ACS Applied Polymer Materials最新文献

We performed permeation experiments using PEGDA-based hydrogel membranes in which we added free polymer chains. We know from previous studies that free polymer chains can be trapped in the PEGDA matrix. Therefore, we use this property to trigger the retention of solutes through noncovalent interactions (heterogeneous bonds and electrostatic interactions) between the solute and the free polymer chains. We show that proton-donor molecules bearing carboxylic acid groups can be retained by hydrogen interactions at low pH with the free PEG (poly(ethylene glycol)) chains, which are proton acceptors. PEG is a nonionic hydrophilic polymer based on ethylene oxide units (−CH₂CH₂O−) which is a proton acceptor and can establish hydrogen bonds with proton-donor groups (such as COOH). The extent of retention increases with the number of acidic groups on the solute. By adding PAA (poly(acrylic acid), based on acrylic acid (−CH₂CHCOOH), these groups are negatively charged at pH > pK_a, i.e., pH > 5) in the PEGDA/PEG membranes, we show that positively charged molecules can be retained inside the membranes at a pH where the PAA is ionized. This retention is reversible, and solute molecules can be flushed out by reducing the pH below the pK_a of PAA. By measuring the adsorption isotherm of molecules in the membranes, we obtain the interaction energy between the solute and PAA, which is consistent with electrostatic interactions. Finally, we photopolymerize our membranes directly in a microfluidic chip to perform tangential filtration of a mixture of fluorescein (negatively charged) and rhodamine B (zwitterionic). Fluorescein is repelled by negatively charged PAA and does not penetrate the membrane, while rhodamine B is retained and eventually permeates through. These findings pave the way to functionalization of hydrogel membranes by trapping free polymer chains for selective retention and filtration.

Enzyme inhibitors have emerged as promising therapeutic agents and valuable tools for commercial applications due to their effectiveness. Despite their success, these agents often require delivery vehicles to enhance their efficacy, reduce the effective dose, and enable controlled release. Nanoparticles have been employed as drug carriers, offering not only improved delivery but also additional functionalities such as cellular tracking. Tyrosinase, a multifunctional enzyme, plays a critical role in cellular processes including melanin synthesis. It is closely associated with dermatological conditions such as melanoma, making tyrosinase inhibitors potential candidates for treating such diseases. Tranexamic acid (TXA), widely used to reduce melanin synthesis, has also gained attention as a key raw material for functional melanin-inhibiting cosmetics. In this study, a conjugated polymer with thiophene and fluorene units in its main chain was synthesized, characterized, and subsequently conjugated with TXA to prepare p-(Fle:3-TAl) NPs-TXA. This TXA-conjugated nanoparticle exhibits multiple functionalities. Its inherent electrochemical properties make it an ideal candidate for use in electrochemical sensors to monitor tyrosinase activity and detect tyrosinase-related diseases. Enzyme kinetic analysis revealed a mixed inhibition profile, achieving 60% inhibition of tyrosinase activity. Furthermore, p-(Fle:3-TAl) NPs was administered to melanoma cells, where its fluorescent properties enabled cellular tracking. The nanoparticles demonstrated a 62% reduction in melanin production and a significant decrease in metastatic factors at the gene level and cancer cell viability. These findings highlight the multifunctional capabilities of the designed nanoparticles, showcasing their potential for broader applications in medical research and therapy.

Additive manufacturing of elastomers enables the fabrication of many technologically important structures and devices. However, it remains a challenge to develop soft and stretchable elastomers for vat photopolymerization (VP) printing, one of the most used additive manufacturing techniques for producing objects with relatively high resolution and smooth finishes. Here, we report a modular soft stretchable low-cost elastomer resin for VP printing. The resin consists of mainly commodity acrylates and can be photocured to form a dual-network containing covalent crosslinks and reversible double hydrogen bonds. Controlling the ratio of covalent and reversible crosslinks enables elastomers with an exceptional combination of softness and stretchability (Young's modulus of 20-150 kPa and tensile breaking strain of 510-1350%) that cannot be achieved by existing VP resins. Using a customized VP printing platform, we transform this resin into complex three-dimensional (3D) structures. We develop an instrument to show that the 3D structures possess extreme dissipative properties, such that they can protect brain-like soft gels from impact damage in reducing the severity of impact by 75%. Together with the low cost of raw chemicals and modular nature of the design, these soft stretchable elastomer resins provide a class of feedstock for high-fidelity additive manufacturing of functional structures.

