ACS Applied Polymer Materials最新文献

Electrospun nanofiber-based waterproof and breathable membranes (WBMs) that can provide a high level of protection and excellent air permeability and functionality are becoming promising core materials in numerous fields. However, large challenges still remain in the facile preparation of high-performance and smart WBMs capable of forecasting the failure of waterproof protection. Herein, amphiphobic TPU/PVDF-HFP nanofiber membranes with an interlaced fibrous structure are prepared by a one-step multineedle electrospinning technology. The obtained membranes demonstrate outstanding waterproofness with a hydrostatic pressure of over 108 kPa, a high air permeability of over 10 mm s^–1, and a water vapor transmission rate (WVTR) of 8.40 kg m^–2 d^–1, as well as excellent mechanical properties with a tensile strength of 6.07 MPa and a tensile strain of 117.11%. These make them extremely suitable for WBM applications. More importantly, due to the robust interlaced fibrous structure and the piezoelectric property of PVDF-HFP, the hydrostatic pressure of the TPU/PVDF-HFP membranes can be easily monitored and predicted by measuring the voltage output, indicating excellent hydrostatic pressure monitoring capability. The addition of low-surface-energy chemical materials endows the membranes with durable amphiphobicity against various harsh conditions, which further enhances the waterproof property. Such versatile nanofiber membranes would be desirable for potential applications in protective clothing and wearable electronic products and would provide a source of inspiration for the fabrication of smart WBMs.

Dendrimers and dendrons are widely studied in the industrial and academic fields, but their efficient synthesis remains challenging. We herein report the synthesis of a type of urethane-based dendron through a facile, tailor-made, iterative click-addition process (iCAP). Hydroxyl-group-terminated first–5th generation dendrons were synthesized through iCAP, in which nucleophilic urethane and thiol–ene addition reactions were repeated alternately. ¹H NMR spectroscopic and SEC measurements showed that each reaction progressed quantitatively at all stages. Because iCAP involves only two types of addition reactions, it is different from conventional polyurethane-type dendrimer and dendron syntheses in that it has high atom utilization efficiency. In addition to the iCAP to first–5th generation dendrons, the urethane-forming addition reaction to the terminal hydroxyl group also proceeded quantitatively, giving dendrons having long alkyl chain termini. Differential scanning calorimetry measurements showed that the thermophysical properties of the dendrons changed as the number of generations increased. Additionally, when we investigated the aggregation of the dendrons by scanning electron microscopy images of the solution-growth solids, unique morphologies were observed. It is expected that by expanding this synthetic process, we will be able to design and synthesize a variety of topological sequence-defined polymers and impart them with a wide variety of polymer functionalities.

Surface-enhanced Raman spectroscopy (SERS) can significantly enhance Raman scattering signals of samples located at or very close to the Ag nanoparticles. The flexible SERS substrates may broaden the application of SERS technology because of high SERS efficiency, conveniently collecting or in situ detecting liquid samples. The glutaraldehyde cross-linked branched polyethylenimine loading silver nanoparticles (bPEI/AgNPs) composite with dual three-dimensional (3D) network structures was in situ synthesized under vortex at room temperature and lyophilization. The first molecular-level 3D network with a topological cross-linking structure provided uniformity and stability of Ag nanoparticles in the flexible bPEI/AgNPs composite, while the second micro-3D network with a coarsely porous structure further endowed the flexibility of the bPEI/AgNPs composite, and rapid and effective absorbing the liquid sample, in addition to bringing about the SERS effect. UV–vis spectroscopy, X-ray diffraction analysis, and energy dispersive spectroscopy confirmed the formation of Ag nanoparticles in the bPEI/AgNPs composite. The microimage of the spongy bPEI/AgNPs composite with 3D porous microstructure and the shapes of Ag nanoparticles were analyzed using scanning electron microscopy and transmission electron microscopy. Mechanical property analysis showed good flexibility of the bPEI/AgNPs composite. The bPEI/AgNPs composite exhibited the strong SERS effect for Rhodamine 6G (R6G), thiram, and bovine serum albumin (BSA), of which the detection limits were 1.0 × 10^–6, 1.0 × 10^–5, and 5.0 × 10^–6 mol/L, respectively. The SERS enhancement factor of R6G was further determined to be 2.0 × 10⁵. The 3D rough and porous microstructure of the bPEI/AgNPs composite absorbing R6G was observed in the 3D micro-Raman image. The Raman bands of the amino acid residues and the second structural domains of BSA molecules approaching Ag nanoparticles were significantly enhanced by the bPEI/AgNPs composite. The bPEI/AgNPs composite is thus promising for use as a spongy flexible SERS substrate for Raman active compound analysis through convenient and fast sampling.

