Potassium-ion batteries are an emerging post-lithium technology that are considered ecologically and economically benign in terms of raw materials’ abundance and cost. Conventional cell configurations employ flammable liquid electrolytes that impose safety concerns, as well as considerable degrees of irreversible side reactions at the reactive electrode interfaces (especially against potassium metal), resulting in a rapid capacity fade. While being inherently safer, solid polymer electrolytes may present a solution to capacity losses owing to their broad electrochemical stability window. Herein, we present for the first time a stable solid-state potassium battery composed of a potassium metal negative electrode, a Prussian blue analogue K2Fe[Fe(CN)6] positive electrode, and a poly(ethylene oxide)-potassium bis(trifluoromethanesulfonyl)imide polymer electrolyte. At an elevated operating temperature of 55 °C, the solid-state battery achieved a superior capacity retention of 90% over 50 cycles in direct comparison to a conventional carbonate-based liquid electrolyte operated at ambient temperature with a capacity retention of only 66% over the same cycle number interval.

Thermal regulation and waste heat energy harvesting have been a concern in different industries, including the electronics sector that sees an increasing usage with technological advancement and automation. A form-stable phase change material (FSPCM) is an excellent solution to the problem, where device temperatures can be regulated without any PCM leakage. However, most FSPCMs are generally too stiff and bulky for coating onto delicate component parts, and their integration does not fit easily in a segment of a manufacturing line. Therefore, a UV-curable form-stable polyethylene-glycol (PEG)-based PCM was investigated with trimethylolpropane ethoxylate triacrylate (TMPEOTA) as the UV matrix to present a fast-curing and coatable PCM for irregular surfaces. PEG composites of four different molecular weights, i.e., PEG 400, PEG 750, PEG 1050, and PEG 2050, were successfully fabricated with 50–80% PEG loading in TMPEOTA. UV curing was achieved instantaneously, and Fourier transform infrared (FTIR) spectrometry confirmed the success with the disappearance of the distinct C═C peak at 1620 cm–1. All samples were found to be form-stable even at temperatures above their melting point, with matrix features present and no liquid observed by optical microscopy, suggesting a solid–solid phase transition. Differential scanning calorimetry (DSC) measured the phase change temperature to be tunable between 2 and 48 °C depending on the molecular weight of the PEG employed, and the enthalpy change of melting achieved a maximum of 117 J g–1. Thermogravimetric analysis (TGA) also validated their thermal stability up to 150 °C. These UV-curable FSPCMs would be useful in providing a thermal regulatory coating or complex 3D-printed shapes.

The heterologous origin of the enzyme usually induces some unwanted enzyme-related complications including immunological responses and decreased plasma half-life, which limits its greater therapeutic effects and applications in patients. Poly(zwitterion) offers a promising opportunity to evolve a generation of nanoparticles with their huge potential to prevent the nonspecific adsorption of biomolecules and enormous capacity to preserve the circulation half-lives and divert the recognition of the mononuclear phagocytic system. In this study, we encapsulated the l-asparaginase enzyme in superbiocompatible phosphorylcholine polymer shells, forming a zwitterion-coated enzyme nanocapsule. This formulated structure presents the encapsulated enzyme with an improved stability against proteolysis, extended half-life in vivo, and lower immunogenicity after repeated treatments. Such nanocapsules along with these improved characteristics propose an alternative delivery platform for l-asparaginase to break through the previous limitations and translate more efficiently to clinical applications. The demonstrated technology presents a suitable approach for enzyme delivery, but it can also be used to encapsulate the emerging classes of protein therapeutics, bioimaging agents, and biosensors.

The hole structure has great impact on the performance of polymeric film materials. In the current work, we focused on the formation mechanism and control of nascent holes that frequently appeared when preparing polymer films on poor wetting substrates. Number density and dewetting area of nascent holes on nanofilms of two model polymers, polystyrene and polymethyl methacrylate prepared from various solvents and spin-coating conditions, were systematically studied. Sufficiently large spin speed and prolonged immersion time demonstrated both inducing more and larger holes as a result of high capillary stress and chain adsorption at the surface, respectively. Moreover, solvents played the most critical roles on the formation of nascent holes. Faster evaporative, intermediate Hassen parameter between the polymer and the solvent, and smaller surface tension of solvents promote the formation of more intact films. This work provided deeper understandings on the formation mechanism of polymer nanofilms and an effective approach for controlling nascent holes, which were both of particular importance in the fabrication of functional organic thin-film materials.

