The growing polymer chain is typically viewed as a passive product of catalysis, yet here we show that its microstructure can actively govern catalytic rate. In the ring-opening copolymerisation (ROCOP) of fluorinated epoxides with cyclic anhydrides, rate acceleration occurs most clearly when both monomers are aromatic and only one is fluorinated. Density functional theory and mechanistic experiments rule out interactions with the catalyst as the origin of this effect, instead implicating intrachain π–π stacking between the fluorinated carboxylate chain end and aromatic units of the growing polyester as the dominant transition-state-stabilising interaction. With each turnover, the polymer chain constructs a structured non-covalent environment around the active centre, a role conceptually analogous to the binding cavity of an enzyme. This principle is accompanied by a broad fluorinated polyester library with tunable glass transition temperatures spanning below −14 °C to 144 °C, straightforward post-polymerisation modification via para-fluoro thiol-click chemistry, and quantitative fluorine recovery as sodium fluoride upon degradation. These findings reframe chain microstructure as an underexploited handle for controlling reactivity in chain-growth polymerisation.

Fluorinated polymers offer outstanding material properties but lack viable end-of-life options. Here we report a general ring-opening copolymerisation strategy that delivers a broad library of fluorinated polyesters with tunable thermal properties, straightforward post-polymerisation modification and quantitative fluorine recovery as sodium fluoride upon degradation. In mapping the scope of this methodology across diverse anhydride partners, we found that fluorination accelerates catalysis mostly when both monomers are aromatic and one is fluorinated. Density functional theory and mechanistic experiments reveal that the rate enhancement does not originate at the catalyst but within the growing polymer chain itself, through intrachain π–π stacking interactions that stabilise the transition state. The polymer chain constructs a structured non-covalent environment around the active centre with every turnover making chain microstructure an unexpected determinant of catalytic rate. These findings reframe how we think about chain-derived effects in polymerisation catalysis, and are accompanied by a modifiable fluoropolyester library spanning glass transition temperatures from below -14 °C to 144 °C, from which fluorine can be recovered upon degradation.

Silver nanowires (AgNWs) are extensively reported as 2D conductive composites for their neural metaplasticity mimicking behavior, crucial for next-generation computing. While 2D networks rely on junction-mediated ballistic transport, 3D AgNW bulk composites exhibit diffuse and percolation driven conduction. Comparing these systems could reveal key dimensional effects, though scaling the intricate 2D networks into the bulk remains challenging. We report a highly reproducible 3D metastable powder composite of anisotropic AgNW with poly(vinylpyrrolidone) as a supporting matrix, produced via spray drying. With rapid drying kinetics, affinity-driven anisotropic morphologies are observed with ellipsoidal microstructures bent at flexural angles. First-principles electronic percolation characterization of the compressed composite is determined by a four-point probe (4PP), and the percolative regimes are allotted. 2D AgNW networks reach ∼1-500 S/cm at network densities of ∼0.4-11 μm-2. The 3D composites, on the other hand, span a wider range, from ∼10-8 S/cm at 3 wt % to ∼102 S/cm at ∼90 wt % of AgNW loading. These values reflect the dominant conductive pathways within the interaction volume. Complementary electrochemical impedance spectroscopy confirms pressure-driven extremization in percolation, with conductivity rising by 2 orders of magnitude from ∼10-2 to ∼1 S/cm at applied pressures of 0.3 to 50 MPa even for 10 wt % AgNW, where 4PP measurements show values near 10-5 S/cm. Spray drying was chosen, as scalability was prioritized over nanoscale precision, making it suitable for bulk materials where microstructure control is secondary to throughput. Hence, the morphologically free AgNWs serve as a versatile precursor for industrially relevant down streaming and reprocessing. When the metastable composite was coextruded at high shear with a commercial elastomer, stretching induced alignment of the initially randomly oriented AgNWs was revealed by SEM micrographs.

