Wide Range Of Functional Materials Research Articles

Self-Healable Multifunctional Fibers via Thermal Drawing.

The development of soft electronics and soft fiber devices has significantly advanced flexible and wearable technology. However, they still face the risk of damage when exposed to sharp objects in real-life applications. Taking inspiration from nature, self-healable materials that can restore their physical properties after external damage offer a solution to this problem. Nevertheless, large-scale production of self-healable fibers is currently constrained. To address this limitation, this study leverages the thermal drawing technique to create elastic and stretchable self-healable thermoplastic polyurethane (STPU) fibers, enabling cost-effective mass production of such functional fibers. Furthermore, despite substantial research into the mechanisms of self-healable materials, quantifying their healing speed and time poses a persistent challenge. Thus, transmission spectra are employed as a monitoring tool to observe the real-time self-healing process, facilitating an in-depth investigation into the healing kinetics and efficiency. The versatility of the fabricated self-healable fiber extends to its ability to be doped with a wide range of functional materials, including dye molecules and magnetic microparticles, which enables modular assembly to develop distributed strain sensors and soft actuators. These achievements highlight the potential applications of self-healable fibers that seamlessly integrate with daily lives and open up new possibilities in various industries.

Stable peri-Naphthoisatogens without C2 Protection: Synthesis via Aldrone Condensation, Optical Properties and 1,3-Dipolar Cycloaddition Reaction.

peri-Annulation of naphthalane, an important tool for realization of wide range of functional materials, is presently accomplished with limited few functional groups like imide, amide and diamine-derivative (perimidine). To increase the diversity, we have incorporated α-keto aldonitrone as a new functional group, and herein report about five peri-naphthoisatogens (PNTIs) dyes. The synthesis were accomplished using an unusual reaction of aromatic nitro group, which is nucleophilic attack of a C-nucleophile (enol) to the N-atom of nitro group. In five different 5-alkylamino-8-nitro-1-acetylnaphthalenes, intramolecular acid-catalyzed nucleophilic attack of enol moiety to the N-atom of nitro group produced α-keto aldonitrone via addition-elimination mechanism. The PNTIs showed characteristics of 1,3-dipole and reacted with ethyl acrylate to produce isoxazolidine ring, which subsequently converted into aza phenalenone derivative via ring cleavage. Both the PNTI and the corresponding derivative strongly absorb in the visible region, displaying absorption maximum at 551 and 561 nm (in CHCl3 ) respectively. Compared to the popular analogous dye naphthalene monoimides, PNTIs showed bathochromic shift of absorption maximum by more than 100 nm. The emission maximum for the PNTI and its derivative in chloroform were observed at 594 and 635 nm respectively.

A simple, validated approach for design of two-dimensional periodic particle patterns via acoustophoresis

Two-dimensional patterning of microparticles enables a wide range of functional materials, including patterned energy storage electrodes, flexible electronics, and sensor arrays. Particle patterning via acoustics offers an attractive path to generate a wide variety of 2D periodic patterns that introduce tailorable hierarchical porosity, useful for controlling surface area, transport distances, and other properties. This method is most effective with micron scale particles and patterns of tens to hundreds of microns. To enable systematic exploration of the broad design space for such patterns, this work develops a model of 2D and 3D assembly of particles at high loadings and validates the obtained patterns against both experiments and more computationally intensive modeling techniques. Using this simple model, connections are mapped between input parameters (like actuation conditions, particle volume fraction, material properties) and output geometrical features (like void size and shape, pattern connectivity, and surface area) so that they can be tailored to given applications. The utility of this simple model is illustrated by predicting and then experimentally demonstrating new hierarchical patterns resulting from multiple waves of different frequencies interacting. These multiscale patterns offer the potential to lift the limits on surface area, diffusion distances, and other features.

Taming Multiscale Structural Complexity in Porous Skeletons: From Open Framework Materials to Micro/Nanoscaffold Architectures.

