applications, such as rapid-time-scale experiments. Here, device miniaturization into photonic integrated circuits (PICs) with maintained optical capabilities is key to revolutionize mid-IR photonics. Subwavelength mode confinement in plasmonic structures enabled such miniaturization approaches in the visible-to-near-IR spectral range. However, adopting plasmonics for the LWIR needs suitable low-loss and -dispersion materials with compatible integration strategies to existing mid-IR technology. In this paper, we further unlock the field of LWIR/mid-IR PICs by combining photolithographic patterning of organic polymers with dielectric-loaded surface plasmon polariton (DLSPP) waveguides. In particular, polyethylene shows favorable optical properties, including low refractive index and broad transparency between ∼2 μm and 200 µm. We investigate the whole value chain, including design, fabrication, and characterization of polyethylene-based DLSPP waveguides and demonstrate their first-time plasmonic operation and mode guiding capabilities along S-bend structures. Low bending losses of ∼1.3 dB and straight-section propagation lengths of ∼1 mm, pave the way for unprecedented complex on-chip mid-IR photonic devices. Moreover, DLSPPs allow full control of the mode parameters (propagation length and guiding capabilities) for precisely addressing advanced sensing and telecommunication applications with chip-scale devices.

Flexible dispersion engineering using polymer patterning in nanophotonic waveguides

We demonstrate the engineering of waveguide dispersion by lithographically patterning the polymer cladding on silicon nitride waveguide resonators. Both normal and anomalous dispersion, ranging from − 462 to 409 ps/nm/km, can be achieved for the same waveguide dimension within an integrated photonic chip. In the meantime, this simple process shows no impact on the waveguide loss and the quality factor of the waveguide resonators, offering flexibility in tailoring designable dispersion for a universal photonic platform. In addition, by adjusting the coverage ratio of cladding, relatively low dispersion (≈ − 130 ps/nm/km) is also demonstrated in the same waveguide resonator, yielding the potentials for zero-dispersive waveguide resonators by a proper coverage ratio of the polymer cladding.

Sidewall patterning of organic–inorganic multilayer thin film encapsulation by adhesion lithography

A simple sidewall patterning process for organic–inorganic multilayer thin-film encapsulation (TFE) has been proposed and demonstrated. An Al2O3 thin film grown by atomic layer deposition (ALD) was patterned by adhesion lithography using the difference in interfacial adhesion strength. The difference in interfacial adhesion strength was provided by the vapor-deposited fluoro-octyl-trichloro-silane self-assembled monolayer (SAM) patterns formed by a shadow mask. The sidewall patterning of multilayer TFE was shown possible by repeating the adhesion lithography and the vapor deposition of organic polymer and SAM patterns using shadow masks. The proposed process has the advantage of being able to pattern the blanket ALD-grown Al2O3 thin films by adhesion lithography using a SAM pattern that can be more accurately predefined with a shadow mask.

1D Van der Waals Polymers with Nonlinear Optical Performance Approaching Theoretical Upper Limit

AbstractNonlinear optical (NLO) materials are of great importance for applications in lasers, atomic clocks, free‐space communication, etc. Herein, inspired by the recent prediction of excellent second harmonic generation (SHG) performance in van der Waals (vdW) materials with 1D building blocks, 14 new NLO materials are found from 244 bulk crystals constructed with 1D polymers using high‐throughput first‐principles calculations. Nearly half of the new NLO materials exhibit superior NLO performance with SHG susceptibilities approaching the theoretical upper limit. The 2D form of 11 candidates inherits the NLO property covering UV, visible, and infrared regions. Bader charge analysis reveals that the SHG susceptibility is determined by the charge difference of ions on the chains. Finally, it is proposed that superior NLO materials can be found in materials with proper bandgaps and large charge differences on the chains. This work not only screens out candidates with outstanding NLO performance in vdW materials with 1D building blocks but also provides a guideline for the search and design of NLO vdW 1D polymer patterns with excellent NLO properties.

