Journal of Polymer Science最新文献

In situ gel polymer electrolytes (GPEs) are promising for lithium metal batteries due to their high ionic conductivity (≈ 10⁻³ S cm⁻¹) and outstanding compatibility with electrode interface. However, challenges such as initiator and monomer residue, high initiation temperatures, and low mechanical properties hinder their development. To address these challenges, a low-temperature, catalyst-free method utilizing the Diels-Alder reaction between fulvene and maleimide is proposed, offering a by-product-free solution. With this method, a GPE was prepared through the Diels-Alder reaction between PEG-fulvene and bismaleimide diphenylmethane (BMI), using lithium-sulfur electrolyte (1.0 M LiTFSI in DOL (1,3-dioxolane): DME (Dimethoxyethane) = 1:1 vol% with 1.0% LiNO₃) as the solvent. The in situ GPE demonstrates an ionic conductivity of up to 1.11 mS cm⁻¹ at 30°C and maintains stable cycling for 2000 h at a current density of 0.1 mA cm⁻². Furthermore, the formation of lithium dendrites is effectively suppressed. The discharge capacity of the LFP/GPE/Li battery was 118.9 mAh g⁻¹ after 200 cycles at 0.5C, with a capacity retention of 88.20%. These results demonstrate that the in situ GPE has excellent capacity retention and cycle life, making the catalyst-free crosslinking strategy at room temperature a new plan for preparing in situ GPE.

Synthesis of chain length-controlled oligo-p-phenylenes, formylation through post-functionalization, photophysical and biochemical properties are described herein. Synthesis of oligo-p-phenylene oligomers with controlled chain length is facilitated by using multivalent dendritic Pd^II catalysts. Suzuki–Miyaura oligomerization of bromo/iodophenylboronic acids in H₂O:THF (3:1) solutions, mediated by one to three generations of poly(propyl ether imine) (PETIM) dendritic catalysts, leads to oligomers with degree of polymerization (DP) 14–26. Upon synthesis, the oligomers are subjected to formylation with the aid of Vilsmeier–Haack reaction. The resulting formylated oligomers are soluble in organic solvents and aqueous solutions, thereby permitting a series of studies to be conducted solution. A Stokes shift of ~70 nm occurs in the emission spectrum of the formylated oligomer (λ _em = 470; λ _em = 340) and a quantum yield of 12% in MeOH solution. The particle sizes vary between 100 nm in MeOH and 410 nm in 25% MeOH in water solution. The functionalized oligomers show morphological features, primarily consisting of twisted rod-like morphologies. The cytotoxicities of functionalized oligomer with DP14 are adjudged to be 85 and 105 μg mL⁻¹ in HEK293 and HeLa cells. The emission behavior of the functionalized oligo-p-phenylenes is taken advantage to assess the cellular imaging properties of HEK293 and HeLa cells.

π-Conjugated polymers containing coumarin backbone in the main chain show acid–base responsive fluorescence. The α-pyrone ring in the coumarin unit undergoes hydrolysis by inorganic bases and triggers the change of the expanded π-conjugated system, resulting in the reversible fluorescence on/off switching, dual-colored halochromic fluorescence, and alkali metal ion recognition. We assume that the coumarin polymers form complexes with alkali metal ions during hydrolysis. In this study, we investigated the fluorescence quenching behaviors and acid–base responsivity of 3,7-dibromo-4-methylcoumarin, 3,7-bis(phenylethynyl)-4-methylcoumarin (model compound), and two types of coumarin-based π-conjugated polymers by the addition of organic bases for comparison. Consequently, the model compound demonstrated remarkably reversible on/off switching behaviors, highlighting the significant role of the metal-free organic bases and HCl aqueous solution in facilitating the ring-opening and closing properties. The coumarin-based polymers demonstrated notable reversibility specifically in PL intensity. These results are expected to enhance our understanding of how alkali metal ions are recognized by coumarin π-conjugated polymers.

The poly(butylene adipate-co-terephthalate) (PBAT) nanofiber film prepared by electrospinning method exhibits limited application in many fields due to its poor flame retardancy and machinal property, despite being a biodegradable material with exceptional toughness and ductility properties. In this work, we employed microfluidic technology to continuously produce blue fluorescent carbon dots (CDs) on an aluminum-based microfluidic chip using citrate and ethanolamine as precursors. Subsequently, utilizing microfluidic electrospinning technology, the CDs/PBAT composite nanofiber films with blue fluorescence were prepared in situ reaction. Interestingly, compared to pure PBAT nanofiber membranes, the CDs/PBAT composite nanofiber membranes exhibit a tensile strength of 4.31 MPa, representing a remarkable increase of 3.24 times, and an elongation at break of 491%, indicating an improvement of 1.62 times. More importantly, it had demonstrated that the incorporation of CDs into PBAT can achieve flame-retardant effects. We firmly believe that the microfluidic strategy could open up a new idea for the synthesis of CDs and point out the direction for the meaningful fabrication of PBAT nanofiber film with high tensile strength and flame-retardant property.