Recent developments in the design and synthesis of more and more sophisticated organic building blocks with controlled structures and physical properties, combined with the emergence of novel assembly modes and nanofabrication methods, make it possible to tailor unprecedented structurally complex porous systems with precise multiscale control over their architectures and functions. By tuning their porosity from the nanoscale to microscale, a wide range of functional materials can be assembled, including open frameworks and micro/nanoscaffold architectures. During the last two decades, significant progress is made on the generation and optimization of advanced porous systems, resulting in high-performance multifunctional scaffold materials and novel device configurations. In this perspective, a critical analysis is provided of the most effective methods for imparting controlled physical and chemical properties to multifunctional porous skeletons. The future research directions that underscore the role of skeleton structures with varying physical dimensions, from molecular-level open frameworks (<10nm) to supramolecular scaffolds (10-100nm) and micro/nano scaffolds (>100nm), are discussed. The limitations, challenges, and opportunities for potential applications of these multifunctional and multidimensional material systems are also evaluated in particular by addressing the greatest challenges that the society has to face.

Minimal conditions for solidification and thermal processing of colloidal gels

Colloidal gelation is used to form processable soft solids from a wide range of functional materials. Although multiple gelation routes are known to create gels of different types, the microscopic processes during gelation that differentiate them remain murky. A fundamental question is how the thermodynamic quench influences the microscopic driving forces of gelation, and determines the threshold or minimal conditions where gels form. We present a method that predicts these conditions on a colloidal phase diagram, and mechanistically connects the quench path of attractive and thermal forces to the emergence of gelled states. Our method employs systematically varied quenches of a colloidal fluid over a range of volume fractions to identify minimal conditions for gel solidification. The method is applied to experimental and simulated systems to test its generality toward attractions with varied shapes. Using structural and rheological characterization, we show that all gels incorporate elements of percolation, phase separation, and glassy arrest, where the quench path sets their interplay and determines the shape of the gelation boundary. We find that the slope of the gelation boundary corresponds to the dominant gelation mechanism, and its location approximately scales with the equilibrium fluid critical point. These results are insensitive to potential shape, suggesting that this interplay of mechanisms is applicable to a wide range of colloidal systems. By resolving regions of the phase diagram where this interplay evolves in time, we elucidate how programmed quenches to the gelled state could be used to effectively tailor gel structure and mechanics.

Fast One-Step Fabrication of Highly Regular Microscrolls with Controllable Surface Morphology.

Although rolling origami technology has provided convenient access to three-dimensional (3D) microstructure systems, the high yield and scalable construction of complex rolling structures with well-defined geometry without impeding functionality has remained challenging. The straightforward, one-step fabrication that uses external mechanical stress to scroll micrometer thick, flexible planar films with centimeter lateral dimensions into tubular or spiral geometry within a few seconds is demonstrated. The method allows controlling the scrolls' diameter, number of windings and nanostructured surface morphology, and is applicable to a wide range of functional materials. The obtained 3D structures are highly promising for various applications including sensors, actuators, microrobotics, as well as energy storage and electronic devices.

Printing on Particles: Combining Two-Photon Nanolithography and Capillary Assembly to Fabricate Multimaterial Microstructures.

Additive manufacturing at the micro- and nanoscale has seen a recent upsurge to suit an increasing demand for more elaborate structures. However, the integration of multiple distinct materials at small scales remains challenging. To this end, capillarity-assisted particle assembly (CAPA) and two-photon polymerization direct laser writing (2PP-DLW) are combined to realize a new class of multimaterial microstructures. 2PP-DLW and CAPA both are used to fabricate 3D templates to guide the CAPA of soft- and hard colloids, and to link well-defined arrangements of functional microparticle arrays produced by CAPA, a process that is termed "printing on particles." The printing process uses automated particle recognition algorithms to connect colloids into 1D, 2D, and 3D tailored structures, via rigid, soft, or responsive polymer links. Once printed and developed, the structures can be easily re-dispersed in water. Particle clusters and lattices of varying symmetry and composition are reported, together with thermoresponsive microactuators, and magnetically driven "micromachines", which can efficiently move, capture, and release DNA-coated particles in solution. The flexibility of this method allows the combination of a wide range of functional materials into complex structures, which will boost the realization of new systems and devices for numerous fields, including microrobotics, micromanipulation, and metamaterials.