Abstract The fragmentation and direct release of plastic debris have emerged as a pressing ecological concern. Once dispersed, these particles infiltrate food webs, accumulate within organisms, and bind toxic co-contaminants, posing long-term risks to ecosystems and human health. Despite growing awareness, the characterization of nanoplastics remains highly challenging. Moreover, obtaining additional information, such as particle shape or material composition, further exacerbates these detection hurdles. Here, we introduce a photonic sensing platform based on nanoscale voids that enables the simultaneous material- and morphology-sensitive detection of particles below 500 nm. Void arrays embedded in a high-refractive-index material act in parallel as both sorting elements and color reporters. Spherical and elongated particles are selectively trapped in circular and elliptical voids, while different polymer types are distinguished simultaneously. This approach offers a scalable route toward optical identification of nanoplastics in environmental settings. Its compatibility with high-throughput analysis positions it as a promising tool for real-time studies.

Coplanar microelectrodes, particularly interdigitated electrodes (IDEs), are widely employed in electrochemical sensing owing to low cost, scalable fabrication, and high surface sensitivity. However, accurate and quantitative interpretation requires precise determination of the cell constant (k). This becomes nontrivial when the electrode's electric field is only partially immersed in the electrolyte, as is common in thin film or confined-volume systems. This work presents a fast, reproducible, and low-cost experimental platform for measuring film thickness-dependent correction factors (alpha) of k. Electrochemical impedance spectroscopy (EIS) was applied on printed circuit board (PCB) IDEs comprising five different electrode finger widths (w) and spacings (s) (w = s: 250 mu m, 500 mu m, 1000 mu m, 1500 mu m, and 2000 mu m). k was determined while fully immersed, and alpha was subsequently empirically derived as a function of electrolyte film thickness (alpha(d)). The results were compared to finite element methods (FEM; COMSOL), revealing consistent trends but notable deviations in absolute values of alpha(d). These findings highlight the limitations of simplified field models and provide a practical approach for a more accurate characterization of thin films on coplanar electrodes.

The growing polymer chain is typically viewed as a passive product of catalysis, yet here we show that its microstructure can actively govern catalytic rate. In the ring-opening copolymerization (ROCOP) of fluorinated epoxides with cyclic anhydrides, rate acceleration occurs most clearly when both monomers are aromatic and only one is fluorinated. Density functional theory and mechanistic experiments rule out interactions with the catalyst as the origin of this effect, instead implicating intrachain pi-pi stacking between the fluorinated carboxylate chain end and aromatic units of the growing polyester as the dominant transition-state-stabilizing interaction. With each turnover, the polymer chain constructs a structured noncovalent environment around the active center, a role conceptually analogous to the binding cavity of an enzyme. This principle is accompanied by a broad fluorinated polyester library with tunable glass transition temperatures spanning below -14 to 144 degrees C, straightforward postpolymerization modification via para-fluoro thiol-click chemistry, and quantitative fluorine recovery as sodium fluoride upon degradation. These findings reframe chain microstructure as an underexploited handle for controlling reactivity in chain-growth polymerization.

ABSTRACT In this study, transparent passive radiative cooling coatings are introduced by immobilizing solid and hollow silica (SiO2) spheres on glass substrates. It is showcased that particle morphology within a sub‐monolayer coating strongly influences visible and atmospheric window reflectance of glass. Solid and hollow‐sphere particles of total diameter within the Mie regime reduce atmospheric window reflectance (RAW) at the expense of higher visible reflectance (RVIS). This trade‐off is dependent on particle and core diameter. Solid particles with particle diameter >1000 nm can reduce the RAW of glass by up to 65 %, though increase RVIS by 25 %. Meanwhile, the use of hollow‐sphere nanoparticles of similar diameters and thin shells (25–50 nm) can reduce the RAW of glass by up to 35 % with minimal changes to RVIS. These spectroscopic trends are validated numerically via both Mie theory and effective medium theory. The work demonstrates that hollow‐sphere morphology is a valuable lever to control passive radiative cooling for various solar applications requiring transparency, such as coatings for windows or photovoltaic devices.

