Tunable Properties Research Articles

Synthesis of Dendronized Polymers via a “m+n” Grafting‐onto Strategy with Reaction‐Enhanced Reactivity of Intermediates (RERI) Mechanism

Comprehensive SummaryDendronized polymers (DenPols) with tunable shape and surface property have been recognized as a type of promising unimolecular nanomaterials. However, it still has lacked a rapid and efficient approach to the facile synthesis of DenPols with high‐generation and well‐defined structures. Herein, we report a “m+n” grafting‐onto strategy combined with the copper‐catalyzed azide‐alkyne cycloaddition (CuAAC) reaction with reaction‐enhanced reactivity of intermediates (RERI) mechanism for synthesizing DenPols Gm+n by attaching n‐generation dendrons (Gn) onto the m‐generation DenPols Gm. In this “m+n” grafting‐onto strategy, the DenPols Gm (m = 1, 2) bearing 1,3‐triazido branches on the repeating unit were capable of RERI effect that guaranteed the CuAAC reaction in an extremely efficient way with ultrafast kinetics to synthesize third‐, fourth‐ and fifth‐generation DenPols (G1+2, G1+3, G1+4, G2+2, and G2+3) with near quantitative grafting density and narrow distribution. Moreover, these resultant DenPols Gm+n had more terminal groups per repeating unit due to the three branches of 1,3‐triazido structure, exhibiting valuable potential opportunities for molecular surface engineering. The development of this “m+n” grafting‐onto strategy with RERI mechanism not only presents a new avenue for ultrafast preparing DenPols but also holds great promise for preparing unimolecular materials with more functional terminal groups.

Chain Shuttling Enantioselective Polymerization: An Effective Strategy for Synthesizing Stereoblock Polythioethers.

Herein, we propose to synthesize stereoblock polythioethers through the chain shuttling enantioselective ring-opening polymerization (ROP) of thiiranes. The use of diastereoisomeric dinuclear Cr complexes with optimized steric hindrance allowed the production of polythioethers with both a head-to-tail content and isotacticity of >99%. In particular, the introduction of dithiols enabled the synthesis of stereoblock polythioethers via a chain shuttling process, thus producing sulfhydryl-telechelic polythioethers with tunable thermal properties. Experimental results and density functional theory calculations indicate that the configuration of the chiral axle of the dinuclear Cr complex determines the enantioselectivity of the asymmetric ROP of thiiranes.

Terahertz conductivity of two-dimensional materials: a review.

Two-dimensional (2D) van der Waals materials are shaping the landscape of next-generation devices, offering significant technological value thanks to their unique, tunable, and layer-dependent electronic and optoelectronic properties. Time-domain spectroscopic techniques at terahertz (THz) frequencies offer noninvasive, contact-free methods for characterizing the dynamics of carriers in 2D materials. They also pave the path toward the applications of 2D materials in detection, imaging, manufacturing, and communication within the increasingly important THz frequency range. In this paper, we overview the synthesis of 2D materials and the prominent THz spectroscopy techniques: THz time-domain spectroscopy (THz-TDS), optical pump THz probe (OPTP) technique, and optical pump--probe (OPP) THz spectroscopy. Through a coalescence of experimental findings, numerical simulation, and theoretical analysis, we present the current understanding of the rich ultrafast physics of technologically significant 2D materials: graphene, transition metal dichalcogenides, MXenes, perovskites, topological 2D materials, and 2D heterostructures. Finally, we offer a perspective on the role of THz characterization in guiding future research and in the quest for ideal 2D materials for new applications.

High-Fidelity Direct Ink Writing of Poly(vinylphosphonate)-Reinforced Polysaccharide Inks with Tunable Properties

High-Fidelity Direct Ink Writing of Poly(vinylphosphonate)-Reinforced Polysaccharide Inks with Tunable Properties

Recent Advances of Macrostructural Porous Silicon for Biomedical Applications.

