70022-27-4Relevant articles and documents
Janus Graft Block Copolymers: Design of a Polymer Architecture for Independently Tuned Nanostructures and Polymer Properties
Guo, Zi-Hao,Le, An N.,Feng, Xunda,Choo, Youngwoo,Liu, Bingqian,Wang, Danyu,Wan, Zhengyi,Gu, Yuwei,Zhao, Julia,Li, Vince,Osuji, Chinedum O.,Johnson, Jeremiah A.,Zhong, Mingjiang
, p. 8493 - 8497 (2018)
The graft-through synthesis of Janus graft block copolymers (GBCPs) from branched macromonomers composed of various combinations of homopolymers is presented. Self-assembly of GBCPs resulted in ordered nanostructures with ultra-small domain sizes down to 2.8 nm (half-pitch). The grafted architecture introduces an additional parameter, the backbone length, which enables control over the thermomechanical properties and processability of the GBCPs independently of their self-assembled nanostructures. The simple synthetic route to GBCPs and the possibility of using a variety of polymer combinations contribute to the universality of this technique.
Crystallization Induced Self-Assembly: A Strategy to Achieve Ultra-Small Domain Sizes
Ji, Ming-Sheng,Guo, Qing-Yun,Yan, Xiao-Yun,Liu, Yuchu,Wu, Yan-Jun,Yue, Kan,Guo, Zi-Hao
supporting information, p. 7992 - 7997 (2021/05/03)
Achieving self-assembled nanostructures with ultra-small feature sizes (e. g., below 5 nm) is an important prerequisite for the development of block copolymer lithography. In this work, the preparation and self-assembly of a series of giant molecules composed of vinyl polyhedral oligomeric silsesquioxane (VPOSS) tethered with monodispersed oligo(L-lactide) chains are presented. Small-angle X-ray scattering (SAXS) and transmission electron microscopy (TEM) results demonstrate that ultra-small domain sizes (down to 3 nm) of phase separated lamellar morphology are achieved in bulk, driven by the strong tendency and fast kinetics for crystallization of VPOSS moieties. Moreover, upon gamma ray radiation, VPOSS cages in the lamellar structure can be crosslinked via polymerization of the vinyl groups. After pyrolysis at high temperature, ultra-thin two-dimensional nano-silica sheets can be obtained.
Synthesis and Self-Assembly of Discrete Dimethylsiloxane-Lactic Acid Diblock Co-oligomers: The Dononacontamer and Its Shorter Homologues
Van Genabeek, Bas,De Waal, Bas F. M.,Gosens, Mark M. J.,Pitet, Louis M.,Palmans, Anja R. A.,Meijer
supporting information, p. 4210 - 4218 (2016/05/02)
Most of the theoretical and computational descriptions of the phase behavior of block copolymers describe the chain ensembles of perfect and uniform polymers. In contrast, experimental studies on block copolymers always employ materials with disperse molecular makeup. Although most polymers are so-called monodisperse, they still have a molecular weight dispersity. Here, we describe the synthesis and properties of a series of discrete length diblock co-oligomers, based on oligo-dimethylsiloxane (oDMS) and oligo-lactic acid (oLA), diblock co-oligomers with highly noncompatible blocks. By utilizing an iterative synthetic protocol, co-oligomers with molar masses up to 6901 Da, ultralow molar mass dispersities (D ≤ 1.00002), and unique control over the co-oligomer composition are synthesized and characterized. This specific block co-oligomer required the development of a new divergent strategy for the oDMS structures by which both bis- and monosubstituted oDMS derivatives up to 59 Si-atoms became available. The incompatibility of the two blocks makes the final coupling more demanding the longer the blocks become. These optimized synthetic procedures granted access to multigram quantities of most of the block co-oligomers, useful to study the lower limits of block copolymer phase segregation in detail. Cylindrical, gyroid, and lamellar nanostructures, as revealed by DSC, SAXS, and AFM, were generated. The small oligomeric size of the block co-oligomers resulted in exceptionally small feature sizes (down to 3.4 nm) and long-range organization.
