Advanced Functional Materials Research Articles

Cation‐Alginate Complexes and Their Hydrogels: A Powerful Toolkit for the Development of Next‐Generation Sustainable Functional Materials

AbstractThe use of materials from renewable sources instead of fossil fuels is a crucial step forward in the industrial transition toward sustainability. Among polysaccharides, alginate stands out as a versatile and eco‐friendly candidate due to its ability to form functional complexes with cations. This review provides an up‐to‐date and comprehensive description of alginate complexation with specific cations, focusing on how interaction forces can be harnessed to tailor the physicochemical properties of cation‐alginate‐based functional materials. Methodologies and approaches for the development and multiscale characterization of these materials are introduced and discussed. Alginate complexes with mono‐, di‐, tri‐, and tetravalent cations (namely Ag+, Mg2+, Ca2+, Sr2+, Ba2+, Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Pb2+, UO22+, Cr3+, Fe3+, Al3+, Ga3+, Y3+, La3+, Ce3+, Nd3+, Eu3+, Tb3+, Gd3+, Zr4+, Th4+) are reviewed. Each cation is discussed individually, highlighting how it can uniquely influence the material properties thereby unlocking new potentials for the design of advanced functional materials. Key challenges and opportunities in applying these complexes across diverse fields, such as biomedicine, environmental remediation, food additives and supplements, flame retardants, sensors, supercapacitors, catalysis, and mechanical isolators are assessed, providing evidence of the transformative potential of cation‐alginate complexes for tackling global challenges and advancing cutting‐edge technologies.

Pd(NHC)(μ-Cl)Cl]2: The Highly Reactive Air- and Moisture-Stable, Well-Defined Pd(II)-N-Heterocyclic Carbene (NHC) Complexes for Cross-Coupling Reactions.

ConspectusPalladium-catalyzed cross-coupling reactions owing to their high specificity and superb chemoselectivity represent a powerful tool for the rapid construction of C-C and C-X bonds across various areas of chemical research, including pharmaceutical development, polymer and agrochemical industries, bioactive natural products, and advanced functional materials, rendering them indispensable for modern synthetic chemists. The major driving force for the advances in this critical field is the design of increasingly more reactive and more selective ligands and precatalysts that aim not only to address challenging cross-coupling processes but also to achieve optimal reactivity, selectivity, and functional group compatibility under mild, user-friendly, operationally simple, and broadly applicable conditions. In this context, Pd(II)-N-heterocyclic carbene complexes (NHC = N-heterocyclic carbene) have garnered prevalent attention among practitioners of organic synthesis due to their unique electronic and steric characteristics that are unmatched among other ligands. In particular, the superior σ-donating ability of NHC ligands in conjunction with conformational flexibility as well as the ease of steric and electronic modification and high stability to air and moisture enable highly effective fundamental elementary steps in catalytic cycles and facile formation of well-defined complexes.The key factor in the design of well-defined, air- and moisture-stable Pd(II) precatalysts involves the incorporation of supporting ligands, which are essential for ensuring the stability of Pd(II)-NHC complexes and facile activation of Pd(II)-NHC precatalysts to catalytically active monoligated Pd(0)-NHC species under the reaction conditions. Notably, [Pd(NHC)(μ-Cl)Cl]2 chloro dimers, which can be readily synthesized via a one-pot, atom-economic process, are the most reactive Pd(II)-NHC complexes synthesized to date. These well-defined, air- and moisture-stable dimers readily dissociate to monomers and are activated to Pd(0)-NHC catalysts under both mild and strong base conditions, showcasing enhanced reactivity and selectivity among their Pd(II)-NHC counterparts. This balance between high, operationally simple stability, which is characteristic of Pd(II) complexes together with the ease of activation to the strongly nucleophilic Pd(0)-NHC catalysts, renders [Pd(NHC)(μ-Cl)Cl]2 the most reactive Pd(II)-NHC precatalysts developed to date for a broad range of general cross-coupling processes, including C-X, C-O, C-N, and C-S activation and enabling the direct late-stage functionalization of complex compounds decorated with a wide range of sensitive functional groups.In this Account, we outline [Pd(NHC)(μ-Cl)Cl]2 as a highly reactive Pd(II)-NHC precatalyst that should be routinely used as the first choice Pd complexes for a wide range of challenging cross-coupling reactions. The advancements in this field over the past 20 years emphasize the critical role of catalyst design to achieve optimal reactivity. Consequently, [Pd(NHC)(μ-Cl)Cl]2 chloro dimers should be recommended as the go-to complexes in the powerful toolbox of Pd-catalyzed cross-coupling reactions. These now commercially available Pd(II)-NHC complexes see widespread use across the synthetic chemistry community and enable the accelerated application of challenging cross-couplings in the synthesis of new molecules.

