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Low-dielectric polymers face prominent development challenges at high frequency. Particularly, the relationship between the high-frequency dielectric loss and polymer structures remains not clear enough. Besides, the strategies for achieving low dielectric loss usually have to scarify other important materials properties, e.g., heat resistance or dimensional stability. Herein, fluorine-containing aromatic polyimides were systematically investigated. Among them, simple fluorine atom (-F) substituted polyimides exhibit remarkable low dielectric loss at high frequency (10 GHz) as well as comprehensive advantages, including near-zero thermal expansion coefficient, extremely high thermal decomposition stability, high optical transmittance and excellent mechanical properties. The fundamental mechanisms of low dielectric loss are fully discussed. Benefiting from the unique electric effect and compact size of -F group, -F substituted polyimides display low dipolar density and strongly restricted dipolar motion, contributing to a reduced permanent dipolar polarization loss. Moreover, the concept of induced dipolar polarization was introduced to illustrate the nontrivial impact of F-substituted effect on conjugated electron cloud polarization loss in aromatic polymer system. This work not only provides valuable insights for understanding the mechanism of dielectric loss at high frequency for aromatic polymers, but also opens up broader application possibilities of polyimides in microelectronic and wireless communications industries.

The novelty of this work consists of synthesizing and exploiting a heterogeneous catalyst containing ammonium chloride as part of the polymeric sponge sites for CO₂ capture. To this aim, the polymerization of 2-acryloyl(oxyethyl)trimethylammonium chloride was performed in cryo-condition, in the presence of a crosslinking agent, obtaining a lightweight macroporous freestanding material. Its efficiency in converting aromatic and aliphatic epoxides to the corresponding carbonates was successfully proved by using proton Nuclear Magnetic Resonance (¹H NMR). Remarkably, the conversion of styrene oxide (SO) to styrene carbonate (SC) reached a yield of 99 % after 24 h of reaction. The calculated yield versus the aliphatic cyclohexene oxide is 71 %. Similar results were obtained by substituting the resin counter anion with Br⁻, although the conversion kinetic was slower than the chloride. It is worth noticing that reactions took place in the mixture without adding the tetrabutylammonium bromide (TBAB), typically used as a co-catalyst to convert epoxides into carbonates. The recyclability of the as-prepared catalyst was evaluated for four reaction cycles, evidencing stable properties without significant depletion of CO₂ capture efficiency. Most importantly, the post-cleaning of the catalytic sponge is not required to be reused. Finally, the green chemistry metrics applied to the process demonstrated that our approach significantly mitigates risks and reduces environmental impact, thus elevating the overall cleanliness of our proof of concept.

A series of K-shaped bolapolyphiles, consisting of a p-terphenyl core, two polar glycerol end-groups and a swallow-tailed alkyl side-chain were synthesized and investigated. By increasing the side-chain volume an astonishing variety of very different liquid crystalline (LC) phases was observed, ranging from a rectangular (Col_rec/c2mm) and a square honeycomb (Col_squ/p4mm) via a highly complex zeolite-like octagon/pentagon honeycomb filled with additional strings of rod-bundles (Col_rec^Z/c2mm), a new 3D-hexagonal (R$\bar{3}$c) double network phase, a double and even a single network cubic phase (double gyroid Cub/Ia$\bar{3}$d and single diamond Cub/Fd$\bar{3}$m, respectively) to a correlated lamellar phase (Lam_Sm/c2mm). Though these LC structures are highly complex and there is a delicate balance of steric and geometric frustration determining the phase formation, there is only a small effect of permanent molecular chirality in the glycerol groups ((R,R)-configuration) on them, which is attributed to a slightly different packing density of uniformly chiral and racemic glycerols, but not to an effect of induced helicity. Compared to related T-shaped bolapolyphiles with a single linear n-alkyl side-chain, which form exclusively honeycomb phases, the complexity of self-assembly is enhanced for the K-shaped compounds due to a competition between the requirements of space filling, chain stretching and geometric frustration, and affected by the shape of the polar glycerol domains at the junctions.