Higher impact resistance and lower antibiotic resistance genes proliferation rate in shortcut nitrification-denitrification process under long-term antibiotics selection pressure

Shortcut nitrification–denitrification (SCND) has been widely concerned due to its high nitrogen removal efficiency and low operating cost. However, little information is available on the fate of antibiotic resistance genes (ARGs) in SCND process. This study investigates the dynamics of nitrogen removal and ARGs between SCND and full nitrification–denitrification (FND) under long-term selective pressure conditions of tetracycline and sulfadiazine. The study explores the response patterns of extracellular polymers, microbial activity, and microbial community. Results show that the SCND process exhibits 9.14% higher extracellular polymers and 119.07% higher respiratory activity than FND process, resulting in better TN removal performance (67.16% vs. 49.24%) and stronger impact resistance. Compared to Phase I (0 µg/L) and Phase II (100 µg/L), the relative abundance of total ARGs experienced a sharp increase in Phase III (500 µg/L). The SCND process maintains a lower total ARGs abundance than the FND process in water phase. Specifically, in phase III, the relative abundance of intI1 and ARGs in the FND process are 0.04–2.1 logs and 0.66–1.60 logs higher than that of the SCND process in sludge and water phases, respectively. More denitrifying microbes (>40%) are enriched in the SCND process, while it changes to hydrolytic acidification bacteria (>20%) in the FND process. The Partial Least Squares Path Modeling reveals that microbial community and microbial activity play a crucial role in ARGs transmission, with microbial activity exerting greater influence. Additionally, potential pathogenic bacteria including Clostridium, Gemnobacter, Klebsiella, Enternobacter, Aeromonas, Burkholderia are identified, and SCND over FND process shows better inhibition effect on potential pathogenic bacteria proliferation (0.022% vs 0.080%). This study provides new insights into removing traditional pollutants and ARGs simultaneously from wastewater treatment system.

Evolution of lignin pyrolysis heavy components through the study of representative lignin monomers

Seven typical lignin monomers with different number of methoxyl groups and different 4-substituted patterns were pyrolyzed at 500 °C and 700 °C for 120 s to simulate the secondary polymerization and side chain conversion reactions of primary pyrolytic lignin monomers. The pyrolytic heavy oil components were identified at molecular scale with Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR-MS) and analyzed with Kendrick mass defect (KMD) and van Krevelen diagrams. The detected heavy components were typically phenolic oligomers formed dominantly through the radical coupling reactions of phenol radicals (C6H4O) and methoxyl radicals (OCH2). Model compounds with CC type 4-substituted groups were prone to produce more phenolic oligomers with more aromatic units. For the CO type model compounds, the number of methoxyl groups have significant influence on the generation of heavy components, thereby affecting the char yields. Rising temperature promotes the generation of heavy components through three main routes, namely the additions of CH2, OCH2 and C6H4O. These routes were mapped on van Krevelen diagrams, shedding light on the evolution patterns of both polymerization and side chain conversion reactions during the secondary pyrolysis of lignin.

Polymerization of Allyltrimethylisilane and 4-Methyl-1-Pentene by Using Metallocene Catalysts.

Polymers of higher olefin, obtained by Ziegler-type polymerization, have been used in some critical fields, e.g., as the membrane for extracorporeal membrane oxygenation (ECMO), which plays an important role in the treatment of patients with severe COVID-19. The polymer obtained by a single-site catalyst, e.g., metallocene catalysts, demonstrated a higher performance. The homo- and co-polymerization of allyltrimethylisilane (ATMS) and 4-methyl-1-pentene (4M1P) were conducted using syndiospecific (cat 1) and isospecific (cat 2) metallocene catalysts. Cat 1 showed low conversions and provided a polymer with a higher molecular weight, while cat 2 behaved oppositely. 13C-NMR spectra certified the stereotacticity of the resultant polymer, and the resonance of the carbon atom of CH2 (αα') between the two tertiary carbon atoms of the ATMS and 4M1P units were observed. This could be the evidence of the formation of a true copolymer. The crystallization of the polymer was explored using a differential scanning calorimeter (DSC) and wide angle X-ray diffraction (WAXD). All homopolymers and some of the copolymers showed high melting temperatures and low melting enthalpies. The WAXD patterns of the syndiotactic polymer and isotactic homopolymer or the ATMS-rich copolymer were consistent with the reported literature, but the isotactic 4M1P-rich copolymer provided the crystal form I, which is unusual for a 4M1P polymer without any pretreatment.

Modulation of myoblast differentiation by electroactive scaffold morphology and biochemical stimuli