Porous silicon (pSi) has gained substantial attention as a versatile material for various biomedical applications due to its unique structural and functional properties. Initially used as a semiconductor material, pSi has transitioned into a bioactive platform, enabling its use in drug delivery systems, biosensing, tissue engineering scaffolds, and implantable devices. This review explores recent advancements in macrostructural pSi, emphasizing its biocompatibility, biodegradability, high surface area, and tunable properties. In drug delivery, pSi's potential for controlled and sustained release of therapeutic agents has been well-studied, making it suitable for chronic disease treatment. Innovative approaches, like microneedle arrays and hybrid drug delivery systems, are highlighted, along with challenges, such as scalability and stability, in biological environments. pSi-based biosensors offer exceptional sensitivity for detecting biomarkers, benefiting early disease diagnosis. In tissue engineering, fibrous and particulate pSi scaffolds mimic the extracellular matrix, promoting cell proliferation and tissue regeneration. pSi is also gaining momentum in orthopedic implants, demonstrating the potential for bone regeneration. Despite its promise, challenges like mechanical strength, scalability, and long-term stability must be addressed. Looking forward, future research should focus on optimizing production methods, enhancing stability, and exploring hybrid materials for pSi, paving the way for its widespread clinical use in personalized medicine, advanced drug delivery, and next-generation biosensors and implants.

Tuning Electrical Conductivity and Ultrafast Optical Nonlinearity of Reduced-GO Films Ablated by Femtosecond Laser Direct Writing

Carbon-based nanomaterials with excellent electrical and optical properties are highly sought after for a plethora of hybrid applications, ranging from advanced sustainable energy storage devices to opto-electronic components. In this contribution, we examine in detail the dependence of electrical conductivity and the ultrafast optical nonlinearity of graphene oxide (GO) films on their degrees of reduction, as well as the link between the two properties. The GO films were first synthesized through the vacuum filtration method and then reduced partially and controllably by way of femtosecond laser direct writing with varying power doses. Subsequently, the four-point probe measurements of the reduced-GO (r-GO) films were demonstrated to exhibit superior resistivity and electrical conductivity compared with the pristine-GO counterpart. It was found that the conductivity of the film increases and then decreases with increasing ablation laser power (P), and GO was completely reduced at P = 100 mW, with a resistivity and electrical conductivity of 1.09 × 10−3 Ω·m and 9.19 × 102 S/m, respectively. GO was over-reduced at P = 120 mW, with its resistivity and electrical conductivity being 3.72 × 10−3 Ω·m and 2.69 × 102 S/m, respectively. We further tested the ultrafast optical nonlinearity (ONL) of the as-prepared pristine and reduced GO with the femtosecond Z-scan technique. The results show that the behavior of ONL is reversed whenever GO is reduced in a controlled manner. More interestingly, the higher the ablation laser power is, the stronger the optical nonlinearity of r-GO is. In particular, the nonlinear absorption and refraction coefficients of the r-GO films reach up to 3.26 × 10−8 m/W and −1.12 × 10−13 m2/W when P = 120 mW. The nonlinear absorption and refraction coefficients reach 1.9 × 10−8 m/W and −3 × 10−13 m2/W, respectively, for P = 70 mW. GO/r-GO thin films with tunable photovoltaic response properties have potential for a wide range of applications in microelectronic circuits, energy, and environmental sustainability.

Gastric Cancer Models Developed via GelMA 3D Bioprinting Accurately Mimic Cancer Hallmarks, Tumor Microenvironment Features, and Drug Responses.

Current in vitro models for gastric cancer research, such as 2D cell cultures and organoid systems, often fail to replicate the complex extracellular matrix (ECM) found in vivo. For the first time, this study utilizes a gelatin methacryloyl (GelMA) hydrogel, a biomimetic ECM-like material, in 3D bioprinting to construct a physiologically relevant gastric cancer model. GelMA's tunable mechanical properties allow for the precise manipulation of cellular behavior within physiological ranges. Genetic and phenotypic analyses indicate that the 3D bioprinted GelMA (3Db) model accurately mimics the clinical tumor characteristics and reproduces key cancer hallmarks, such as cell proliferation, invasion, migration, angiogenesis, and the Warburg effect. Comparisons of gene expression and drug responses between the 3Db model and patient-derived xenograft models, both constructed from primary gastric cancer cells, validate the model's clinical relevance. The ability of the 3Db model to closely simulate in vivo conditions highlights its crucial role in identifying treatment targets and predicting patient-specific responses, showcasing its potential in high-throughput drug screening and clinical applications. This study is the first to report the pivotal role of GelMA-based 3D bioprinting in advancing gastric cancer research and regenerative medicine.