Passive icephobic coatings attract increasing attention due to their harmless strategy for preventing undesirable ice accumulation. Slippery liquid-infused surfaces display extremely low ice adhesion (τ_ice) but are argued for their poor stabilities and longevities due to inevitable liquid consumption. Herein we reported a class of lubricated polysiloxane coatings that can maintain low τice (∼2.2 kPa) for a long time (>800 icing/deicing cycle). The coatings have slippery lubricated surfaces and switchable porous matrices loading a large amount of liquid in isolated porevoids. Such droplet-embedded structure allows the surfaces to continuously maintain highly swelling states in a self-adaptive manner, i.e., only in the conditions icing or oil consumption occur dose oil is released, and thus show excellent long-term icephobicity. Besides, these materials exhibit good mechanical properties, antifatigue, and substrate adhesion. Because the coatings can be prepared via facile and green method from cheap starting materials, we foresee their broad application prospect in many fields.

For liquid crystals (LCs) and liquid crystalline polymers (LCPs), a chiral smectic C (SmC*) phase has been mandatory for breaking the symmetry and achieving ferroelectricity. However, this SmC* phase leads to rather low spontaneous polarization (P_s, 0.1–5 mC/m²), which has limited their usage in various electronic and electro-optical applications. In this mini-review, we highlight three new types of ferroelectric LCPs with high P_s values reported in the last decade. The first system refers to the ferroelectric nematic LCs and LCPs. The large dipole moment (>9 Debye or D) and oblique molecular shape induce a polar packing of calamitic nematics. The P_s can reach as high as 40 mC/m². The second example is a ferroelectric supramolecular LCP, in which the highly polar cyano groups in the core lead to a polar structure of the hexagonal columnar phase after electric poling. The P_s can reach ∼ 20 mC/m². The third system utilizes highly dipolar sulfonyl groups (dipole moment ∼4.5 D) in the side chains of mesogen-free comb-shaped LCPs. By combining finely tuned dipolar interactions and mobile LC order, these mesogen-free comb-like LCPs have shown good potential for ferroelectricity with high P_s. These ferroelectric LCPs with high P_s will enable new electronic and electro-optical applications in the future.

Nanofibers serve as widely employed tissue engineering scaffolds in diverse biomedical applications. When implanted in vivo, it is crucial for tissue engineering scaffolds to be visualizable, enabling the monitoring of their shape, position, and performance. This capability facilitates the effective assessment of implant deformations, displacements, degradations, and functionalities. However, in many biomedical imaging techniques such as magnetic resonance imaging (MRI), the contrast of tissue engineering scaffolds is often inadequate. MRI is particularly notable for its effectiveness in imaging soft tissues. Previous endeavors to enhance the contrast of tissue engineering scaffolds in MRI have involved the use of negative contrast agents (CAs). Nonetheless, negative CAs can result in artifacts, thus favoring the preference for positive CAs due to their ability to generate clearer boundaries. In this study, we successfully prepared composite polyamide 6 nanofibrous scaffolds with ultrafine dispersion Fe(OH)₃ nanoparticles using electrospinning and in-situ growth techniques. The relaxation properties of the magnetic nanofibrous scaffolds confirmed the successful production of scaffolds suitable for positive imaging. In vitro cell seeding experiments demonstrated the efficient proliferation and adhesion of endothelial cells and fibroblasts. In vivo studies further revealed the biocompatibility and functionality of the scaffolds. These findings indicate that the prepared PA6/Fe(OH)₃ composite nanofibrous scaffolds can enable straightforward, safe, and efficient in vivo positive contrast MRI monitoring, thereby playing a pivotal role in the integration of diagnosis and treatment within tissue engineering scaffolds.

