Rational Route Toward the Frank–Kasper Z Phase: Effect of Precise Geometrical Tuning on the Supramolecular Assembly of Giant Shape Amphiphiles

Theoretically, 27 types of Frank–Kasper (FK) phases could be constructed with three cornerstones, the FK A15, C15, and Z phases. They are all spherical packing phases composed of spherical motifs. In single-component soft matter, the experimental observation(s) of the A15 phase is common while C15 and Z phases are rare. Recently, a serendipitous observation of an FK Z phase with significant volume asymmetry of the constructing spherical motifs from a giant shape amphiphile assembly has been reported. In single-component soft matter, it is anticipated that the significant volume asymmetry of spherical motifs consisting of μ and μ ± 1 molecules could be readily reached when the μ is small. Herein, we present a design strategy to precisely control the number of molecules inside a spherical motif by geometrical tuning of the molecular building blocks, thus leading to the formation of the FK Z phase in a rational manner

Modularly Constructed Polyhedral Oligomeric Silsesquioxane-Based Giant Molecules for Unconventional Nanostructure Fabrication

Controlled assembly of nanoscale building blocks is a promising approach to obtain functional materials with unique properties. Here, we report a way to manipulate the supramolecular structures of giant molecules based on discotic triangle cores and isobutyl polyhedral oligomeric silsesquioxanes (BPOSS) nanoparticles (NPs). It is found that depending upon the number of BPOSS at the periphery of the discotic cores, the packing of these nanoscale components (discotic core and POSS) could be manipulated into either cylindrical or Frank–Kasper (F–K) A15 (Pm3̅n) phases. The formation of these supramolecular nanostructures is mandated by the balance between the stacking of the discotic cores and the steric hindrance effect of the BPOSS NPs. This strategy to manipulate the packing of nanoscale building blocks for different supramolecular nanostructures including the fabrication of cylindrical structures and A15 (Pm3̅n) phases may be extended to other nanoscale building blocks for future development of materials with complex structures as well as tailored functionalities and properties

Superlattice Engineering with Chemically Precise Molecular Building Blocks

Correlating nanoscale building blocks with mesoscale superlattices, mimicking metal alloys, a rational engineering strategy becomes critical to generate designed periodicity with emergent properties. For molecule-based superlattices, nevertheless, nonrigid molecular features and multistep self-assembly make the molecule-to-superlattice correlation less straightforward. In addition, single component systems possess intrinsically limited volume asymmetry of self-assembled spherical motifs (also known as “mesoatoms”), further hampering novel superlattices’ emergence. In the current work, we demonstrate that properly designed molecular systems could generate a spectrum of unconventional superlattices. Four categories of giant molecules are presented. We systematically explore the lattice-forming principles in unary and binary systems, unveiling how molecular stoichiometry, topology, and size differences impact the mesoatoms and further toward their superlattices. The presence of novel superlattices helps to correlate with Frank–Kasper phases previously discovered in soft matter. We envision the present work offers new insights about how complex superlattices could be rationally fabricated by scalable-preparation and easy-to-process materials

Ordered Mesoporous Silica Pyrolyzed from Single-Source Self-Assembled Organic–Inorganic Giant Surfactants

We report the preparation of hexagonal mesoporous silica from single-source giant surfactants constructed via dihydroxyl-functionlized polyhedral oligomeric silsesquioxane (DPOSS) heads and a polystyrene (PS) tail. After thermal annealing, the obtained well-ordered hexagonal hybrid was pyrolyzed to afford well-ordered mesoporous silica. A high porosity (e.g., 581 m2/g) and a uniform and narrow pore size distribution (e.g., 3.3 nm) were achieved. Mesoporous silica in diverse shapes and morphologies were achieved by processing the precursor. When the PS tail length was increased, the pore size expanded accordingly. Moreover, such pyrolyzed, ordered mesoporous silica can help to increase both efficiency and stability of nanocatalysts