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The structure of supraparticles (SPs) is a key parameter for achieving advanced functionalities arising from the combination of different nanoparticle (NP) types in one hierarchical entity. However, whenever a droplet-assisted forced assembly approach is used, e.g., spray-drying, the achievable structure is limited by the inherent drying phenomena of the method. In particular, mixed NP dispersions of differently sized colloids are heavily affected by segregation during the assembly. Herein, the influence of the colloidal arrangement of Pt and SiO 2 NPs within a single supraparticulate entity is investigated. A salt-based electrostatic manipulation approach of the utilized NPs is proposed to customize the structure of spray-dried Pt/SiO 2 SPs. By this, size-dependent separation phenomena of NPs during solvent evaporation, that limit the catalytic performance in the reduction of 4-nitrophenol, are overcome by achieving even Pt NP distribution. Additionally, the textural properties (pore size and distribution) of the SiO 2 pore framework are altered to improve the mass transfer within the material leading to increased catalytic activity. The suggested strategy demonstrates a powerful, material-independent, and universally applicable approach to deliberately customize the structure and functionality of multi-component SP systems. This opens up new ways of colloidal material combinations and structural designs in droplet-assisted forced assembly approaches like spray-drying., (© 2024 The Authors. Small published by Wiley‐VCH GmbH.)

Materials are the fundament of the physical world, whereas information and its exchange are the centerpieces of the digital world. Their fruitful synergy offers countless opportunities for realizing desired digital transformation processes in the physical world of materials. Yet, to date, a perfect connection between these worlds is missing. From the perspective, this can be achieved by overcoming the paradigm of considering materials as passive objects and turning them into perceptual, information-providing matter. This matter is capable of communicating associated digitally stored information, for example, its origin, fate, and material type as well as its intactness on demand. Herein, the concept of realizing perceptual, information-providing matter by integrating customizable (sub-)micrometer-sized communicating supraparticles (CSPs) is presented. They are assembled from individual nanoparticulate and/or (macro)molecular building blocks with spectrally differentiable signals that are either robust or stimuli-susceptible. Their combination yields functional signal characteristics that provide an identification signature and one or multiple stimuli-recorder features. This enables CSPs to communicate associated digital information on the tagged material and its encountered stimuli histories upon signal readout anywhere across its life cycle. Ultimately, CSPs link the materials and digital worlds with numerous use cases thereof, in particular fostering the transition into an age of sustainability., (© 2023 The Authors. Advanced Materials published by Wiley-VCH GmbH.)

Spray-drying is a popular and well-known "drying tool" for engineers. This perspective highlights that, beyond this application, spray-drying is a very interesting and powerful tool for materials chemists to enable the design of multifunctional and hybrid materials. Upon spray-drying, the confined space of a liquid droplet is narrowed down, and its ingredients are forced together upon "falling dry." As  detailed in this article, this enables the following material formation strategies either individually or even in combination: nanoparticles and/or molecules can be assembled; precipitation reactions as well as chemical syntheses can be performed; and templated materials can be designed. Beyond this, fragile moieties can be processed, or "precursor materials" be prepared. Post-treatment of spray-dried objects eventually enables the next level in the design of complex materials. Using spray-drying to design (particulate) materials comes with many advantages-but also with many challenges-all of which are outlined here. It is believed that multifunctional, hybrid materials, made via spray-drying, enable very unique property combinations that are particularly highly promising in myriad applications-of which catalysis, diagnostics, purification, storage, and information are highlighted., (© 2023 The Authors. Advanced Materials published by Wiley-VCH GmbH.)

Luminomagnetic composites have been synthesized that allow for an individual tuning of luminescence intensity, chromaticity and magnetization by combination of superparamagnetic, citrate-stabilized iron oxide nanoparticles with the luminescent MOFs 3 ∞ [Ln 2 (BDC) 3 (H 2 O) 4 ] (Ln=Eu, Tb; BDC 2- =terephthalate). The components are arranged to a concept of inverse structuring compared to previous luminomagnetic composites with MOF@magnetic particle (shell@core) composition so that the luminescent MOF now acts as core and is covered by magnetic nanoparticles forming the satellite shell. Thereby, the magnetic and photophysical properties are individually tuneable between high emission intensity (1.2 ⋅ 10 6  cps mg -1 ) plus low saturation magnetization (6 emu g -1 ) and the direct opposite (0.09 ⋅ 10 6  cps mg -1 ; 42 emu g -1 ) by adjusting the particle coverage of the MOF. This is not achievable with a core-shell structure having a magnetic core and a dense MOF shell. The composition of the composites and the influence of different synthesis conditions on their properties were investigated by SEM/EDX, PXRD, magnetization measurements and photoluminescence spectroscopy., (© 2022 The Authors. ChemPlusChem published by Wiley-VCH GmbH.)

