Macromolecular Research最新文献

Epoxy-based materials, known for their exceptional durability, are extensively used across various fields. However, a significant drawback of epoxy resins is that their curing agents, typically derived from petroleum, can pose environment risks. This study aims to develop new systems as alternatives to petroleum-derived curing agents. The incorporation of environmentally friendly curing agents in epoxy resins has the potential to significantly reduce the carbon footprint and decrease health risks to living organisms. For this purpose, the amine modified three-dimensional zeolite imidazolate framework (ZIF) was first prepared. Subsequently curing studies were carried out using epoxy resins composed of a petroleum-derived resin, a plant-based resin, and their mixtures. The resulting ZIF and amine-functionalized ZIF were characterized using FTIR and XRD techniques. Epoxy films were then prepared with three different curing agents across three distinct epoxy resin systems. Mechanical, thermal, and chemical analyses of the films were performed. Additionally, coatings were applied to glass surfaces, and their surface properties were evaluated. In reactions involving ZIF for epoxidized resorcinol, it was observed that the curing temperature shifted slightly to a higher range from 95 to 131 °C. The thermal degradation temperatures of the films containing ZIF also increased, resulting in more thermally stable materials. The maximum weight loss temperatures increased by 168 °C for RDGE and by 88 °C for the mixture of RDGE and ESO. Improved thermal stability can lead to a longer service life and greater performance in extreme conditions.

Graphical Abstract

Explores sustainable alternatives to petroleum-based curing agents in epoxy resins. ZIF with amine groups as eco-friendly curing agents was synthesized and functionalized. Thermal stability in epoxy films using ZIF-based curing agents was enhanced. Mechanical, thermal, and surface properties of ZIF-incorporated epoxy coatings were evaluated

Hydrogels have made significant contributions to biomedical applications in recent years and have made remarkable progress. However, uniform hydrogels have limitations in mimicking the in vivo environment. Gradient hydrogels are attracting attention as innovative biomaterials that can effectively mimic the properties of complex biological tissues by implementing continuous changes in physical, chemical, and biological properties. To contribute to the exploration of the development of scaffolds utilizing gradient hydrogels and their potential applications, this work comprehensively reviews the latest research trends focusing on the major fabrication methods of gradient hydrogels (bioprinting, diffusion method, microfluidic technology, and multilayer structure design) and application cases of each technology. In addition, the applicability and performance of gradient hydrogels in the field of tissue engineering are discussed in depth. Despite these developments, the challenges remain in precise controlling gradient formation, ensuring long-term stability, and achieving scalable fabrication for clinical applications. Taken together, the future research directions of gradient hydrogel design and fabrication to overcome them is discussed.

Graphical abstract

We summarize about the latest trends in the fabrication of gradient hydrogels and their various applications in tissue engineering. We also look at their challenges and future perspectives.

Uniform dispersion of nanoparticles (NPs) in polymeric binders is crucial in determining the mechanical properties of dielectric sheets, which can reduce factors contributing to the electrical failure of multilayer ceramic capacitors (MLCCs). Selecting the appropriate dispersants is essential for optimizing the interfacial interaction between the surface of NPs and binders. General strategies for designing dispersants involve making the chemical structures of dispersants similar to those of binders to increase material compatibility. However, to diversify the range of material choices, it is necessary to consider dispersants with chemical structures different from those of the binders. In this study, polyvinylpyrrolidone (PVP) was selected as a dispersant for barium titanate (BaTiO₃; BT) NPs and PVP-coated NPs were incorporated into a polyvinylbutyral (PVB) binder. PVP enhanced the dispersibility of the BT slurries and improved the mechanical properties of the dielectric sheets, which ultimately enhanced the electrical characteristics of MLCC. Therefore, the findings of this study demonstrate that PVP is a promising dispersant for BT NPs, contributing to the manufacturing of MLCCs with superior electrical performance.

Graphical abstract

The BT NP was well-coated with PVP dispersants and was stably dispersed in mixed solvent (EtOH/Tol). The PVP provides hydrogen bond acceptor sites on the surface of BT, which enhanced the interfacial interaction between the surface of BT and the PVB binder. This result leads to the increase of the mechanical properties of the dielectric sheet and the improvement of the electrical properties (BDV and short rate) of MLCC

We report a mechanically stretchable smart window passive radiative cooler (SW-PRC) that can reversibly switch between opaque and transparent states in response to external mechanical stress while maintaining efficient heat dissipation through the atmospheric window in both optical states. To fabricate the SW-PRC, we modify the surface of SiO₂ nanoparticles (NPs) using trimethylchlorosilane (TMSCl). The surface-modified SiO₂ nanoparticles (SM-SiO₂ NPs) exhibit hydrophobic properties, preventing agglomeration of SiO₂ NPs within a polydimethylsiloxane (PDMS) matrix and achieving a homogenous SW-PRC with a low haze factor (20–30%) and high visible-light transmittance (≥ 90%). These composites also demonstrate high emissivity in the long-wave infrared region, confirming their radiative cooling capabilities. When the SW-PRC is stretched by more than 5%, air voids form around the SiO₂ NPs, causing visible-light scattering and resulting in hazy, non-transparent films. This optical conversion between transparent and hazy states can be repeated over 20 times. The switchable SW-PRC has shown a temperature drop of 3.25 °C in its unstretched state and up to 4.75 °C when stretched by 30%. We believe that our switchable SW-PRC represents an advancement in overcoming the limitations of current smart window applications.