Radioactive iodine species, ¹²⁹I and ¹³¹I, are volatile radioactive nuclides generated from nuclear fission processes. The exposure of these isotopes has caused severe effects on the environment as a result of the long half-life of ¹²⁹I and high radiation energy of ¹³¹I. Therefore, ideal adsorbents capable of effectively adsorbing iodine from gas and solution phases have received particular attention. In this study, we applied the concept of supramolecular noncovalent interactions to design the functional polymeric adsorbents for efficient iodine removal. A series of nitrogen-functionalized hyper-crosslinked polymers (HCPs) containing hydrazine (P-Hz), azide (P-Az), and amine (P-Am) were synthesized from the reactive tosylated HCP (P-OTs) through facile organic transformations. After being characterized by Fourier transform infrared (FTIR), thermogravimetric analysis (TGA), UV–vis, scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) surface area analysis, iodine adsorption in the gas phase and solutions was investigated, and the results revealed that the interplay between the electron-donating ability of nitrogen functional groups of HCPs and the molecular iodine (I₂) resulted in enhanced iodine adsorption compared to the nitrogen-free HCPs. Density functional theory (DFT) computational studies and UV–visible spectroscopic titrations revealed the formation of the N···I–I halogen bonding, where the electron-donating nature of nitrogen in hydrazine, azide, and amine, as well as the solvent medium, significantly governed the strength of interactions. Importantly, P-Am exhibited a high iodine adsorption capacity of 2.83 g·g^–1 in the gas phase and 506.8 mg·g^–1 in the hexane phase, albeit with low porosity, suggesting the importance of specific functional groups in the adsorption capacity. X-ray fluorescence (XRF) and Raman spectroscopic analysis of P-Am after iodine adsorption suggested that iodine species are stabilized on the polymer matrix in the form of polyiodides such as I₃^– and I₅^–.

The advancement of functional stimulus-responsive materials is highly important for achieving bionic artificial intelligence. Nevertheless, it is difficult to fabricate hydrogels that exhibit both fluorescence brightness and shape variation simultaneously in response to various stimuli. This work presents the design of a fluorescent hydrogel that responds to stimuli in a layered and asymmetric manner. The pH response layer consists of poly(acrylamide-sodium methacrylate) [P(AAm-NaMA)], while the T response layer consists of poly(acrylamide-N-isopropylacrylamide) [P(AAm-NIPAM)]. Furthermore, the hydrogel matrix contains a water-soluble polymer, tetraphenylethylene-3-sulfopropyl methacrylate potassium salt (TPE-PSPMA) with aggregation-induced emission (AIE). At strong acidic pH, the protonation of PNaMA chains leads to dehydration and shrinkage of the hydrogel network, resulting in hydrogel deformation toward the side of P(AAm-NaMA). When T is higher than lower critical solution temperature (LCST), PNIPAM has intramolecular interaction, causing the network to lose water and shrink, and then the hydrogel bends backward. Furthermore, the hydrogel network contracts when exposed to T or pH, which restricts the internal rotation and vibration of the TPE-PSPMA molecules. As a result, the hydrogel exhibits an AIE effect, leading to a shift in the fluorescence intensity. This finding offers valuable insights for the development of intelligent systems and holds significant potential for applications in the domains of soft robotics and smart wearable devices.

