A key challenge in the development of electrochromiccoatings isestablishing fabrication methods that utilize sustainable materialsand green solvents. This must be achieved while also optimizing multipleparameters, including color contrast, stability, switching time, andoptical transmittance. In this study, we report water-soluble, redox-activeiron-polypyridyl complexes as building blocks for electrochromic coatingsand devices fabricated by layer-by-layer spin coating and automatedspray coating. The solubility of these complexes in polar and nonpolarmedia was modulated by tuning the counterions (PF6–, Cl–, and SO42–), without affecting the electrochromic performance of their assemblies.Furthermore, the use of two water-soluble palladium complexes, [PdCl4]2– and trans-[Pd­(3-SO3H-py)2Cl2], allowed us to demonstratethat the resulting molecular assemblies can be formed using aqueoussolutions. Overall, the molecular assemblies exhibited excellent opticaland electrochromic properties with switching times between 0.9 and1.8 s and up to 95% charge retention even after 2000 cycles. The practicalityof our approach was demonstrated by fabricating laminated devicesthat retain the physicochemical properties of the original molecularassemblies.

It is unambiguously demonstrated that the low-temperaturemagnonspecific heat in a ferromagnet varies as T3/2 and the magnon thermal conductivity, due to the T1/2-dependent effective velocity of magnons, varies as T2. The confirmation of these model behaviorsis based on the experimental study of chalcospinel CdCr2Se4, which represents a relatively rare example of a ferromagneticinsulator (TC = 130 K) without undesirable“masking” contributions from itinerant electron excitationsand nuclear specific heat, both of which make it impossible to conclusivelyunveil the role of magnons. The ratio of the magnon to lattice specificheat is found to reach 87:13 at 2 K and is in accordance with predictionsbased on the spin-wave stiffness D = 33.5 meV Å2 and Debye temperature θD = 237 K. On the other hand, the ratio of the magnon to phonon thermalconductivity, reaching 27:73 at 2 K, is much lower than expected forthe standard model of grain boundary-limited transport. This suggeststhat mean free paths for long-wavelength magnon/phonon heat carriersare largely differentshorter than the grain size (∼1μm) for magnons and longer than the grain size for phonons.The phonon-dominated low-temperature thermal conductivity, moreover,exhibits a ∼T2.3 temperature dependenceinstead of the standard predicted model of T3. The relevant scattering mechanisms, both the phonon frequency-independentand frequency-dependent ones, are discussed in detail.

Polymer blends in thin films offer versatile opportunitiesfortailoring material properties. Among available deposition methods,the Langmuir film technique enables the formation of well-controllednanometer-thick films at the air–water interface, revealingunique miscibility and phase behaviors not observed in bulk. In thiswork, we investigate 2D polymer blends composed of amphiphilic PEO11–PPO35–PEO11 and hydrophobicPDMS using a multiscale approach that combines surface pressure–areaisotherms, Brewster angle microscopy (BAM), neutron reflectometry(NR), and sum-frequency generation (SFG) spectroscopy. This methodologyenabled us to construct a 2D surface pressure–composition phasediagram, identifying miscibility regions and two distinct first-orderphase transitions. Across all compositions, no lateral phase separationwas observed at the mesoscopic scale by BAM, even during phase transitions.Instead, NR revealed vertical segregation at specific surface pressuresand compositions. In PEO11–PPO35–PEO11-rich blends, a homogeneous monolayer undergoes a transitionto a bilayer, with hydrophobic PDMS positioned atop PEO11–PPO35–PEO11. PDMS-rich blendsdisplay a similar bilayer structure at all pressures, with the phasetransition mainly involving thickening of the PDMS layer, as seenin pure PDMS films. SFG spectroscopy reveals that both polymers havedistinct behavior in the blends and in pure films, due to either lateralor vertical interactions. Notably, despite their contrasting hydrophobicities,the polymers exhibit miscibility over a range of compositions andsurface pressures, with evidence of attractive interactions. Thesefindings underscore the unique behavior of confined polymer blendsand the importance of 2D-specific phase diagrams for designing functionalinterfacial materials.

Inorganic nanoparticles (NP), particularly gold nanoparticles,hold great promise for biomedical applications. However, one of themajor challenges in the implementation of therapeutic applicationsbased on inorganic nanoparticles is the individuation of appropriatecoatings, which are indeed responsible for stability, escape fromthe immune system, and further functionalization. In this paper, weexplore the properties of the multi-azide-containing and highly nonfoulingpolymer PAcrAm-g-(PMCA, NH2, ND), based on poly­(oxazoline)derivatives grafted to a poly­(acrylamide), as a coating for gold nanoparticlesthat can grant stability and easiness of derivatization and can preventnonspecific protein adhesion on gold nanoparticles (Au-NP). We foundthat the addition of the polymer to citrate-stabilized gold nanoparticlesled to the formation of NP suspensions with excellent colloidal stability,as confirmed by dynamic light scattering (DLS), ζ potential,thermogravimetric analysis (TGA), and transmission electron microscopy(TEM) investigations. In addition, the AuNP coating strongly decreasesthe protein adsorption corona and does not activate dendritic cells(DCs), showing low immunogenicity and potentially decreasing the NPclearance by the mononuclear phagocyte system.