The physico-chemical properties of the scaffold materials used for tissue regeneration strategies have a direct impact on cell shape, adhesion, proliferation, phenotypic and differentiation. Herewith, biophysical and biochemical cues have been widely used to design and develop biomaterial systems for specific tissue engineering strategies. In this context, the patterning of piezoelectric polymers that can provide electroactive stimuli represents a suitable strategy for skeletal muscle tissue engineering applications once it has been demonstrated that mechanoelectrical stimuli promote C2C12 myoblast differentiation. In this sense, this works reports on how C2C12 myoblast cells detect and react to physical and biochemical stimuli based on micropatterned poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-TrFE)) electroactive scaffolds produced by soft lithography in the form of arrays of lines and hexagons (anisotropic and isotropic morphology, respectively) combined with differentiation medium. The scaffolds were evaluated for the proliferation and differentiation of C2C12 myoblast cell line and it is demonstrated that anisotropic microstructures promote muscle differentiation which is further reinforced with the introduction of biochemical stimulus. However, when the physical stimulus is not adequate to the tissue, e.g. isotropic microstructure, the biochemical stimulus has the opposite effect, hindering the differentiation process. Therefore, the proper morphological design of the scaffold combined with biochemical stimulus allows to enhance skeletal muscle differentiation and allows the development of advanced strategies for effective muscle tissue engineering.

Automated Multi‐ and Block‐Copolymer Writing in Mesoporous Films Using Visible‐Light PET‐RAFT and a Microscope (Small 16/2023)

Mesoporous Films An oxygen tolerant, DDMAT-initiated and visible-light induced photo electron/energy transfer-reversible addition-fragmentation chain-transfer (PET-RAFT) allows for direct polymer writing in a mesoporous silica thin film. Using a commercially available microscope, micrometer scale resolution of the placement of three different polymers as well as block-copolymer functionalization are achieved. This flexible approach makes rapid prototyping of polymer patterns in mesoporous silica thin film easily accessible. More details can be found in article number 2207762 by Annette Andrieu-Brunsen and co-workers.

Effects of gate cross-section area and vaccum pressure on mold filling in lost foam casting

The lost foam casting process utilizes polymeric foam patterns to produce the metallic components. Foamed polymer patterns are coated with a refractory slury, dried and embedded in unbonded sand. Molten metal is poured directly on the coated polymer. The polymer is thermally decomposed and is gradually replaced by the liquid metal to create the casting after solidification. Expanded polystyrene (EPS) is the most common pattern material used in commercial practice. In this paper, experiments are conducted to examine the filling of an aluminum alloy melt into the molds. The purpose is to observe some parameters such as the gate cross-section area, vaccum pressure, gas gap length, metal pouring temperature in lost foam casting of aluminum. The results indicate that the gate section, metal pouring temperature and vaccum pressure affect directly the mold-filling time.

Solid-State Surface Patterning on Polymer Using the Microcellular Foaming Process

This study proposes a novel process that integrates the molding and patterning of solid-state polymers with the force generated from the volume expansion of the microcellular-foaming process (MCP) and the softening of solid-state polymers due to gas adsorption. The batch-foaming process, which is one of the MCPs, is a useful process that can cause thermal, acoustic, and electrical characteristic changes in polymer materials. However, its development is limited due to low productivity. A pattern was imprinted on the surface using a polymer gas mixture with a 3D-printed polymer mold. The process was controlled with changing weight gain by controlling saturation time. A scanning electron microscope (SEM) and confocal laser scanning microscopy were used to obtain the results. The maximum depth could be formed in the same manner as the mold geometry (sample depth: 208.7 μm; mold depth: 200 μm). Furthermore, the same pattern could be imprinted as a layer thickness of 3D printing (sample pattern gap and mold layer gap: 0.4 mm), and surface roughness was increased according to increase in the foaming ratio. This process can be used as a novel method to expand the limited applications of the batch-foaming process considering that MCPs can impart various high-value-added characteristics to polymers.

Precise identification and transport of specific molecules through framework-functionalized membranes with multiple binding sites

Membranes with specific-recognition and superfast-filtration have significant practical applications in water purification and chiral separation. However, membrane technique still remains challenging to high selectivity and permeation in aqueous-and-organic solvents. Here, we reported a new approach to designing framework-functionalized membranes with multiple binding sites (FMMBSs) that enabled structure&size-exclusion selectivity and fast transport performance towards specific compound of shikimic acid (SA). The as-prepared FMMBSs, based on intrinsic core-shell structure of the boronate-affinity sol-gel imprinted polymers, demonstrated that exquisite control over polymerization pattern and functionalization of characteristic membrane construction played important roles in achieving fast molecule transport combined with high molecular selectivity. The superior property of the membrane-based core-shell structure had been initially demonstrated by testing nitrogen adsorption capacity, showing about a 3.0 times higher result (63.65 cm3/g) than that of original membrane (20.71 cm3/g). These framework-functionalized membranes were then regarded as the platforms to construct the FMMBSs through a first-time-developed boronate-affinity sol-gel imprinting strategy. Therefore, the FMMBSs always kept remarkably static rebinding capacity (45.48 mg g−1) and perm-selectivity factors (>10). The dynamic transport results showed that much higher SA-based rebinding capacities than that of other molecules could be still observed under pump-pressure-driven for a long time, which strongly confirmed the preparation of high-efficiency selective membrane separation system. The strategy of introducing framework-functionalized structure on porous membrane would offer a window of opportunity for preparation of high-intensitive selective separation membrane systems not only for continuous high permeability, but also for competitive selectivity.

