Block copolymers are versatile building blocks for the self-assembly of functional nanostructures in bulk and solution. While spheres, cylinders, and bilayer sheets are thermodynamically preferred shapes and frequently observed, ring-shaped nanoparticles are more challenging to realize due to energetic penalties that originate from their anisotropic curvature. Today, a handful of concepts exist that produce core-shell nanorings, while more complex (e.g. patchy) nanorings are currently out of reach and have only been predicted theoretically. Here, we demonstrate that confinement assembly of properly designed ABC triblock terpolymers is a general route to synthesize Janus nanorings in high purity. The triblock terpolymer self-assembles in the spherical confinement of nanoemulsion droplets into prolate ellipsoidal microparticles with an axially-stacked lamellar-ring (lr)-morphology. We clarified and visualized this complex, yet well-ordered, morphology with transmission electron tomography (ET). Blocks A and C formed stacks of lamellae with the B

We report on the formation of shape-and surfaceanisotropic Janus nanocups (JNCs) by evaporation-induced confinement assembly (EICA) of ABC triblock terpolymers. During microphase separation in spherical confinement, the triblockt erpolymer spontaneously adopted ah emispherical shape with an inner concentric lamella-lamella (ll) morphology.C ross-linking and disassembly of the microparticles resulted in well-defined JNCs with different chemistry on the inside and outside.B ys ynthesizing polymers with increasing length of the cross-linkable block, we tuned the mechanical stability of the nanocups,w hichi sr elevant to control opening and closing of the cup cavity.Weutilize the Janus properties for selective uptake of cargo exemplified by the filling of JNCs with polymer or gold nanoparticles.The directional properties of JNCs suggest applications in locomotion, oil-spill recovery, storage and release,t emplating,a nd as nanoreactors with attoliter volume. Angewandte ChemieCommunications 7123

Understanding the self-assembly behavior of polymers of various topologies is key to a reliable design of functional polymer materials. Self-assembly under confinement conditions emerges as a versatile avenue to design polymer particles with complex internal morphologies while simultaneously facilitating scale-up. However, only linear block copolymers have been studied to date, despite the increasing control over macromolecule composition and architecture available. This study extends the investigation of polymer self-assembly in confinement from regular diblock copolymers to diblock molecular polymer brushes (MPBs). Block-type MPBs with polystyrene (PS) and polylactide (PLA) compartments of different sizes are incorporated into surfactant-stabilized oil-in-water (chloroform/water) emulsions. The increasing confinement in the nanoemulsion droplets during solvent evaporation directs the MPBs to form solid nano/microparticles. Microscopy studies reveal an intricate internal particle structure, including interpenetrating networks and axially stacked lamellae of PS and PLA, depending on the PS/PLA ratio of the brushes.

We report on the evaporation-induced confinement assembly (EICA) of polystyrene-b-polybutadiene-b-poly­(methyl methacrylate) (PS-b-PB-b-PMMA, SBM) triblock terpolymers into multicompartment microparticles and follow their morphological evolution during solvent-adsorption annealing. We initially obtain elliptic microparticles with axially stacked PS/PB/PMMA morphology using cetyltrimethylammonium bromide (CTAB) as surfactant. Exchanging the surfactant to poly­(vinyl alcohol) (PVA) during solvent vapor annealing with chloroform (CHCl3), PMMA preferentially interacts with the interface, and microparticles change their shape into spheres with concentric morphology. Surprisingly, this transformation initiates at both poles of the microparticles simultaneously and then proceeds toward the equator, resulting in particles with inner morphology and patchy topography. We observed this evolution for different PB fractions, suggesting the mechanism to be more general and the EICA process to be a suitable method to generate patchy particle surfaces.

Janus particles have drawn considerable interest as colloidal surfactants, microswimmers, and building blocks for colloidal lattices. So far, research primarily focused on spherical Janus particles for which a number of fabrication methods are well established. Janus particles with geometric anisotropy offer shapedependent properties in addition to surface anisotropy, but their synthesis is more challenging. Here, we report a variety of polymeric Janus nanoparticles synthesized from ABC triblock terpolymer microphases in microemulsion droplets. Evaporationinduced assembly of the ABC triblock terpolymers led to prolate microparticles with A/C lamellae stacked along the particle's major axis. By admixing a B homopolymer during microphase separation, the morphology of the B microphase was gradually tuned in between the A/C lamellae. Cross-linking of the B microdomain created Janus nanodiscs, where the topology could be controlled to unconventional inner structures. We follow the morphology evolution and rationalize their stability with theoretical considerations in the strong segregation limit and dissipative particle dynamics simulations.

Lamella-forming ABC triblock terpolymers are convenient building blocks for the synthesis of soft Janus nanoparticles (JNPs) by crosslinking the B domain that is “sandwiched” between A and C lamellae. Despite thorough synthetic variation of the B fraction to control the geometry of the sandwiched microphase, so far only Janus spheres, cylinders, and sheets have been obtained. In this combined theoretical and experimental work, we show that the blending of polybutadiene homopolymer (hPB) into lamella morphologies of polystyrene-block-polybutadiene-block-polymethylmethacrylate (SBM) triblock terpolymers allows the continuous tuning of the polybutadiene (PB) microphase. We systematically vary the volume fraction of hPB in the system, and we find in both experiments and simulations morphological transitions from PB-cylinders to perforated PB-lamellae and further to continuous PB-lamellae. Our simulations show that the hPB is distributed homogeneously in the PB microdomains. Through crosslinking of the PB domain and redispersion in a common solvent for all blocks, we separate the bulk morphologies into Janus cylinders, perforated Janus sheets, and Janus sheets. These studies suggest that more complex Janus nanostructures could be generated from ABC triblock terpolymers than previously expected.

Hybrid inorganic/block copolymer (BCP) materials have become increasingly relevant for application in heterogeneous catalysis, microelectronics, and nanomedicine. While block copolymer templates are widely used for the formation of inorganic nanostructures, multicompartment templates could give access to more complex shapes and inner structures that are challenging to obtain with traditional processes. Here, we report the formation and characterization of hybrid platinum/polymer helices using multicompartment nanofibers (MCNFs) of polystyrene-block-polybutadiene-block-poly­(tert-butyl methacrylate) (PS-b-PB-b-PT) triblock terpolymers as templates. Cross-linking of a PS-b-PB-b-PT helix-on-cylinder morphology resulted in uniform nanofibers with a diameter of 90 nm and a length of several micrometers, as well as an inner PB double helix (diameter 35 nm, pitch 25 nm, core 12 nm). The PB double helix served as template for the sol–gel reaction of H2PtCl6 into hybrid Pt double helices (Pt@MCNFs) as verified by STEM, electron tomography, AFM, and SEM. Carbonization of the Pt hybrids into Pt decorated carbon nanofibers (Pt@C) was followed in situ on a TEM heating state. Gradual heating from 25 to 1000 °C induced fusion of amorphous Pt NPs into larger crystalline Pt NP, which sheds light on the aging of Pt NPs in BCP scaffolds under high temperature conditions. The Pt@MCNFs were further sulfonated and incorporated into a filter to catalyze a model compound in a continuous flow process.

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