ACS Applied Polymer Materials最新文献

Poly(lactide-co-glycolide) nanoparticles (PLGA NPs) loaded with Perfluoro-15-crown-5-ether (PFCE) have been developed for imaging applications. A slight modification of the formulation led to the formation of two distinct particle ultrastructures: multicore particles (MCPs) and core–shell particles (CSPs), where poly(vinyl alcohol) (PVA), a nonionic surfactant, and sodium cholate (NaCh), an anionic surfactant, were used, respectively. Despite their similar composition and colloidal characteristics, these particles have previously demonstrated significant differences in their in vivo distribution and clearance. We hypothesize that these differences are collectively driven by variations in their structural, chemical, and mechanical properties, which are investigated in this study. Nanomechanical characterizations of MCPs and CSPs by atomic force microscopy (AFM) revealed elastic modulus values of 54 and 270 MPa in water, respectively, indicating a better permeability and deformability of the multicore ultrastructure. The impact of the surfactant on the NP surface chemistry was evidenced by their protein corona, which was significantly greater in the CSPs. Additionally, an important amount of residual NaCh was found on the surface of CSPs, which formed strong interactions with bovine serum albumin (BSA), accounting for the difference in protein coronas and surface chemistry. Surprisingly, in vitro cell uptake studies showed a higher uptake of MCPs by RAW macrophages but a preference for CSPs by HeLa cells. We conclude that for this specific formulation and in this stiffness range, mechanical differences have a stronger impact in HeLa cells, while surface properties and chemical recognition play a more important role in uptake by macrophages. Overall, the extent to which a physical factor impacts cell uptake is highly dependent on the specific uptake mechanism. With this study, we provide an integrated perspective on the role of different surfactants in the particle formation process, their impact on particle ultrastructure, mechanical properties, and surface chemistry, and the overall effect on cell uptake in vitro.

Hydrophobic eutectogels represent an emerging class of soft materials with significant potential to revolutionize underwater body signal recording and sensing technologies. Existing materials, however, are limited by poor performance or low biocompatibility. To address these challenges, herein, we propose a biobased eutectogel that combines hydrophilic and biocompatible deep eutectic solvents (DES) with a nontoxic and highly hydrophobic polymer matrix based on acrylated epoxidized soybean oil (AESO). We demonstrate fine-tuning of electrochemical, rheological, mechanical, and water-repelling properties by varying the degree of AESO functionalization and their DES composition and content. The resulting formulations demonstrated excellent suitability as inks for VAT photopolymerization three-dimensional (3D) printing, enabling the fabrication of structured hydrophobic gel electrodes. Underwater electromyography (EMG) recordings highlight the potential of these materials for use in marine biology, exploration, and environmental monitoring applications.

Poly(lactic acid) (PLA) is a biopolymer that resembles oil-based plastics in its mechanical properties. However, in manufacturing techniques such as fused deposition modeling (FDM), the inherent characteristics of the process led to a reduction in the mechanical properties of PLA-based pieces. To improve the material performance, one strategy is photo-cross-linking PLA chains. Functionalization of PLA requires grafting a molecule capable of reacting with it and ultimately cross-linking the polymeric chains. In this research, methacrylate coumarin was incorporated into PLA via free-radical grafting under reactive extrusion conditions for 5 min. The highest grafting degree value was 0.7% after the addition of 10 and 5 wt % coumarin and dicumylperoxide, respectively. Thereafter, a thin film of the material was ultraviolet (UV)-exposed for 48 h, and photo-cross-linking was confirmed with a gel formation of 16.9%. As a result, the thermal stability and melt strength of pure PLA increased by 7 °C and 1 order of magnitude, respectively. Finally, the tensile properties were evaluated by printing 3D specimens. Photo-cross-linked films were blended with nonirradiated coumarin-based PLA to obtain high infill density values (89% ± 0.8). The mechanical strength (17.8%) and stiffness (26%) of the neat PLA were enhanced.

The widespread use of plastics has caused serious environmental pollution, and the use of cellulose paper products to replace plastics has attracted worldwide attention. However, the rich hydroxyl groups and structure voids lead to poor barrier properties of cellulose paper products to water and oil. Herein, a rosin-based polymer coating (RB) is reported, which is prepared by cross-linking a rosin-modified silane coupling agent (RM) with hydroxyl-capped polydimethylsiloxane (OH-PDMS) and ethyl orthosilicate (TEOS). The RB can form a dense and uniform barrier layer on the surface of the cellulose paper product, so that the RB-coated paper (RB paper) exhibits excellent properties, including (1) water resistance (exhibiting a water contact angle of 102.3°, the relative water absorption rate decreased by over 90% at both 25 and 90 °C, reaching 35.1% and 45.9%, respectively), (2) oil resistance (Kit test reaches no. 10, and the relative oil absorption rate decreased by over 90% at both 25 and 90 °C, reaching 4.1% and 6.4%, respectively), and (3) high mechanical properties (tensile strength increased from 23.2 to 40.6 MPa, stronger than partly commercial plastics). Moreover, RB paper exhibits biodegradability and recyclability. These impressive performances position RB paper as a viable alternative to plastic.

