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Radical polymers hold great potential as solid-state conducting materials due to their distinctive charge transport mechanism and intriguing optical properties resulting from their singly occupied molecular orbital energy levels. Furthermore, the paramagnetic nature of their open-shell structures broadens their applicability, allowing them to be magnetic field-active while also offering promising spin transport properties. These molecular design features position radical polymers as interesting materials for next-generation quantum information systems as well. In this review, we highlight the progress regarding several stable open-shell radical macromolecular architectures. We commence by examining their synthetic methods along with the mechanisms governing charge transport in such materials, followed by emphasizing their significant development of solid-state optoelectronic materials, and we conclude by discussing their emerging roles in spintronic applications.

Thermoresponsive polymers have become a highly sought-after “smart material” due to their ability to modify their physical characteristics due to temperature changes. This research aimed to determine the biocompatibility of specific thermoreversible gels for immunocompetent cell models containing ImmuPHAGETM, human alveolar macrophage-like cells. Four polymers were selected based on their transition temperatures, including three commercially available pharmaceutical excipients, namely poloxamer 407, soluplus, and methylcellulose. The fourth system, poly(N-isopropyl acrylamide)-b-poly(ethylene oxide)-b-poly(N-isopropyl acrylamide), was synthesised in-house. Initially, the phase behaviour of these four polymers was evaluated visually by warming the polymer solutions and determining the state of the solution by vial inversion. Subsequently, a combination of rheological measurements was employed to compare the properties of these thermoreversible gels in culture media. The physical characterisation was followed by conducting cytocompatibility tests using human alveolar macrophages to assess their suitability as a scaffold for cell culture in vitro and to determine the cell response to different culturing environments. The study concluded that methylcellulose is the most promising and cost-effective material worth further exploration as a responsive matrix for immune cell encapsulation. Keywords: Thermoresponsive, Thermogelling, Alveolar macrophages, Foamy macrophages, immunocompetent in vitro models.

The drug overdose epidemic in America has intensified over the past 20 years and has led to hundreds of thousands of deaths. Opioids account for most of these deaths, but overdose can be effectively reversed using naloxone, an FDA-approved medication. The rate of non-****** drug fatalities has also risen in recent years—but unlike opioids—many of these drugs do not have specialized treatments in cases of overdose. Instead, activated charcoal is ingested to decontaminate the gastrointestinal tract before the drug is absorbed by the blood. Although activated charcoal is an effective drug adsorbent, there are many adverse side effects following respiratory and oral exposure. To address the drawbacks of this treatment, a new class of aromatic polypeptide amphiphiles (termed “KEYs”) were developed to adsorb drugs from the stomach and intestines without harmful side effects. This manuscript details the rational design and synthesis of KEY polypeptide adsorbents. KEYs were evaluated against model compounds acid yellow 3 and amitriptyline in simulated biological media and compared to activated charcoal. Adsorption studies indicate that KEYs are capable of adsorbing drugs. KEYs adsorb molecules as rapidly as activated charcoal and adsorb certain compounds with comparable or higher adsorption capacity in a pH-dependent manner. This work represents a novel application of aromatic polypeptide amphiphiles as a gastrointestinal decontamination technology. Further, these studies provide insight for how future generations of polypeptide-based adsorbents can be rationally designed to selectively target and improve drug adsorption from the gastrointestinal tract.