Sulfur dioxide (SO₂) is a hazardous pollutant that significantly poses a risk to human health and the environment. However, the development of SO₂ sensors that work at room temperature has been significantly hindered due to their inadequate recovery properties. In this context, we have introduced a thiazole decorated conjugated polymer (BBT) for the detection of SO₂ at 25 °C. Moreover, we improve the SO₂ sensing performance at 25 °C by modifying the backbone of the BBT polymer with a benzo[2,1,3]selenadiazole ring (BSe), resulting in BBTBSe. The BBTBSe sensor exhibits a 4.3× higher response compared to the BBT sensor. When exposed to 100 ppm of SO₂, the BBTBSe and BBT sensors show response values (R_g/R_a) of 199.4 and 45.7, respectively, with a rapid response/recovery time of 60/70 s at 25 °C. Additionally, both the BBTBSe and BBT sensors show excellent selectivity to SO₂ in comparison to other gases, with a selectivity factor greater than 5.3. The BBTBSe sensor exhibits a linear behavior in the concentration range of 1–50 ppm, with limit of detection (LOD) and limit of qualification (LOQ) values of 0.23 and 0.76 ppb, respectively. The BBTBSe sensor also exhibits complete reversibility and repeatability with prolonged stability. Additionally, a possible mechanism for SO₂ sensing has been proposed, based on acid–base and dipole–dipole interactions between the lone pair of nitrogen and SO₂ gas molecules. As a result, we believe that the results of the BBTBSe sensor offer a significant opportunity to develop a sensor with high sensitivity and selectivity, expanding its application in medical diagnosis and environmental pollution monitoring.

Cross-linkers employed to enhance cyclodextrin’s (CD) stability and mechanical strength in composite polymers may additionally enhance micropollutant removal. The impact of cross-linker types on the interaction, removal, and uptake of steroid hormones (SHs) with cross-linked β-cyclodextrin polymer (βCDP) in functionalized composite nanofiber membranes (CNMs) was investigated. The primary objective of the study was to assess the efficiency of CNM cross-linking with triphenylolmethane triglycidyl ether (TMTE) and trimethylolpropane triglycidyl ether (TPTE) in eliminating SH, as compared to the extensively used epichlorohydrin (EP) that is recognized for its higher toxicity and epoxy-based structure. Fourier-transform infrared spectroscopy (FTIR) confirmed the formation of the cross-linked βCDP structure, while thermogravimetric analysis (TGA) validated the successful immobilization of βCDP in nanofiber matrix membranes before and after filtration. The type of cross-linker influenced the uptake of SHs and their removal by the βCD molecules during filtration. The highest SH removal was achieved with βCD-EP and βCD-TPTE, reaching 67 ± 4 and 59 ± 5%, with respective uptake values of 10.6 and 9.7 ng/cm² at a flux of 600 L/m²h and using the nanofiber matrix thickness of 320 and 528 μm. βCD-TMTE exhibited the lowest removal (22 ± 7%) and uptake (4.9 ng/cm²) due to the hindrance posed by its Y-shaped polymeric chain, which limited access to the βCD cavity. Molecular dynamics simulations further supported these experimental findings, illustrating a more dispersed spatial distribution of SH molecules around the βCD cavity when TPTE and TMTE were used as cross-linkers, in contrast to EP. In conclusion, triphenylphosphine glycidyl ether (TPTE) could be used as a potential alternative for EP in βCDP CNMs, given the comparable efficacy in SH removal and uptake. This study highlights the significance of cross-linker selection for designing cyclodextrin-based materials applied to micropollutant removal from water.

Water pollution is a critical global environmental challenge, necessitating efficient and innovative remediation strategies. This work outlines the successful synthesis of poly(vinylidene fluoride) (PVDF) composite membranes infused with varying proportions of magnesium-doped zinc oxide (MgZnO) using an economical and simplified interfacial film-forming method. The MgZnO0.1PVDF1–1 composite membrane demonstrates exceptional and stable purification performance, significantly reducing the amount of antibiotics in water through a combination of static adsorption and ultrasound-guided piezoelectric degradation. SEM/FTIR/XPS/BET analyses postulate the underlying adsorption mechanisms as surface complexation, ion-dipole interaction, and cation exchange coupled with piezoelectric catalysis via the ion-dipole moment effect. The degradation process leverages a unique converse and positive piezoelectric effect, inducing surface mechanical deformation and internal free radical polarization and fostering outstanding tetracycline (TC) degradation. Comprehensive experiments considering variables such as pH, concentration, and reaction time further substantiate the superior performance of MgZnO0.1PVDF1–1, achieving an impressive maximum TC removal ratio of 86%. The high TC removal efficiency, enduring recycle performance, and economical operative method underline MgZnO0.1PVDF1–1 as a significant potential for mitigating antibiotic water pollution.