Double Thermoresponsive Block Copolymers Featuring a Biotin End Group

2010 ◽  
Vol 11 (9) ◽  
pp. 2432-2439 ◽  
Author(s):  
Florian D. Jochum ◽  
Peter J. Roth ◽  
Daniel Kessler ◽  
Patrick Theato
Keyword(s):  
2017 ◽  
Vol 5 (38) ◽  
pp. 20412-20421 ◽  
Author(s):  
Youngmin Lee ◽  
Melissa P. Aplan ◽  
Zach D. Seibers ◽  
S. Michael Kilbey ◽  
Qing Wang ◽  
...  

Control of conversion, end group composition, and feed ratio is crucial to minimize homopolymer impurities in the synthesis of conjugated block copolymers for photovoltaics.


2013 ◽  
Vol 66 (12) ◽  
pp. 1564 ◽  
Author(s):  
Lily A. Dayter ◽  
Kate A. Murphy ◽  
Devon A. Shipp

A single reversible addition–fragmentation chain transfer (RAFT) agent, malonate N,N-diphenyldithiocarbamate (MDP-DTC) is shown to successfully mediate the polymerization of several monomers with greatly differing reactivities in radical/RAFT polymerizations, including both vinyl acetate and styrene. The chain transfer constants (Ctr) for MDP-DTC for both these monomers were evaluated; these were found to be ~2.7 in styrene and ~26 in vinyl acetate, indicating moderate control over styrene polymerization and good control of vinyl acetate polymerization. In particular, the MDP-DTC RAFT agent allowed for the synthesis of block copolymers of these two monomers without the need for protonation/deprotonation switching, as has been previously developed with N-(4-pyridinyl)-N-methyldithiocarbamate RAFT agents, or other end-group transformations. The thermal properties of the block copolymers were studied using differential scanning calorimetry, and those with sufficiently high molecular weight and styrene composition appear to undergo phase separation. Thus, MDP-DTC may be useful for the production of other block copolymers consisting of monomers with highly dissimilar reactivities.


1996 ◽  
Vol 102 (1) ◽  
pp. 91-98 ◽  
Author(s):  
Eberhard Esselbom ◽  
Jürgen Fock ◽  
Arno Knebelkamp

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1608 ◽  
Author(s):  
Elaine Rahmstorf ◽  
Volker Abetz

The combination of controlled anionic polymerization and subsequent introduction of hydrogen bonding groups was established to form thermo-reversible, supramolecular networks. Several polyisoprene-block-polystyrene-block-polyisoprene (ISI) copolymers—with polystyrene (PS) as the main block, and consequently giving the decisive material characteristics—were synthesized. The novel modification approach to post-functionalize the polyisoprene (PI) end-blocks and to introduce different motifs, which are able to form self-complementary hydrogen bonds, was attained. In the first step, hydroxylation was accomplished using 9-borabicyclo[3.3.1]nonane. Starting from the hydroxylated polymer, esterification with succinic anhydride was implemented to form an ester group with carboxylic end-group (-O-CO-CH2-CH2-COOH). In a second approach, 1,1’-carbonyldiimidazole was used as coupling agent to introduce various types of diamines (diethylenetriamine, triethylentetramine, and 2,6-diaminopyridine) to prepare urethane groups with amine end-group (-O-CO-NH-R-NH2). 1H NMR spectroscopy was used to confirm the successful synthesis and to calculate the degree of functionalization Df. Differential scanning calorimetry (DSC) showed a difference of the glass transition temperature Tg between unfunctionalized and functionalized block copolymers, but no greater influence between the different types of modification, and thus, on the Tg of the PS block. In temperature dependent FTIR spectroscopy, reversible processes were observed.


2015 ◽  
Vol 53 (24) ◽  
pp. 2838-2848 ◽  
Author(s):  
Xu Xiang ◽  
Xiaochu Ding ◽  
Ning Chen ◽  
Beilu Zhang ◽  
Patricia A. Heiden

Polymer ◽  
2010 ◽  
Vol 51 (2) ◽  
pp. 355-367 ◽  
Author(s):  
Telmo J.V. Prazeres ◽  
Mariana Beija ◽  
Marie-Thérèse Charreyre ◽  
José Paulo S. Farinha ◽  
José M.G. Martinho

e-Polymers ◽  
2005 ◽  
Vol 5 (1) ◽  
Author(s):  
Sandrine Lenoir ◽  
Christophe Pagnoulle ◽  
Christophe Detrembleur ◽  
Moreno Galleni ◽  
Robert Jérôme

AbstractA commercially available poly(ethylene-co-butylene) copolymer, endcapped by a short polyisoprene block and a hydroxyl group (PI-b-PEB-OH), has been derivatized into a macroinitiator for atom transfer radical polymerization (ATRP) by esterification of the hydroxyl end-group by an activated bromidecontaining acyl bromide. Two types of triblock copolymers, PI-b-PEB-b-poly- (dimethylaminoethyl methacrylate) (PDMAEMA) and PI-b-PEB-b-poly[2-(tert-butylamino) ethyl methacrylate] (PTBAEMA), have been synthesized and used to coat polystyrene particles. These coatings have been permanently immobilized by UV cross-linking of the isoprene units. They exhibit a biocidal activity against Gramnegative bacteria either intrinsically in case of the PTBAEMA block or upon quaternization of the PDMAEMA block by octyl bromide. The antimicrobial activity is directly related to the concentration of coated PS particles in the medium.


2017 ◽  
Vol 8 (18) ◽  
pp. 2860-2871 ◽  
Author(s):  
Lewis D. Blackman ◽  
Kay E. B. Doncom ◽  
Matthew I. Gibson ◽  
Rachel K. O'Reilly

We demonstrate that the PISA of identical block copolymers by either a photo or thermally initiated approach leads to structures that are both chemically and morphologically distinct.


Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 284 ◽  
Author(s):  
Changjun Park ◽  
Jaewon Heo ◽  
Jinhee Lee ◽  
Taehyoung Kim ◽  
Sang Youl Kim

Here we report the dual light- and thermo-responsive behavior of well-defined rod-coil block copolymers composed of an azobenzene unit, 2-(2-methoxyethoxy)ethyl methacrylate (MEO2MA) and oligo(ethylene glycol) methacrylate (OEGMA). Azobenzene-containing rigid rod blocks prepared by chain growth condensation polymerization of the azobenzene containing monomer were used as a macroinitiator of atom transfer radical polymerization (ATRP) after attaching an α-bromoisobutyryl group as an end group. Synthesis of well-defined rod-coil block copolymers with different coil block lengths was achieved by copolymerization of MEO2MA and OEGMA monomers. The synthesized polymers exhibited amphiphilic properties and polymeric micelles were formed in aqueous solution. The light-responsive behaviors of azobenzene moieties, photoisomerization by irradiation of light, and thermo-responsive behaviors of P(MEO2MA-co-OEGMA) coil blocks, aggregation by increment of temperature over lower critical solution temperature, were investigated. A dual stimuli-responsive behavior of the rod-coil block copolymers was observed when exposed to light and heat.


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