Bacterial Cellulose Applications in Electrochemical Energy Storage Devices.

Bacterial cellulose (BC) is produced via the fermentation of various microorganisms. It has an interconnected 3D porous network structure, strong water-locking ability, high mechanical strength, chemical stability, anti-shrinkage properties, renewability, biodegradability, and a low cost. BC-based materials and their derivatives have been utilized to fabricate advanced functional materials for electrochemical energy storage devices and flexible electronics. This review summarizes recent progress in the development of BC-related functional materials for electrochemical energy storage devices. The origin, components, and microstructure of BC are discussed, followed by the advantages of using BC in energy storage applications. Then, BC-related material design strategies in terms of solid electrolytes, binders, and separators, as well as BC-derived carbon nanofibers for electroactive materials are discussed. Finally, a short conclusion and outlook regarding current challenges and future research opportunities related to BC-based advanced functional materials for next-generation energy storage devices suggestions are proposed.

Super-hybrid transition metal sulfide nanoarrays of NiS nanoparticle/WS2 nanosheet/Ni3S4 nanoparticle with abundant plane- and edge-type active interfaces for robust all-pH hydrogen evolution

Transition metal sulfides (TMSs) are primitive composition of biocatalysts that are active for molecular hydrogen production. The development of non-precious TMSs with appropriate spatial ordering has great potentials to contribute high-level hydrogen generation. Herein, super-hybrid transition metal sulfide nanoarrays of NiS nanoparticle/WS2 nanosheet/Ni3S4 nanoparticle (Super-NiS/WS2/Ni3S4) with high spatial ordering and abundant plane- and edge-type WS2-NiS and WS2-Ni3S4 heterointerfaces were elaborately constructed though manipulating the sequential dissociation of phosphotungstic acid (PW12) as W precursor and nickel foam as Ni precursor in one pot. When evaluated for the electrocatalytic hydrogen evolution reaction (HER), the Super-NiS/WS2/Ni3S4 only required overpotentials of 57, 95, and 151 mV to drive HER in alkaline, acid, and neutral media, respectively, and presented favorable reaction kinetics and test stability. The theoretical and experimental results verify the adsorption and dissociation of water molecules are preferential on WS2-plane-related heterointerfaces. The Gibbs free energy (ΔGH*) analysis indicated the WS2-plane-NiS interface is thermodynamically optimal for HER. Moreover, the collaborations of the abundant plane- and edge-type active interfaces, the open nanosheet-based vertical array, and the phosphorus doping in Super-NiS/WS2/Ni3S4 strengthen mass transport and electron transfer in electrocatalysis. The polyoxometalates-based synthetic strategy will inspire the new vision for the rational design and construction of advanced functional materials.

Enhanced optical, dielectric and transport properties in PVDF based (La0.5Bi0.5FeO3)0.5-(BaTiO3)0.5 composites

