ACS Applied Polymer Materials最新文献

Postoperative residual tumor cells and their oxidative stress-induced injury to normal skin cells often cause tumor recurrence. Hence, doxorubicin-loaded mesoporous silica (SiO₂@DOX) nanoparticles were incorporated into polydopamine-polyacrylamide (PDA–PAM) hydrogel through hydrogen bond interaction to obtain a hydrogel patch (SiO₂@DOX/PDA–PAM). The covalent and noncovalent cross-linked SiO₂@DOX/PDA–PAM hydrogel exhibits flexible mechanical properties (toughness of 7.38 kJ/m³, compressive strength of 62.28 kPa) and strong adhesion properties (adhesive strength of 8.04 kPa). The porous structures of SiO₂@DOX greatly increased the DOX loading ability, and those were uniformly dispersed in the hydrogel. In vitro DOX release of the SiO₂@DOX/PDA–PAM hydrogel avoided DOX burst release and realized slow release in a sustained manner (about 84.74% at 120 h), resulting in excellent in vitro antitumor efficacy (92.84%) after 48 h treatment. Besides, the hydrogel also protected normal cells from oxidative damage by scavenging massive reactive oxygen species (ROS). Therefore, the hydrogel patch holds great promise in elimination of postoperative residual tumor.

High-performance multifunctional hydrogels exhibit immense potential for transforming health technology, particularly through applications in wearable healthcare devices and therapeutic systems. These materials are valued for their ability to closely mimic biological tissues while integrating key functional attributes. However, achieving a combination of outstanding mechanical strength, high conductivity, and self-healing properties in a single hydrogel remains challenging. In this study, we present a one-pot synthesis method for fabricating the PVA/PAM/NaCl/CB (PPNC) hydrogel, composed of poly(vinyl alcohol) (PVA), polyacrylamide (PAM), sodium chloride, and carbon black. By leveraging physical entanglement within the PPNC network along with dynamic chemical bonds and reversible physical interactions, the hydrogel achieves superior mechanical robustness and self-healing properties. The PPNC hydrogel demonstrates impressive mechanical performance, with a tensile strength of 688 kPa and elongation over 700%, alongside high electrical conductivity (4.9 S·m^–1 at 25 °C). Additionally, its exceptional antifreezing capabilities allow it to maintain these properties at −20 °C. As a proof-of-concept, the hydrogel has been successfully applied as a motion-sensing device, accurately tracking human movement for health monitoring, and as a heating device, delivering effective thermal therapy to the human body. These findings highlight the hydrogel’s significant potential in healthcare innovation, including wearable technology, biological sensors, and therapeutic devices.

Shape memory polymers (SMPs) can transform between initial and programmed shapes under certain stimuli and have promising potential in developing shape-adaptative bone scaffolds to treat irregular bone defects in minimally invasive implantation. Polylactic acid (PLA) is a degradable, biocompatible polymer that has thermal-responsive shape memory properties; however, its high transition temperature (approximately 50–60 °C) limits clinical applicability. This study proposes to develop a shape memory PLA based composite bone scaffold that can be gently thermally driven under a moderate temperature near the body by adding tributyl citrate (TBC) and fabricated via FDM 3D printing. The 3D-printed PLA/TBC composite scaffolds showed ordered porous structures with an orthogonal periodic interconnection. The mechanical test showed that TBC significantly increased the toughness of the scaffolds while it decreased its strength and modulus. The thermal physical property test showed that the glass transition temperature was successfully reduced from 54.9 °C (pure PLA) to 40.2 °C (10% TBC), approaching body temperature through TBC’s plasticization mechanism where low-MW ester molecules increased PLA chain mobility, thereby enhancing their flexibility. The shape memory test showed the shape fixation rate of the PLA/TBC scaffold achieved 97.2% with 10% TBC, and it can transform from programmed shape to initial shape in 30 s with a shape recovery rate of 92.8% under a gentle thermal stimulation at 45 °C. Then, proof of concept of this scaffold for minimally invasive implantation of the irregular bone defect model was presented. Besides, other tests showed that the hydrophilicity and degradation performance of the scaffolds were improved with TBC. Meanwhile, TBC also promoted the biomineralization and cellular response of the scaffold. This study provides an insight for developing shape- and temperature-adaptive bone scaffolds for minimally invasive repair of irregular bone defects.

