Desalination 200 (2006) 29–31
Presented at EUROMEMBRANE 2006, 24–28 September 2006, Giardini Naxos, Italy.
0011-9164/06/$– See front matter © 2006 Elsevier B.V. All rights reserved.
Toward nanoporous composite membranes with
tailored block copolymers as selective layer
Marcel Gawenda
a
*, Alexandra Sperschneider
b
, Felix Schacher
c
,
Georg Krausch
b
, Axel Müller
c
, Mathias Ulbricht
a
a
Lehrstuhl für Technische Chemie II, Universität Duisburg-Essen, 45117 Essen, Germany
email: marcel.gawenda@uni-essen.de
b
Lehrstuhl für Physikalische Chemie II, Universität Bayreuth, 95440 Bayreuth, Germany
c
Lehrstuhl für Makromolekulare Chemie II, Universität Bayreuth, 95440 Bayreuth, Germany
Received 25 October 2005; accepted 6 March 2006
The development of synthetic membranes
featuring transport selectivity for molecules dif-
ferent from water is a challenge of outstanding
relevance. This field is strongly inspired by nature
where highly specific transport through biological
membranes is based on molecular recognition
processes within macromolecular assemblies.
In this collaborative project we are preparing
and characterizing novel composite membranes
for size- or charge-based membrane separation
processes with higher selectivity. Commercially
available porous membranes are used as support
for thin layers of self-assembled block copoly-
mers. The tailored diblock or triblock copolymers
are synthesized by living ionic or controlled radi-
cal polymerization [1], so that they can form
microphase-separated nanostructures which may
even be aligned into cylindrical morphologies
with the characteristic axis perpendicular to the
film surface [2,3]. Supported nanoporous films
may then be obtained either via the selective
dissolution of another polymer which had been
added to form a polymer blend and which is
compatible with the block of the copolymer
forming the cylindrical domains, or via selective
degradation of the copolymer block forming the
cylindrical domains [3]. Depending on the pre-
cursor block copolymer those pores may be also
charged, and this charge may depend on the pH
so that permeability and selectivity can be con-
trolled by size or charge.
As support membranes we use track-etched
poly(ethylene terephthalate) (PET) membranes
(Fig. 1) and commercial ultrafiltration mem-
branes with barrier pore diameters ranging from
~5 to 3000 nm.
In order to provide methods for anchoring
and stabilizing the block copolymer film on the
support membranes, surface functionalisations
of the membranes by polymer-analogous reac-
tions or graft copolymerization of thin functional
copolymer layers are investigated [4]. Various
surfaces are created to that the requirements in
terms of surface energy and reactivity (by
mixing/entanglement, by chemical reaction or
by UV irradiation) for orienting and anchoring
the block copolymer films on the support can be
explored. *Corresponding author.
doi:10.1016/j.desal.2006.03.230