TY  - JOUR
A1  - Marsat, Jean-Noel
A1  - Stahlhut, Frank
A1  - Laschewsky, André
A1  - von Berlepsch, Hans
A1  - Böttcher, Christoph
T1  - Multicompartment micelles from silicone-based triphilic block copolymers
JF  - Colloid and polymer science : official journal of the Kolloid-Gesellschaft
N2  - An amphiphilic linear ternary block copolymer was synthesised in three consecutive steps via reversible addition-fragmentation chain transfer polymerisation. Oligo(ethylene glycol) monomethyl ether acrylate was engaged as a hydrophilic building block, while benzyl acrylate and 3-tris(trimethylsiloxy)silyl propyl acrylate served as hydrophobic building blocks. The resulting "triphilic" copolymer consists thus of a hydrophilic (A) and two mutually incompatible "soft" hydrophobic blocks, namely, a lipophilic (B) and a silicone-based (C) block, with all blocks having glass transition temperatures well below 0 A degrees C. The triphilic copolymer self-assembles into spherical multicompartment micellar aggregates in aqueous solution, where the two hydrophobic blocks undergo local phase separation into various ultrastructures as evidenced by cryogenic transmission electron microscopy. Thus, a silicone-based polymer block can replace the hitherto typically employed fluorocarbon-based hydrophobic blocks in triphilic block copolymers for inducing multicompartmentalisation.
KW  - Amphiphiles
KW  - Triphilic block copolymers
KW  - Core-shell-corona micelles
KW  - RAFT
KW  - Cryo-TEM
KW  - Multicompartment micelles
Y1  - 2013
U6  - https://doi.org/10.1007/s00396-013-3001-2
SN  - 0303-402X
SN  - 1435-1536
VL  - 291
IS  - 11
SP  - 2561
EP  - 2567
PB  - Springer
CY  - New York
ER  - 
TY  - JOUR
A1  - Skrabania, Katja
A1  - von Berlepsch, Hans
A1  - Böttcher, Christoph
A1  - Laschewsky, André
T1  - Synthesis of ternary, hydrophilic-lipophilic-fluorophilic block copolymers by consecutive RAFT polymerizations and their self-assembly into multicompartment micelles
N2  - Linear amphiphilic diblock and ternary triblock copolymers were synthesized by the RAFT method in three Successive Steps, using oligo(ethylene oxide) monomethyl ether acrylate, butyl or 2-ethylhexyl acrylate, and 1H, 1H, 2H, 2H-perfluorodecyl acrylate. The diblock and the triblock copolymers, which consist of a hydrophilic, a lipophilic, and a fluorophilic block, self-assemble in water into spherical micellar aggregates. Imaging by cryogenic transmission electron microscopy (cryo-TEM) revealed that the cores of the micellar aggregates made from these "triphilic" copolymers undergo local phase separation to form various ultrastructures, which depend sensitivity on the given block sequence. While the sequence hydrophilic-lipophilic-fluorophilic resulted in multicompartment cores with core-shell-corona morphology, the sequence lipophilic-hydrophilic-fluorophilic provided new "patched double micelle" and larger "soccer ball" structures.
Y1  - 2010
UR  - http://pubs.acs.org/journal/mamobx
U6  - https://doi.org/10.1021/Ma901913f
SN  - 0024-9297
ER  - 
TY  - JOUR
A1  - Weiss, Jan
A1  - Böttcher, Christoph
A1  - Laschewsky, André
T1  - Self-assembly of double thermoresponsive block copolymers end-capped with complementary trimethylsilyl groups
JF  - Soft matter
N2  - A set of double thermoresponsive diblock copolymers poly(N-n-propylacrylamide)-block-poly(N-ethylacrylamide) (PNPAM-b-PNEAM) was synthesised by sequential reversible addition-fragmentation chain transfer (RAFT) polymerisations. Using a twofold trimethylsilyl (TMS)-labeled RAFT-agent, the relative size of the two blocks was varied. While soluble as unimers below 15 degrees C, all copolymers exhibited thermally induced two-step self-assembly in water, due to distinct lower critical solution temperature (LCST) phase transitions of PNPAM (around 20 degrees C) and PNEAM (around 70 degrees C). Their temperature-dependent self-organisation in dilute aqueous solution was studied by turbidimetry, dynamic light scattering, transmission electron microscopy, and (1)H NMR spectroscopy. The copolymers show distinct, two-step self-organisation behaviour with respect to transition temperatures, aggregate type and size, which can be correlated to the relative lengths of the low and high LCST blocks. For polymers having short blocks with low LCST, the first thermal transition induces the formation of individual micelles. Further heating above the second thermal transition results reversibly either in a shrink of the micelle size or in aggregation of the micelles, with hydrodynamic diameters below 250 nm. In contrast in the case of polymers having a long block with low LCST, the first thermal transition already leads to clusters of micelles, while the second thermal transition makes the clusters shrink. Noteworthy, the twofold TMS-labeled end groups report not only on the molar masses of the polymers, but can simultaneously serve as NMR-probes for the self-assembly process. The signal of the TMS-aryl end group displays a reversible temperature dependent, two-step splitting that is indicative of the self-organisation of the block copolymers.
Y1  - 2011
U6  - https://doi.org/10.1039/c0sm00531b
SN  - 1744-683X
VL  - 7
IS  - 2
SP  - 483
EP  - 492
PB  - Royal Society of Chemistry
CY  - Cambridge
ER  -