Aerogels, which are ultralightweight and highly porous materials, are excellent insulators with applications in thermal management, acoustic impedance, and vibration mitigation. Aerogels have huge potential in the aerospace industry as a lightweight solution for thermally insulating electronic components which are confined within a small volume. However, the application of aerogels is currently hampered by the primary processing method of molding, which is costly, time-consuming, requires tooling, and limits geometric complexity. The extrusion-based 3D printing method of direct ink writing (DIW) provides an avenue to move past these constraints. However, rheology modifying additives are commonly used to make a sol printable, which may negatively impact the performance of the product aerogel. Here, we report the DIW of pure polyimide aerogels by subjecting the sol to mild heating (60 °C for 5 min) to promote gelation and produce a printable ink. This approach yielded printed aerogels with comparable microstructural, mechanical, and thermal properties to cast aerogels. The printed aerogel is stable up to 500 °C and has potential for high temperature applications relevant to the aerospace industry. We highlight the utility of this system by printing a bespoke enclosure to insulate a heating plate as a model for batteries; even at a plate temperature of 120 °C, the surface of the 8 mm thick aerogel maintained ambient temperature, indicating excellent inhibition of heat transfer. Additionally, a printed aerogel casing for a solid-state electrolyte coin cell battery resulted in a tenfold increase in ionic conductivity sustained for 100 min. This novel, simple method for 3D printing aerogels opens exciting opportunities to move beyond the geometric limitations of molding to expand the application space of these ultralightweight materials.

Antiperspirants are commonly used daily, or even multiple times a day, by a large percentage of the global population, in order to address the problems associated with sweating. However, there has been no simple way to test and evaluate the effectiveness of antiperspirants in real time. To address this, we have developed a polydiacetylene based chemosensor that undergoes a blue to red colour change when in contact with acids and alcohols found in sweat, but not when exposed to water. The sensor is prepared via inkjet-printing an imidazolium derivative of a diacetylene monomer onto normal paper to give a transparent square followed by UV curing to produce the navy blue 5 × 5 cm “SweatSENSE” patch. A sensor is applied to the underarm for 5 s and the colour changes to red in the presence of sweat and the intensity of the colour change is recorded. From an in vivo trial involving 52 panellists, the sensor was shown to demonstrate a reduction in total sweat area following the application of an antiperspirant, when compared with a deodorant only control. This sensor will allow consumers to test the effectiveness of their antiperspirants during daily life, in real time, without the need for specialised equipment.

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We report the employment of single-boron compounds as readily available cross-linkers for strengthening ethylene-methacrylic acid ionomers. The novel cross-linking strategy effectively strengthened the ionomers with enhanced mechanical and rheological properties, affording excellent (re)processability without changing the transparent appearance.

Polyaniline (PANI), being one of the best chemically stable conducting polymers endowed with coupled electron and proton transport, has been poorly evaluated in vanadium redox flow batteries (VRFBs) due to its poor processability. Here, we have reported the synthesis of processable poly(2-ethylaniline) (E-PANI) and its blend with sulphonated poly(ether sulfone) (SPES) with proposed applications in VRFBs. The synthesis of E-PANI was confirmed by 1H-NMR, FT-IR, and powder XRD. Membranes EP1, EP2, and EP3 were prepared by solution blending of 5, 10, and 15 wt% E-PANI with 95, 90, and 85 wt% of SPES, respectively, in N-methyl-2-pyrrolidone. The membrane with the highest loading of E-PANI, i.e., EP3, delivered the best VRFB performance of 99.5, 53.0, and 52.7% of CE, VE, and EE, respectively, at 140 mA cm−2 current density for 300 charge/discharge cycles with 65% capacity retention for the initial 100 cycles. This performance is far better than that of Nafion 117 in identical experimental conditions, which exhibits merely 15% capacity retention in the initial 100 cycles at the same current density. The EP3 membrane delivered a peak power density of 266 mW cm−2. The membrane analysis revealed no E-PANI leaching or fouling, indicating its potential utility in VRFB applications.

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Functionalized polymer fibers were prepared by microfluidic spinning involving simultaneous photopolymerization and surface modification. A capillary-based microfluidic device was used with two miscible coaxially co-flowing phases to afford polymer fibers by the photopolymerization of poly(ethylene glycol) diacrylate present in the core phase and the surface modification of the fibers thanks to the presence of molecules (i.e., thiol and amine groups) reactive towards acrylate groups in the sheath phase. The use of molecules with higher functionality in thiol groups or higher concentration of these molecules increased the number of functional groups present at the surface of the fibers, while an increase of the flow rate of the sheath phase decreased it. The modification of the surface properties of the fibers was demonstrated by contact angle measurements showing differences in wetting properties and by incubation with RAW264.7 macrophages exhibiting a significant increase in cell adhesion for the thiol-modified microfibers.