Recently, ionic thermoelectric hydrogels have attracted much attention, and it is desirable to use ionic thermoelectric hydrogels to couple thermoelectric properties and strain sensing performance, enabling potential applications in the field of wearable electronics. Nevertheless, simultaneously improving the Seebeck coefficient and ionic conductivity of ionic thermoelectric hydrogels remains a challenge. Here, a dual-cation doping strategy is used to regulate ion diffusion rate to improve the thermoelectric properties of ionic hydrogels, and a series of poly(vinyl alcohol) (PVA)-based hydrogels doped by dual cations (i.e., hydrogen ions and alkali metal cations, such as Li⁺, Na⁺, and K⁺) are prepared by a facile cyclic freeze–thaw method. With dual-cation doping, H⁺ and alkali metal cations interact with the hydroxyl on PVA chains, resulting in partial destruction of hydrogen bonding, which is beneficial for improving ion diffusion rate. The results show that PVA/HCl/NaCl hydrogels demonstrate a high Seebeck coefficient of 7.43 mV K^–1 and a good ionic conductivity of 33 mS cm^–1 at ambient temperature, which are much higher than those of the PVA/NaCl hydrogel. Furthermore, the PVA/HCl/NaCl ionic hydrogels exhibit good tensile strength (0.65 MPa) and sensitivity (GF = 1.25), making them suitable as flexible strain sensors to monitor body movement, with potential application in the field of wearable electronics.

This work presents a 6FDA-DAM polyimide (PI) ((4,4′-hexafluoroisopropylidene) diphthalic anhydride 1,3,5-trimethyl-2,6-phenylenediamine) as the continuous polymeric phase for preparing mixed matrix membranes. The successful synthesis of the 6FDA-DAM polymer was verified by FTIR spectroscopy. N-heterocyclic linkers were incorporated into the UiO-67 framework, creating highly stable materials with exceptional surface areas. This enhancement improved CO₂ affinity and polymer adhesion. Field emission scanning electron microscopy images showed that the resulting films were uniformly coated with the synthesized UiO-67s, reducing the likelihood of nonselective defects in the interphase region. Gas permeation measurements demonstrated that these functionalized porous nanofillers significantly enhanced the CO₂ separation performance of the membranes. By optimizing the functionality and loading of the porous fillers, the CO₂/CH₄/N₂ separation performance was dramatically improved. Specifically, the insertion of 20 wt % of bpy25 (a mixture of biphenyl-4,4′-dicarboxylate (bpdc) and 2,2′-bipyridine-5,5′-dicarboxylic acid (bpy) in a 3:1 ratio) resulted in an exceptional CO₂ permeability of ∼1299 Barrers, a CO₂/CH₄ selectivity of ∼41.3, and a CO₂/N₂ selectivity of ∼50.7. These values are approximately 180%, 170%, and 166% higher than those of the unfilled PI. The improved separation factor is likely attributed to the abundant presence of the bipyridine moiety within the 6FDA-DAM matrix. This presence facilitates the interactions between Lewis acidic CO₂ and Lewis basic bipyridine, ultimately delivering outstanding performance that surpasses the Robeson curves for CO₂/CH₄/N₂ separations.

To develop high-performance epoxy resins (EP) that can be used to produce aircraft primary structure composite parts via vacuum-assisted resin infusion technology (VARI), low resin viscosity and high fracture toughness requirements must be met as well as maintaining the usual thermomechanical properties. Polymeric core/shell nanoparticles have demonstrated effectiveness in achieving these objectives, but their use at high level causes reduction of composites’ glass transition temperature and modulus. By investigating the fracture toughness of 180 °C-cured epoxy resins containing poly(2-ethylhexyl acrylate) core/poly(methyl methacrylate) shell nanoparticles (E/M), together with a poly(ether sulfone) (PES) thermoplastic polymer, the synergistic toughening effect is obtained and high fracture toughness is achieved, which is an over 101% increase in K_IC over the untoughened resin, without lowering the resin properties and still having viscosities suitable for resin infusion. Morphological studies using scanning electron microscopy (SEM) led to a mesoscopic toughening model comprising macroscale “core/shell particles” formed with thermoplastic PES domains as “cores” and the polyacrylate core/shell nanoparticles as the “shells”, resulting in much more effective functioning of common toughening mechanisms, i.e., crack deflection, bridging, and pinning, plastic deformation, and shear banding.

