Polymer brush grafted anionic SiO 2 @PMAA (poly(methacrylic acid)) and cationic SiO 2 @PDMAEMA (poly(2-(dimethylamino)ethyl methacrylate)) inorganic/polymer hybrid nanoparticles with different core radii (d NP = 50− 140 nm) and different amounts of attached polymer were synthesized via surface-initiated atomic transfer radical polymerization (ATRP). To avoid irreversible aggregation, a three-step surface modification had to be employed, thereby keeping the nanoparticles always dispersed. For SiO 2 @PMAA the shell thickness changes with the monomer concentration, while for SiO 2 @PDMAEMA the grafting density was changed by monomer concentration and the shell thickness remained constant. We assume that the control over the grafting density relies on the nature of the complexation potential of the PDMAEMA. The structural characterization of the polymer grafted SiO 2 -NPs was done in detail by different scattering methods combined with thermogravimetric analysis, and details of the brush characteristics are obtained by small-angle neutron scattering (SANS). With this approach we were able to produce silica nanoparticles with anionic and cationic polymer shells, where the softness of the NPs can be controlled by the amount of polymer, which are pH-responsive and colloidally stable over a large pH range.

This article presents a study on the formation of anisometric, ellipsoidal supraparticles by evaporation‐induced self‐assembly from multicomponent colloidal dispersion droplets deposited on a superhydrophobic surface. Performing the formation process on bent surface substrates grants precise control on the shape and spatial orientation of the final dried supraparticles. Due to the V‐shaped surfaces providing interfacial blockage, anisotropic evaporation rates occur with respect to the direction of the bending channel. This proportionally leads to inhomogeneous accumulation of fumed silica (FS), used as structure guiding component. Thus, upon the increase of FS‐particle interaction via ionic strength (NaCl), this so‐formed shell provides enough anisotropic stiffness resulting in predictable droplet deformation with the elongation orientation being perpendicular to the bending axis. The anisotropic evaporation rates were monitored and quantified using an established, empiric kinetic model and taking into account surface geometry. Employing this reliable control of elongation direction and using additional Fe3O4@SiO2 core–shell nanoparticles, anisometric magnetic Janus supraparticles with defined patch position were prepared, which are not accessible on flat surfaces. The results can find application in the controlled, easy to scale up, nanofabrication process of patchy anisometric supraparticles.

Nonionic ethylene oxide (EO)‐based surfactants are widely employed in commercial applications and normally form gel‐like liquid crystalline phases at higher concentrations, rendering their handling under such conditions difficult. By incorporating CO2 units in their hydrophilic head groups, the consumption of the petrochemical EO was reduced, and the tendency to form liquid crystals was suppressed completely. This surprising behavior was characterized by rheology and studied with respect to its structural origin by means of small‐angle neutron scattering (SANS). These experiments showed a strongly reduced repulsive interaction between the micellar aggregates, attributed to a reduced hydration and enhanced interpenetration of the head groups owing to the presence of the CO2 units. In addition, with increasing CO2 content the surfactants became more efficient and effective with respect to their surface activity. These findings are important because the renewable resource CO2 is used, and the CO2‐containing surfactants allow handling at very high concentrations, an aspect of enormous practical importance.

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