NAMS 2002 Workshop - ICOM 2008

Asymmetric Polymeric Membrane Formation – 1 – Keynote
Tuesday July 15, 8:15 AM-9:00 AM, Wai’anae
Manipulation of Block Copolymer Nanostructure in Membranes Prepared
by Solvent Evaporation and Non-Solvent Induced Phase Separation
W. Yave (Speaker), Institute of Polymer Research, GKSS Research Centre Geesthacht GmbH,
Germany, Wilfredo.Yave.Rios@gkss.de
A. Boschetti-de-Fierro, Institute of Polymer Research, GKSS Research Centre Geesthacht
GmbH, Germany
V. Garamus, Institute of Materials Research, GKSS Research Centre Geesthacht GmbH,
Germany
K. Peinemann, Institute of Polymer Research, GKSS Research Centre Geesthacht GmbH,
Germany
V. Abetz, Institute of Polymer Research, GKSS Research Centre Geesthacht GmbH, Germany
P. Simon, Institute of Polymer Research, GKSS Research Centre Geesthacht GmbH, Germany
Self-assembly of macromolecular components is considered as a key for the
fabrication of periodically nanostructured materials [1]. Block copolymers, having
two or more polymer blocks chemically bound to each other have received great
attention due to their chemical functionality and physical properties [2, 3]. These
copolymers have the ability to self-assemble into microdomains, and the
manipulation of these patterns by a variety of physical and chemical methods has
been the challenge of many scientists.
For membrane technology, block copolymers showing a perpendicular cylindrical
structure at the surface combined with the simplicity of membrane preparation is
of special interest [4, 5]. In our previous work we combined the self-assembly of
a block copolymer with the well established non- solvent induced phase
separation technique. An asymmetric membrane with an extremely well ordered
top-layer was obtained [5]. After the first works it was noticed that not only the
typical parameters as composition of copolymer solution, evaporation time and
precipitation conditions are essential for the final membrane structure, but also
the age of copolymer solution due to the structure formation in solution.
Therefore, we prepared microphase separated films by evaporation of block
copolymer solutions, after storing them for different times. Small angle neutron
scattering experiments carried out on these solutions indicated structural
changes as a function of time. The time dependence on the final nanostructure of
the cast films will be discussed.
The process described above was then combined with the phase inversion
process, and nanostructured asymmetric membranes could be produced. By
using block copolymers of different compositions and different casting conditions,
the quality of the self-assembly in the top layer could be controlled.