Understanding heat transport in hierarchical materials is essential for the rational design of next-generation thermal management systems. In this study, we utilize a combination of electrospinning and functionalization techniques to fabricate a series of polystyrene (PS) nonwovens with defined variations in fiber alignment and fusion, as well as functionalization with metals. Using lock-in thermography, we analyze in-plane thermal transport with directional sensitivity and correlate the results with morphological characteristics. We show that increasing fiber alignment enhances thermal anisotropy only up to a certain threshold, beyond which the quality of interfiber contact becomes the dominant factor. The incorporation of nonpercolating silver nanowires is only effective when phonon scattering is minimized. Otherwise, fiber boundaries significantly limit the potential transport enhancement offered by these costly additives. In contrast, copper coatings form percolating networks that markedly enhance thermal transport, yet they remain governed by the global architecture of the fiber network. Altogether, this work experimentally highlights that minimizing phonon scattering and controlling structural features are more critical than maximizing fiber or filler alignment. The insights contribute to a deeper understanding of heat conduction in fibrous systems and offer guidance for designing such materials with targeted performance.

Increasingly frequent and severe heat waves pose a significant threat to human health, intensifying the demand for cooling solutions. Conventional air conditioning offers relief but escalates energy consumption and CO 2 emissions, exacerbating global warming. Here, a passive daytime cooling composite made from kitchen‐sourced materials, providing a zero‐energy cooling technology accessible to everyone, is introduced. Composed of starch and finely ground eggshell powder, this eco‐friendly composite demonstrates an average solar reflectance of 0.91 and thermal emissivity of 0.95. Applied to concrete, it achieves a temperature reduction of approximately 15 °C compared to uncoated concrete under 800 W m − 2 solar irradiation. With universally accessible ingredients and a simple fabrication process, this cooling composite provides a viable solution for households with limited infrastructure to tackle the growing threat of heat waves.

ABSTRACT Polypropylene (PP) homopolymers and copolymers play a pivotal role in the plastics industry. With applications spanning automotive components, electronic housings, construction materials, and food packaging, understanding their thermal transport properties is essential. This study investigates the impact of a highly efficient 1,3,5‐benzenetrisamide (BTA) nucleator ( N,N′,N″‐tris(3‐methylbutyl)benzene‐1,3,5‐tricarboxamide ) on the thermal diffusivity of injection‐ and compression‐molded propylene‐ethylene random copolymer (racoPP). Results are compared with those for a less efficient BTA ( N,N′,N″‐tris(n‐butyl) benzene‐1,3,5‐tricarboxamide ) and a control sample without additives. We supplement our thermal characterizations with x‐ray diffraction (XRD) and small‐angle x‐ray scattering (SAXS) analyses and demonstrate that the processing method and the presence of BTAs can impact the crystallinity and orientation of the PP lamellae. However, the thermal diffusivity of racoPP exhibits remarkable resilience to these changes, ensuring the consistent performance that is often required in industrial applications.

Advanced thermal management is crucial in mitigating the escalating global energy consumption and alleviating associated climatic and environmental issues. Here, a dual‐mode film that integrates solar heating and radiative cooling functionalities for year‐round thermal management is introduced. The cooling side of the film, composed of PCL‐SiO 2 composite nanofibers, exhibits an impressive solar reflection of 0.98 and a mid‐infrared emissivity of 0.91, resulting in sub‐ambient cooling performance under intensive sunlight. Meanwhile, the heating side of the film, based on the ink side of the upcycled chip bags, efficiently harvests thermal energy from sunlight, leading to a temperature rise of 16.5 °C. The cooling and heating modes of the film can be switched by flipping it. With its outstanding optical properties, weathering durability, and switchable heating and cooling modes, the dual‐mode film holds great potential for year‐round energy savings with minimal environmental impact due to its sustainable composition and easy fabrication.

Polymer cubosomes (PCs) are a recent class of self-assembled nanostructures with great application potential due to their high porosity and surface area. Currently, most reported PCs consist of polystyrene block copolymers (BCPs), for which self-assembly parameters are rather well understood. Changing the block chemistry would be desirable to introduce more functionality; however, knowledge of adapting the self-assembly process to new chemistries remains limited. This work, reports on synthesizing poly(ethylene oxide)-block-poly(4-acetoxystyrene) and its copolymers with styrene, and provide conditions for their self-assembly into PCs with high yield and high inner order. It is shown that the polarity of the starting solvent toward the corona block allows tuning of the final morphology by controlling the corona volume and packing parameter. Polymer cubosomes of poly(4-acetoxystyrene) is realized by RAFT polymerization and subsequent self-assembly in water. By adjusting the solvent conditions, the same polymer could be directed into polymersomes, cubosomes or hexosomes. The study provides new insights into the formation of polymer cubosomes using functional wall chemistries. image