This study demonstrates the preparation of nanofiltration (NF) membranes using the high degree of tunability of an asymmetric polyelectrolyte multilayer (PEM) coating. The developed membranes are much more open with a high molecular weight cutoff (MWCO ∼1000 Da) compared to typical PEM NF membranes (MWCO ∼300–500 Da). A layer-by layer (LbL) assembly approach is applied to prepare PEM coatings to serve as the active separation layer of membranes. This approach allows additional control over the fine-tuning of the membrane’s effective pore size and surface chemistry (charge density, hydrophilicity), which are important aspects in membrane separation processes. The membrane selectivity can be further tailored by utilizing asymmetric PEM coatings, where the first support pores are coated with loose PEM followed by the application of a denser and thinner PEM separation layer. Following this approach, PEM-based NF membranes were prepared using poly(allylamine hydrochloride) (PAH)/poly(styrenesulfonate) (PSS) on a charged flat-sheet polyether sulfone (PES) membrane support prepared via a non-solvent induced phase inversion (NIPS) process. Coating with PAH/PSS quickly filled the support pores, and the selectivity was further enhanced by subsequent coating by replacing PSS with poly(acrylic acid) (PAA) to form (PAH/PAA) multilayers, followed by cross-linking. This led to significantly improved membrane performance while maintaining the thin film composite design. Further, it is shown that the PEM structure can itself be carefully tuned toward the removal of specific pollutants from specific feeds. The resulting membranes are highly hydrophilic, as confirmed through contact angle results, and rejection is governed by Donnan and size exclusion mechanisms, with retentions of divalent ions (up to 80%), dyes (100%), and neutral solutes (∼90%). These membranes can be an excellent choice for the simultaneous treatment of water and resource recovery applications in the textile industry to retain/recover dyes and heavy metal ions.

Poly(lactide-co-glycolide) nanoparticles (PLGA NPs) loaded with Perfluoro-15-crown-5-ether (PFCE) have been developed for imaging applications. A slight modification of the formulation led to the formation of two distinct particle ultrastructures: multicore particles (MCPs) and core-shell particles (CSPs), where poly(vinyl alcohol) (PVA), a nonionic surfactant, and sodium cholate (NaCh), an anionic surfactant, were used, respectively. Despite their similar composition and colloidal characteristics, these particles have previously demonstrated significant differences in their in vivo distribution and clearance. We hypothesize that these differences are collectively driven by variations in their structural, chemical, and mechanical properties, which are investigated in this study. Nanomechanical characterizations of MCPs and CSPs by atomic force microscopy (AFM) revealed elastic modulus values of 54 and 270 MPa in water, respectively, indicating a better permeability and deformability of the multicore ultrastructure. The impact of the surfactant on the NP surface chemistry was evidenced by their protein corona, which was significantly greater in the CSPs. Additionally, an important amount of residual NaCh was found on the surface of CSPs, which formed strong interactions with bovine serum albumin (BSA), accounting for the difference in protein coronas and surface chemistry. Surprisingly, in vitro cell uptake studies showed a higher uptake of MCPs by RAW macrophages but a preference for CSPs by HeLa cells. We conclude that for this specific formulation and in this stiffness range, mechanical differences have a stronger impact in HeLa cells, while surface properties and chemical recognition play a more important role in uptake by macrophages. Overall, the extent to which a physical factor impacts cell uptake is highly dependent on the specific uptake mechanism. With this study, we provide an integrated perspective on the role of different surfactants in the particle formation process, their impact on particle ultrastructure, mechanical properties, and surface chemistry, and the overall effect on cell uptake in vitro.

Segmented styrenic block copolymers, such as poly(styrene-b-ethylene-butylene-b-styrene) (SEBS), exhibit temperature-sensitive mechanical properties that can be fine-tuned, making them highly promising for shape-memory applications. So far, the addition of crystalline materials not only enhanced the shape memory via solid-to-liquid transition but also increased the risk of leakage during repeated cycles. To address this issue, we explored the self-assembly phenomenon of acylated cellulose as a phase-change material (PCM). They work as a stable PCM when they are grafted onto the cellulose surface. We improved the shape-memory performance of SEBS by incorporating myristoylated cellulose nanofibers (MCN) with a DS of 2.4 into the matrix and systematically investigated how varying the MCN content affects the mechanical properties, torsional shape memory, and residual strain of SEBS. The addition of MCN enhanced the dynamic mechanical properties, reduced the residual strain, and facilitated the formation of an additional crystalline phase within SEBS. The crystalline phase showed a melting temperature, T_m, of 64–66 °C. The optimized SEBS/MCN composite demonstrated 92.6% thermoresponsive shape fixity and 92.8% shape recovery across three cycles. To achieve an electrically driven shape-memory effect, we further doped the composite with silver nanowires (AgNWs). The final composite demonstrated excellent electro-thermal heating, reaching 80 °C within 30 s. It achieved 75% shape recovery within 5 min at just 8 V. This electro-thermal shape-memory composite is well suited for applications in aerospace, smart grippers, actuators, and soft robotics.