Zernike Institute for Advanced Materials Colloquium Yushu Matsushita
|10 mei 2012||FWN-Building 5111.0080, Nijenborgh 4, 9747 AG, Groningen|
|Speaker:||Prof. Dr. Yushu Matsushita|
Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Nagoya, Japan
|Title:||New class of self-assembly in complex block copolymer systems|
|Date:||Thu May 10, 2012|
|Start:||16.00 (Doors open and coffee available at 15.30)|
Block copolymers with incompatible components are known to show various microphase-separated structures depending on their molecular parameters such as molecular weight, composition and chain architectures. This lecture focuses on chain connectivity of block components by addressing the following topics:
1) ABC star molecules possess peculiar structure formation restriction, i.e., junction point have to be aligned on lines not on surfaces. And hence if chain lengths are similar, cylindrical structures are naturally formed, whose cross sections show various tiling patterns as are shown in the Figure. Most of them are categorized as periodic Archimedean tiling patterns, which are composed of regular polygons. And some compositional perturbation was applied to the system, quasicrystalline tiling is appeared, as shown at the center of the Figure.
2) To the contrary, AB and CD two block copolymers, whose B and D components include hydrogen bond forming units, are blended, hierarchical structures can be easily formed. As an example, a three-phase structure from four components is displayed here, in which B and D are mixed into one phase(gray) and the mixed phase is periodically phase-separated from A(dark phase) and C(bright phase).
3) Finally telechelic carboxylic acid ended polymer and amine polymer is mixed in a proper solvent, supramolecular polymer gels being formulated spontaneously as is shown in the Figure, even two component polymers are basically liquid at room temperature, and these gels were found to be thermoreversible.
On the whole, many periodic and aperiodic structures are conformed from complex polymer systems based on their self-assembly manner, sometimes coupled with non-covalent bonding interactions.
|Laatst gewijzigd:||22 oktober 2012 14:30|