In this comprehensive study, we investigated PVDF composites incorporating LaBiFeO3-BaTiO3 (LaBiFO-BaTO) perovskite fillers, focusing on their structural, optical, dielectric, impedance, modulus and DC-conductivity properties. The fabrication involved precise preparation of LaBiFO-BaTO perovskite via solid-state reaction, ensuring phase purity conducive to composite integration. Using a solution casting method, PVDF films with varying LaBiFO-BaTO concentrations (5 %, 10 %, and 15 % wt) were successfully synthesized. XRD confirmed the synthesis of single-phase LaBiFO-BaTO and revealed structural modifications in PVDF composites, highlighting improved filler-matrix interactions at higher concentrations. Scanning electron microscopy and atomic force microscopy depicted the morphological evolution and surface roughness changes with increasing filler content. Optical studies indicated a red shift in absorption spectra with higher LaBiFO-BaTO concentrations, correlating with a decrease in the direct band gap energy of the composites. Electrical characterization demonstrated enhanced dielectric properties and impedance behaviour in PVDF/LaBiFO-BaTO composites, suggesting their suitability for applications in capacitors and optoelectronic devices. This systematic investigation provides valuable insights into optimizing PVDF-based composites for advanced functional materials. The composites exhibit enhanced dielectric permittivity at room temperature, attributed to space charge polarization and the high dielectric constant of LaBiFO-BaTO. Dielectric loss (tanδ) remains minimal (<0.1), decreasing with frequency, indicative of low energy dissipation suitable for high-frequency applications. Further the dielectric relaxation have been examined using Havrilak-Negami model. Impedance and modulus analyses reveal temperature-dependent behaviours, with reduced impedance and enhanced charge transfer kinetics in higher concentration composites. DC conductivity measurements demonstrate increased charge transport properties with temperature, influenced by thermally activated charge hopping mechanisms. Overall, PVDF/LaBiFO-BaTO composites show promising characteristics for capacitors, sensors, and optoelectronic devices, suggesting avenues for further optimization and broader application in advanced technologies.

Advanced functional polymer materials for biomedical applications

AbstractPolymer structures are essential in biomedical applications due to their biocompatibility, biodegradability, and ability to form intricate structures on micro‐ to nanometer scales. This review, emphasizing electrospinning and phase inversion techniques, examines the fabrication strategies and chemical design of polymer structures for biomedical use. Electrospinning, particularly needleless electrospinning, produces nanofibres with high porosity and flexibility and is widely applied in tissue engineering and drug delivery. Phase inversion, including thermal, nonsolvent‐, vapor‐ and evaporation‐induced phase separation, allows precise control over polymer properties but faces challenges in terms of cooling rates and solvent characteristics. Chemical design through doping, functionalization, cross‐linking and copolymerization enhances the biocompatibility, biodegradability and mechanical properties of polymers, facilitating advanced applications in drug delivery, tissue scaffolding and biosensors. Advanced functional polymers are revolutionizing biomedical fields, offering innovative solutions for therapeutic medicine delivery, disease detection, diagnostics, and regenerative medicine. Despite remarkable progress, challenges, such as scalability, cost‐effectiveness, and environmental impact, persist. This review underscores the transformative potential of advanced polymer materials in medical treatments and advocates for continuous research and interdisciplinary collaboration to overcome existing challenges and fully exploit the capabilities of these materials in improving patient care and medical outcomes. Future perspectives highlight enhancing precision control mechanisms, integrating phase inversion with other techniques and developing large‐scale production methods to advance the field further.

Bioinspired Mechanochromic Liquid Crystal Materials: From Fundamentals to Functionalities and Applications.

Inspired by intriguing color changeable ability of natural animals, the design and fabrication of artificial mechanochromic materials capable of changing colors upon stretching or pressing have attracted intense scientific interest. Liquid crystal (LC) is a self-organized soft matter with anisotropic molecular alignment. Due to the sensitivity to various external stimulations, LC has been considered as an emerging and appealing responsive building block to construct intelligent materials and advanced devices. Recently, mechanochromic LC materials have becoming a hot topic in multifields from flexible artificial skins to visualized sensors and smart biomimetic devices. In this review, the recent progress of mechanochromic LCs is comprehensively summarized. Firstly, the mechanism and functionalities of mechanochromic LC is introduced, followed by preparation of various functional materials based on mechanochromic LCs. Then the applications of mechanochromic LCs are provided. Finally, the conclusion and outlooks of this field is given. This overview is hoped to provide inspiration in fabrication of advanced functional soft materials for scientists and engineers from multidisciplines including materials science, elastomers, chemistry, and physical science.

RETRACTION: Boroxine Nanotubes: Moisture‐Sensitive Morphological Transformation and Guest Release

AbstractRETRACTION: K. Ishikawa, N. Kameta, M. Masuda, M. Asakawa, T. Shimizu, “Boroxine Nanotubes: Moisture‐Sensitive Morphological Transformation and Guest Release,” Advanced Functional Materials 24, no. 5 (2013): 603–609, https://doi.org/10.1002/adfm.201302005.The above article, published online on 16 September 2013 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the authors; the journal Editor‐in‐Chief, Jörn Ritterbusch; and Wiley‐VCH GmbH, Weinheim. The retraction has been agreed upon authors' request and following an investigation by the National Institute of Advanced Industrial Science and Technology (AIST) due to image falsification in electron microscopy images in Figures 1g, 1h, 1i, 2a, 2b, 2c, S1a, S1b, and S1c, where the second author falsified incorrect scale bars; all affecting the interpretation of the data and research results presented.