Doping Tunable CDW Phase Transition in Bulk 1T-ZrSe2.

Tunable electronic properties in transition metal dichalcogenides (TMDs) are essential to further their use in device applications. Here, we present a comprehensive scanning tunneling microscopy and spectroscopy study of a doping-induced charge density wave (CDW) in semiconducting bulk 1T-ZrSe2. We find that atomic impurities that locally shift the Fermi level (EF) into the conduction band trigger a CDW reconstruction concomitantly to the opening of a gap at EF. Our findings shed new light on earlier photoemission spectroscopy and theoretical studies of bulk 1T-ZrSe2 and provide local insight into the electron-doping-mediated CDW transition observed in semiconducting TMDs.

Recent progress in synthesis and properties of two-dimensional boron carbon nitride for application in energy storage devices

Abstract Two-dimensional (2D) Boron Carbon Nitride (BCN) has recently gained significant attention as a convoluted ternary system owing to its remarkable capability to exhibit a wide range of finely tunable physical, chemical, optical, and electrical properties. In this review, we discuss a variety of stable structure forms of BCN nanosheets. In addition, this review provides recent approaches for synthesizing BCN nanostructures, and properties of BCN derivatives. BCN is a promising material for sustainable energy and energy storage devices. Since BCN application is a challenge in the field of energy, we present potential applications of BCN in the field of energy including supercapacitors and batteries, wastewater treatment, electrochemical sensing, and gas adsorption.

Integration of Motion and Stillness: A Paradigm Shift in Constructing Nearly Planar NIR-II AIEgen with Ultrahigh Molar Absorptivity and Photothermal Effect for Multimodal Phototheranostics.

The two contradictory entities in nature often follow the principle of unity of opposites, leading to optimal overall performance. Particularly, aggregation-induced emission luminogens (AIEgens) with donor-acceptor (D-A) structures exhibit tunable optical properties and versatile functionalities, offering significant potential to revolutionize cancer treatment. However, trapped by low molar absorptivity (ε) owing to the distorted configurations, the ceilings of their photon-harvesting capability and the corresponding phototheranostic performance still fall short. Therefore, a research paradigm from twisted configuration to near-planar structure featuring a high ε is urgently needed for AIEgens development. Herein, by introducing the strategy of "motion and stillness" into a highly planar A-D-A skeleton, we successfully developed a near-infrared (NIR)-II AIEgen of Y5-2BO-2BTF, which boasts an impressive ε of 1.06 × 105 M-1 cm-1 and a photothermal conversion efficiency (PCE) of 77.8%. The modification of steric hindrance on the benzene ring in the acceptor unit of the aggregation-caused quenching counterpart Y5-2BO, to a meta-CF3-substituted naphthyl, leads to reversely staggered packing and various intermolecular noncovalent conformational locks in Y5-2BO-2BTF ("stillness"). Furthermore, the -CF3 moiety acted as a flexible motion unit with an ultralow energy barrier, significantly facilitating the photothermal process in loose Y5-2BO-2BTF aggregates ("motion"). Accordingly, Y5-2BO-2BTF nanoparticles enabled tumor eradication and pulmonary metastasis inhibition through NIR-II fluorescence-photoacoustic-photothermal imaging-navigated type I photodynamic-photothermal therapy. This work provides the first evidence that the highly planar conformation with a reversely staggered stacking arrangement could serve as a novel molecular design direction for AIEgens, shedding new light on constructing superior phototheranostic agents for bioimaging and cancer therapy.

Copper Benzene‐1,3,5‐Tricarboxylate Metal‐Organic Framework Performance as a Heterogeneous Catalyst for Biodiesel Production