A polymer-supported iron catalyst, Poly(PDA/TF)@Fe³⁺Cat, was developed via the condensation of m-phenylenediamine and terephthalaldehyde, followed by metal incorporation. Structural and compositional features were confirmed using FT-IR, SEM, TGA, powder XRD, elemental mapping, and ICP–MS analyses. TEM images displayed a crumpled porous structure with particle dimensions averaging around 72 nm, while XPS spectra showed a binding energy peak at 711.2 eV, indicating the presence of Fe³⁺. ICP–MS further confirmed effective iron loading with minimal leaching after repeated use. This catalyst demonstrated excellent activity in a one-pot, five-component synthesis of 1,2,5,6-tetrahydropyridine-3-carboxylate derivatives using ethanol as a green solvent, achieving yields up to 89%. It maintained its efficiency over seven reaction cycles, showcasing its stability and recyclability. Biological assessment and molecular docking of the synthesized compounds revealed promising anticancer activity. Complementary DFT and molecular dynamics studies provided further insight into electronic behavior and binding interactions, supporting the therapeutic relevance of these molecules. The catalyst thus offers a robust, reusable, and environmentally responsible platform for multicomponent organic transformations with medicinal potential.

Transition metals from the first series have recently attracted attention as potential photocatalysts in photopolymerization reactions and 3D printing applications. However, manganese(II) complexes are among the least explored in photopolymerization reactions. Hence, in this study, an organomanganese complex was developed bearing two pyridine-NHC ligands. The complex [Mn^II(PyImes)₂](PF₆)₂ (Mn-PyImes), where PyImes = N-mesityl-N′-2-pyridylimidazolium, was isolated upon heating a tetrahydrofuran (THF) solution of MnCl₂ with a 2-fold excess of PyImes(PF₆) in the presence of potassium tert-butoxide (KOtBu). Mn-PyImes was characterized by FTIR, UV–vis, fluorescence (steady state and time-resolved), and ESR spectroscopies, elemental analysis, cyclic voltammetry, and mass spectrometry. Mn-PyImes was applied in the reactions of controlled radical photopolymerization (CRP2) and free radical photopolymerization (FRP). Mn-PyImes showed slight control in the CRP2 of methyl acrylate (MA) using triethylamine (TEA) and phenacyl bromide (PhBr) as additives under LED@365 and LED@390–405. Mn-PyImes also showed a good catalytic ability in the FRP of ethoxylated trimethylolpropane triacrylate (TMPETA) under LED@405 nm, LED@455 nm, and laser diode@532 nm using di-tert-butyldiphenyl iodonium hexafluorophosphate (Iod) and ethyl dimethylaminobenzoate (EDB) as additives in a photoinitiating system. The CRP2 chemical mechanism was studied by electron spin resonance spin trapping, fluorescence, cyclic voltammetry, laser flash photolysis, and steady state photolysis techniques. Although Mn-PyImes demonstrated good light absorption properties under LED@365 nm, it also enabled effective photopolymerization of acrylates in thick films upon exposure to LED@405 nm, LED@455 nm, and laser diode@532 nm. More interestingly, stereoscopic 3D patterns were successfully fabricated by the laser writing technique.

A dielectric film with high breakdown strength and dielectric constant are crucial for the reliable operation of electrowetting on dielectric (EWOD). In this study, barium titanate (BaTiO₃) nanoparticles modified with a silane coupling agent (KH550) were incorporated into poly(vinyl fluoride-trifluoroethylene-chlorotrifluoroethylene) (P(VDF-TrFE-CTFE)) and poly(methyl methacrylate) (PMMA) to prepare a BaTiO₃–KH550/P(VDF-TrFE-CTFE)/PMMA composite film to enhance the breakdown strength and dielectric constant of a dielectric layer. Results revealed that BaTiO₃–KH550 is uniformly dispersed within the P(VDF-TrFE-CTFE)/PMMA polymer matrix. When the BaTiO₃–KH550 content is 10 wt %, the dielectric constant reached 24.6, and the energy density was 2.65 J cm^–3, representing increases of 94% and 73%, respectively, compared to the pure P(VDF-TrFE-CTFE)/PMMA film, where was 12.7 and 1.53 J cm^–3. Additionally, the breakdown strength of all films remains above 150 kV mm^–1 due to the strong interfacial interaction between PMMA and P(VDF-TrFE-CTFE). Furthermore, the breakdown strength can keep at 194.90 kV mm^–1. Electrowetting experiments demonstrated that the composite film exhibited a high initial contact angle of 105.04°, with a contact angle variation range of 35.3° under a low DC voltage ranged from 0 to 50 V. The results indicated that this film is potential for applications in low-cost and high-dielectric-performance EWOD dielectric layer materials.