RETRACTION: Soft Nanotubes with a Hydrophobic Channel Hybridized with Au Nanoparticles: Photothermal Dispersion/Aggregation Control of C60 in Water

AbstractRETRACTION: K. Ishikawa, N. Kameta, M. Aoyagi, M. Asakawa, T. Shimizu, “Soft Nanotubes with a Hydrophobic Channel Hybridized with Au Nanoparticles: Photothermal Dispersion/Aggregation Control of C60 in Water,” Advanced Functional Materials 23 no. 13 (2012): 1677–1683, https://doi.org/10.1002/adfm.201202160.The above article, published online on 22 October 2012 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the authors; the journal Editor‐in‐Chief, Jörn Ritterbusch; and Wiley‐VCH GmbH, Weinheim. The retraction has been agreed upon the authors' request following an investigation by the National Institute of Advanced Industrial Science and Technology (AIST), due to image falsification in electron microscopy images. In Figure 1a, the second author used an incorrect scale bar and carelessly placed incorrect scale bars in Figures 1b, 5a, 5b, and 5c. As a result, the research results presented are considered unreliable.

Polymerization-Induced Self-Assembly Providing PEG-Gels with Dynamic Micelle-Crosslinked Hierarchical Structures and Overall Improvement of Their Comprehensive Performances.

Polymer gels are fascinating soft materials and have become excellent candidates for wearable electronics, biomedicine, sensors, etc. Synthetic gels usually suffer from poor mechanical properties, and integrating good mechanical properties, adhesiveness, stability, and self-healing performances in one gel is more difficult. Herein, polymerization-induced self-assembly (PISA) providing PEG-gels with an overall improvement in their comprehensive performances is reported. PISA synthesis is carried out in PEG (solvent) to efficiently produce various nanoparticles, which are used as the nanofillers in the subsequent synthesis of PEG-gels with dynamic micelle-crosslinked hierarchical structures. Compared to hydrogels, PEG-gels show excellent long-term stability due to the nonvolatile feature of PEG solvent. The hierarchical PEG-gels (with nanofillers) exhibit better mechanical and adhesive properties than the homogeneous-gels (without nanofillers). The energy dissipation mechanism of the PEG-gels is analyzed via stress relaxation and cyclic mechanical tests. High-density hydrogen bonds between the micelles and PAA matrix can be broken and reformed, endowing better self-healing properties of the dynamic micelle-crosslinked PEG gels. This work provides a simple strategy for producing hierarchical structural gels with enhanced properties, which offers fundamentals and inspirations for the designing of various advanced functional materials.

Introducing Phosphorus into the Overcrowded Thiele's hydrocarbon Family: Unveiling Contorted Main Group Diradicaloids with Dynamic Redox Behavior

AbstractThiele's Hydrocarbons (THs) featuring a 9,10‐anthrylene core with switchable geometric and electronic configurations offer exciting possibilities in advanced functional materials. Despite significant advances in main group‐based diradicaloids in contemporary chemistry, main group THs containing an anthrylene cores have remained elusive, primarily due to the lack of straightforward synthetic strategies and the inherent high reactivity of these species. In this study, we utilize an anthracene‐based phosphine synthon to demonstrate, for the first time, a facile and high‐yielding synthetic strategy for robust P‐functionalized overcrowded ethylenes (OCEs) within the TH family. These OCEs feature a non‐symmetric environment, incorporating (thio) xanthyl and phosphaalkene termini. We systematically probe the electronic structures of these derivatives to illustrate the impact of the isolobal phosphaalkene motif on the quinoidal/diradicaloid character. Notably, the compounds exhibit dynamic redox behavior, leading to orthogonally twisted conformational changes upon oxidation, with a kinetically locked redox‐couple.