Utilizing soft optical materials in mechanochromic sensing is an intriguing concept with several application areas in soft robotics and functional wearables. Herein, we developed stretchable cholesteric cellulosic liquid crystal filaments by simply encapsulating the aqueous hydroxypropyl cellulose (HPC) mesophases in a sealed thermoplastic elastomeric tubing. The tubular confinement of the HPC induced a well-defined cholesteric structure in which the quasi-layers are concentrically distributed along the fiber axis. The flow properties of the aqueous HPC showcased the ability to mimic the stretching and relaxing behavior of the elastomeric tubing, resulting in a spontaneous color change in response to mechanical deformation. This soft optical system can act as a stretchable colorimetric sensor for both tensile and compression forces enabled by the uniform alignment and dynamic deformation of the HPC mesophase.

To develop a polymer that leaves no microplastic traces in compost and is recyclable, this study investigates the degradation behavior of custom-designed synthetic aliphatic–aromatic polyesters. These polyesters, synthesized via melt polycondensation from 1,4-benzenedimethanol and aliphatic diacids of varying chain lengths, underwent comprehensive degradation experiments in alkaline solutions, industrial compost, sludge water, and with five enzymes: commercially obtained Hi-Cutinase (HiC), Esterase EL-01, and in-house-produced Ideonella sakaiensis PETase (IsPETase), Cryptosporangium aurantiacum PETase variant M9(CaPETase), and metagenomic leaf-branch compost cutinase variant ICCG (LCC^ICCG). The degradation behavior was correlated with polymer properties, including chemical structure, melting point, hydrophobicity, and crystallinity. Spiking and compost extraction experiments confirmed complete degradation of all polyesters under study within 12 weeks in industrial compost, leaving no detectable plastic residues. Enzymatic studies identified HiC as the most effective enzyme for these polyesters at 30 °C, while odd-carbon-containing polyesters served as good substrates for Esterase EL-01, HiC, and IsPETase. In contrast, aromatic PET, even with low crystallinity, showed no enzymatic specificity with these enzymes.

Polyethylene-grafted layered silsesquioxanes, termed polyethylene-clays (PEC), are nanocomposites comprising polyethylene chains tethered to inorganic sheets with a phyllosilicate-like structure. Here, we report that these nanocomposites show two-stage crystallization on cooling, qualitatively different from previous reports on polyethylene nanocomposites. We employ differential scanning calorimetry (DSC) and small-angle X-ray scattering (SAXS) to study the melting and crystallization of PEC. End tethering of the polyethylene chains to a nanosheet strongly influences the manner in which PEC crystallizes from the melt on cooling. PEC exhibits two-step crystallization, characterized by a sharp high-temperature exotherm, followed by a broader exotherm at lower temperatures, in contrast to a single sharp exotherm for neat polyethylene. SAXS indicates that lamellar stacks form at high temperatures and that the low-temperature exotherm corresponds to the formation of additional lamellae and their insertion within these stacks. PEC exhibits lower peak melting temperature, lower crystallinity, and a wider melting range relative to polyethylene. We show that the progress of crystallization of PEC is determined by its ultraslow relaxation dynamics. In contrast, PEC in xylene solution exhibits a significantly shorter relaxation time than the melt PEC. Such systems exhibited a single exotherm on cooling and SAXS structure factor peaks with peak positions in a ratio of 1:2. We hypothesize that the high melt viscosity inhibits the crystallization-induced decrease in the specific volume of PEC, resulting in tensile internal stresses that determine the observed thermal behavior.

In recent years, poly(vinylidene fluoride) (PVDF), widely used in piezoelectric applications, has been associated with health and environmental concerns due to issues regarding per- and polyfluoroalkyl substances (PFASs). There is an urgent need to find flexible piezoelectric materials. This study introduces a promising solution by developing flexible composite papers from boron nitride nanotubes (BNNTs) and cellulose nanofiber (CNF). CNF was modified with amine groups via ultrasonication and then combined with BNNT to form a flexible composite paper with exceptional thermal, mechanical, and piezoelectric properties. Notably, the paper demonstrated a 220% increase in thermal conductivity at 10 wt % BNNT compared to raw CNF paper and a d₃₃ piezoelectric response of −11.2 pC/N without a high-voltage poling process or mechanical stretching. BNNT-CNF composite paper provides a robust platform for advancing future energy technologies, paving the way for replacing PVDF in various flexible electronic and piezoelectric applications.