Development of removal modes of 3D-printed polymer patterns from ceramic molds

The use of additive technologies, particularly 3D printing, to make patterns instead of traditional wax patterns is promising for casting into ceramic molds. However, when using polymer patterns, there is a problem of cracking ceramic shells during their firing. The goal of the work was to develop optimal thermo-kinetic modes of removal of disposable plastic patterns from ceramic molds, which will prevent the formation of cracks in ceramics. During the study, samples of patterns made by 3D printing from various plastics were selected and examined. Laboratory tests were carried out on a batch of ceramic shells made of electrocorundum. The methods of removing plastic patterns from ceramic molds by means of two-stage firing in thermal furnaces were investigated. The low-temperature stage of firing consisted in gradually heating the ceramics up to 350 °C. During it, the material of the patterns was compacted, softened, melted, and partially gasified. This reduced uncontrolled gas pressure and stress in the ceramic and prevented the formation of cracks in it. The high-temperature firing phase (1000—1100 °С) was performed for sintering ceramics and removing the remains of plastic materials. The influence of different plastic materials on the quality of the casting mold was investigated. It is proposed to use PLA plastic for the 3D printing of patterns, as it meets the requirements of environmental friendliness and cost. The possibility of improving the surface quality of ceramic shells by coating them with a thin layer of wax-like material is also considered. According to the results of research on the surface of ceramic forms, it is proposed to add structural elements to plastic patterns that reduce deformations of ceramic forms during firing. The developed firing modes of the patterns are used in the production of ceramic molds for endoprostheses.

In Situ Polymer‐Imprinted Architecture of Textured Perovskite Single‐Crystal Sheets for Ultraweak‐Light Photodetection

AbstractA facile double flexible interfacial imprinting method is reported to obtain the cubic single‐crystal CH3NH3PbBr3 sheets with in situ polymer patterns by capillary effect. The imprinted CH3NH3PbBr3 sheets offer good crystallinity and light‐trapping structure. As a result, the textured single‐crystal photodetector exhibits the superior responsivity of 63.0 A W−1, external quantum efficiency of 1.50 × 104%, and detectivity D* of 8.12 × 1012 Jones under 520 nm irradiations with a weak power density of 0.54 µW cm−2 at 3 V, which are more than 4200% and 80000% higher than those of the photodetector based on single‐crystal bulk and polycrystalline film, respectively. The exciting ultraweak‐light photoelectric performance is achieved due to the good light trapping and high carrier collection. Especially, the photodetector also exhibits excellent self‐powered performance.

High-resolution maskless patterning of AgNWs based on adhesion enhancement of a printed conductive polymer

Facile high-resolution patterning of silver nanowires (AgNWs) is a key enabling technology for expanding their usage to flexible and stretchable electronics applications. Although various patterning methods have been proposed, only high-cost and complex mask-based methods have demonstrated potential micrometer-scale pattern-ability, which have no design freedom of changing patterns in a facile manner. Herein, we suggest a maskless high-resolution patterning method by combining an adhesive underlayer and inkjet-printed conductive polymer patterns. AgNWs located between them are tightly bonded and thus are resistant to a solvent-based rinsing process. AgNWs under the conductive polymer patterns remain while uncovered AgNWs are removed during the rinsing process. Our approach allows easy patterning of AgNWs on various substrates including glass, plastic, and stretchable elastomer. The excellent mechanical properties of AgNW interconnects are demonstrated in a stretchable light-emitting diode array. By introducing an electrohydrodynamic printing method, high-resolution AgNW patterns with linewidths below 20 µm are fabricated, which are used for a heater based on transparent grid AgNW electrodes. Based on our results, we believe that our method paves the way for a convenient patterning process of high-resolution electrode circuits with a high degree of freedom even on a deformable platform.