Externally-triggerable optical pump-probe scanning tunneling microscopy with a time resolution of tens-picosecond

Photoinduced carrier dynamics of nanostructures play a crucial role in developing novel functionalities in advanced materials. Optical pump-probe scanning tunneling microscopy (OPP-STM) represents distinctive capabilities of real-space imaging of such carrier dynamics with nanoscale spatial resolution. However, combining the advanced technology of ultrafast pulsed lasers with STM for stable time-resolved measurements has remained challenging. The recent OPP-STM system, whose laser-pulse timing is electrically controlled by external triggers, has significantly simplified this combination but limited its application due to nanosecond temporal resolution. Here we report an externally-triggerable OPP-STM system with a temporal resolution in the tens-picosecond range. We also realize the stable laser illumination of the tip-sample junction by placing a position-movable aspheric lens driven by piezo actuators directly on the STM stage and by employing an optical beam stabilization system. We demonstrate the OPP-STM measurements on GaAs(110) surfaces, observing carrier dynamics with a decay time of sim 170 ps and revealing local carrier dynamics at features including a step edge and a nanoscale defect. The stable OPP-STM measurements with the tens-picosecond resolution by the electrical control of laser pulses highlight the potential capabilities of this system for investigating nanoscale carrier dynamics of a wide range of functional materials.

Capping layer enabled controlled fragmentation of two-dimensional materials by cold drawing.

Cold drawing, a well-established processing technique in the polymer industry, was recently revisited and discovered as an efficient material structuring method to create ordered patterns in composites consisting of both cold-drawable polymers and brittle target materials. Such a high-yield and low-cost manufacturing technique enables the large-scale fabrication of micro-ribbon structures for a wide range of functional materials, including two-dimensional (2D) layered materials. Compared to the abundant phenomenological results from experiments, however, the underlying mechanisms of this technique are not fully explored. Here, supported by experimental investigation, finite element calculations, and theoretical modeling, we systematically study the effect of a capping layer on the controlled fragmentation of 2D materials deposited on polymer substrates during the cold drawing. The capping layer is found to prevent the premature fracture of the 2D thin films during elastic deformation of the substrate, when a specific requirement proposed by the theoretical model is satisfied. Controlled fragmentation is enabled in the necking stage due to the protective effect of the capping layer, which also influences the size of the resulting fragments. Flexible and stretchable electrodes based on 2D material ribbons are fabricated to demonstrate the effectiveness of the proposed roadmap. This study gives an accurate understanding of interactions between 2D materials, polymer substrates, and capping layers during cold drawing, and offers guidance for potential applications such as flexible electronics.

Role of Molecular Interactions in Supramolecular Polypeptide-Polyphenol Networks for Engineering Functional Materials.

Supramolecular assembly affords the development of a wide range of polypeptide-based biomaterials for drug delivery and nanomedicine. However, there remains a need to develop a platform for the rapid synthesis and study of diverse polypeptide-based materials without the need for employing complex chemistries. Herein, we develop a versatile strategy for creating polypeptide-based materials using polyphenols that display multiple synergistic cross-linking interactions with different polypeptide side groups. We evaluated the diverse interactions operating within these polypeptide-polyphenol networks via binding affinity, thermodynamics, and molecular docking studies and found that positively charged polypeptides (Ka of ∼2 × 104 M-1) and polyproline (Ka of ∼2 × 106 M-1) exhibited stronger interactions with polyphenols than other amino acids (Ka of ∼2 × 103 M-1). Free-standing particles (capsules) were obtained from different homopolypeptides using a template-mediated strategy. The properties of the capsules varied with the homopolypeptide used, for example, positively charged polypeptides produced thicker shell walls (120 nm) with reduced permeability and involved multiple interactions (i.e., electrostatic and hydrogen), whereas uncharged polypeptides generated thinner (10 nm) and more permeable shell walls due to the dominant hydrophobic interactions. Polyarginine imparted cell penetration and endosomal escape properties to the polyarginine-tannic acid capsules, enabling enhanced delivery of the drug doxorubicin (2.5 times higher intracellular fluorescence after 24 h) and a corresponding higher cell death in vitro when compared with polyproline-tannic acid capsules. The ability to readily complex polyphenols with different types of polypeptides highlights that a wide range of functional materials can be generated for various applications.