When consumed in excessive amounts, histamine (HIS), a naturally occurring component in seafood, is known to produce an unpleasant inflammatory reaction. Hence, proper histamine measurement and detection in seafood are of utmost importance. Herein, a histamine electrochemical biosensor based on a molecularly imprinted polymer (MIP) was fabricated using a gold (Au) inverse opal (IO) electrode. Prior to the MIP synthesis, the scaffold of Au IO was modified by electropolymerizing 3,4-ethylenedioxythiophene (EDOT), providing a substrate with improved electrical characteristics. The fabrication of the MIP film was achieved by electropolymerizing aniline in circumstances that preserved the chemical structure of HIS. The electron transport properties of a standard redox probe [Fe(CN)6]3–/4– were evaluated by making use of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). We describe a synergistic strategy for constructing a hierarchical recognition material using an electrochemical approach that successfully integrates three independent approaches, including semicovalent, molecular imprinting, and inverse opal structure, to enhance selectivity and sensitivity. The fabricated HIS electrochemical biosensor exhibited a linear response from 50 nM to 500 μM, a detection limit of 1.07 nM, and was selective against different analytes as well. Moreover, the fabricated HIS electrochemical biosensor outperforms its contemporary counterparts as it also exhibited low error, high accuracy, specificity, stability, and good relative standard deviation % (RSD %).

We investigated the influence of neutral and charged crosslinkers on the physicochemical properties of ionogels (IGs) as well as their applicability in lithium–metal batteries (LMBs). Specifically, IGs with varying compositions of covalent crosslinker, that is, poly(ethylene glycol) diacrylate (PEGDA; charge neutral) or 1-(p-vinylbenzyl)-3-vinyl imidazolium bis(trifluoromethane sulfonyl)imide ([VBVI]TFSI; charged), ionic liquid monomer, ionic liquid, and lithium bis(trifluoromethane sulfonyl)imide (LiTFSI) were synthesized by photopolymerization. Furthermore, the mechanical properties and ionic conductivities (ICs) of the samples were investigated by a unique setup allowing for simultaneous rheology and broadband dielectric spectroscopy. In general, higher mechanical stability and lower ICs were obtained with increasing content of ionic liquid monomer and crosslinker. Furthermore, VBVI-based IGs showed superior mechanical shear strength (G′ = 4 × 105 vs 105 Pa), while PEGDA-based IGs displayed higher ICs (e.g., for 30/70-V50-20 vs 30/70-P50-20: 0.17 vs 0.25 mS cm–1 at 25 °C). As the IC however includes the diffusion of all ions present, the Li+-transference number (tLi+) was determined to judge the actual Li+ conductivity and thus the potential performance in LMBs. Here, tLi+ was found to be 3–7 times higher for the VBVI-based IGs in comparison to the PEGDA-based ones despite their lower ICs. These results were corroborated by lithium plating/stripping experiments with alternating current densities (CDs). Here, higher CDs for VBVI-based IGs were found in comparison to their PEGDA-based counterpart (0.8 vs 0.1 mA cm–2), therefore demonstrating the improved Li+ transport. Finally, the compatibility of the IGs with the lithium metal was investigated by long-term plating/stripping experiments (53 full cycles, 106 h) at 30 °C. Our results highlight (1) the significance of tLi+ measurements in comparison to solely the ICs to judge the performance of IGs in LMBs and reveal (2) the superiority of VBVI-based IGs as a polymer electrolyte compared to conventional PEGDA-based IGs.

