Stable Thermotropic 3D and 2D Double Gyroid Nanostructures with Sub‐2‐nm Feature Size from Scalable Sugar–Polyolefin Conjugates

Abstract

Ultra-low molecular weight disaccharide-polyolefin conjugates with cellobiose, lactose and maltose head groups and atactic polypropene tails, such as 1, undergo a series of irreversible thermotropic order-order transitions with increasing temperature to provide nanostructured phases in the sequence: lamellar (L), hexagonal perforated lamellar (HPL), double gyroid (DG) and hexagonal cylindrical (C). The DG phase displays exceptional stability at ambient temperature and features two interpenetrating sugar domain networks having a sub-2-nm strut width and a lattice parameter, a DG , of 13.1 nm. The unique stability of this DG phase extends further within ultrathin films all the way down to the two-dimensional limit of 15 nm in which film thickness, l, is now less than the surface-oriented unit cell height, h DG. In addition to raising the fundamental question of what minimally constitutes a Schoen triply periodic minimal surface and DG lattice, these results serve to establish the class of sugarpolyolefin conjugates as a new material platform for nanoscience and nanotechnology. Scheme 1. Structures of sugar-polyolefin conjugates 1-5.

Stabilizing Differential Interfacial Curvatures by Mismatched Molecular Geometries: Toward Polymers with Percolating 1 nm Channels of Gyroid Minimal Surfaces

“…In contrast, self-assembly of amphiphilic molecules − or block copolymers − can give rise to thermodynamically stable 3-D continuous nanostructures with precisely defined geometry over long-length scales, as exemplified by bicontinuous cubic (Q) mesophases. Furthermore, the feature sizes are highly tunable in the range from 1 to ∼100 nm, depending on the employed amphiphilic building blocks.…”

Self-Assembly of Unusually Stable Thermotropic Network Phases by Cellobiose-Based Guerbet Glycolipids

“…Supramolecular network morphologies stemming from the self-assembly of molecular amphiphiles offer opportunities for the bottom-up construction of materials with applications including organic semiconductors and energy storage media, size-selective molecular separations membranes, membrane-bound protein crystallization platforms, , and internally structured lipid nanoparticles for therapeutic delivery. , Exemplified by functional bicontinuous double gyroid (DG), double diamond, and other periodic networks, applications of these materials crucially depend on their interpenetrating, labyrinthine nanochannels with tailored chemical constitutions and physical properties. These intricate self-assembled structures are known to arise from thermotropic self-assembly of various liquid crystal (LC) mesogens comprising chemically dissimilar segments of widely varied structures, including polycatenars, rod-like polyphiles, , wedge-shaped molecules, disk-like molecules, bolamphiphiles, , and glycolipids. − However, these thermotropic phases often form only with restricted molecular compositions and in narrow thermal stability windows, since the negative Gaussian (“saddle splay”) curvature microdomain interfaces of these assemblies exhibit substantial mean curvature deviations that result in molecular packing frustration. − The lack of robust molecular designs that drive mesoscale network self-assembly substantially curtails exciting current and future applications of these nanostructures.…”

Highly Ordered Gyroid Nanostructured Polymers: Facile Fabrication by Polymerizable Pluronic Surfactants

“…The self-assembly of block copolymers (BCPs) is well-recognized for generating a diverse range of nanostructures, with feature sizes ranging from 5 to 100 nm. ,,− Although this process has unveiled complex network nanostructures like GYR, − double diamonds, and plumber’s nightmare structures, the widespread use is hindered by their exceptionally limited accessibility, a result of high-degree packing frustration with excessive local chain stretching. ,, To overcome this limitation, several successful approaches have been explored, including blending with different BCPs or homopolymers to alleviate chain stretching, , employing diverse BCP architectures, , and manipulating chain conformation near interfaces. , However, these successes rely on precise molecular engineering, which may be challenging to achieve in large-scale production.…”