The effects of zinc dimethacrylate (ZDMA), serving as a modifier, on the mechanical, thermal, and flame-retardant properties of ethylene-propylene-diene rubber (EPDM) composite materials were investigated. The incorporation of ZDMA effectively introduced Zn²⁺ ions into the composite rubbers, resulting in the formation of a dual cross-linking network that significantly bolstered both the tensile strength and tear resistance of the composite rubbers. Meanwhile, the addition of ZDMA optimized the compatibility between flame retardant ammonium polyphosphate (APP) and the EPDM matrix, giving rise to a synergistic flame retardant effect that maximized the flame retardant performance of the composite rubber. Furthermore, ZDMA contributed to improving the aging resistance of the material, resulting in a remarkably low compression deformation rate (CDR). Notably, the inclusion of ZDMA elevated the limiting oxygen index (LOI) value of the EPDM composite rubbers to 34%, thereby achieving a V-0 flame retardancy classification. This research holds profound implications for the preparation and application of EPDM composite materials, especially in their utilization as sealing materials especially in energy vehicles.

Functional conjugated microporous polymers (CMPs) were studied for chemical sensing and photocatalytic application. However, CMPs showing dual functional properties of electrochemical sensing and photocatalytic activity are rare yet unique and are associated with the choice of building blocks. Herein, we demonstrate a dual-function conjugated microporous polymer, pTPETTz (S_BET = 331.8 m² g^–1) and lpTPETTz (S_BET = 11.4 m² g^–1), based on conducting and photo functional thiazolothiazole (TTz) units for selective detection of metronidazole (MNZ) and photocatalytic degradation of micropollutants. pTPETTz-modified electrodes (glassy carbon and screen-printed electrode) exhibited a selective current response to MNZ among other antibiotics, interfering biomolecules etc. Among them, pTPETTz@GC showed the lowest detection limit (LoD) of 5.74 nM. The pTPETTz@SPE showed similar detection limits as pTPETTz@GC in the urine sample analysis and showed a high recovery percentage. Interestingly, the sensing response of pTPETTz is significantly higher than that of lpTPETTz due to the lower charge transfer resistance (R_ct) of pTPETTz (259.84 Ω cm²) compared to lpTPETTz (360.41 Ω cm²) and bare ITO (642.35 Ω cm²) as evidenced by electrochemical impedance spectroscopy (EIS). Apart from this, pTPETTz (E_g = 2.41 eV) and lpTPETTz (E_g = 2.37 eV) also showed efficient photocatalytic degradation (up to 98.21%) of aqueous food colorants under direct sunlight due to the formation of a highly reactive species superoxide anion (O₂^•–) and photogenerated holes (h⁺). The degradation follows pseudo-first-order kinetics with a relatively higher rate constant (k = 0.05 min^–1).

Achieving target properties of polybenzoxazines generally can be realized based on the flexible molecular design capability of benzoxazine monomers. However, the structural effects on mechanical performance, especially in terms of tribological properties, still remain unclear. In this paper, a series of benzoxazine monomers (PH-bzd, PH-ddm, and PH-eda) with various backbones were synthesized by a three-step method using salicylaldehyde, paraformaldehyde, and three different dianilines as raw materials. The chemical structure of each benzoxazine monomer was characterized by nuclear magnetic resonance, Fourier transform infrared spectroscopy (FT-IR), and high-resolution mass spectrometry. Their polymerization behavior was investigated using differential scanning calorimetry and in situ FT-IR spectroscopy. In addition, dynamic thermomechanical analysis (DMA), thermogravimetric analysis (TGA), microscale combustion calorimetry, universal material testing machine (UTM), and Shore D hardness (HD) were used to detect the thermal and mechanical properties of the resulting polybenzoxazines. Moreover, the tribological properties of each polybenzoxazine matrix were further systematically evaluated. With this work, we demonstrate the benzoxazine structural effects on the tribological performance for the first time and provide a theoretical basis for the structural design of polybenzoxazines with outstanding tribological performance.