All-Aromatic (AB)n-Multiblock Copolymers via Simple One-Step Melt Condensation Chemistry

Qingbao Guan; Ben Norder; Liangyong Chu; Nicolaas A. M. Besseling; Stephen J. Picken; Theo J. Dingemans

doi:10.1021/acs.macromol.6b01341

Linear/Ladder-Like Polysiloxane Block Copolymers with Methyl-, Trifluoropropyl- and Phenyl- Siloxane Units for Surface Modification

Polymers ◽

10.3390/polym13132063 ◽

2021 ◽

Vol 13 (13) ◽

pp. 2063

Author(s):

Stepan A. Ostanin ◽

Alexei V. Kalinin ◽

Yurij Yu. Bratsyhin ◽

Natalia N. Saprykina ◽

Vjacheslav V. Zuev

Keyword(s):

Mechanical Properties ◽

Surface Modification ◽

Solid State ◽

Nmr Spectroscopy ◽

29Si Nmr ◽

Multiblock Copolymers ◽

Adhesion Properties ◽

Sem Study ◽

One Step ◽

29Si Nmr Spectroscopy

Multiblock copolymers containing linear polydimethylsiloxane or polymethyltrifluoropropylsiloxane and ladder-like polyphenylsiloxane were synthesized in a one-step pathway. The functional homopolymer blocks and final multiblock copolymers were characterized using solution and solid-state multinuclear 1H, 13C, 19F, and 29Si NMR spectroscopy. It was shown that the ladder-like block contains silanol units, which influence the adhesion properties of multiblock copolymers and morphology of their casted films. The adhesion to metals and mechanical properties of multiblock copolymers were tested. The SEM study of casted films of multiblock copolymers shows the variety of formed morphologies, including long-strip-like or globular.

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One-step synthesis of sequence-controlled multiblock polymers with up to 11 segments from monomer mixture

Nature Communications ◽

10.1038/s41467-021-27830-3 ◽

2022 ◽

Vol 13 (1) ◽

Author(s):

Xiaochao Xia ◽

Ryota Suzuki ◽

Tianle Gao ◽

Takuya Isono ◽

Toshifumi Satoh

Keyword(s):

Ring Opening ◽

Ring Opening Polymerization ◽

Epoxide Ring ◽

Multiblock Copolymers ◽

Monomer Sequence ◽

Component Systems ◽

Direct Preparation ◽

One Step ◽

Complex Polymers ◽

Catalytic Cycles

AbstractSwitchable polymerization holds considerable potential for the synthesis of highly sequence-controlled multiblock. To date, this method has been limited to three-component systems, which enables the straightforward synthesis of multiblock polymers with less than five blocks. Herein, we report a self-switchable polymerization enabled by simple alkali metal carboxylate catalysts that directly polymerize six-component mixtures into multiblock polymers consisting of up to 11 blocks. Without an external trigger, the catalyst polymerization spontaneously connects five catalytic cycles in an orderly manner, involving four anhydride/epoxide ring-opening copolymerizations and one L-lactide ring-opening polymerization, creating a one-step synthetic pathway. Following this autotandem catalysis, reasonable combinations of different catalytic cycles allow the direct preparation of diverse, sequence-controlled, multiblock copolymers even containing various hyperbranched architectures. This method shows considerable promise in the synthesis of sequentially and architecturally complex polymers, with high monomer sequence control that provides the potential for designing materials.

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Highly efficient one-pot/one-step synthesis of multiblock copolymers from three-component polymerization of carbon dioxide, epoxide and lactone

Chemical Science ◽

10.1039/c4sc03593c ◽

2015 ◽

Vol 6 (2) ◽

pp. 1530-1536 ◽

Cited By ~ 28

Author(s):

Yang Li ◽

Jiali Hong ◽

Renjian Wei ◽

Yingying Zhang ◽

Zaizai Tong ◽

...

Keyword(s):

Carbon Dioxide ◽

Exchange Reaction ◽

Multiblock Copolymers ◽

Cyclohexene Oxide ◽

One Pot ◽

Highly Efficient ◽

One Step

Carbon dioxide-based multiblock copolymers were synthesized by a one-pot/one-step three-component polymerization of cyclohexene oxide, ε-caprolactone and CO2via cross-chain exchange reaction at two catalysts.