Application of Resistive Random Access Memory in Hardware Security: A Review

AbstractNowadays, advancements in the design of trusted system environments are relying on security provided by hardware‐based primitives, while replacing resource‐hungry software security measures. Emerging nonvolatile memory devices are promising candidates to provide the required hardware security functionalities at very low area‐energy‐runtime budget. Resistive random access memory (RRAM) offers high‐density integration with outstanding performance among the state‐of‐the‐art nonvolatile memory devices. The RRAM device technology is currently getting significant attention from both academia and industry for constructing beyond Von Neumann architectures. This technology's strength is its scalable two‐terminal structure, the availability of wide range of functional materials, and multi‐bit storage capability. The fluctuations in switching resistances, random telegraph noise, and sneak path current are detrimental characteristics of RRAM integrations for storage and in‐memory computing applications, and more research focuses on alleviating these effects. Interestingly, these characteristics make them suitable for designing security hardware. In recent times, there has been significant progress in the design and analysis of RRAM‐based security primitives such as, Physical Unclonable Function, true random number generator, and hash function. This review discusses the detailed developments in RRAM security and presents the demanded security requirement and available opportunities to be explored.

High‐performance photocatalyst containing noble metals selectively deposited inside mesopore

AbstractWe describe a general photoelectrical deposition process for the priority deposition of noble metals inside surface mesopores, which are selectively formed in the interstitial regions between crystal arrays composed of sintered photoactive nanocrystals. The basis of our approach is to prepare continuous coherent bonds between photoactive nanocrystals aligned toward the surface accompanied by the formation of interstices (2–20 nm) filled with a heterogeneous insulator phase between the crystal arrays; the subsequent removal of part of the heterogeneous phase creates surface mesopores. The coherent crystalline structure causes a smooth electron flow from the outside to the inside of the array through the coherent boundaries of the nanocrystals during photodeposition using an ultraviolet lamp, accompanied by outside‐hole consumption and noble metal deposition in the recesses of the surface mesopores. The size and morphology of the deposited noble metals are restricted to the shape of the formed mesopores, which can be easily controlled. This approach is applicable to a wide range of functional materials and is expected to be applicable to the preparation of excellent photocatalysts, redox catalysts, and photochromic materials. Using our new process, we also achieved a remarkable increase in the photocatalytic activity of the obtained Pd‐deposited TiO2/SiO2 photocatalytic fiber.

(Invited) Conformal Deposition of Li-Based Thin Films for 3D Lithium-Ion Microbatteries

Lithium-ion batteries have been the premiere power source in the mobile electronics industry due to their superior energy density and cycle life as compared to other battery chemistries. In the Era of the Internet of Things (IoT) there is an increasing need to find a viable power source to support millimeter-size and smaller scale devices in the fields of environmental sensing, biomedical devices, and wearable electronics. Three-dimensional battery architectures mitigate the limitations of traditional thin film batteries through improvement of ion transport properties allowing for higher areal loading of active materials. Atomic layer deposition not only offers the ability to synthesize a wide range of functional materials, but crucially is a non-line-of-sight deposition technique that allows for conformal deposition necessary for fabrication of 3D lithium-ion batteries. In this work, two ALD processes were developed to synthesize conformal thin films applicable to 3D battery fabrication—LiAlSiO4, a solid-state electrolyte, and LiMn2O4, a high-rate thin film cathode.LiAlSiO4 is a solid-electrolyte of interest, in which its quartz-like framework produces unique 1D channels for Li-ion transport along the c-axis, exhibiting ionic conductivities as high as 4.7x10-5 S/cm at room temperature,1, 2 where the ionic conductivity in its thin film form has shown to increase upon decreasing thicknesses, 3 In this work, ALD of LixAlySizO was demonstrated with careful tuning of the stoichiometry to allow for crystallization into the ionically conductive β-Eucryptite LiAlSiO4 phase. The rapid thermal annealed ALD film developed a well-defined epitaxial relationship to the silicon substrate: β-LiAlSiO4 (12 ̅10) || Si (100) and β-LiAlSiO4 (101 ̅0) || Si(001). The extrapolated room temperature ionic conductivity was found to be 1.2 x 10-7 S/cm in the [12 ̅10] direction with an activation energy of 0.63 eV, as compared to amorphous ALD LASO films with ionic conductivities on the order of 10-9 S/cm.Beyond the electrolyte layer, an equally crucial material is a thin film cathode with optimal interfacial properties to ensure homogeneous active material utilization, adequate cycle-life, and high rate performance. To realize this goal, LiMn2O4 was demonstrated utilizing O2 plasma and Tris(2,2,6,6Tetramethyl-3,5-heptanedione) Mn(III), where lithium incorporation was performed through a thermal ALD LiOtBu/H2O process. Thin films with stoichiometries of Li1+xMn2-xO4, where x>0 were observed (as-characterized via XPS) with LiOH ALD sub-cycle percentages lower than 1% of the total ALD supercycle. LiMn2O4 thin films exhibited great rate capability (66% capacity retention after increasing the rate from C/2 to 50C) as well as capacity retention (97% capacity retention after 100 cycles at 5C).Lastly, a proof-of-concept nanobattery consisting of a SiGe nanowire (anode) coated with LixAlySizO (electrolyte) and LiMn2O4 (cathode) was fabricated. Both materials show great promise for direct integration with three-dimensional lithium-ion microbatteries.1. V. Thangadurai and W. Weppner, Ionics 8 (3), 281-292 (2002). 2. P. G. Bruce, Solid State Electrochemistry. (Cambridge University, Press, 1995).3. S.-i. Furusawa, H. Tabuchi and T. Tsurui, Solid State Ionics 178 (15), 1033-1038 (2007).

