An Exceptionally Stable and Scalable Sugar–Polyolefin Frank–Kasper A15 Phase

Abstract

One-component" soft material Frank-Kasper (FK) phases are an intriguing structural form of matter that possess periodically ordered structures arising from the self-reconfiguration and close packingo fa ni nitial assembly of identical "deformable" spheres into two or more size-or shape-distinct sets of particles.S ignificant challenges that must still be addressed to advance the field of soft matter FK phases further,h owever,i nclude their rare and unpredictable occurrence,u ncertain mechanisms of solid-state assembly,a nd low thermodynamic stability.H ere we show that ar eadily-accessible sugar-polyolefin conjugate quantitatively produces an exceptionally stable solid-state FK A15 phase through arapid and irreversible thermotropic order-order transition, which contrary to other prevailing proposed mechanisms,d oes not require mass transfer between particles or large structural reorganization in the bulk to establish unit cell non-equivalency.Our results provide the basis for arealistic strategy for obtaining practical and scalable quantities of adiverse range of sugar-polyolefin FK A15 phases with unique intrinsic physical properties and chemical reactivities not previously seen in such systems.Periodically-ordered, "one-component" soft matter Frank-Kasper (FK) phases,w hich arise from the topological close packing (TCP) of "deformable" sphere-shaped particles,have now been experimentally verified for amphiphilic liquid crystals and dendrons,b lock copolymers," giant" molecules and surfactants,a nd colloidal nanoparticles. [1][2][3][4][5][6][7][8][9] Frank and Kasper [10] originally developed the concept of TCP to rationalize how the complex crystal structures of certain intermetallic alloys arise through the packing of asymmetric polyhedra that are associated with different sets of atoms that define ap articular coordination number, CNx, where x = 12,14,15, or 16. Forexample,asshown in Figure 1, the unit cell of the cubic FK A15 (Pm3 n)p hase,w hich is found for some bimetallic alloys with A 3 Bstoichiometry (e.g. Nb 3 Sn), can be seen as arising from two crystallographically equivalent B sites that reside within CN12 distorted icosahedra, while six equivalent face-shared As ites are associated with CN14 polyhedra. Other commonly encountered bimetallic FK phases include the Laves C14 and C15 structures for A 2 B alloys (e.g.MgZn 2 ), and the complex s phase for AB alloys of

Impact of Architectural Asymmetry on Frank–Kasper Phase Formation in Block Polymer Melts

“…A15 begins to emerge at 170 °C, becomes pure at 180 °C, and disorders at 200 °C. The direct DDQC → A15 transition is relatively uncommon among self-assembling soft materials; in previous reports, HEX C → A15 50,51,54 or σ → A15 16,52 transitions are more commonly observed. In order to probe the DDQC → A15 transition, a second unannealed sample of PN2M-b-PN2D(0.26, 46) was heated from 25 to 170 °C at 10 °C/min, and then from 170 to 213 °C at approximately 1.5 °C/min (Figure 7).…”

Discrete Block Copolymers with Diverse Architectures: Resolving Complex Spherical Phases with One Monomer Resolution

“…Block copolymers with chemically distinct components continue to fascinate the scientific community for their capability to spontaneously form exquisitely ordered structures at the nanometer scale, offering a broad and expanding range of practical applications . The recent discovery of intriguing unconventional spherical packing lattices, e.g., Frank–Kasper phases and quasicrystalline phases, in block copolymer system − disrupts the long-standing principles of block copolymer phase behaviors, − representing significant advances in fundamental polymer science and opening up numerous possibilities for designing materials with unique properties. Despite interesting and unusual structures, detailed mechanisms of the formation and evolution of these complex lattices have yet to be fully established .…”

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

“…In addition to raising the fundamental question of what minimally constitutes a Schoen TPMS DG lattice, these results serve to establish the class of sugar-polyolefin conjugates as a new material platform for nanoscience and nanotechnology. [10] Using previously published methods, the sugar-polyolefin conjugates 1-4 of Scheme 1 were easily prepared through copper-mediated "click chemistry" between a corresponding disaccharide-based N-acetyl propargyl amide starting material and an ultra-low molecular weight, azido-terminated amorphous atactic polypropene (N 3 -aPP) building block. [10][11][12] The ether-linked cellobiose-aPP conjugate 5 was further obtained by employing standard carbohydrate synthetic methods and an ultra-low molecular weight hydroxy-terminated aPP (HO-aPP) precursor.…”

“…[10] Using previously published methods, the sugar-polyolefin conjugates 1-4 of Scheme 1 were easily prepared through copper-mediated "click chemistry" between a corresponding disaccharide-based N-acetyl propargyl amide starting material and an ultra-low molecular weight, azido-terminated amorphous atactic polypropene (N 3 -aPP) building block. [10][11][12] The ether-linked cellobiose-aPP conjugate 5 was further obtained by employing standard carbohydrate synthetic methods and an ultra-low molecular weight hydroxy-terminated aPP (HO-aPP) precursor. [12] Importantly, both the N 3 -aPP and HO-aPP starting materials were, in turn, easily prepared with a tunable DP n value and very narrow molecular weight distribution, as evidenced by a polydispersity index, (= M w /M n ), that is typically 1.1, through the living coordinative chain transfer polymerization (LCCTP) of propene followed by reactive quenching and end-group functionalization.…”

“…[12] Importantly, both the N 3 -aPP and HO-aPP starting materials were, in turn, easily prepared with a tunable DP n value and very narrow molecular weight distribution, as evidenced by a polydispersity index, (= M w /M n ), that is typically 1.1, through the living coordinative chain transfer polymerization (LCCTP) of propene followed by reactive quenching and end-group functionalization. [10,11] Finally, for each new sample of 1-5 that was separately synthesized, a combination of gel permeation chromatography (GPC), high-field 1D-and 2D 1 H and 13 C NMR spectroscopy, and matrix-assisted laser desorption ionization (MALDI) mass spectrometry was used to establish the number-average and weight-average molecular weight indices, M n and M w , DP n , and values. [12] Here it must be pointed out that, due to the ultra-low molar masses of the aPP domains that are being targeted, slight synthetic variation in the molecular weight-related parameters of each sugarpolyolefin is unavoidable in going from one batch to another.…”