General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/about/ebr-terms Abstract:Self-assembly of molecular and block copolymer amphiphiles represents a well-established route to micelles with a wide variety of shapes and gel-like phases. We demonstrate an analogous process, but on a longer lengthscale, in which amphiphilic P-H-P and H-P-H cylindrical triblock comicelles with hydrophobic (H) or polar (P) segments that are monodisperse in length are able to self-assemble side-byside or end-to-end in non-solvents for the central or terminal segments, respectively. This allows the formation of cylindrical supermicelles and 1D or 3D superstructures that persist in both solution and the solid state. These assemblies possess multiple levels of structural hierarchy in combination with existence on a multimicron length scale, features that are generally only found in natural materials. Main Text:Amphiphiles such as molecular surfactants and block copolymers have been shown to form a rich variety of self-assembled nanoscopic structures, including spherical micelles, cylinders, nanotubes, bilayers, and vesicles as well as gel-like phases (1, 2). The construction of hierarchical colloidal materials on a longer length scale using spherical nanoparticles (3, 4), branched nanocrystals (5), nanorods (6), and nanocubes (7) has also recently been the subject of intense investigation. Control over the size, shape and composition of these nanoscopic building blocks has enabled the formation of superstructures with significant structural diversity (3, 7). Self-assembly of Janus and patchy nanoparticles formed by surface modification (8, 9) or from block copolymers (10), including diblock (11) and star (12) or linear triblock copolymers (13-15), has further broadened the range of superstructures that can be prepared.Nevertheless, despite these impressive recent advances, the use of anisotropic amphiphilic building blocks derived from soft-matter remains limited: examples include polymer-based (16) and polymer-metal hybrid nanorods (17, 18) and self-assembled nanotubes and cylinders (19,20). These approaches

General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above.

The use of crystallization as a tool to control the self-assembly of polymeric and molecular amphiphiles in solution is attracting growing attention for the creation of non-spherical nanoparticles and more...

The design and fabrication of chiral nanostructures is a promising approach to realize enantiomeric recognition and separation. In our work, gold nanorod@chiral mesoporous silica core-shell nanoparticles (GNR@CMS NPs) have been successfully synthesized. This novel material exhibits strong and tunable circular dichroism signals in the visible and near-infrared regions due to the optical coupling between the CMS shells and the GNR cores. When chiral cysteine molecules are loaded in the porous shells, the corresponding surface enhanced Raman scattering spectroscopy demonstrates a distinct chiral recognition effect, which can be used to semiquantitatively measure the composition of chiral enantiomers. A detailed sensing mechanism has been disclosed by density functional theory calculations.

We have found that the width and shape (from rectangular to elliptical, to almost circular in cross-section) of the crystalline core of fiberlike micelles of polyferrocenyldimethylsilane (PFDMS) diblock copolymers can be varied by altering the degree of polymerization of PFDMS, and also the chemistry of the complementary corona-forming block. This enabled detailed studies of living crystallization-driven self-assembly (CDSA) processes that involved the addition of unimers with a short, crystallizable core-forming PFDMS block to a seed solution of short micelles with a large diameter crystalline core, derived from block copolymers with a longer PFDMS block. The morphology of resultant micelles was found to be highly dependent on the polarity of the solvent and temperature. For example, linear micelles were formed in less polar solvents (which are moderately poor solvents for PFDMS) and/or at higher temperatures. In contrast, the formation of branched structures could be "switched on" when the opposite conditions were used. Thus, the use of more polar solvents (which are very poor solvents for PFDMS) and ambient or subambient temperatures allowed the formation of branched micelles and block comicelles with variable and spatially distinct corona chemistries, including amphiphilic nanostructures. Rapid crystallization of added unimers at the seed micelle termini under nonequilibrium self-assembly conditions appears to facilitate the formation of the branched micellar structures as a kinetically trapped morphology. This is evidenced by the transformation of the branched micelles into linear micelles on heating at elevated temperatures.

The synthesis mechanism of anionic surfactant-templated mesoporous silica (AMS) is described. A family of highly ordered mesoporous silica structures have been synthesized via an approach based on the self-assembly of anionic surfactants and inorganic precursors by using aminopropylsiloxane or quaternized aminopropylsiloxane as the co-structure-directing agent (CSDA), which is a different route from previous pathways. Mesophases with differing surface curvatures, varying from cage type (tetragonal P42/mnm; cubic Pm3̄n with modulations; cubic Fd3̄m) to cylindrical (two-dimensional hexagonal p6mm), bicontinuous (cubic Ia3̄d and Pn3̄m), and lamellar have been obtained by controlling the charge density of the micelle surfaces by varying the degree of ionization of the carboxylate surfactants. Changing the degree of ionization of the surfactant results in changes of the surfactant packing parameter g, which leads to different mesostructures. Furthermore, variation of the charge density of positively charged amino groups of the CSDA also gives rise to different values of g. Mesoporous silicas, functionalized with amino and quaternary ammonium groups and with the various structures given above, have been obtained by extraction of the surfactant. This report leads to a deeper understanding of the interactions between the surfactant anions and the CSDA and provides a feasible and facile approach to the mesophase design of AMS materials.

Fabrication of chiral materials and revealing the mechanisms involved in their formation are crucial issues in scientific research. The combination of cooperative self-assembly routes and the chiral templating process favors the formation of inorganic chiral materials with highly ordered mesostructures. This tutorial review highlights the recent research on chiral mesoporous silica (CMS) of hierarchical helical constructions transcribed from organic templates. The rules and mechanisms involved in the synthesis of CMS and related materials, especially the novel expression of chirality and imprinting of helical micellar superstructure by the functional groups immobilized on the mesopore surface, provide us with a deeper insight into the chiral self-assembly process and new strategies for the design and application of chiral materials. This review is addressed to researchers and students interested in chiral chemistry, supramolecular chemistry and mesoporous materials (53 references).

We report the preparation of multi-armed micelles and block co-micelles using the crystallization-driven self-assembly of crystalline-coil polyferrocenylsilane block copolymers from nanocrystals of the homopolymer. The resulting multi-armed micelles possessed hierarchical multipod structures with monodisperse and tunable arm lengths. The termini of the arms remained active to the addition of further block copolymer unimers, and multi-armed block co-micelles with segmented arm chemistries and variable segment sequences were prepared. Coronal cross-linking followed by nanocrystal dissolution led to the release of non-centrosymmetric AB cylindrical diblock co-micelles.