High‐throughput computational materials screening and discovery of optoelectronic semiconductors

AbstractIn the recent past, optoelectronic semiconductors have attracted significant research attention both experimentally and theoretically toward large‐scale applications in energy conversion, lighting, imaging, detection, and so on. With advancement in computing power and rapid development of computational algorithms, scientific community resorts to materials simulation to explore the hidden potential behind thousands of potentially unknown materials within short timeframes that the real experiments might take a long time. Within this context, the high‐throughput (HT) computational materials screening has emerged as a useful tool to accelerate materials discovery, especially in the field of optoelectronic semiconductors. One of the important consequences is the construction of a number of material databases containing wide range of functional materials with their diverse physical properties and applications. Herein, we reviewed the recent progress on HT computational screening of optoelectronic semiconductors, with focus on photovoltaic solar absorbers, photoelectrochemical cells, semiconductor light‐emitting diodes, and transparent conducting materials. We have also summarized the general workflow of HT computational screening, released workhorse models, and existing material databases. Finally, we offer perspectives for future research with a hope that this study could inspire new ideas for computational‐driven optoelectronic semiconductor discovery in the HT routine.This article is categorized under: Structure and Mechanism &gt; Computational Materials Science

Don't Forget Langmuir-Blodgett Films 2020: Interfacial Nanoarchitectonics with Molecules, Materials, and Living Objects.

Designing interfacial structures with nanoscale (or molecular) components is one of the important tasks in the nanoarchitectonics concept. In particular, the Langmuir-Blodgett (LB) method can become a promising and powerful strategy in interfacial nanoarchitectonics. From this viewpoint, the status of LB films in 2020 will be discussed in this feature article. After one section on the basics of interfacial nanoarchitectonics with the LB technique, various recent research examples of LB films are introduced according to classifications of (i) growing research, (ii) emerging research, and (iii) future research. In recent LB research, various materials other than traditional lipids and typical amphiphiles can be used as film components of the LB techniques. Two-dimensional materials, supramolecular structures such as metal organic frameworks, and biomaterials such as DNA origami pieces are capable of working as functional components in the LB assemblies. Possible working areas of the LB methods would cover emerging demands, including energy, environmental, and biomedical applications with a wide range of functional materials. In addition, forefront research such as molecular manipulation and cell fate control is conducted in LB-related interfacial science. The LB technique is a traditional and well-develop methodology for molecular films with a ca. 100 year history. However, there is plenty of room at the interfaces, as shown in LB research examples described in this feature article. It is hoped that the continuous development of the science and technology of the LB method make this technique an unforgettable methodology.

