Macromolecular Rapid Communications最新文献

The demand for insulating materials with superior dielectric properties has increased. Among these materials, polymers containing cyclic structure including cyclic olefin copolymer (COC) and cyclic olefin polymer (COP) stand out because of their excellent dielectric properties originating from the pure hydrocarbon structure. Introducing fluorine into polymers is one efficient strategy for optimizing the dielectric and the related important properties. Here, three fluorinated norbornene derivatives with high fluorine content are synthesized and copolymerized via coordination-insertion polymerization (CIP) and ring-opening metathesis polymerization (ROMP). The obtained fluorinated COCs and COPs have high fluorine contents (up to 48.2 wt.%) and exhibit excellent dielectric properties with dielectric constant (D_k) of 2.11-2.24 and dielectric loss (D_f) of 0.0021-0.0031 at 10 GHz. Moreover, these fluoropolymers show good solvent tolerance, high toughness (elongation at break up to 779%), enhanced thermal stability (T_d,5% of 427-440 °C), low hydrophilicity (water uptake <0.01%), and excellent gas separation properties. These results imply that these fluoropolymers are suitable as a potential candidate for substrate material utilized in the application of insulating materials.

Conjugated polymers have attracted extensive attention as semiconducting materials in wearable and flexible electronics. In this study, we utilize atom-economical Knoevenagel reaction to construct two conjugated polymers, PTDPP-CNTT and PFDPP-CNTT, based on dialdehyde-thiophene/furan-flanked diketopyrrolopyrrole (DPP) and 2,2'-(thieno[3,2-b]thiophene-2,5-diyl)diacetonitrile (CNTT). The resulting polymers exhibited suitable highest occupied molecular orbital/lowest unoccupied molecular orbital (HOMO/LUMO) energy levels, small bandgaps, and broad UV-vis-NIR absorptions (≈400-1000 nm), endowing them with photothermal and balanced ambipolar semiconducting properties with hole and electron mobilities over 10^-3 cm²V^-1s^-1. Additionally, PTDPP-CNTT-based organic field-effect transistors (OFETs) devices show photo-responsive characteristics at 808 and 980 nm in the hole transport channel with the photo-responsivenesses of 9.0 × 10^-3 A/W and 0.4 A/W, respectively, suggesting potential application in organic NIR-phototransistors.

The self-assembly of macromolecular segments promotes the fabrication of polymer microspheres with multiple morphologies. Inspired by the xanthium shells, A dual-driven self-assembly method have defined that enables the construction of multi-dimensional morphologies on the microsphere surface at emulsion-confined interfaces. The two driving forces are derived from the phase separation caused by the immiscibility of macromolecular segments and the different interactions between chain segments of different hydrophilicity and water molecules. The synergistic effects of these two forces, the xanthium shell structure is constructed on the microsphere surface, enabling the development of increasingly complex superstructure. This scalable approach provides extensive potential for the self-assembly technology of block copolymers with opposite properties.

Critical issues such as leakage, degradation, and thermal response hysteresis have become the focus in the application of phase change materials (PCMs) in area such as thermal management of fabrics. The encapsulation of PCMs prepared as microcapsules using polysiloxanes, etc. as a component unit of crosslinking agents represents a highly promising avenue of research. In this work, organosilicon crosslinkers are prepared and employed for the crosslinking of poly (methyl methacrylate) (PMMA) for microencapsulation of paraffin wax in microcapsule phase change materials (mPCMs). The results showed that increasing the degree of crosslinking helps to improve the performance of mPCMs by smoothing the shell surface, but excessive crosslinking leads to flocculation, which reduces its performance. The mPCMs produced with 10% wt crosslinking agent gave the highest performance with encapsulation efficiency, melting enthalpy and crystallization enthalpy of 81.3%, 285.0 J g^-1 and 253.1 J g^-1, respectively. The obtained mPCMs are also combined with epoxy resin and fabrics to form composite materials. Notably, the polysiloxane-modified mPCMs permit epoxy resins to achieve a maximum temperature reduction of 25 °C. By adjusting the mass ratio of organosilicon crosslinkers, the obtained mPCMs enable textiles to reach a maximum temperature reduction of 17 °C while maintaining satisfactory air permeability.

A novel aggregation-induced emission (AIE)-based artificial light-harvesting system (LHS) is successfully assembled via the host-guest interaction of bis-naphthylacrylonitrile derivative (BND), water-soluble pillar[5]arene (WP5), and sulforhodamine 101 (SR101). After host-guest assembly, the formed WP5⊃BND complexes spontaneously self-aggregated into WP5⊃BND nanoparticles (donors) and SR101 (acceptors) is introduced into WP5⊃BND to fabricate WP5⊃BND-SR101 LHS. Through the investigation of energy transfer between donors and acceptors, the artificial light-harvesting processes are certified in WP5⊃BND-SR101 LHS and the absolute fluorescence quantum yields (Φ_f(abs)) are significantly improved from 8.9% (for WP5⊃BND) to 31.1% (for WP5⊃BND-SR101), exhibiting the excellent light-harvesting capabilities. Notably, by tuning the donor/acceptor (D:A) molar ratio to 250:1, a conspicuous white light emission (CIE coordinate is (0.32, 0.32)) is realized and the fluorescence quantum yield of white light emission (Φ_{f(abs) WP5 ⊃ BND-SR101-White}) is 29.2%. Moreover, the antenna effect of white fluorescence emission (AE_{WP5 ⊃ BND-SR101-White}) can reach 36.2, which is higher than that of recent artificial LHSs in water environments, suggesting vast potential applications in aqueous LHSs.