Bioinspired Molecular Scalpel for Two-Dimensional Metal-Organic Nanosheet: Design Strategies and Recent Progress.

Ultrathin two-dimensional (2D) metal-organic nanosheets (MONs) have attracted continued attention in the field of advanced functional materials. Their nanoscale thickness, high surface-to-volume ratio, and abundant accessible active sites, are superior advantages compared with their 3D bulk counterparts. Bioinspired molecular scalpel strategy is a promising method for the creation of 2D MONs, and may solve the current shortcomings of MONs synthesis. This review aims to provide a state-of-the-art overview of molecular scalpel strategies and share the results of current development to provide a better solution for MONs synthesis. Different types of molecular scalpel strategies have been systematically summarized. Both mechanisms, advantages and limitations of multiform molecular scalpel strategies have been discussed. Besides, the challenges to be overcome and the question to be solved are also introduced.

E-Skin and Its Advanced Applications in Ubiquitous Health Monitoring.

E-skin is a bionic device with flexible and intelligent sensing ability that can mimic the touch, temperature, pressure, and other sensing functions of human skin. Because of its flexibility, breathability, biocompatibility, and other characteristics, it is widely used in health management, personalized medicine, disease prevention, and other pan-health fields. With the proposal of new sensing principles, the development of advanced functional materials, the development of microfabrication technology, and the integration of artificial intelligence and algorithms, e-skin has developed rapidly. This paper focuses on the characteristics, fundamentals, new principles, key technologies, and their specific applications in health management, exercise monitoring, emotion and heart monitoring, etc. that advanced e-skin needs to have in the healthcare field. In addition, its significance in infant and child care, elderly care, and assistive devices for the disabled is analyzed. Finally, the current challenges and future directions of the field are discussed. It is expected that this review will generate great interest and inspiration for the development and improvement of novel e-skins and advanced health monitoring systems.

In Situ Construction of Highly Dispersed Pd on Cobalt Nanoparticle on Hollow Functional Cubic Graphene by Double Framework for ORR.

Developing advanced functional carbon materials is essential for electrocatalysis, caused by their vast merits for boosting many key energy conversion reactions. Herein, the covalent organic frameworks (COFs) is utilized on metal-organic frameworks (MOFs) as the template, under the controllable metal atoms thermal migration process successfully in situ constructs Pd-Co alloy nanoparticles on hollow cubic graphene. The electrocatalytic oxygen reduction reaction (ORR) evaluation showed excellent performances with a half-wave potential of 0.866V, and a limited current density of 4.975mA cm-2, that superior to the commercial Pt/C and Co nanoparticles. The contrast experiments and X-ray absorption spectrum demonstrated the aggregated electrons at highly dispersed Pd atoms on Co nanoparticle that promoted the main activities. This work not only enlightens the novel carbon materials designing strategies but also suggests heterogeneous electrocatalysis.

Inherent porosity of Zeolitic Imidazolate Framework-62 melt leading to formation of the porous melt-quenched glass

Porous glasses produced through melt-quenching of some selective metal organic frameworks like Zeolitic Imidazolate Framework-62 (ZIF-62) and ZIF-4 belong to the advanced functional materials because of their inherent porosity, ease of processing, high gas adsorption capacity and gas separation selectivity. We have delineated thermal induced modifications in the porosity features (pore size, size-distribution and pore density) of crystalline ZIF-62 from room temperature (RT) to its melt-state (> melting point, Tm) followed by its quenching, back to RT, carrying out the depth sensitive positron annihilation lifetime spectroscopy (PALS) measurements in-situ at varying temperatures (RT−Tm). On heating under vacuum, the pores' size as well as size-distribution of crystalline ZIF-62 increases up to ∼473 K as a consequence of removal of entrapped solvent molecules and nonuniform thermal expansion. At higher temperatures (∼473 −573 K), a reduction in pores’ size and size-distribution is observed due to the loss of long range ordering and volume collapse. On melting, ZIF-62 turns into a porous liquid having ∼1.4 times larger pores compared to its crystalline form. The quenching of this porous melt is fully irreversible, and results in the formation of a porous glass having the pores larger than its crystalline counterpart. The in-situ PALS investigation provides the first experimental evidence of inherent porosity in ZIF-62 melt existing at high temperature that has been predicted before through molecular dynamics simulation of the ZIFs-based melts.

