title: Unraveling the Driving Forces in the Self-Assembly of Monodisperse Naphthalenediimide-Oligodimethylsiloxane Block Molecules.
abstract: Block molecules belong to a rapidly growing research field in materials chemistry in which discrete macromolecular architectures bridge the gap between block copolymers (BCP) and liquid crystals (LCs). The merging of characteristics from both BCP and LCs is expected to result in exciting breakthroughs, such as the discovery of unexpected morphologies or significant shrinking of domain spacings in materials that possess the high definition of organic molecules and the processability of polymers. Here we report the bulk self-assembly of two families of monodisperse block molecules comprised of naphthalenediimides (NDIs) and oligodimethylsiloxanes (ODMS). These materials are characterized by waxy texture, strong long-range order, and very low mobility, typical properties of conformationally disordered crystals. Our investigation unambiguously reveals that thermodynamic immiscibility and crystallization direct the self-assembly of ODMS-based block molecules. We show that a synergy of high incompatibility between the blocks and crystallization of the NDIs causes nanophase separation, giving access to hexagonally packed columnar (Colh) and lamellar (LAM) morphologies with sub-10 nm periodicities. The domain spacings can be tuned by mixing molecules with different ODMS lengths and the same number of NDIs, introducing an additional layer of control. X-ray scattering experiments reveal macrophase separation whenever this constitutional bias is not observed. Finally, we highlight our "ingredient approach" to obtain perfect order in sub-10 nm structured materials with a simple strategy built on a crystalline "hard" moiety and an incompatible "soft" ODMS partner. Following this simple rule, our recipe can be extended to a number of systems.
authors.affiliation: Institute for Complex Molecular Systems and Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology , 5600 MB Eindhoven, The Netherlands.
authors.forename: José Augusto
authors.initials: JA
authors.lastname: Berrocal
authors.affiliation: Institute for Complex Molecular Systems and Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology , 5600 MB Eindhoven, The Netherlands.
authors.forename: R Helen
authors.initials: RH
authors.lastname: Zha
authors.affiliation: Institute for Complex Molecular Systems and Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology , 5600 MB Eindhoven, The Netherlands.
authors.forename: Bas F M
authors.initials: BFM
authors.lastname: de Waal
authors.affiliation: Institute for Complex Molecular Systems and Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology , 5600 MB Eindhoven, The Netherlands.
authors.forename: Jody A M
authors.initials: JAM
authors.lastname: Lugger
authors.affiliation: Crystal and Structural Chemistry, Bijvoet Center for Biomolecular Research, Utrecht University , 3584 CH Utrecht, The Netherlands.
authors.forename: Martin
authors.initials: M
authors.lastname: Lutz
authors.affiliation: Institute for Complex Molecular Systems and Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology , 5600 MB Eindhoven, The Netherlands.
authors.forename: E W
authors.identifier: 0000-0003-4126-7492
authors.initials: EW
authors.lastname: Meijer
keywords: block molecules; conformationally disordered crystals; monodispersity; nanophase separation; nanostructured materials; oligodimethylsiloxanes; plastic crystals