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Synthesis of Polyphthalaldehyde-Based Block Copolymers: Utilization of a Thermo-Sacrificial Segment for an Easy Access to Fine-Tuned Poly(3-hexylthiophene) Nanostructured Films
journal contribution
posted on 2016-04-14, 18:38 authored by Laurence Pessoni, Julien De Winter, Mathieu Surin, Noémie Hergué, Nicolas Delbosc, Roberto Lazzaroni, Philippe Dubois, Pascal Gerbaux, Olivier CoulembierThis
work deals with the synthesis and characterization of new diblock
copolymers based on π-conjugated and depolymerizable units.
These diblock copolymers are based on a regioregular poly(3-hexylthiophene)
sequence associated with a sacrificial block, namely polyphthalaldehyde.
The conjugated polymer was obtained by Grignard metathesis polymerization
and end-capped by an alkynyl group while the depolymerizable segment
was synthesized by an anionic cyclopolymerization from an azide moiety.
Diblock copolymers with different molecular weights were then successfully
synthesized via an alkyne–azide coupling reaction. Under specific
conditions, these copolymers self-assemble into fibrillar nanostructures
in thin films. The elimination of polyphthalaldehyde was carried out
by thermal treatment, generating nanoporous poly(3-hexylthiophene)
films. The use of a dry treatment to remove the polyphthalaldehyde
block strongly reduces the morphological damages that would occur
with a “wet” processing route. These nanoporous poly(3-hexylthiophene)
films could be useful for controlling the morphology of the heterojunction
in organic photovoltaic devices after successful filling with an electron-acceptor
material.