Ladder polysilsesquioxanes with a closed cyclic structure are of great interest due to a combination of unique physical and chemical properties. Synthesis is performed using toxic organic solvents, catalysts, and expensive precursors and at high temperatures or in highly concentrated solutions. We describe an environmentally benign one-step formation of ladder polysilsesquioxanes in aqueous solutions on nano/microfibrillar cellulose aerogels. The synthesis is carried out by sol–gel chemistry using the precursor tris(2-hydroxyethoxy)methylsilane, which along with the methyl group contains three residues of ethylene glycol, facilitating the solubility of silane in water up to 20 wt %. This eliminates the use of organic─often toxic─solvents. The formation of ladder polysilsesquioxanes, as shown by attenuated total reflectance-Fourier transform infrared (FTIR) spectroscopy, occurs in dilute neutral solutions (≤0.1 M) without heating and the addition of a catalyst. The catalysis of the sol–gel process is achieved by nano/microfibrils, which are revealed by small-angle X-ray scattering. They also serve as a structure-directing template. The proposed mineralization of aerogels in the form of ladder polysilsesquioxanes coating, as demonstrated in a number of examples, opens up wide possibilities for the development of hydrophobic, mechanically strong, and flame-resistant materials for various applications.

To meet the requirements of high-frequency signal transmission in 5G or 6G applications, the development of high-performance functional polyimide possessing a low dielectric constant (D_k) and low dielectric loss (D_f) at high frequencies, along with melting processing capabilities and good adhesion to copper foil, is both urgent and highly challenging. In this work, three diamines containing tert-butyl moieties and ether bonds but different substitution positions of amine groups were designed and synthesized, and high-performance poly(ether imide)s (PEIs; TBPI, TTBPI, ATBPI, and PTBPI) were obtained from their polycondensation with 4,4′-(4,4′-isopropylidenediphenoxy) diphthalic anhydride (BPADA). The introduction of flexible groups such as ether bond and bisphenol A structure has the potential to improve the flexibility of the molecular chains and reduce the density of the imide ring, the molecular polarity, and the glass transition temperature of the PEIs. The incorporation of the unique spatial structure of the nonpolar tert-butyl side group may help to increase the free volume and exceptional hydrophobicity of the PEIs. Both give the as-prepared fluorine-free PEIs a range of beneficial characteristics, such as melting processing property, excellent solubility, low water absorption (0.42, 0.35, and 0.50% at P/P₀ = 0.50 (50% relatively humidity (RH)), respectively), high-frequency low D_k (2.83, 2.84, and 2.82 at 10 GHz and 50% RH), low D_f (0.00339, 0.00257, and 0.00366 at 10 GHz and 50% RH), and good peel strength with copper foil via hot-pressing molding. The successful development of such functional PEIs enables the preparation of truly adhesive-free flexible copper clad laminates (FCCLs) via hot-pressing molding. This significantly simplifies the preparation process and structure of high-performance FCCLs and enhances the reliability of electronic circuits, thereby presenting attractive application prospects for high-frequency mobile communication.

Phase change materials (PCMs) are crucial in energy storage. However, they often suffer from high rigidity, poor thermal conductivity, and weak light absorption capabilities. In this study, a phase change hydrogel was developed by incorporating a hydrated salt, polymers, and carbon nanotubes (CNTs). The energy storage material used was disodium hydrogen phosphate dodecahydrate (DHPD), with sodium polyacrylate (PAAS) formed through thermally initiated in situ polymerization and starch (ST) serving as the flexible matrix. The results demonstrated that CNTs enhanced the composite’s thermal conductivity and light absorption ability. Under a simulated light intensity of 1000 W/m², the light-thermal conversion efficiency of the composite reached up to 89.57%, and under a voltage of 10 V, the electric-thermal conversion efficiency reached a maximum of 81.85%. The enthalpy value reached 137.6 J/g, along with good thermal cycle stability. The proposed method not only overcomes the shortcomings in the development of traditional PCMs but also demonstrates its potential applications in solar thermal harvesting systems, flexible wearable thermal management devices, and electric-thermal energy conversion, effectively contributing to the advancement of sustainable development and energy management technologies.