АДАПТАЦІЯ ПРОЦЕСУ АДИТИВНОГО ВИГОТОВЛЕННЯ МОДЕЛЕЙ ДЛЯ ГАЗИФІКАЦІЇ ЇХ В ПІЩАНІЙ ФОРМІ ПРИ ЗАЛИВАННІ МЕТАЛУ, А ТАКОЖ ДЛЯ УТИЛІЗАЦІЇ ВІДХОДІВ ПІНОПОЛІСТИРОЛУ

The technological method in the field of foundry production is described, which combines additive manufacturing (AM) of disposable foundry polymer patterns with waste polystyrene (EPS) waste disposal. It was created to switch to the method of Lost Foam casting on gasified patterns (LFC), from the current method of casting on printed patterns of fired. The latter method is used because modern printed patterns have a high density and ash content, which degrades the quality of metal castings when used for LFC. EPS disposal gives an environmental effect, and AM patterns are an example of the spread of digitalization and automation of foundry production. Examples of EPS disposal, examples of castings after firing additively manufactured patterns and the ash residue, consisting of carbon, found in the working cavities of molds after firing such patterns are described. Examples of printing patterns with a cellular core and a ventilation channel are shown, an unsuccessful example of aluminum casting by the LFC method in a vacuumed sand mold, as well as an example of a 3D printer for printing using crushed plastic or plastic granules. The developed method of printing one-time foundry patterns for gasification in sand foundry mold corresponds to the trend of spreading AM in foundry production. If the specific weight of the printed pattern is too high, then new LFC methods are used with the removal of excess gases from the gasification of the pattern through the ventilation duct in the pattern and tubular evaporation outside the mold and their oxidation, in particular by our method. Such neutralization of gaseous waste at LFC rightly complements the utilization of EPS solid waste as a raw material for AM foundry patterns, together these methods give a synergistic effect on environmental protection, improving the working conditions of foundries and reducing the cost of cast products while improving its quality. Keywords: Lost Foam casting; gasified patterns; 3D printing; additive manufacturing; one-time patterns; burning patterns; expanded polystyrene; disposal of polymer waste.

Fabrication of three-dimensional opal nanolattices using template-directed colloidal assembly

Three-dimensional (3D) nanostructures play a crucial role in nanophotonics, lasers, and optical systems. This article reports on the fabrication of 3D nanostructures consisting of opal structures that are spatially aligned to an array of holes defined in the photoresist. The proposed method uses colloidal lithography to pattern a hexagonal array of holes, which are then used to direct the subsequent 3D assembly of colloidal particles. This approach allows the 3D opal structures to be aligned with the 2D array of holes, which can enhance spatial-phase coherence and reduce defects. The polymer patterns can be used as a sacrificial template for atomic layer deposition and create free-standing nanolattices. The final structure consists of a combination of nanolattice, upon which controlled deposition of opal structures is achieved. These structures result in nanostructured materials with high porosity, which is essential to create low-index materials for nanophotonics. A thick layer of titanium oxide with high refractive index is deposited over nanolattices to demonstrate the mechanical stability of underlying structures. These nanolattice structures with precisely controlled height can serve as a low-index layer and can find applications in Bragg reflectors, nanophotonics, and optical multilayers.

Low-Cost Fabrication of High-Performance Fluorinated Polythiophene-Based Vis–NIR Electrochromic Devices toward Deformable Display and Camouflage

Flexible electrochromic devices (FECDs) are extensively used in smart windows, deformable electronic displays, and wearable electronics. However, it remains very challenging to fabricate low-cost yet high-performance visible–near-infrared (vis–NIR) FECDs. In this work, we overcome this hurdle by developing a fluorinated polythiophene derivative with superior overall electrochromic performance and simple electropolymerization patterning. Fluorophenyl-modified polythiophene (band gap: 1.74 eV) can be readily synthesized via a one-step Grignard coupling with a high yield of >90% together with successive low-potential electropolymerization at 1.0 V vs Ag/AgCl. The intermolecular hydrogen bonding from the fluorine substitution of polythiophene backbones allows the facile electrodeposition of free-standing polymer films with a compact morphology and also leads to mechanical strength and electrical conductivity enhancement. Interestingly, such polymer films exhibit intriguing overall electrochromic performances with reversible color changes between deep red and light green upon doping/dedoping, including high optical contrast throughout the NIR region (max. 80% at 1600 nm), fast response time (0.93 s), high coloration efficiency (up to 752 cm2 C–1), outstanding stability against cycling (<3% reduction after 5,000 cycles), and excellent optical memory effect. The fabricated FECDs by electropolymerization patterning of such polymers display robust mechanical stability (<5% decay in optical contrast after 5,000 bending cycles with a bending radius of 1 cm) under a low driving voltage (0.85 V). We further demonstrate the applications of such patterned electrochromic devices toward deformable displays, color-changing electronic on-skin tattoos, and infrared camouflage with stable color-switching and robust mechanical properties.