The discovery of high-performance shape memory polymers (SMPs) with enhanced glass transition temperatures (Tg) is of paramount importance in fields such as geothermal energy, oil and gas, aerospace, and other high-temperature applications, where materials are required to exhibit shape memory effect at extremely high-temperature conditions. Here, we employ a novel machine learning framework that integrates transfer learning with variational autoencoders (VAE) to efficiently explore the chemical design space of SMPs and identify new candidates with high Tg values. We systematically investigate the effect of different latent space dimensions on the VAE model performance. Several machine learning models are then trained to predict Tg. We find that the SVM model demonstrates the highest predictive accuracy, with R ² values exceeding 0.87 and a mean absolute percentage error as low as 6.43% on the test set. Through systematic molar ratio adjustments and VAE-based fingerprinting, we discover novel SMP candidates with Tg values between 190°C and 200°C, suitable for high-temperature applications. These findings underscore the effectiveness of combining VAEs and SVM for SMP discovery, offering a scalable and efficient method for identifying polymers with tailored thermal properties.

Synthetic helical polymers have gained tremendous attention due to their superior efficiency in mimicking the complex self-assembly “helix” of biological systems. Prolinate-based chiral polyelectrolytes bearing chloride counter anion (poly-(L-)-Pro-Cl) is circular dichroism (CD) silent and exist as random coils. For instance, the same chiral polymer with methoxide counter anion (poly-(L-)-Pro-OMe) shows CD response with preferred-handed helical sense. Here we have used partial anion exchange of chloride anion with methoxide as a simple and effective technique to bring the induced CD, eventually helical sense to poly-(L-)-Pro-Cl. Even with 1 mol% of methoxide exchange, the obtained chiral random copolymer poly-(L-)-Pro-Cl_0.99-co-poly-(L-)-Pro-OMe_0.01 showed induced CD. The random copolymer poly-(L-)-Pro-Cl_0.50-co-poly-(L-)-Pro-OMe_0.50 with 50 mol% of the methoxide anion exchanged, showed induced CD identical to that of poly-(L-)-Pro–OMe. In partial anion exchange-induced random copolymers, methoxide-containing polymer units act as sergeants and chloride-containing units act as soldiers. Through the “sergeants- and soldiers-like effect,” partial anion exchange reactions trigger the helical sense into the polymer chains. CD analysis provided strong support for the study. Here, the study provides a novel approach to the helical amplification phenomenon, which corresponds to the “sergeants- and soldiers-like effect.”

Carbon aerogel (CA), derived from phenolic (resorcinol and formaldehyde) resin, has being regarded as a promising porous adsorbent for water purification. In this study, we provided an effective strategy for preparing CA with a hierarchical porous microstructure. Acetic acid was introduced as an additive in the precursor solution to modify the microstructure of the xerogel, followed by KOH activation to further transform it into a hierarchical porous structure. The specific surface area of the hierarchical porous CA reached up to 1205.44 m²/g with a total pore volume exceeding 1.60 cm³/g. Consequently, the CA demonstrated an excellent adsorption rate, reaching adsorption equilibrium in approximately 240 min and exhibited a remarkable maximum dye adsorption capacity of 1.25 times its own mass. Furthermore, the adsorption processes of the CA for dye adhered to the second-order kinetic model and the Langmuir isotherm model. This study provided an effective approach to preparing hierarchical porous CA for efficient adsorption of organic pollutants for water purification.

Constructing continuous proton transport channels in proton exchange membranes (PEMs) has been considered as an efficient strategy to improve proton conductivity. In this work, a water-insoluble hybrid graphene oxide (HDGO) is prepared via the hydrothermal reaction between polydopamine-coated graphene oxide (DGO) and a strong proton conductor phosphotungstic acid (HPW), in which HPW is chemically bonded onto DGO. The two-dimensional structure of DGO and the strong acidity of HPW favor the rapid proton transport in the sulfonated poly(ether ether ketone) (SPEEK) membranes. As compared to that of the SPEEK control membrane, the proton conductivity of the SPEEK composite membrane containing 6 wt% HDGO increases from 0.035 to 0.061 S cm⁻¹ at 25°C, an increase of ~75%. The composite membrane containing 10 wt% HDGO exhibits ~49% lower area swelling ratio than the SPEEK control membrane. Meanwhile, the proton conductivity of the composite membrane remains stable during the 1440 h immersing in liquid water.