High-temperature laser sintering (HT-LS) is a very promising additive manufacturing process for the production of parts of complex geometry for highly demanding applications. Poly(aryl ether ketone) polymers such as poly(ether ketone), poly(ether ether ketone), and poly(ether ketone ketone) (PEKK) have attracted increasing interest during the last decade for use in HT-LS. Among them, PEKK offers the advantage of exhibiting tunable melting temperature and crystallization rate due to its copolymer structure. Indeed, PEKK is synthesized by Friedel–Crafts polyacylation condensation of diphenyl ether with terephthaloyl chloride (T units) and isophthaloyl chloride (I units). In this work, we focus on a specific member of the PEKK family having a regular alternated T/I structure, PEKK 50/50, and study its isothermal crystallization from the melt at various crystallization temperatures (TC), from 200 °C to 290 °C. A quantitative analysis based on X-ray scattering and differential scanning calorimetry experiments is performed. Primary crystallization dominates the process with a half-time of crystallization higher than 6 min and an Avrami exponent between 2.2 and 3. Stacks of periodic crystalline lamellae are first created, followed by lateral growth of these crystalline lamellae, leading to a gradual increase of the weight crystallinity. Crystalline form I, with traces of form III, is mostly observed regardless of TC. The amount and perfection of the crystalline phase increase with TC. The crystalline state achieved, as well as the thermal and rheological behavior of PEKK 50/50 during crystallization at high TC (∼280–290 °C), are promising for use in HT-LS manufacturing.

Thermally activated shear stiffening viscoelastic fluid can help to improve the performance of viscoelastic dampers and high-temperature adhesives. Polymer nanocomposites with heterogeneous interphases are applied to design such adaptive materials. In this work, shear stiffening in polymer-grafted nanoparticle composites is investigated. We report the linear rheological responses of grafted particle composites before and after large-amplitude oscillatory shear application. We found that interfacial mixing of short grafts with chemically different long matrix chains led to the enhancement of plateau moduli and terminal relaxations, unlike with the long grafts. Moreover, we showed that the elastic modulus of grafted chains was enhanced upon deformation through inter-diffusion and entanglements of interfacial layers with the short matrix chains in both grafted systems. These results suggest that dynamic coupling between chemically different polymers away from nanoparticle surfaces is a design strategy to achieve the thermally stiffening behavior in polymer nanocomposites.

Multifunctional, monodisperse, and hyperbranched poly(p-phenyl ester) phenol (HPPEP) colloids are prepared using commercially available inexpensive monomers (i.e., terephthaloyl chloride (A2) and phloroglucinol (B3)) via a simple condensation polymerization reaction (A2 + B3) at room temperature. Because of their symmetrical, rigid, highly branched, and cross-linked structure and the presence of the terminal phenolic units, the formation of highly monodisperse HPPEP colloids (coefficient of variation < 1.6%) can be realized under trimethylamine base conditions without any emulsifier (or surfactants) and expensive catalyst. Owing to their rigid aromatic and cross-linked structure, the HPPEP colloids exhibit excellent thermal, chemical, and mechanical resistances. Furthermore, the phenolic surface groups of HPPEP colloids enable the generation of highly negative surface charges (−60 mV) and catalytic protons (0.26 mmol H+/g) while enhancing surface functionality by chemically binding to red, green, and blue fluorescent dye molecules. Through carbonization, HPPEP colloids can be directly transformed into monodisperse porous carbon spheres with a large surface area (as,BET = 644.99 m2 g–1). Moreover, the HPPEP colloids can fully decompose into environmentally benign monomers after being exposed to an alkali environment.

A one-dimensional (1D) fluorescent coordination polymer (CP) [Zn(nip)(cis-nvp)(H2O)]·CH3OH (1) has been synthesized by the reaction of Zn(NO3)2·6H2O and mixed ligand system; 5-nitrosopthalic acid (H2nip) and trans-4-(1-naphthylvinyl)pyridine (trans-nvp). Here, trans-nvp has been converted into cis-nvp via in situ trans–cis isomerization in visible light. The CP 1 has been structurally characterized by single crystal and powder X-ray diffraction techniques, and thermogravimetric analysis. The solid-state structure of CP 1 reveals that the nip ligands bridge the Zn(II) centers to generate 1D polymeric chain. The cis-nvp ligands are attached to Zn(II) centers and have undergone interdigitation via π···π stacking interactions to furnish a two-dimensional (2D) network. Interestingly, CP 1 exhibits sensing activity toward highly mutagenic pollutant and explosive nitroaromatic compounds (epNACs) in liquid as well as vapor phase.