Invasive fungal infections have been an increasingly global issue with high mortality. Amphotericin B (AmB), as the "gold standard" antifungal drug, has broad-spectrum antifungal activity and low clinical resistance. Therefore, AmB is the most commonly used polyene antibiotic for the treatment of invasive fungal infections. However, the serious side effects as well as the low bioavailability of AmB strongly restrict its clinical applications. Polymer, with its diversified molecular design, is widely used in drug delivery in the form of polymeric prodrugs, nanoparticles, hydrogels, etc. Therefore, polymers hold great promise for the delivery of AmB in treating fungal infections. This review summarizes recent advances in polymer-based delivery systems of AmB for the treatment of fungal infections, including polymer-AmB conjugates, nanotechnology-based polymeric delivery systems, hydrogels, and polymeric microneedles. Taking advantage of polymer-based delivery strategies, special attention is paid to reducing the side effects and improving the bioavailability of AmB for safe and effective antifungal therapy. Finally, the limitations and possible future directions of polymer-based AmB delivery systems are discussed.

Pressure-sensitive adhesives (PSAs) bond surfaces with minimal pressure, eliminating the need for heat, water, or solvents. Ethylene vinyl acetate (EVA) is a well-established polymer in hot melt adhesives; however, research on EVA-based PSAs is limited. This study introduces nonylated diphenylamine (NDPA), a liquid derivative of diphenylamine, as a novel tackifier and antioxidant for EVA-based PSAs. By simply mixing NDPA with EVA at elevated temperatures, an EVA-based PSA is successfully formulated without the use of toxic solvents. The molecular structure of NDPA, characterized by alkyl chains and secondary amines, allows it to interact effectively with both the polyethylene (PE) and vinyl acetate moieties in EVA. These interactions significantly enhance the viscoelastic properties and adhesive strength of the formulations. Notably, the addition of NDPA increases lap shear strength from 98.67 kPa for pure EVA to 516.67 kPa for the EVA-NDPA formulation containing 40 wt.% NDPA. Furthermore, a 50 wt.% inclusion of NDPA achieves the highest peel strength of 6.5 N mm⁻¹, surpassing that of commercial PSA tape. Additionally, NDPA contributes to preventing oxidative degradation, significantly enhancing the longevity of adhesive properties and positioning it as a promising additive for improved EVA-based PSA formulations.

Nonwoven mats of electrospun nanofibers are widely used in an array of applications, including those related to filtration, textiles, and tissue engineering. The performance of the mats is often plagued by their relatively weak mechanical strength due to the lack of bonding at the junction points between fibers. To address this issue, here a controllable technique is demonstrated for welding a nonwoven mat of poly(ε-caprolactone) fibers into an interconnected network by leveraging the photothermal effect of Au nanocages under the irradiation of a near-infrared laser. Upon irradiation for 2 s only, the poly(ε-caprolactone) fibers in a nonwoven mat are permanently welded at the junction points. When the irradiation time is increased to 5 s, the fibers fused together transforming the porous and opaque mat into a transparent solid film. In addition to strengthening nonwoven mats of electrospun nanofibers, this technique may open the door to new applications such as masking, patterning, and printing.

Hydrogen bond, as a type of high-strength non-covalent interaction, is adopted in the construction of highly planar polymer frameworks. In this context, a new type of conjugated polymer, P(5MeOII-Pyr) is synthesized by copolymerizing 5,5'-dimethoxy isoindigo (5MeOII) with pyrazine (Pyr). By demethylation, P(5OHII-Pyr) is obtained, in which the hydrogen bond between the hydroxyl group on the isoindigo core and the nitrogen atom on the pyrazine core is formed. Compared to P(5MeOII-Pyr), P(5OHII-Pyr) exhibits a red shift of ∼20 nm in UV-vis absorption, which is related to the planarization of the polymeric backbone due to the hydrogen bond formation. Both materials demonstrate high thermal stability, with thermal decomposition temperatures around 400 °C. Organic field-effect transistor devices (OFETs) with a top-gate bottom-contact configuration are fabricated using these two materials and their charge transport behaviors are compared. Notably, the electron mobility of P(5OHII-Pyr) increases more than tenfold compared to P(5MeOII-Pyr), while its hole mobility is greatly suppressed, making it a n-type-transport preferred material. This improvement is primarily due to the introduction of hydroxyl groups, which makes the polymer more planar, allowing better delocalization of LUMO, thereby facilitating electron transport along the polymer backbone.

This study reports the synthesis of acrylate-based polymers with diverse topologies, including cyclic and 8-shaped structures, using a combination of atom transfer radical polymerization (ATRP) and click coupling reactions. The linear and tetra-arm poly(tert-butyl acrylate) (PtBA) polymers with similar molar masses are synthesized via the activators regenerated by electron transfer atom transfer radical polymerization. These polymers are further transformed into cyclic and 8-shaped topologies, respectively, through a click reaction. All topologies possessed similar molar mass are confirmed using ¹H NMR, FT-IR, SEC, and MALDI-TOF mass spectrometry. The influence of macromolecular topology on intrinsic viscosity and glass transition temperature (T_g) is systematically investigated. The findings show that within the PtBA topology series, T_g increases with structural compactness, with cyclic polymers exhibiting higher T_g than their precursors. Additionally, intrinsic viscosity decreases as compactness increases across the various topological macromolecules. These observations highlight the potential of topology as a tool for fine-tuning polymer properties, facilitating the development of advanced materials with specific behaviors in solution and bulk properties.