Colloidal glasses (CGs) made of polymer (polymethylmethacrylate) nanoparticles are promising metamaterials for light and sound manipulation, but fabrication imperfections and fragility can limit their functionality and applications. Here, the vibrational mechanical modes of nanoparticles are probed to evaluate the nanomechanical and morphological properties of various CGs architectures. Utilizing the scanning micro-Brillouin light scattering (µ-BLS), the effective elastic constants and nanoparticles' sizes is determined as a function of position in a remote and non-destructive manner. This method is applied to CG mesostructures with different spatial distributions of their particle size and degree of order. These include CGs with single-sized systems, binary mixtures, bilayer structures, continuous gradient structures, and gradient mixtures. The microenvironments govern the local mechanical properties and highlight how the granular mesostructure can be used to develop durable functional polymer colloids. A size effect is revealed on the effective elastic constant, with the smallest particles and ordered assemblies forming robust structures, and classify the various types of mesoscale order in terms of their mechanical stiffness. The work establishes scanning µ-BLS as a tool for mapping elasticity, particle size, and local structure in complex nanostructures.

Polymeric microsieves bearing elliptical pores were successfully prepared via float-casting: a dispersion comprising nonvolatile acrylate monomers and ellipsoidal polystyrene particles was spread onto a water surface. The resulting self-organized monolayer was laterally compressed, and the monomer was photopolymerized, giving rise to a membrane comprising ellipsoidal particles laterally embedded in a 0.5 mu m thin polymer membrane. The particles were dissolved, leaving behind elliptical pores. These pores had an average length of the major axis of 0.87 +/- 0.1 mu m and of the minor axis of 0.42 +/- 0.07 mu m and an aspect ratio of approximately 2. The microsieve bearing these submicrometric elliptical pores was transferred to a hierarchical structure made out of microsieves bearing circular pores of 6 mu m diameter on top of a microsieve with 70 mu m diameter pores. The resulting hierarchically structured microsieve had a porosity of 0.13. At a pressure difference of typically 10(3) Pa (Reynolds number aprox. 0.002), the volumetric permeance for water was Pe = V /A/Delta p = 0.510(-6) m/s/Pa, the product viscositypermeance is eta V /A/Delta p = 0.510(-9 )m. This value is lower than the corresponding values of microsieves with circular pores of similar diameter produced by the same technique. The beneficial effects of higher permeance per pore caused by the elliptical shape are countered by lower porosity caused by less efficient packing of the ellipsoidal particles.

Passive daytime radiative cooling (PDRC) has emerged as a promising strategy to mitigate the increasing impact of heat waves. However, achieving effective PDRCs requires cost-effective, ecofriendly, and industrially scalable materials. In this study, we investigate the potential of anodic aluminum oxide (AAO) nanostructures coated with metals as passive radiative coolers. We explore the effects of different metallic coatings (Al and Au) with varying thicknesses (ranging from 20 to 100 nm) on the cooling performance of the AAO nanostructures. Our finding reveals a maximum temperature reduction (Delta T) of 12.5 degrees C for 60 nm of Au coating. Furthermore, we demonstrate the dependence of the cooling performance on ambient temperature, emphasizing the practical benefits of these enhanced AAO-based radiative coolers for real-world applications. Notably, our results surpass previous works, offering an avenue to enhance the PDRC capability.

Colloidal particles play a pivotal role in numerous applications across various disciplines, many of which necessitate precise control over particle size and size distribution. Seeded growth reactions have been established as effective methods for reproducibly accessing tailor-made particles. However, conventional batch-wise syntheses only yield discrete particle sizes. With the increasing focus on complex structures in current research, there is a demand for innovative and adaptable techniques to produce colloidal particles with precise sizes and size distributions. The Controlled Emulsion Extraction Process (CrEEP) is capable of addressing this challenge. Here, we present in detail how this synthesis works and demonstrate its reliability and versatility. Our approach exploits the time-dependent particle growth and enables accessing dispersions of controlled particle size distributions. We highlight these possibilities through a variation of the monomer feed and feed composition, resulting in gradual changes in both size and glass transition temperature, respectively. Beyond its application to polymer particles, CrEEP can be seamlessly extended to other seeded-growth mechanisms, such as the silica Stöber synthesis. Consequently, the Controlled Extraction Stöber Process (CrESP) similarly yields a size gradient, showcasing the generality of this synthetic advancement.