Optical microscale shear-stress indicator particles are of interest for the in situ recording of localized forces, e.g., during 3D printing or smart skins in robotic applications. Recently developed particle systems are based on optical responses enabled by integrated organic dyes. They thus suffer from potential chemical instability and cross-sensitivities toward humidity or temperature. These drawbacks can be circumvented using photonic balls as shear-stress indicator particles, which employ structural color as the element to record forces. Here, such photonic balls are prepared from silica and iron oxide nanoparticles via the scalable and fast spray-drying technique. Process parameters to create photonic balls with a disordered core and an ordered particle structure toward the exterior of the supraparticles are reported. This hybrid disordered-ordered structure is responsible for a color loss of the indicator particles during shear-stress application because of irreversible structural destruction. By adjusting the primary silica particle sizes, nearly all colors of the visible spectrum can be achieved and the sensitivity of the response to shear stress can be adjusted., (© 2022 The Authors. Small published by Wiley-VCH GmbH.)

Small-sized temperature indicator additives autonomously record temperature events via a gradual irreversible signal change. This permits, for instance, the indication of possible cold-chain breaches or failure of electronics but also curing of glues. Thus, information about the materials' thermal history can be obtained upon signal detection at every point of interest. In this work, maximum-temperature indicators with magnetic readout based on micrometer-sized supraparticles (SPs) are introduced. The magnetic signal transduction is, by nature, independent of the materials' optical properties. This facilitates the determination of valuable temperature information from the inside, that is, the bulk, even of dark and opaque macroscopic objects, which might differ from their surface. Compared to state-of-the-art optical temperature indicators, complementary magnetic readout characteristics ultimately expand their applicability. The conceptualized SPs are hierarchically structured assemblies of environmentally friendly, inexpensive iron oxide nanoparticles and thermoplastic polymer. Irreversible structural changes, induced by polymer softening, yield magnetic interaction changes within and between the hierarchic sub-structures, which are distinguishable and define the temperature indication mechanism. The fundamental understanding of the SPs' working principle enables customization of the particles' working range, response time, and sensitivity, using a toolbox-like manufacturing approach. The magnetic signal change is detected self-referenced, fast, and contactless., (© 2022 The Authors. Advanced Materials published by Wiley-VCH GmbH.)

Small scratches and abrasion cause damage to packaging coatings. Albeit often invisible to the human eye, such small defects in the coating may ultimately have a strong negative impact on the whole system. For instance, gases may penetrate the coating and consequently the package barrier, thus leading to the degradation of sensitive goods. Herein, the indicators of mechanical damage in the form of particles are reported, which can readily be integrated into coatings. Shear stress-induced damage is indicated by the particles via a color change. The particles are designed as core-shell supraparticles. The supraparticle core is based on rhodamine B dye-doped silica nanoparticles, whereas the shell is made of alumina nanoparticles. The alumina surface is functionalized with a monolayer of a perylene dye. The resulting core-shell supraparticle system thus contains two colors, one in the core and one in the shell part of the architecture. Mechanical damage of this structure exposes the core from the shell, resulting in a color change. With particles integrated into a coating lacquer, mechanical damage of a coating can be monitored via a color change and even be related to the degree of oxygen penetration in a damaged coating., (© 2022 The Authors. Small published by Wiley-VCH GmbH.)

Communicating objects are demanded for product security and the concepts of a circular economy or the Internet of Nano Things. Smart additives in the form of particles can be the key to equip objects with the desired materials intelligence as their miniaturized size improves applicability and security. Beyond their proposed identification by optical signals, magnetic signals deriving from magnetic particles can hypothetically be used for identification but are to date only resolved roughly. Herein, a magnetic particle-based toolbox is reported, that provides more than 77 billion (77 × 10 9 ) different magnetic codes, adjustable in one single particle, that can be read out unambiguously, easily, and quickly. The key towards achieving the vast code variety is a hierarchical supraparticle design that is inspired by music: similarly to how the line-up variation of a musical ensemble yields distinguishable overtones, the variation of the supraparticle composition alters their magnetic overtones. By minimizing magnetic interactions, customizable signals are spectrally decoded by the simple method of magnetic particle spectroscopy. A large number of chemically adjustable magnetic codes and the possibility of their remote, contactless detection from within materials is a breakthrough for unexploited labeling applications and pave the way towards materials intelligence., (© 2021 The Authors. Small published by Wiley-VCH GmbH.)