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An Interactive Minicomputer Program for the Indexing and Simulation of Electron Diffraction Patterns

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100092670 ◽

1976 ◽

Vol 34 ◽

pp. 542-543

Author(s):

R.P. Goehner ◽

W.T. Hatfield ◽

Prakash Rao

Keyword(s):

Electron Diffraction ◽

Real Time ◽

Pattern Analysis ◽

Flow Diagram ◽

Hard Copy ◽

Time Analysis ◽

Real Time Analysis ◽

Transmission Electron ◽

One Step ◽

Diffraction Patterns

Computer programs are now available in various laboratories for the indexing and simulation of transmission electron diffraction patterns. Although these programs address themselves to the solution of various aspects of the indexing and simulation process, the ultimate goal is to perform real time diffraction pattern analysis directly off of the imaging screen of the transmission electron microscope. The program to be described in this paper represents one step prior to real time analysis. It involves the combination of two programs, described in an earlier paper(l), into a single program for use on an interactive basis with a minicomputer. In our case, the minicomputer is an INTERDATA 70 equipped with a Tektronix 4010-1 graphical display terminal and hard copy unit.A simplified flow diagram of the combined program, written in Fortran IV, is shown in Figure 1. It consists of two programs INDEX and TEDP which index and simulate electron diffraction patterns respectively. The user has the option of choosing either the indexing or simulating aspects of the combined program.

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Morphological studies of linear (AB)n multiblock copolymers and their blends

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100122320 ◽

1992 ◽

Vol 50 (1) ◽

pp. 384-385

Author(s):

Richard J. Spontak ◽

Steven D. Smith ◽

Arman Ashraf

Keyword(s):

Electron Microscopy ◽

Microphase Separation ◽

Multiblock Copolymers ◽

First Order ◽

Morphological Studies ◽

Transmission Electron ◽

First Order Phase Transition ◽

Covalently Bonded ◽

Total Molecular Weight ◽

First Order Phase

Block copolymers are composed of sequences of dissimilar chemical moieties covalently bonded together. If the block lengths of each component are sufficiently long and the blocks are thermodynamically incompatible, these materials are capable of undergoing microphase separation, a weak first-order phase transition which results in the formation of an ordered microstructural network. Most efforts designed to elucidate the phase and configurational behavior in these copolymers have focused on the simple AB and ABA designs. Few studies have thus far targeted the perfectly-alternating multiblock (AB)n architecture. In this work, two series of neat (AB)n copolymers have been synthesized from styrene and isoprene monomers at a composition of 50 wt% polystyrene (PS). In Set I, the total molecular weight is held constant while the number of AB block pairs (n) is increased from one to four (which results in shorter blocks). Set II consists of materials in which the block lengths are held constant and n is varied again from one to four (which results in longer chains). Transmission electron microscopy (TEM) has been employed here to investigate the morphologies and phase behavior of these materials and their blends.

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Nutrient-regulated gene expression in eukaryotes

Biochemical Society Symposium ◽

10.1042/bss0730085 ◽

2006 ◽

Vol 73 ◽

pp. 85-96 ◽

Cited By ~ 8

Author(s):

Richard J. Reece ◽

Laila Beynon ◽

Stacey Holden ◽

Amanda D. Hughes ◽

Karine Rébora ◽

...

Keyword(s):

Gene Expression ◽

Rna Polymerase ◽

Rna Polymerase Ii ◽

Transcriptional Control ◽

Direct Interaction ◽

Signalling Pathways ◽

A Cell ◽

One Step ◽

Higher Eukaryotes ◽

Regulated Gene Expression

The recognition of changes in environmental conditions, and the ability to adapt to these changes, is essential for the viability of cells. There are numerous well characterized systems by which the presence or absence of an individual metabolite may be recognized by a cell. However, the recognition of a metabolite is just one step in a process that often results in changes in the expression of whole sets of genes required to respond to that metabolite. In higher eukaryotes, the signalling pathway between metabolite recognition and transcriptional control can be complex. Recent evidence from the relatively simple eukaryote yeast suggests that complex signalling pathways may be circumvented through the direct interaction between individual metabolites and regulators of RNA polymerase II-mediated transcription. Biochemical and structural analyses are beginning to unravel these elegant genetic control elements.

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