Carbon materials comprise a wide range of microstructures and excellent electrical and thermal properties while being cost-effective and readily available. They can be obtained through carbothermal processes at high temperatures, starting from cellulose. Catalytically active compounds, for example, iron salts, strongly influence the carbon microstructure during the graphitization process. Different degrees of structural order can, therefore, be achieved by adjusting the concentration of the iron salts. An infusion withdrawal impregnation approach is used on filter paper to prepare a continuous gradient of the carbon microstructure. This structural change is accompanied by a continuous variation of the closely related electrical and thermal transport properties. Even more, the synergistic interplay of local sheet resistance and thermal diffusivity results in the formation of switchable temperature gradients when an external current is applied. Steady state temperature differences of up to 80 degrees C are observed along the centimeter-scaled samples. The controllable temperature gradient formation will be of great interest for applications requiring a fast temperature screening. Furthermore, the temperature gradient can be imposed onto other materials, which will be particularly relevant for advanced thin film characterization applications. Infusion withdrawal coating allows impregnation of cellulose with various FeCl3 concentrations. Carbonization leads then to gradual changes in the carbon microstructure and transport properties. This results in an exciting material with a controllable temperature gradient. image

Structural colors arise from selective light interaction with (nano)structures, which give them advantages over pigmented colors such as resistance to fading and possibility to be fabricated out of traditional low-cost and non-toxic materials. Since the color arises from the photonic (nano)structures, different structural features can impact their photonic response and thus, their color. Therefore, the detailed characterization of their structural features is crucial for further improvement of structural colors. In this work, we present a detailed multi-scale structural characterization of ceramic-based photonic glasses by using a combination of high-resolution ptychographic X-ray computed tomography and small angle X-ray scattering. Our results uncover the structure-processing-properties' relationships of such nanoparticles-based photonic glasses and point out to the need of a review of the structural features used in simulation models concomitantly with the need for further investigations by experimentalists, where we point out exactly which structural features need to be improved.

With the ongoing electrification of vehicles, thermal management is on everyone's lips. To prevent overheating in electronic systems, new design strategies for thermal dissipation are needed. Thermally anisotropic materials enable targeted directional heat transport due to their anisotropic thermal conduction. Laminates made of unidirectionally aligned carbon fibers in a polymer matrix can be tailored regarding their in-plane anisotropy. Exposing the laminates to a temperature gradient reveals that the thermal transport is determined by their anisotropic properties. The corresponding heat flow can be visualized by IR thermography. The combination of anisotropic laminate discs into composite materials, similar to building with toy bricks, enables precise control of heat transport in the macroscopic composite materials. Thus, we achieve control of heat flow at the level of the individual components. In addition, we show that the orientation of anisotropy relative to the temperature gradient is crucial to guide the heat flow selectively. We found that the ratio of thermal anisotropy, the amount and arrangement of anisotropic components, and their positioning in the composite strongly influence heat transport. By combining all these factors, we are able to locally control the heat flow in composites by creating materials to either dissipate heat or block heat transport. The proposed concept can be extended to different shapes of building blocks in two or three dimensions.

A thorough knowledge and understanding of the structure–property relationship between thermal conductivity and C-fiber morphology is important to estimate the behavior of carbon fiber components, especially under thermal loading. In this paper, the thermal conductivities of different carbon fibers with varying tensile modulus were analyzed perpendicular and parallel to the fiber direction. Besides the measurement of carbon fiber reinforced polymers, we also measured the thermal conductivity of single carbon fibers directly. The measurements clearly proved that the thermal conductivity increased with the tensile modulus both in fiber and perpendicular direction. The increase is most pronounced in fiber direction. We ascribed the increase in tensile modules and thermal conductivity to increasing anisotropy resulting from the orientation of graphitic domains and microvoids. Graphical abstract