4th EucheMs chemistry congress

tuesday, 28-Aug 2012
s786
chem. Listy 106, s587–s1425 (2012)
organic Chemistry, Polymers – ii
Polymer chemistry – i
o - 2 2 1
MuLtiCoMPArtMent MiCeLLeS froM
MuLtiBLoCK MuLtiCoMPonent PoLyMerS in
SeLeCtive SoLventS
n. hAdJiChriStidiS 1 , n. houBenov 1
1 King Abdullah university of science and Technology (KAUST),
Chemical and Life Sciences and Engineering, Thuwal 23955-
6900, Saudi Arabia
Controlled formation of compartmentalized spherical
micelles with self-assembled complex hierarchical structures was
demonstrated by using linear and non-linear
multiblock multicomponent polymers {ABCD, ABCED,
and (ABC) D, where A:polystyrene; B:polyisoprene-1,4;
2
C:poly(dimethylsiloxane); D:poly(2-vinylpyridine) and
E:poly(tert-butylmethacrylate)} in selective solvents. These
tetrablock quarter and pentablock quinto polymers were
synthesized by using anionic polymerization high vacuum
techniques and appropriate chlorosilane-based heterofunctional
linking agents. The molecular characteristics of the multiblock
multicomponent polymers were obtained by osmometry, light
scattering, size exclusion chromatography (SEC) and NMR. The
multicompartment character of the micellar aggregates was
studied by Static/Dynamic Light Scattering (SLS/DLS),
Transmission Electron Microscopy (TEM/Tomography), and
Atomic Force Microscopy (AFM). Using suitable solvent systems
we have constructed well-defined micellar hierarchies
with collapsed unprecedented tri-componential core and
compartmentalized or mixed corona. The ratio of the different
blocks in the core and corona was varied by the quality of the
solvents and solvent mixtures used in the experiments.
Keywords: multiblock multicomponent copolymers; selective
solvents; multicompartment micelles; transmission electron
microscopy; static/dynamic light scattering;
Polymer chemistry – i
4 th EucheMs chemistry congress
o - 2 2 2
CryStALLine ProPertieS of PvAC-B-PCL BLoCK
CoPoLyMerS: infLuenCe of the SyntheSiS
route
S. BiStAC 1 , C. deLAite 1 , o. GLAied 2
1 Université de Haute Alsace, LPIM, Mulhouse cedex, France
2 Hochschule für Life Sciences, Institut für Chemie und
Bioanalytik, Muttenz, Switzerland
Poly(vinyl acetate)/poly(ε-caprolaclone) block copolymers
(PVAc-b-PCL) were synthesized using two different approaches:
a “coupling reaction” approach and a “macroinitiator” one. For
the coupling approach, a chain transfer agent, with an azide
function, was used to initiate the polymerization of VAc. PCL
containing an alkyne termination was also prepared. These two
reaction products, PVAc and PCL, were then coupled by a click
chemistry reaction to obtain the corresponding block copolymer.
For the macroinitiator approach, PCL-b-PVAc block copolymers
were obtained by a two-step procedure: first, a macroinitiator PCL
with a xanthate end group was prepared, then, the polymerization
of VAc was initiated by RAFT polymerization from the PCL,
allowing to obtain PVAC-b-PCL block copolymers. Different
copolymers, varying by their blocks lengths, were prepared with
both methods. Elsewhere, PCL is a semi-crystalline polymer, and
consequently, PCL blocks of PVAc-b-PCL are able to
crystallize.The objective of this work is then to analyse the
influence of the synthesis way of copolymers on the crystallinity
of PCL blocks. Crystalline properties have been investigated by
differential scanning calorimetry (DSC).
The results indicate a decrease of the crystallinity of the PCL
block in copolymers obtained by the “coupling” method,
compared to PCL homopolymers, contrary to copolymers
obtained through the “macroinitiator” approach for which the
crystallinity of the PCL was much less affected. This influence of
the synthesis method was explained by the presence, in the
copolymers obtained by click reaction, of a rigid triazol cycle
(cycle binding the two blocks of polymer). This triazol cycle limit
the relative mobility of the two blocks and decrease the possibility
of organization and the crystal formation. This study has
evidenced the great influence of the synthesis route on copolymers
crystallinity and the major effect of the presence of the triazol
cycle, inducing a high decrease of the crystallinity degree
Keywords: Crystal growth; Polymers; Calorimetry;
AUGUst 26–30, 2012, PrAGUE, cZEcH rEPUbLIc