Diatom biosilica modified with Ce-Tb mixed oxide twinning nanoparticles and with polyphases quasi-crystalline Tb oxide nanoparticles

In this study, we developed a novel composite material by combining natural diatom biosilica with Ce-Tb mixed oxide and polyphase quasi-crystalline Tb oxide nanoparticles. Diatom biosilica, characterised by its highly ordered three-dimensional structure and excellent thermal, mechanical, and optical properties, serves as an ideal matrix for the synthesis of advanced functional materials. The composites were extensively characterised using techniques such as SEM, TEM, TGA, EDS, XRD, FTIR, and PL spectroscopy. The results indicate significant UV absorption (250–400 nm), strong visible photoluminescence (300–500 nm), and notable anti-Stokes emission (∼420 nm) under 800 nm excitation. Additionally, the composites exhibit remarkable thermal stability and hydrophobicity, making them promising candidates for applications in optoelectronic devices, photovoltaic systems, and high-resolution display technologies.

Metal Organic Frameworks (MOFs) as Advanced Functional Materials for Food Applications

Metal Organic Frameworks (MOFs) as Advanced Functional Materials for Food Applications

Advances in Machine Learning Applications in Material Science: From Non-2D to 2D Materials

This mini-review presents recent advancements in the application of machine learning to both non-2D and 2D materials. For non-2D materials, the main focus is on construction materials, energy and environmental materials, and advanced functional materials. In the case of 2D materials, the mini-review emphasizes the role of machine learning in predicting electronic and structural properties, as well as in identifying defects and phase preferences. The mini-review underscores the crucial role that machine learning plays in advancing materials science by enabling rapid screening of materials, predicting their properties, and significantly reducing the time required for such processes.

Crafting Nanostructured Hybrid Block Copolymer-Gold Nanoparticles by Confined Self-Assembly in Evaporative Droplets.

Hybrid organic-inorganic nanostructures offer significant potential for developing advanced functional materials with numerous technological applications. However, the fabrication process is often tedious and time-consuming. This study presents a facile method for fabricating block copolymer-based photonic microspheres incorporating plasmonic gold nanoparticles. Specifically, the confined self-assembly of poly(styrene)-b-poly(2-vinylpyridine) in emulsion droplets allows the formation of spherical, noniridescent, concentric lamellar structures, i.e., onion-like particles that are subsequently infiltrated with gold salt. Using ethanol as a preferential solvent allows the loading of metal ions exclusively into the poly(2-vinylpyridine) domains, which are subsequently reduced, leading to the in situ, spatially controlled formation of gold nanoparticles. The hybrid structures exhibit a well-defined photonic bandgap and plasmonic resonance at low gold concentrations. These results demonstrate the feasibility of fabricating optically active photonic structures comprising metal nanoparticles in a block copolymer array via a simple two-step fabrication process.

Microbial Mineralization with Lysinibacillus sphaericus for Selective Lithium Nanoparticle Extraction.

Lithium is a critical mineral in a wide range of current technologies, and demand continues to grow with the transition to a green economy. Current lithium mining and extraction practices are often highly ecologically damaging, in part due to the large amount of water and energy they consume. Biomineralization is a natural process that transforms inorganic precursors to minerals. Microbial biomineralization has potential as an ecofriendly alternative to current lithium extraction techniques. This work demonstrates Lysinibacillus sphaericus biomineralization of lithium chloride to lithium hydroxide. Quantitative analysis of biomineralized lithium via the 2-(2-hydroxyphenyl)-benzoxazole fluorescence assay reveals significantly greater recovery with L. sphaericus than without. Furthermore, L. sphaericus biomineralization is specific to lithium over sodium. The nanoparticles produced were further characterized via Fourier transform infrared and transmission electron microscopy analysis as crystalline lithium hydroxide, which is an advanced functional material. Finally, ESI-LC/MS was used to identify several proteins involved in this microbial biomineralization process, including the S-layer protein. Through the isolation of L. sphaericus ghosts, this work shows that the S-layer protein alone plays a critical role in the biomineralization of crystalline lithium hydroxide nanoparticles. Through this study of microbial biomineralization of lithium with L. sphaericus, there is potential to develop innovative and environmentally friendly extraction techniques.