ABSTRACTThe increasing demand for sustainable fuels has driven extensive research into biodiesel production, which typically relies on the use of active catalysts to facilitate the transesterification of oils. While homogeneous catalysts are commonly employed, they pose challenges in terms of recyclability and environmental impact, leading to growing interest in heterogeneous catalysts. Among these, metal‐organic frameworks (MOFs) have gained attention due to their high surface area and tuneable properties. This study investigates the performance of a copper benzene‐1,3,5‐tricarboxylate (CuBTC) MOF as an effective heterogeneous catalyst for biodiesel production. CuBTC was synthesised via solvothermal method and thoroughly characterised using scanning electron microscopy to examine the morphology, powder X‐ray diffraction to determine the crystalline structure, and Fourier transform infrared spectroscopy to identify the functional groups. The synthesised CuBTC has an octahedral morphology and successfully catalysed biodiesel production with unsaturated fatty acids within the C16 to C18 range, achieving a yield of 78.6% using 1 wt.% CuBTC and a 10:1 methanol‐to‐oil molar ratio. The iodine value of the produced biodiesel was 59.3 g I/g, and the higher heating value was 39.2 MJ/kg. Recycled CuBTC maintained its efficacy, yielding 76.6% and 63.4% fatty acid methyl esters in the first and second recycling runs, respectively, with 16.6% and 15.3% of C16 to C18 fatty acids. The produced biodiesel met quality standards outlined in EN 14214, highlighting CuBTC's potential for sustainable biodiesel production.

Plasmon-Enhanced CO2 Reduction to Liquid Fuel via Modified UiO-66 Photocatalysts

Metal–organic frameworks (MOFs) have emerged as versatile materials with remarkably high surface areas and tunable properties, attracting significant attention for various applications. In this work, the modification of a UiO-66 MOF with metal nanoparticles (NPs) is investigated for the purpose of enhancing its photocatalytic activity for CO2 reduction to liquid fuels. Several NPs (Au, Cu, Ag, Pd, Pt, and Ni) were loaded into the UiO-66 framework and employed as photocatalysts. The synergistic effects of plasmonic resonance and MOF characteristics were investigated to improve photocatalytic performance. The synthesized materials were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS), confirming the successful integration of metal NPs onto the UiO-66 framework. Morphological analysis revealed distinct distributions and sizes of NPs on the UiO-66 surface for different metals. Photocatalytic CO2 reduction experiments demonstrated enhanced activity of plasmonic MOFs, yielding methanol and ethanol. The findings revealed by this study provide valuable insights into tailoring MOFs for improved photocatalytic applications through the incorporation of plasmonic metal nanoparticles.

Electrochemical Switching of Laser-Induced Graphene/Polymer Composites for Tunable Electronics

Laser reduction of graphene oxide (GO) is a promising approach for achieving flexible, robust, and electrically conductive graphene/polymer composites. Resulting composite materials show significant technological potential for energy storage, sensing, and bioelectronics. However, in the case of insulating polymers, the properties of electrodes show severely limited performance. To overcome these challenges, we report on a post-processing redox treatment that allows the tuning of the electrochemical properties of laser-induced rGO/polymer composite electrodes. We show that the polymer substrate plays a crucial role in the electrochemical modulation of the composites’ properties, such as the electrode impedance, charge transfer resistance, and areal capacitance. The mechanism behind the reversible control of electrochemical properties of the rGO/polymer composites is the cleavage of polymer chains in the vicinity of rGO flakes during redox cycling, which exposes rGO active sites to interact with the electrolyte. Sequential redox cycling improves composite performance, allowing the development of devices such as electrolyte-gated transistors, which are widely used in chemical sensing applications. Our strategy enables the engineering of the electrochemical properties of rGO/polymer composites by post-treatment with dynamic switching, opening up new possibilities for flexible electronics and electrochemical applications having tunable properties.

Polarization-dependent vibrational strong coupling in a metamaterial

Abstract We report on polarization-dependent vibrational strong coupling between vibrational transitions and the electromagnetic mode of a molecule-embedded metamaterial cavity. Our metamaterial cavity consists of a modified trilayer composed of a metal-insulator-metal, where an infrared-activated polymer layer is sandwiched between an array of linear antennae on top and a continuous metal film at the bottom. In comparison with previous reports, the coupling between the metamaterial resonance and the vibrational modes of the polymer spacer layer reveals three distinct dips corresponding to upper and lower polaritons, and an additional dip attributed to the emergence of dark states. Using polarization-selective reflectivity simulation of the cavity, we analyze their response to different light polarization and find two orthogonally polarized optical systems with different coupling strengths, one strongly coupled and one weakly coupled. The strong coupling gives rise to the formation of lower and upper polaritons, while dark states emerge because of weak coupling. The ability to engineer new physical systems with tunable properties can pave the way for ultrasensitive vibrational spectroscopy, infrared photonic devices, chemical reaction control, and quantum information processing.