Multi-component structured filaments offer the potential for enhanced mechanical performance in 3D printed plastics. Here, the interactions between filament components in the core (polycarbonate, PC)–shell (polypropylene, PP) geometry are manipulated by light maleation (1%) of PP to understand how the inclusion of favorable polar interactions and potential grafting reactions at the core–shell interface impact the mechanical performance of the 3D printed parts. The elastic modulus of the 3D printed tensile bars is essentially independent of the shell selection for the fully isotactic PP (iPP) or maleated PP (miPP), but the strain at break is generally significantly improved with the miPP shell to increase the toughness of the printed parts for both flat and stand-on build orientations. This is counter to compression molded specimens where iPP is more ductile than miPP. The mechanical behavior in the flat orientation is consistent with long fiber composites, where the PC core essentially acts as fiber-reinforcement. Tribo-testing results indicate increased friction between miPP and PC through the interaction of the maleate anhydride group with the carbonate relative to the iPP with PC. This small increase in the interfacial interaction between the core and shell polymers with miPP increases the work required to pull out fibers of the stiffer PC from the PP matrix for the flat build orientation and more energy is required to delaminate the core from the shell, which is the loci of failure, when the stand-on build orientation is stretched. The subtle change in chemistry with a maleation of 1% of PP leads to a larger strain at failure and tougher parts due to the interaction with PC. These results illustrate that the selection of the polymers in structured filaments needs to also consider their potential intermolecular interactions including the potential for grafting reactions to best enhance the mechanical response of 3D printed parts.

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In the future, well-engineered and optimized flexible electronic devices will be woven into everyday accessories such as clothes, furniture, and healthcare monitoring devices. Herein, a series of multifunctional, flexible, conductive, and self-healing polymer nanocomposites that contribute to multiple electronic applications are reported. RAFT polymerization is employed in a modular approach to synthesize dynamic polymer nanocomposites (DPNs) using different architectures including interpenetrating (IPN) and block copolymer (BCN) networks through dynamic Diels–Alder and hydrogen bond cross-links. Structure–property relationships highlighting the impact of network architecture, chain-length, cross-link density, and carbon nanotubes loading are explored. Controlled addition of multiwalled carbon nanotubes (CNTs) as nano-reinforcements produces electrically conductive and mechanically enhanced DPNs with demonstrated application in the regulation of current flow towards a dimmable light emitting diode (LED). Further application of DPNs as strain sensors and customizable/tunable electrical resistors is demonstrated. Overall, this report furnishes new insights into designing next-generation custom resistors and materials for smart LED lighting.

Seawater is a huge store of uranium, and the related uranium retraction technology has become a critical step in the sustainable development of nuclear power. For obtaining uranium U(VI) from seawater cheaply and environmentally, we introduced K2FeO4 during the polyamidoxime (PAO) preparation process in water to endow PAO with high antibacterial and low agglomeration properties. In this reaction, only water was used as the solvent with the goal of extracting U(VI) from seawater in a low-cost, pollution-free manner. Studies showed that the adsorption of U(VI) on K2FeO4@PAO conformed to a pseudo-second-order model, and the maximum adsorption capacity calculated by the Langmuir model was 137 mg g−1 at 298 K and pH 8.2. Moreover, K2FeO4@PAO showed high selectivity for U(VI) compared with a range of metal ions. K2FeO4@PAO also showed good recyclability, and the recovery rate only decreased by 3% after six cycles. In addition, antibacterial experiments indicated that K2FeO4@PAO could effectively inhibit the growth of Escherichia coli (E. coli) and Vibrio alginolyticus (V. alginolyticus) that are commonly found in seawater.

