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Aqueous multi-phase systems have attracted a broad interest in recent years, which is mainly due to their applicability in biology for purification and isolation of biomolecules and also for separation of particles as well as environment for enzymatic reactions. Here, three polyacrylamides poly(N,N-dimethylacrylamide), poly(acrylamide), and poly(4-acryloylmorpholine) with ultra-high molar mass were synthesized via photo-induced reversible addition–fragmentation chain-transfer polymerization (Mn > 700,000 g·mol–1). The polymers were combined to form aqueous multi-phase systems with low total polymer concentration as low as 1.1 to 2.1 wt %. Furthermore, the aqueous multi-phase system could be transformed into water-in-water (w/w) emulsions, stabilized by layered double hydroxide nanoparticles. Due to the low polymer content, these aqueous multi-phase systems open up new pathways, for example, in the separation of biomolecules or the compartmentalization of aqueous environments in catalysis.

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The phase separation in aqueous solutions of a double-hydrophilic block copolymer (DHBC) at concentrations mimicking the crowded environment in cells and its performance as a potential protein purification system are investigated. Similar to processes of self-coacervation, the coexistence of aqueous polymer-rich and polymer-depleted microscopic phases is observed and the partitioning of various species in them is investigated. Whereas small molecules, poly(ethylene glycol), and dextran can moderately partition in both phases, proteins and DNA are strongly enriched in the polymer-depleted phase, offering a pathway for biomacromolecule purification. While aqueous two-phase systems based on a pair of polymers are also used for purification of biological material, DHBC has the remarkable advantage that the proteins and DNA segregate in the polymer-depleted phase, enhancing and facilitating purification. Future optimization of DHBC chemistry may offer higher partition efficiency and a way for large-scale applications.

Das Jahr 2020 steht im Zeichen der Polymere, deren erste Beschreibung auf Hermann Staudinger zurückgeht.1,2) Dieser Trendbericht behandelt die Forschung des wissenschaftlichen Nachwuchses, also von Habilitanden, Juniorprofessoren, Postdoktoranden, Privatdozenten und Gruppenleitern. Es geht um Biopolymere und biomedizinische Anwendungen von Polymeren, Polymermaterialien und ‐synthese sowie stimuliresponsive Polymersysteme und Polymerarchitekturen und deren Selbstanordnung.

Photocatalysis for clean hydrogen production and waste water remediation holds a great promise on society. However, despite the significant progress in this field the recyclability of the photocatalytic materials together with good photoactivity remain a great challenge. photocatalytic materials for waste water cleaning and hydrogen production based on the utilization of photoactive macrogel beads as the photocatalyst. To do so, we design a graphitic carbon nitride based macrogels with tailored size, swelling behavior and photocatalytic properties. Detailed studies reveal that the catalytic activity is correlated with the polymer particle size, g-C3N4 content and swelling behavior, enabling the optimization of the photocatalytic processes. We believe that the presented strategy together with the good photocatalytic activity and excellent recyclability constitute open the path for a substantial progress in this field.

Owing to their large ratio of surface area to mass and volume, metal–organic frameworks and porous carbons have revolutionized many applications that rely on chemical and physical interactions at surfaces. However, a major challenge today is to shape these porous materials to translate their enhanced performance from the laboratory into macroscopic real-world applications. In this review, we give a comprehensive overview of how the precise morphology control of metal oxides can be transferred to metal–organic frameworks and porous carbon materials. As such, tailored material structures can be designed in 0D, 1D, 2D, and 3D with considerable implications for applications such as in energy storage, catalysis and nanomedicine. Therefore, we predict that major research advances in morphology control of metal–organic frameworks and porous carbons will facilitate the use of these materials in addressing major needs of the society, especially the grand challenges of energy, health, and environment.

Photopolymerization is a common method in the synthesis of polymers with various applications. Herein, a simple and effective route for surfactant-free emulsion photopolymerization (EPP) under visible light irradiation is described. Therein, graphitic carbon nitride (g-CN) was utilized as an stabilizer and a photoinitiator at the same time. As such, g-CN provides the starting point for polymer chain growth and particle formation. Notably, the as-prepared polymer latexes are directly crosslinked by g-CN, and the existence of g-CN is confirmed inside of the particle, as well as outside, where it forms relatively stable latexes. Moreover, surface functionalized g-CN was utilized to tailor the g-CN/monomer interactions for improved particle formation. g-CN quantum dots with enhanced photoluminescence properties were introduced in EPP as well, providing polymer latexes with enhanced photoluminescence. The obtained polymer nanoparticles might be promising candidates for bioimaging applications.