On-demand spatial modes and vortex beams from a visible Pr:YLF orbital Poincaré laser with a hybrid pumping scheme

The controlled visible spatial modes and vortex beams with tunable properties are highly sought after in cutting-edge applications, such as optical communication. In this study, by utilizing a hybrid pumping scheme, we demonstrate an ultra-compact, 607 nm orbital Poincaré laser based on a diode-pumped Pr:YLF laser. The system can generate various structured modes, including Laguerre-Gaussian (LG), Hermite-Gaussian (HG), and Hermite-Laguerre-Gaussian (HLG), all of which are mapped onto a first-order orbital Poincaré sphere. A numerical analysis of the coherent superposition of HG modes with varying phases is in complete agreement with the experimental results. The handedness of the generated vortex beam can be selectively controlled by precisely adjusting the angle of output coupler. In comparison to other schemes, the hybrid pumping scheme offers advantages of high precision and excellent tunability, enabling the emitting of high-order HG modes, LG modes, along with a wide range of spatial modes on the orbital Poincaré sphere. Our scheme can also be extended to different gain media, which could lead to the creation of structured beams with richer wavelength, offering a promising platform for innovative studies on multidimensional light-field control.

Recent Advances in the Synthesis, Characterization, and Application of Carbon Dots in the Field of Wastewater Treatment: A Comprehensive Review

Carbon dots (CDs), as a revolutionary nanomaterial, exhibit unique advantages in terms of wastewater treatment, offering new opportunities for the development of water treatment technologies due to their simple synthesis methods, excellent biocompatibility, tunable optical properties, and favorable environmental performance. This review systematically discusses the synthesis methods, structural characteristics, and application progress of carbon dots in wastewater treatment, highlighting several key findings. (1) Excellent adsorption performance: CDs can effectively remove heavy metal ions, dyes, and organic pollutants from water. (2) Outstanding photocatalytic performance: Some carbon-dot-enhanced photocatalytic systems can efficiently remove pollutants under visible light. (3) Exceptional selective detection ability: CDs are capable of highly sensitive detection of heavy metals and organic pollutants in water, with the detection limits reaching the nanomolar level. (4) Enhanced membrane separation performance: The high water flux and excellent selectivity of carbon-dot-modified membranes make them suitable for efficient water treatment and water quality separation. (5) Enhancement of biological treatment: In biological treatment systems, CDs can significantly improve the microbial activity and electron transfer efficiency to enhance the efficiency of biological degradation processes. (6) Sustainable utilization of waste as a raw material and regeneration of CDs are conducive to reducing the cost of preparation of CDs. These findings indicate that CDs have broad application potential in wastewater treatment. Furthermore, this review looks ahead to the future development directions of CDs in wastewater treatment, proposing potential innovations in catalytic performance enhancement, cost control, and practical applications, aiming to provide important references and guidance for future research and industrial application of CDs in wastewater treatment.

Nano carbon powder‐multiwalled carbon nanotubes/poly(vinylidene fluoride) percolating composites with low‐percolation binary functional phases and negative permittivity

AbstractPolymer percolating composites with negative permittivity via the construction of percolating structures are of great interest in electromagnetism. In this study, nano carbon powder‐multiwalled carbon nanotubes/poly(vinylidene fluoride) (CP‐MWCNTs/PVDF) composites comprising binary functional phases CP‐MWCNTs were fabricated using hot‐pressing method. The composites achieved both low percolation threshold and tunable negative permittivity properties across the entire frequency range of testing. Percolation phenomenon was observed as functional phases content reaching 5 wt%, which was reflected as the establishment of percolation network and the occurrence of electrical percolation, resulting in a shift toward metal‐like conduction mechanism. Additionally, the notably low percolation threshold can be ascribed to the synergistic effect between the binary functional phases. The plasma oscillation of free electrons within conductive percolation network plays a crucial role in achieving negative permittivity, a phenomenon that can be elucidated using the Drude model from the free electron theory. Furthermore, analyses of the impedance and equivalent circuit illuminate the connection between percolation phenomenon and dielectric behavior. These findings further reveal the influence of functional phases' morphology and composition on percolation behavior and negative permittivity properties, while expanding the application of polymer‐based percolating composites in electromagnetic devices.Highlights Tunable negative permittivity related to plasma oscillation is achieved. Binary functional phases exhibit a low percolation threshold. Synergistic effect of functional phases leads to low percolation threshold.