A metal-free and solvent-free method for the synthesis of quinazolin-4(3H)-ones is proposed by condensation cyclization of 2-aminobenzamides and aldehydes using 1-butyl-3-methylimida-zolium tetrafluoride ([Bmim]BF₄) as ionic liquid catalyst. In this reaction, [Bmim]BF₄ acts as both a catalyst and a solvent without need for additional catalysts and solvents. This method exhibits favorable functional group tolerance in substrates and affords a series of desired products in moderate to excellent yields. In addition, it is noteworthy that the reaction yield is still as high as 87% after [Bmim]BF₄ is recycled at least four times.

In recent years, significant advancements in nanotechnology have yielded remarkable improvements in biomedical applications. Nanocarriers, harnessed from the principles of nanotechnology, have garnered widespread utilization in medicine delivery and diagnostics. However, the progression of nanocarriers has been hindered by two key challenges: low drug loading capacity and the potential for carrier-induced toxicity. To surmount these obstacles, the rapid development and expansion of carrier-free drug delivery systems (CFDDSs) composed of pure drugs and prodrugs have emerged as a promising solution. Extensive endeavors have been undertaken to explore novel excipients, therapeutic agents, self-assembly processes, and therapeutic mechanisms, aimed at expanding the horizons of CFDDSs and enhancing their therapeutic efficacy. This comprehensive review provides an overview of CFDDSs, elucidating their self-assembly mechanisms. Additionally, we examine their diverse biomedical applications while shedding light on the challenges ahead for the future development and clinical implementation of CFDDSs. This review serves to enhance our understanding of the intricate mechanisms governing drug nanoassembly formation and fosters the advancement of CFDDSs in the expansive realm of biomedical research.

The emerging interests in high-performance biocomposites grows significantly driven by their superior environmental sustainability. This study proposes a unique biocomposite strategy by implementing an acetic and ball-milled treatment to disrupt the bamboo cell wall structure, thereby facilitating further processing by effectively increasing the active sites and specific surface area in the bamboo fiber. The fibers are subsequently carboxymethylated to introduce carboxyl groups which facilitate physical bonding between the fibers and Mg²⁺ ions that are added to the system. These ions form metal-coordination bonds with the carboxyl groups, acting as ion bridges that significantly strengthen the inter-fiber bonding. The resulted biocomposite exhibits impressive mechanical properties, including a high tensile strength (94.24 MPa) and flexural strength (104.14 MPa), not only that, changes in elastic modulus also highlight changes in fiber bonding, the flexural modulus is 21.29 GPa and the tensile modulus is 7.01 GPa. Moreover, it maintains a low water uptake capacity of only 6.8 % despite being submerged for 12 h. The thermal conductivity and fire retardancy have also been improved. The synergic bonding ability between the cellulose and lignin in the fibers, coupled with the glue-free thermoforming process, enhances the material performance and renders it fully recyclable, thus reducing environmental pollution and providing cost-effective engineering materials to society.

Synthetic chemistry has played a vital role in miscellaneous fields of human civilization over the past century. The synthetic stage yet remains time-consuming and labor-intensive. To overcome these limitations, automation has been introduced to transform synthetic chemistry, leading to the development of high-throughput methods for molecular discovery. Automated flow chemical synthesis (AFCS) has recently emerged as a promising candidate, offering improved efficiency, scalability, and sustainability over the well-known automated solid-phase peptide synthesis. To further advance AFCS, elements like artificial intelligence-based computer-aided structure design and synthesis planning, autonomously assembled compatible synthesis with enhanced automated process control, and autonomous optimization can be considered. This review focuses on recent advances in computer-aided automated flow chemical synthesis (CAAFCS) of polymers in living polymerization and iterative synthesis strategy. The current challenges and outlook are finally discussed for developing more powerful CAAFCS systems and expanding their applicability across numerous fields, potentially providing brand-new perspectives and guidelines for future developments in this field.