Synthesis of 3D flower‐like zinc‐nitrilotriacetic acid (ZnNTA) mesocrystals and their conformal transformation to hierarchically porous N‐doped carbon superstructures is reported. During the solvothermal reaction, 2D nanosheet primary building blocks undergo oriented attachment and mesoscale assembly forming stacked layers. The secondary nucleation and growth preferentially occurs at the edges and defects of the layers, leading to formation of 3D flower‐like mesocrystals comprised of interconnected 2D micropetals. By simply varying the pyrolysis temperature (550–1000 °C) and the removal method of in the situ‐generated Zn species, nonporous parent mesocrystals are transformed to hierarchically porous carbon flowers with controllable surface area (970–1605 m2 g−1), nitrogen content (3.4–14.1 at%), pore volume (0.95–2.19 cm3 g−1), as well as pore diameter and structures. The carbon flowers prepared at 550 °C show high CO2/N2 selectivity due to the high nitrogen content and the large fraction of (ultra)micropores, which can greatly increase the CO2 affinity. The results show that the physicochemical properties of carbons are highly dependent on the thermal transformation and associated pore formation process, rather than directly inherited from parent precursors. The present strategy demonstrates metal‐organic mesocrystals as a facile and versatile means toward 3D hierarchical carbon superstructures that are attractive for a number of potential applications.

Compartmentalized hydrogels constitute a significant research area, for example, for catalytic and biomedical applications. As presented here, a generic method is used for compartmentalization of supramolecular hydrogels by using water-in-water emulsions based on aqueous two-phase systems. By forming the supramolecular hydrogel throughout the continuous phase of all-aqueous emulsions, distinct, microcompartmentalized materials were created. The basis for the presented compartmentalized water-in-water hydrogels is polydopamine particle-stabilized water-in-water emulsions from dextran and poly(ethylene glycol) (PEG). Addition of α-cyclodextrin (α-CD) led to supramolecular complexation with PEG and subsequent hydrogel formation showing no signs of creaming. Due to the supramolecular nature of the compartmentalized hydrogels, selective network cleavage could be induced via competing guest addition, while keeping the emulsion substructure intact.

Hydrogels constitute an important class of polymeric materials, mainly due to their promising applications in the biomedical field. Particularly, mechanical properties are a limiting factor for applications, and reinforcement and improved wear resistance are major directions in current research. In here, graphitic carbon nitride (g-CN)-based hydrogels are presented. The hydrogels are formed in a two-step procedure. In the first step, a prepolymer is synthesized that leads to a significantly improved g-CN dispersibility and stability of g-CN dispersions. Hence, the g-CN content in the final hydrogels can be increased to obtain tough hydrogels. More importantly, hydrogels from charged monomers can be formed as well, which leads to lubricant properties. As such, the investigated route opens up new opportunities to fabricate functional hydrogels with significant toughness, compressibility and lubricity.

The self-assembly of a novel combination of hydrophilic blocks in water is presented, namely poly(2-ethyl-2-oxazoline)-b-poly(N-vinylpyrrolidone) (PEtOx-b-PVP). The completely water-soluble double hydrophilic block copolymer (DHBC) is formed via copper-catalyzed polymer conjugation, whereas the molecular weight of the PVP is varied in order to study the effect of block ratio on the self-assembly process. Studies via dynamic light scattering, static light scattering as well as microscopy techniques, e.g., cryo scanning electron microscopy or laser scanning confocal microscopy, show the formation of spherical particles in an aqueous solution with sizes between 300 and 400 nm. Particles of the DHBCs are formed without the influence of external stimuli. Moreover, the efficiency of self-assembly formation relies significantly on the molar ratio of the utilized blocks. The nature of the formed structures relies further on the concentration, and indications of particular and vesicular structures are found.

A Cu(II) MOF can serve as an efficient catalyst for activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP), e.g. for the synthesis of poly(benzyl methacrylate) (PBzMA) and polystyrene (PS). Furthermore, poly(isoprene) (PI) and poly(4-vinylpyridine) (P4VP) can be formed in a controlled fashion as well, which used to be challenging to achieve by traditional strategies. Taking advantage of the heterogeneous nature of the catalyst, recycling via centrifugation and repeated utilization for at least six cycles are demonstrated.