Photo-Crosslinking Hydrogel Based on Porcine Small Intestinal Submucosa Decellularized Matrix/Fish Collagen/GelMA for Culturing Small Intestinal Organoids and Repairing Intestinal Defects

Organoid technology, as an innovative approach in biomedicine, exhibits promising prospects in disease modeling, pharmaceutical screening, regenerative medicine, and oncology research. However, the use of tumor-derived Matrigel as the primary method for culturing organoids has significantly impeded the clinical translation of organoid technology due to concerns about potential risks, batch-to-batch instability, and high costs. To address these challenges, this study innovatively introduced a photo-crosslinkable hydrogel made from a porcine small intestinal submucosa decellularized matrix (SIS), fish collagen (FC), and methacrylate gelatin (GelMA). The cost-effective hydrogel demonstrated excellent biocompatibility, tunable mechanical properties, rapid gelation properties, and low immunogenicity. Importantly, the proliferation and differentiation capacities of small intestinal organoids cultured in hydrogel were comparable to those in Matrigel, with no significant disparity observed. Furthermore, after one week of transplantation in nude mice, the hydrogel–organoid complex exhibited sustained structural and functional stability while preserving the differentiation characteristics of small intestinal organoids. Our study also demonstrated the effective potential of FC/SIS/GelMA hydrogel in accelerating the repair process of small intestinal defects, reducing the area of scar formation, and promoting the regeneration of both intestinal villi and smooth muscle tissue. In summary, this study presents a novel protocol for culturing small intestinal organoids, offering potential implications for future clinical applications and serving as an experimental foundation for the development of tissue-engineered intestines based on small intestinal organoids.

Exploring Natural Deep Eutectic Solvents (NADES) for Enhanced Essential Oil Extraction: Current Insights and Applications

Essential oils (EOs) are highly valued in the cosmetic and food industries for their diverse properties. However, traditional extraction methods often result in low yields, inconsistent compositions, lengthy extraction times, and the use of potentially harmful solvents. Natural deep eutectic solvents (NADES) have emerged as promising alternatives, offering advantages such as higher efficiency, cost-effectiveness, biodegradability, and tunable properties. This review explores the application of NADES in enhancing EO extraction, focusing on current methodologies, key insights, and practical applications. It examines the factors that influence EO extraction with NADES, including the optimization of their physicochemical properties, extraction techniques, operational conditions, and the role of sample pretreatment in improving efficiency. Additionally, this review covers the chemical characterization and biological activities of EOs extracted using NADES. By providing a comprehensive overview, it highlights the potential of NADES to improve EO extraction and suggests directions for future research in this field.

Revealing the Dynamics of Sustainable Epoxy-Acrylate Networks from Recycled Plastics Blends and Oligomeric Lignin Precursors.

The growing pursuit of carbon circularity in material fabrication has led to the increased use of recycled and biobased resources, especially in epoxy resin systems. Fossil-based bisphenols are being replaced with recycled bisphenol A (r-BPA) and lignin derivatives, both derived from previous processes. In this study, r-BPA was chemically recycled from end-of-life televisions, then converted into r-DGEBA and r-DAGBA through glycidylation and acrylic acid ring-opening. These monomers were used to create six thermosets by reacting Jeffamine D230 with r-DGEBA/r-DAGBA in varying epoxide:acrylate ratios. Acrylates introduced thermo-reversible β-amino esters, enabling dynamic bonding in the epoxy formulation. To increase biobased content, glycidylated depolymerized lignin (GDL) was added to produce five additional polymers. The crosslinked networks were thoroughly characterized, examining their thermomechanical properties and establishing a structure-property relationship. The dissociative acrylate-amine interactions allowed for reversible crosslinks under specific thermal conditions, enabling shape programming and crosslink reversibility. The study demonstrates that incorporating recycled and biobased aromatic monomers facilitates the creation of dynamic, crosslinked structures with tunable properties. This represents progress toward versatile, reusable, and circular materials.