Graphical Abstract

The surface-modified SiO₂ nanoparticles within a polydimethylsiloxane matrix demonstrate an optically switchable and stretchable passive radiative cooler.

In this work, we developed three-dimensional (3D) porous chitosan/nano-hydroxyapatite scaffolds (CS/HAp) for bone tissue engineering (BTE) using a solvent casting-salt leaching technique. The physicochemical, morphological, and porous analyses of the scaffolds were performed using X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy (SEM), and the liquid displacement method. Results indicated that nano-HAp particles were successfully integrated into the CS matrix to produce 3D CS/HAp scaffolds. These scaffolds exhibited a highly porous structure with a thickness of 2 mm and average pore sizes from 285 to 345 µm and porosity (76.76–86.52%), which are beneficial for cell growth. Additionally, the scaffolds showed increased Young’s modulus (10.9–14.8 MPa) and tensile strength (2.4–2.6 MPa) compared to pure CS scaffolds that are well-compatible with trabecular bone. The degradation rate of the CS/HAp scaffolds was slower than that of the CS scaffolds alone. Notably, a bone-like apatite layer was formed on the CS/HAp scaffold’s surfaces after 15 days of immersion in simulated body fluids (SBF). In contrast, no such mineral layer was observed on the CS scaffolds. The protein adsorption on the surfaces of the CS/HAp scaffolds was significantly high, with 840.96 µg of proteins adsorbed after 24 h in 10% of fetal bovine serum (FBS) in a minimum essential medium. In vitro tests with bone marrow-derived mesenchymal stem cells (BMSCs), including live/dead staining, MTT assay, and SEM, confirmed that all scaffolds exhibit excellent biocompatibility, providing a suitable substrate for cell proliferation and adhesion. Furthermore, the CS/HAp scaffolds demonstrated a high removal efficiency of E. coli, reaching up to 84.92% in 180 min. Our results revealed that the CS/HAp scaffolds are potential biomaterials for BTE applications.

Graphical abstract

In polymer nanocomposites, the enhancement efficiency of single-walled carbon nanotubes (SWNTs) on the thermal conductivity of polymers is primarily influenced by the length of the SWNTs. This study analyzes the thermodynamic properties of carbon nanotube/polyvinyl alcohol (SWNT/PVA) composites and investigates the impact of varying SWNT lengths on the thermal conductivity of the composite system through the application of the reverse non-equilibrium molecular dynamics simulation method (RNEMD). The simulation results reveal that the interaction energy between SWNTs and PVA is markedly enhanced with increasing SWNT length, which augments the interfacial adsorption capacity of the composite system and facilitates heat transfer. Concurrently, the thermal conductivity of the composites rises with the elongation of the SWNTs. Longer SWNTs can establish a robust thermal conductivity pathway, thereby enabling more efficient heat conduction along the axial direction of the SWNTs. This structural characteristics significantly enhances the thermal conductivity of the material and accelerates the transfer of heat.

Graphical Abstract

Based on molecular dynamics simulations, the effect of single-walled carbon nanotube (SWNT) length on the thermal properties of carbon nanotube/polyvinyl alcohol (SWNT/PVA) composites was systematically investigated. The simulation results demonstrate that the thermal conductivity of the composites exhibits a significant increasing trend with the increase in SWCNT length.

This study investigates synthesis, thermal, optical, and morphological properties of two DPP-based copolymers, PBDTTT-DPP-C12 (poly{2,6-bis- 5-(2-butyloctyl)thienothiophene-2-yl)benzo[1,2-b:4,5-b′]dithiophene-6-bis(5-thiophen-2-yl)-2,5-bis(2-decyltetradecyl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione}) and PBDTTT-DPP-C17 (poly{2,6-bis-5-(2–7-butyltridecyl)thienothiophene-2-yl)benzo[1,2-b:4,5-b′]dithiophene-6-bis(5-thiophen-2-yl)-2,5-bis(2-decyltetradecyl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione}), with different alkyl side chains. Both polymers were synthesized using a series of reactions (alkylation, lithiation, and bromination) and Stile coupling polymerization. The obtained polymer structures were confirmed using ¹H NMR (Nuclear Magnetic Resonance). The thermal stability of both polymers, assessed via thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC) showed high decomposition temperatures (T_d) of 377 °C and 367 °C for PBDTTT-DPP-C12 and PBDTTT-DPP-C17, respectively, which indicate sufficient thermal stability. The polymers exhibited dual-band absorption, with maximum absorption at 669 nm for PBDTTT-DPP-C12 and 700 nm for PBDTTT-DPP-C17, showing a slight red shift when transitioning from solution to film. The electrochemical analysis via cyclic voltammetry (CV) revealed similar highest occupied molecular orbital (HOMO) levels of − 5.22 eV and − 5.23 eV for both polymers, while the lowest unoccupied molecular orbital (LUMO) levels were calculated to be 1.47 eV and 1.49 eV, respectively. Grazing incidence wide-angle X-ray scattering (GIWAXS) and atomic force microscopy (AFM) studies revealed differences in morphology and crystallinity of the films, with PBDTTT-DPP-C12 showing a more pronounced edge-on orientation. In photovoltaic devices, PBDTTT-DPP-C17 demonstrated a higher power conversion efficiency (PCE) of 2.8%, outperforming PBDTTT-DPP-C12 with a PCE of 1.8%. This work highlights the significant role of alkyl side chain length in modulating polymer morphology, crystallinity, and miscibility with electron acceptors, thus enhancing the photovoltaic performance of DPP-based polymers for organic solar cells.