High-speed imaging the effect of snap-off distance and squeegee speed on the ink transfer mechanism of screen-printed carbon pastes

Screen printing is the most widely used process in the production of printed electronics due to its ability to consistently transfer inks containing a wide range of functional materials onto a range of substrates. However, despite its extensive use, the mechanism by which the ink is transferred through the mesh and onto the substrate is not fully understood. Existing theories are contradictory and lack experimental validation. Therefore, high-speed imaging was used in combination with a screen-printing simulation rig that was designed to provide good optical access to study ink deposition during the screen-printing process. The variation in the four stages of ink flow through the screen, described in the theory by Messerschmitt, has been quantified with respect to changes in snap-off distance and squeegee speed. Analyses of the images were compared with measurements of the ink properties and corroborated with analyses of the prints. This has provided a better understanding of the mechanism by which the ink transfers from the mesh to the substrate and subsequently separates in screen printing. This could be used as the basis for the development of predictive algorithms, as well as to improve the understanding of how to optimize print quality and performance.

Anisotropic Nano-/Microparticles from Diversified Copolymers by Solvent-Mediated Self-Assembly.

Effective synthesis of anisotropic nano-/microparticles (APs) by the copolymers is of great significance in nanomaterials and nanotechnology. However, achieving regulation of the morphology, composition, property, and particle size of anisotropic nano-/microparticles (APs) with diversified copolymers is difficult due to complex mechanism and formation conditions. In this work, a versatile one-pot solvent-mediated self-assembly (SmSa) strategy had been proposed for the facile one-pot synthesis of shape-tunable anisotropic nano-/microparticles (StAPs). In addition, the formation mechanism of StAPs was determined through numerous characterization methods related to morphology and element distribution. The results revealed that the anisotropic architectures of StAPs were closely related to the nature of poly(methylacrylic acid-methyl methacrylate-butyl acrylate) (L1) and poly(butyl acrylate-styrene) (L2) polymer chains imparted by polymer blocks of different domains. Therefore, the ordered assembly of the rigid and hydrophobic L2 polymer chains in micelles consisting of the flexible and amphiphilic L1 and solvent could be successfully carried out under the mediation of increasing solvent polarity and the strong adsorption of poly(vinylpyrrolidone) for L2. Furthermore, the developed versatile SmSa strategy and the obtained StAPs play an essential role in the development of nanoscience and nanotechnology. Particularly given its adjustable emulsifying properties at different pH values, as well as numerous sites for further modification by fluorescent or other components, it can be employed to synthesize a wide range of functional materials.

Poly(3-hexylthiophene) nanowhiskers filler in poly(ε-caprolactone) based nanoblends as potential bioactive material

The inclusion of a polymeric nanofiller with distinctive optoelectronic properties within a well-processable polymer matrix has enabled the fabrication of a wide range of functional materials. However, most of recent works focused on the characterization of the entire composite, without taking into account the effects of the matrix in the morphology of the nanofillers. This paper reports a comprehensive study about the dispersion of poly(3-hexylthiophene) (P3HT) nanowhiskers (NWs) within a poly(ε-caprolactone) (PCL) matrix, yielding a structurally defined nanoblend that could be applied as photoactive material for tissue engineering. NW formation through P3HT crystallization/aggregation was investigated within anisole solutions of PCL by UV-vis spectroscopy, while the excitation bandwidth and the resonant Coulomb coupling constant were calculated by using a non-isothermal variation of the Avrami’s law. The presence of PCL was demonstrated to increase the rate of P3HT crystallization, and determined the assembly of well-defined NWs, featuring a larger conjugation length than that characteristic of nanocrystals obtained from pure P3HT. P3HT-PCL films presented the semicrystalline morphology typical of PCL, with aggregates of P3HT NWs mainly concentrating at the boundaries of PCL spherulites, and thus forming a semiconducting polymer network that expands through a biodegradable polymer matrix.

Pentafluorosulfanyl group: an emerging tool in optoelectronic materials

The pentafluorosulfanyl (SF5) moiety has emerged as a versatile tool for tailoring optoelectronic properties in a wide range of functional materials.

Tailored Functional Surfaces Using Nanoparticle and Protein "Nanobrick" Coatings.

Surface properties are an essential feature in a wide range of functional materials. In this article, we summarize strategies developed in our group that employ nanoparticles and proteins as nanobricks to create thin-film coatings on surfaces. These coatings contain tailorable surface functionality based on the properties of the predesigned nanobricks, parlaying both the chemical and structural features of the precursor particles and proteins. This strategy is versatile, providing the rapid generation of both uniform and patterned coatings that provide "plug-and-play" customizable surfaces for materials and biomedical applications.