Solution electrospinning produces not only round fibersbut alsomany unexpected features, e.g., ribbons, nets, and fibers with beads,barbs, or branches along the fiber length. These diversified featuresare observed in the electrospun fibers of poly­(vinyl alcohol), Nylon-6,poly­(N-isopropylacrylamide), ultrahigh-molecular-weightpolystyrene, and ultrahigh-molecular-weight polyethylene in this study.All these unique features could be realized through our recent discoveriesthat flow-induced phase separation occurs in the jet to develop polymer-richphases of hierarchical string structures with various diameters. Subsequently,lateral association (or fasciation) of the hierarchical strings ensuesand creates assembled strings of different kinds, which are splitfrom the phase-separated jet and evolve into as-spun features aftersolvent evaporation. Our results indicate that flow-induced phaseseparation in jets cannot be overlooked and is likely to unify theformation mechanism of all diversified morphologies of electrospunproducts.

The presence of hexavalent uranium (U­(VI)) in aqueoussystems posesa severe environmental threat due to its high solubility and toxicity.Herein, we developed a synergistic strategy integrating plasma-synthesizednanoscale zerovalent Fe/Ni nanoparticles supported on biochar (nZVFe/Ni–BC) with a sulfite (S­(IV)) effect for highly efficientU­(VI) removal. The nZV Fe/Ni–BC composite provided a highlyactive and stable scaffold, while S­(IV) served a dual function asradical precursors (generating SO3•– and SO4•–) and antipassivationagents, inhibiting Fe0 surface oxidation. This synergyresulted in a U­(VI) removal efficiency of 96.71% and a high capacityof 187.92 mg g–1 under mild conditions (pH 6.0).Mechanistic investigations confirmed that the reduction of U­(VI) toinsoluble U­(IV) was facilitated through multiple pathways, includingdirect electron transfer from Fe0, atomic hydrogen mediatedby Ni, and S­(IV) derived radicals. The composite exhibited excellentstability over five consecutive cycles, maintaining 88% efficiency,and its performance was significantly enhanced by humic acid up to99.60%, demonstrating robustness in complex water matrices. This workprovides a sustainable and highly effective remediation platform foruranium-contaminated water.

Liesegangpatterns are self-organized macroscopic structures formedby precipitates. Traditional methods for producing these patternsrely on gel phases, which inhibit flow but introduce complications,such as undesired chemical interactions. This study presents a strategicapproach utilizing a “Hele-Shaw cell”, consisting oftwo glass plates that create a narrow gap (30–225 μm).This setup prevents flow due to friction between glass surfaces withoutthe use of a gel. We identified two critical thresholds for the gapthickness: one that inhibits flow and another that facilitates discreteprecipitate bands. For aqueous solutions of CuCl2 and K2CrO4, these thresholds were determined to be 110and 150 μm, respectively. Below the first threshold, the periodof precipitate bands increased with a greater gap thickness. Thisthickness dependency was successfully reproduced using our proposedmathematical model based on the microscopic dynamics of precipitationprocesses instead of the phenomenological step function model commonlyused. Our numerical simulations indicate that the nucleation rateof precipitates significantly influences the formation of bands, withthe nucleation rate having an inverse effect on band spacing. It isassumed that the nucleation rate is proportional to the specific surfacearea of the glass plate, and thus, the practical nucleation rate wasproportional to the inverse of the thickness. This research providesa simplified experimental method and a robust mathematical model forLiesegang pattern formation, potentially paving the way for the furtherexploration of self-organization applications.

Although variousthermoresponsive properties of poly­(N-isopropylacrylamide)(PNIPAM) hydrogels have been investigated duringphase transitions, the effects of the changing gel structure on theelectrochemical properties of PNIPAM gels are poorly understood. Therefore,this study uses rheo-impedance measurements under simultaneous temperaturemodulation and shear deformation to examine the mechanism governingthe conductivity of these gels. The impedance spectra of the PNIPAMhydrogels exhibit a distinct transition near the lower critical solutiontemperature, indicating that the internal conductive pathways dynamicallyreconstruct, associated with gel deswelling. Meanwhile, the nonlinearbehavior of the impedance response with the varying shear rate suggestsshear-induced degradation of the gel structure, followed by conductivenetwork reformation. These results highlight the strong correlationbetween the internal microstructure of the hydrogel and its electrochemicalproperties, thus demonstrating the effectiveness of rheo-impedanceanalysis in determining the coupled mechanical–electrical responsesof stimuli-responsive soft materials. Unlike conventional static measurements,this approach enables dynamic in situ evaluation of functional transitionswithin hydrogels. This study provides new insights into the designand analysis of intelligent hydrogel systems, with potential implicationsfor soft actuators, and establishes a methodological foundation forextending rheo-impedance analysis to other responsive polymer systems,thereby broadening its applicability in smart material research.