This Perspective outlines recent advances concerning the formation and potential uses of block copolymer micelles, a class of soft matter-based nanoparticles of growing importance. As a result of rapidly expanding interest since the mid 1990s, substantial advances have been reported in terms of the development of morphological diversity and complexity, control over micelle dimensions, scale up, and applications in a range of areas from nanocomposites to nanomedicine.

Bassanite is a metastable but industrially important form of calcium sulfate, which is commonly produced by heating of gypsum. Here we show that pure bassanite can also be obtained at ambient conditions by quenching aqueous CaSO 4 solutions in ethanol. This highlights that organic solvents can actually induce the formation of metastable phases rather than freezing precipitation processes.

Calcium sulfate is a naturally abundant and technologically important mineral with a broad scope of applications. However, controlling CaSO4 polymorphism and, with it, its final material properties still represents a major challenge, and to date there is no universal method for the selective production of the different hydrated and anhydrous forms under mild conditions. Herein we report the first successful synthesis of pure anhydrite from solution at room temperature. We precipitated calcium sulfate in alcoholic media at low water contents. Moreover, by adjusting the amount of water in the syntheses, we can switch between the distinct polymorphs and fine-tune the outcome of the reaction, yielding either any desired CaSO4 phase in pure state or binary mixtures with predefined compositions. This concept provides full control over phase selection in CaSO4 mineralization and may allow for the targeted fabrication of corresponding materials for use in various areas.

Biomimetic organic-inorganic composite materials were fabricated via one-step self-organization on three hierarchical levels. The organic component was a polyoxazoline with pendent cholesteryl and carboxyl (N-Boc-protected amino acid) side chains that was able to form a chiral nematic lyotropic phase and bind to positively charged inorganic faces of Laponite. The Laponite particles formed a mesocrystalline arrangement within the liquid-crystal (LC) polymer phase upon shearing a viscous dispersion of Laponite nanoparticles and LC polymer in DMF. Complementary analytical and mechanical characterization techniques (AUC, POM, TEM, SEM, SAXS, μCT, and nanoindentation) covering the millimeter, micrometer, and nanometer length scales reveal the hierarchical structures and properties of the composite materials consisting of different ratios of Laponite nanoparticles and liquid-crystalline polymer.

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Biomimetic composite materials consisting of vanadium pentoxide (V2O5) and a liquid crystal (LC) "gluing" polymer were manufactured exhibiting six structural levels of hierarchy, formed through LC phases. The organic matrix was a polyoxazoline with pendant cholesteryl and carboxyl units, forming a lyotropic phase with the same structural orientation extending up to hundreds of micrometers upon shearing, and binding to V2O5 via hydrogen bridges. Composites consisting of V2O5-LC polymer hybrid fibers with a pronounced layered structuring were obtained. The V2O5-LC polymer hybrid fibers consist of aligned V2O5 ribbons, composed of self-assembled V2O5 sheets, encasing a chiral nematic polymer matrix. The structures of the V2O5-LC polymer composites strongly depend on the preparation method, i.e., the phase-transfer method from aqueous to organic medium, in which the polymer forms LC phases. Notably, highly defined micro- and nanostructures were obtained when initiating the synthesis using V2O5 tactoids with preoriented nanoparticle building units, even when using isotropic V2O5 dispersions. Shear-induced hierarchical structuring of the composites was observed, as characterized from the millimeter and micrometer down to the nanometer length scales using complementary optical and electron microscopy, SAXS, μCT, and mechanical nanoindentation.

Crystalline poly(3-alkylthiophene) (P3AT) nanofibers are promising materials for a myriad of device applications but nanofiber length control and colloidal stability are difficult to achieve. We report an in depth study of the solution self-assembly of regioregular poly(3-octylthiophene)-bpoly(dimethylsiloxane) (P3OT-b-PDMS) diblock copolymers with a crystallizable p-conjugated coreforming block. Use of "living" crystallization-driven self-assembly (CDSA) seeded-growth method in solvents selective for PDMS allowed access to relatively low length dispersity, colloidally stable P3OTb-PDMS fiber-like micelles with a crystalline, tape-like P3OT core and a PDMS corona and lengths up to ca. 600 nm under optimised conditions. Significantly, the presence of a small percentage of common solvent and the use of slightly elevated temperature (35°C) was found to enhance the length control. Analogous studies for P3OT-b-PS (PS = polystyrene) suggest that solvent composition and temperature represent key parameters for the general optimisation of fiber formation by living CDSA for P3AT block copolymers.

Bio-inspired V 2 O 5 -polymer hybrid films were prepared following a one-step self-organization procedure based on liquid crystal formation of organic and inorganic components. These materials were previously reported to exhibit advantageous mechanical properties, comparable to biomaterials, such as human bone and dentin. Here, we show that these hybrid films prepared via a fast and simple synthesis procedure have an additional function as an electrochromic material, exhibiting a long-term cycle stability under alternating potentials. The structures were found to remain intact without visible changes after more than hundred switching cycles and storing the devices for several weeks. Consequently, this multifunctional V 2 O 5 -polymer hybrid system shows great promise for various technical applications.Organic-inorganic biomaterials, such as bone and nacre, consist of high, stiff and brittle, mineral fractions, which are embedded in a so organic matrix.1,2 These materials exhibit a pronounced hierarchical structure and a controlled coupling at the interface between organic and inorganic components. These structural characteristics contribute to their outstanding mechanical properties, combining both high stiffness and toughness.3-6 Very recently, we developed a biomimetic fabrication concept for the synthesis of organic-inorganic composites based on liquid crystal (LC) formation of organic and inorganic components.7 The LC 'gluing' polymer used was a statistical polyoxazoline with pendant cholesteryl and carboxyl side chains, enabling the polymer, on the one hand, to form chiral-nematic lyotropic phases on the length scale of several hundreds of micrometers upon shearing, and on the other hand, to selectively bind to nanoparticle faces via electrostatic interactions or hydrogen bridges.7,8 The inorganic nanoparticles, Laponite 7 and vanadium pentoxide (V 2 O 5 ), 8 are anisotropic in shape and consequently, were also able to form LC phases. V 2 O 5 -LC polymer composites structured on six hierarchical levels exhibiting a well-dened nanostructure and a hierarchical structuring on the length scale of several hundreds of micrometers were fabricated via this one-step selforganization process.8 Long-range orientation of the polymeric lyotropic phase was induced by rotational shearing by means of a shear cell. Remarkably, these materials exhibit advantageous mechanical properties, comparable to mechanical properties of natural hierarchically structured organic-inorganic composites like human bone and dentin (data obtained by nanoindentation; a video visualizing the bending performance of the composite is available in the ESI †).8 In this study, we investigated these materials regarding their electrochromic performance, a second feature of this composite system, besides mechanical reinforcement.Electrochromism of thin lms of transition-metal oxides, such as tungsten oxide (WO 3 ) or V 2 O 5 , have been previously studied. Upon cation intercalation (reduction) of the metal oxide, a change in absorbance in the visib...