Graphical abstract

It highlights the significant role of alkyl side chain length in modulating polymer morphology, crystallinity, and the miscibility with fullerene acceptors, thus enhancing the photovoltaic performance of DPP-based polymers for organic solar cells.

Facile control of surface wettability is demonstrated by introducing a scalable and cost-effective method using candle soot as a hierarchical template. Through soot deposition, silica sol-gel coating, calcination, and self-assembled monolayer (SAM) treatment, surfaces with tunable wettability from superhydrophobic (contact angle >150°) to superhydrophilic (contact angle = 0°) were fabricated. The hierarchical roughness introduced by soot deposition was instrumental for achieving radically biased surface wettability. Silica coating transformed the soot-coated surfaces to superhydrophilic by increasing surface energy, while calcination created a porous silica framework. SAM treatment restored superhydrophobicity by lowering surface energy and re-establishing the Cassie-Baxter wetting regime. Optimized soot deposition times retained transparency, ideal for optical applications, and mechanical stress testing caused a transition from Cassie-Baxter to Wenzel regime, exhibiting pinning of water droplet. This versatile approach enabled designed surface wettability depending on target purposes.

Graphical abstract

Versatile surface wettability control with candle soot template.

In this study, we developed pH-responsive hyaluronated liposomes designed to enable efficient photodynamic therapy in hypoxic tumor environments. First, hyaluronic acid (HA) was chemically conjugated with 3-(diethylamino)propylamine (DEAP, serving as a pH-responsive moiety) and chlorin e6 (Ce6, a photodynamic model drug), resulting in a compound designated as Ce6-HDEA. MnO₂ nanoparticles, serving as oxygen-generating agents through reaction with H₂O₂, were synthesized via an in situ redox reaction by mixing KMnO₄ with bovine serum albumin (BSA). Subsequently, hyaluronated liposomes were prepared with hydrogenated soy phosphatidylcholine (HSPC) and Ce6-HDEA using thin-film hydration, followed by encapsulation of MnO₂ nanoparticles into the liposomes via extrusion, producing a formulation referred to as (MnO₂/Ce6-HDEA)@Lipo. The (MnO₂/Ce6-HDEA)@Lipo liposomes were effectively internalized into MDA-MB-231 tumor cells via HA/CD44 receptor-mediated endocytosis. At an endosomal pH of 6.5, the DEAP moieties in Ce6-HDEA became protonated, destabilizing the liposomal structure and enhancing the release of MnO₂ nanoparticles. These MnO₂ nanoparticles then oxidized H₂O₂, generating oxygen and alleviating hypoxia in the tumor microenvironment. Our findings indicate that upon near-infrared (NIR) laser irradiation, the (MnO₂/Ce6-HDEA)@Lipo substantially increased singlet oxygen production, thereby enhancing photodynamic antitumor efficacy in hypoxic tumor environments.

Graphical abstract

(MnO₂/Ce6-HDEA)@Lipo generating singlet oxygen in hypoxic tumor environments.

Polytetrafluoroethylene (PTFE) materials have a low surface energy, which presents a challenge to bonding with conventional adhesives and consequently limits their application scope. This study explores the copolymerization of fluorinated hexafluorobutyl acrylate (HFBA) and ethyl acrylate (EA) to formulate fluorinated acrylate-based P(EA-co-HFBA) adhesives. The incorporation of the fluorinated component significantly lowers the surface energy of the adhesive, achieving levels comparable to those of PTFE. Optimization reveals that at a molar ratio of EA to HFBA of 1:3, the surface energy is reduced to 20.19 mN/m, facilitating effective wettability on PTFE surfaces. Notably, the peel strength of PTFE tape bonded with the fluorinated adhesive on a mirror-polished stainless-steel substrate reaches 13.8 N/25 mm. Furthermore, the presence of the fluorinated component enhances both the thermal stability and water resistance of the adhesive. The findings of this study offer valuable insights for the development of adhesives specifically designed for materials with low surface energy.

Graphic abstract

Polytetrafluoroethylene (PTFE) is difficult to bond due to its low surface energy. This study examines fluorinated acrylate-based P(EA-co-HFBA) adhesives, which attain a surface energy of 20.19 mN/m. With a 1:3 molar ratio of EA to HFBA, the adhesive achieves a peel strength of 13.8 N/25 mm on PTFE, along with improved thermal stability and water resistance.