Flexible strain sensors play a critical role in wearable human–machine interaction (HMI), allowing for natural and intuitive communication between humans and machines. Conductive hydrogels are promising candidates for flexible sensor materials due to their flexibility, sensitivity, and biocompatibility. However, the conventional hydrogels tend to freeze at subzero temperatures or lose water at room temperature, resulting in decreased electrical conductivity and mechanical flexibility, and thus poor long-term stability. Herein, a multifunctional MXene/polyacrylic acid (PAA) organohydrogel with high toughness and self-healing, self-adhesive, antifreeze, and long-term moisturizing ability was prepared using a facile solvent replacement method. It has a high sensitivity (gauge factor ∼10.96), wide detection range (0–1304%), and stable signal output for 500 cycles, making it an ideal flexible strain sensor for monitoring human joint movements, subtle expression changes, and pronunciation in real time. This work provides a new paradigm for wearable artificial intelligence and human–machine interactions in complex environments.

Vat photopolymerization is able to produce intricate parts at high print speed, good part fidelity, and strong mechanical properties. However, as materials become more complex and printing technologies advance, the post-printing processing conditions of these parts must be considered. Poly(propylene fumarate) (PPF) 4-arm stars with a of degree of polymerization (DP) of 120 were photochemically 3D printed with 5 wt% hydroxyapatite (HAp) nanoparticles (<200 nm) as a filler in a nanocomposite scaffold targeted for bone regeneration applications. Nanocomposites and pure polymers were subjected to a number of post-printing processing conditions including UV post-curing times, cure temperatures and drying times in a vacuum oven. The impact of these conditions on mechanical properties were analyzed in compression, tension, and dynamic mechanical analysis (DMA). Mechanical behavior is highly tunable with the variation of each of these different processing conditions.

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Advances in thermoresponsive materials have significantly impacted many biomedical fields. The unique behavior of reversible phase transition close to the physiological temperatures makes these types of materials a great candidate for a wide variety of biomedical applications including bioimaging, biosensing, injectables, smart surfaces, adhesives, biomanufacturing, and tissue engineering. Thermoresponsive behavior, mainly lower critical solution temperature (LCST) can be easily tuned by shifting the balance between hydrophobicity and hydrophilicity (e.g., by using comonomers or changing end groups) and modifying the molecular weight and architecture of the polymer. Hence, synthetic and characterization tools are critical in tailoring and precisely determining these properties. This review aims to show the full scope of the journey of thermoresponsive polymers from benchtop to potential applications. We especially intend to emphasize the effects of the structural heterogeneity of polymers on thermal transition and highlight the modern characterization techniques used to study thermoresponsive behavior. A better understanding of these structural effects and benchtop tools can help us design and implement more advanced materials for future applications in public health.

Diabetic ocular complications continue to be the leading cause of vision impairment in the world, with a considerable impact to healthcare and the global economy. While there are management strategies currently in place to delay the progression of diabetic ocular disease, risks associated with those strategies still pose a major concern in the clinical field. Management strategies generally involve ocular drug administration and surgical intervention. Some limitations with current ocular drug delivery systems include poor bioavailability of drug formulations and complications arising from drug regimens that require frequent intravitreal injections for drug administration. A vitrectomy is also a common surgical procedure to replace severely damaged vitreous caused by various diabetic ocular complications. However, existing vitreous substitutes used for post-vitrectomy surgery have a certain degree of toxicity to ocular tissues. Thermogels are well-suited materials for the treatment of diabetic ocular diseases as they could mimic the properties of ocular tissues to maintain the viability of therapeutics, serve as drug delivery depots and be tailored to be mechanically robust and non-toxic. Furthermore, the thermoresponsive property of thermogels imparts in situ gelling properties to create injectable mediums for minimally invasive disease management strategies. This review covers some of the latest developments in the field, highlighting the advantages of thermogels as sustained drug delivery systems, biocompatible and non-toxic vitreous substitutes, shape conformable implants and long-acting therapeutics over conventional treatments used for the treatment of diabetic ocular diseases.