Giant Thermal Tunability of the Lamellar Spacing in Block‐Copolymer‐Like Supramolecules Formed from Binary‐End‐Functionalized Polymer Blends

Abstract

In almost all fields of material science, the control of patterns and dimensions of nanometer-sized structures has been extensively pursued in recent years because of the strong potential for such materials to be incorporated into novel materials and devices. Self-assembly of block copolymers has been recognized as a promising strategy to fabricate functional nanostructured materials. In bulk or in concentrated solution, block copolymers form spatially periodic nanostructures; the best-known morphologies are lamellae, hexagonally arranged cylinders, spheres arranged on a body-centered cubic structure, and bicontinuous gyroids. [1][2][3][4] These nanostructures formed by block copolymers offer a number of potentially exciting applications in, e.g., magnetic-storage media, [5] silicon capacitors, [6] flash-memory devices, [7] nanoelectronics, [8] and photonic crystals. [9] Two factors in the fabrication of nanopatterns by block copolymers are technologically very important: one is the control of the form and size of the repeating structure that provides an elemental symmetry to the pattern, and the other is the achievability of perfect patterning over a very large area with a given symmetry. While several strategies have been proposed for the latter, such as those using graphoepitaxy, [10][11][12] electric fields, [13,14] shear fields, [15,16] temperature gradients, [17] solvent evaporation, [18,19] and chemically patterned substrates, [20][21][22][23] control of the form and size of the repeating structure has been pursued only by two basic conventional methods: changing the molecular weight or composition of block copolymers, or mixing of block copolymers with additional additives such as homopolymers. [24,25] In principle, changing the molecular weight or composition of block copolymers ideally can control the size and form of the resulting structure, but synthesis of such block copolymers is not easy and sometimes laborious. On the other hand, mixing of block copolymers with other polymers provides a relatively simple route; however, the controllability is usually hampered by undesirable macroscopic demixing between the constituents. [24][25][26][27][28][29][30] It has recently been demonstrated that noncovalent bonds can be used in constructing block-copolymer-like molecular complexes, [31][32][33][34][35][36][37][38] so-called supramolecules, that serve equally well as building units of nanostructures. Such noncovalent bonds include hydrogen bonding, [33][34][35][36][37][38][39] ionic interactions, [32] coordination complexation, [38] and charge-transfer interactions.[40] These supramolecular routes for block-copolymer-like architectures provide us not only with a new option for creating nanostructured materials but also with a fascinating means to design "smart" materials that respond to external stimuli or conditions. [41,42] Directing formation or cleavage of supramolecular complexes under a desired condition can thus be a basic strategy for developing materials with several tunable morphologies in the sam...

Polymers with Multiple Hydrogen-Bonded End Groups and Their Blends

“…1 H NMR (CDCl 3 ): δ ) 12.91 (br, 1H), 11.91 (br, 1H), 10.45 (br, 1H), 5.74 (s, 1H), 4.27 (t, 2H, J ) 6 Hz), 3.54 (t, 2H, J ) 6 Hz), 2.19 (s, 3H), 1.89 (s, 6H), 1.52 (s, 3H) ppm. 13 …”

“…Several groups have recently demonstrated the synthesis of MHB random copolymers [6][7][8][9][10][11][12] or block copolymer-like materials. [13][14][15][16][17] In the case of MHB block copolymers, as the temperature of the polymer melt is increased, the bonds joining dissimilar blocks break to generate homopolymers that can then swell the microphase-separated domains and reversibly increase the overall domain spacing as much as 300%. 16 Additionally, polymeric systems utilizing strategically placed reversible binding groups provide potential beyond alternative processing methods.…”

Phase Behavior of Complementary Multiply Hydrogen Bonded End-Functional Polymer Blends

“…19 The nature of the interaction varies widely and most commonly consists of either metal-ligand, 20,21 ionic, 22,23 or hydrogen bonding. 24,25 Incorporation of these into various macromolecular architectures such as diblock, [26][27][28][29][30][31][32][33][34][35] triblock, [36][37][38] multiblock, [39][40][41] star 42 and graft copolymers, [43][44][45] blends, 35,46 and gels 47,48 has resulted in remarkably simple thermal control over the polymer structure and related properties.…”

Synthesis, copolymer composition, and rheological behavior of functionalized polystyrene with isocyanate and amine side groups

“…[10][11][12][13] The FPs through the above routes can largely improve the interfacial adhesion of the polymer blends. [14][15][16] The rheological behavior as a relevant material property can provide information about the FP intermolecular interaction and reflect the influence of the molecular weight and functional group on the viscoelasticity behavior. [17] Some theoretical works and comparisons have also been reported for the polymer with functionalized chain end.…”